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 return (u_loop->_irreducible || u_loop->_child)
1035 ? useblock
1036 : u_loop->_head->as_Loop()->skip_strip_mined()->in(LoopNode::EntryControl);
1037 }
1038
1039
1040 bool PhaseIdealLoop::identical_backtoback_ifs(Node *n) {
1041 if (!n->is_If() || n->is_CountedLoopEnd()) {
1042 return false;
1043 }
1044 if (!n->in(0)->is_Region()) {
1045 return false;
1046 }
1047 Node* region = n->in(0);
1048 Node* dom = idom(region);
1049 if (!dom->is_If() || dom->in(1) != n->in(1)) {
1050 return false;
1051 }
1052 IfNode* dom_if = dom->as_If();
1053 Node* proj_true = dom_if->proj_out(1);
1054 Node* proj_false = dom_if->proj_out(0);
1055
1056 for (uint i = 1; i < region->req(); i++) {
1057 if (is_dominator(proj_true, region->in(i))) {
1058 continue;
1059 }
1060 if (is_dominator(proj_false, region->in(i))) {
1061 continue;
1062 }
1063 return false;
1064 }
1065
1066 return true;
1067 }
1068
1069 bool PhaseIdealLoop::can_split_if(Node *n_ctrl) {
1070 if (C->live_nodes() > 35000) {
1071 return false; // Method too big
1072 }
1073
1074 // Do not do 'split-if' if irreducible loops are present.
1075 if (_has_irreducible_loops) {
1076 return false;
1077 }
1078
1079 if (merge_point_too_heavy(C, n_ctrl)) {
1080 return false;
1081 }
1082
1083 // Do not do 'split-if' if some paths are dead. First do dead code
1084 // elimination and then see if its still profitable.
1085 for (uint i = 1; i < n_ctrl->req(); i++) {
1086 if (n_ctrl->in(i) == C->top()) {
1087 return false;
1088 }
1089 }
1090
1091 // If trying to do a 'Split-If' at the loop head, it is only
1092 // profitable if the cmp folds up on BOTH paths. Otherwise we
1093 // risk peeling a loop forever.
1094
1095 // CNC - Disabled for now. Requires careful handling of loop
1096 // body selection for the cloned code. Also, make sure we check
1097 // for any input path not being in the same loop as n_ctrl. For
1098 // irreducible loops we cannot check for 'n_ctrl->is_Loop()'
1099 // because the alternative loop entry points won't be converted
1100 // into LoopNodes.
1101 IdealLoopTree *n_loop = get_loop(n_ctrl);
1102 for (uint j = 1; j < n_ctrl->req(); j++) {
1103 if (get_loop(n_ctrl->in(j)) != n_loop) {
1104 return false;
1105 }
1106 }
1107
1108 // Check for safety of the merge point.
1109 if (!merge_point_safe(n_ctrl)) {
1110 return false;
1111 }
1112
1113 return true;
1114 }
1115
1116 bool PhaseIdealLoop::replace_with_dominating_barrier(LoadBarrierNode* lb, bool last_round) {
1117 LoadBarrierNode* lb2 = lb->has_dominating_barrier(this, false, last_round);
1118 if (lb2 != NULL) {
1119 if (lb->in(LoadBarrierNode::Oop) != lb2->in(LoadBarrierNode::Oop)) {
1120 assert(lb->in(LoadBarrierNode::Address) == lb2->in(LoadBarrierNode::Address), "");
1121 _igvn.replace_input_of(lb, LoadBarrierNode::Similar, lb2->proj_out(LoadBarrierNode::Oop));
1122 C->set_major_progress();
1123 } else {
1124 // That transformation may cause the Similar edge on dominated load barriers to be invalid
1125 lb->fix_similar_in_uses(&_igvn);
1126
1127 Node* val = lb->proj_out(LoadBarrierNode::Oop);
1128 assert(lb2->has_true_uses(), "");
1129 assert(lb2->in(LoadBarrierNode::Oop) == lb->in(LoadBarrierNode::Oop), "");
1130
1131 lazy_update(lb, lb->in(LoadBarrierNode::Control));
1132 lazy_replace(lb->proj_out(LoadBarrierNode::Control), lb->in(LoadBarrierNode::Control));
1133 _igvn.replace_node(val, lb2->proj_out(LoadBarrierNode::Oop));
1134
1135 return true;
1136 }
1137 }
1138 return false;
1139 }
1140
1141 Node* PhaseIdealLoop::find_dominating_memory(Node* mem, Node* dom, int i) {
1142 assert(dom->is_Region() || i == -1, "");
1143 Node* m = mem;
1144 while(is_dominator(dom, has_ctrl(m) ? get_ctrl(m) : m->in(0))) {
1145 if (m->is_Mem()) {
1146 assert(m->as_Mem()->adr_type() == TypeRawPtr::BOTTOM, "");
1147 m = m->in(MemNode::Memory);
1148 } else if (m->is_MergeMem()) {
1149 m = m->as_MergeMem()->memory_at(Compile::AliasIdxRaw);
1150 } else if (m->is_Phi()) {
1151 if (m->in(0) == dom && i != -1) {
1152 m = m->in(i);
1153 break;
1154 } else {
1155 m = m->in(LoopNode::EntryControl);
1156 }
1157 } else if (m->is_Proj()) {
1158 m = m->in(0);
1159 } else if (m->is_SafePoint() || m->is_MemBar()) {
1160 m = m->in(TypeFunc::Memory);
1161 } else {
1162 #ifdef ASSERT
1163 m->dump();
1164 #endif
1165 ShouldNotReachHere();
1166 }
1167 }
1168 return m;
1169 }
1170
1171 LoadBarrierNode* PhaseIdealLoop::clone_load_barrier(LoadBarrierNode* lb, Node* ctl, Node* mem, Node* oop_in) {
1172 Node* the_clone = lb->clone();
1173 the_clone->set_req(LoadBarrierNode::Control, ctl);
1174 the_clone->set_req(LoadBarrierNode::Memory, mem);
1175 if (oop_in != NULL) {
1176 the_clone->set_req(LoadBarrierNode::Oop, oop_in);
1177 }
1178
1179 LoadBarrierNode* new_lb = the_clone->as_LoadBarrier();
1180 _igvn.register_new_node_with_optimizer(new_lb);
1181 IdealLoopTree *loop = get_loop(new_lb->in(0));
1182 set_ctrl(new_lb, new_lb->in(0));
1183 set_loop(new_lb, loop);
1184 set_idom(new_lb, new_lb->in(0), dom_depth(new_lb->in(0))+1);
1185 if (!loop->_child) {
1186 loop->_body.push(new_lb);
1187 }
1188
1189 Node* proj_ctl = new ProjNode(new_lb, LoadBarrierNode::Control);
1190 _igvn.register_new_node_with_optimizer(proj_ctl);
1191 set_ctrl(proj_ctl, proj_ctl->in(0));
1192 set_loop(proj_ctl, loop);
1193 set_idom(proj_ctl, new_lb, dom_depth(new_lb)+1);
1194 if (!loop->_child) {
1195 loop->_body.push(proj_ctl);
1196 }
1197
1198 Node* proj_oop = new ProjNode(new_lb, LoadBarrierNode::Oop);
1199 register_new_node(proj_oop, new_lb);
1200
1201 if (!new_lb->in(LoadBarrierNode::Similar)->is_top()) {
1202 LoadBarrierNode* similar = new_lb->in(LoadBarrierNode::Similar)->in(0)->as_LoadBarrier();
1203 if (!is_dominator(similar, ctl)) {
1204 _igvn.replace_input_of(new_lb, LoadBarrierNode::Similar, C->top());
1205 }
1206 }
1207
1208 return new_lb;
1209 }
1210
1211 void PhaseIdealLoop::replace_barrier(LoadBarrierNode* lb, Node* new_val) {
1212 Node* val = lb->proj_out(LoadBarrierNode::Oop);
1213 _igvn.replace_node(val, new_val);
1214 lazy_update(lb, lb->in(LoadBarrierNode::Control));
1215 lazy_replace(lb->proj_out(LoadBarrierNode::Control), lb->in(LoadBarrierNode::Control));
1216 }
1217
1218 bool PhaseIdealLoop::split_barrier_thru_phi(LoadBarrierNode* lb) {
1219 if (lb->in(LoadBarrierNode::Oop)->is_Phi()) {
1220 Node* oop_phi = lb->in(LoadBarrierNode::Oop);
1221
1222 if (oop_phi->req() == 2) {
1223 // Ignore phis with only one input
1224 return false;
1225 }
1226
1227 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())*/) {
1228 // That transformation may cause the Similar edge on dominated load barriers to be invalid
1229 lb->fix_similar_in_uses(&_igvn);
1230
1231 RegionNode* region = oop_phi->in(0)->as_Region();
1232
1233 int backedge = LoopNode::LoopBackControl;
1234 if (region->is_Loop() && region->in(backedge)->is_Proj() && region->in(backedge)->in(0)->is_If()) {
1235 Node* c = region->in(backedge)->in(0)->in(0);
1236 assert(c->unique_ctrl_out() == region->in(backedge)->in(0), "");
1237 Node* oop = lb->in(LoadBarrierNode::Oop)->in(backedge);
1238 Node* oop_c = has_ctrl(oop) ? get_ctrl(oop) : oop;
1239 if (!is_dominator(oop_c, c)) {
1240 return false;
1241 }
1242 }
1243
1244 Node *phi = oop_phi->clone();
1245
1246 for (uint i = 1; i < region->req(); i++) {
1247 Node* ctrl = region->in(i);
1248 if (ctrl != C->top()) {
1249 assert(!is_dominator(ctrl, region) || region->is_Loop(), "");
1250
1251 Node* mem = lb->in(LoadBarrierNode::Memory);
1252 Node* m = find_dominating_memory(mem, region, i);
1253
1254 if (region->is_Loop() && i == LoopNode::LoopBackControl && ctrl->is_Proj() && ctrl->in(0)->is_If()) {
1255 ctrl = ctrl->in(0)->in(0);
1256 }
1257
1258 LoadBarrierNode* new_lb = clone_load_barrier(lb, ctrl, m, lb->in(LoadBarrierNode::Oop)->in(i));
1259
1260 Node* out_ctrl = new_lb->proj_out(LoadBarrierNode::Control);
1261 if (ctrl == region->in(i)) {
1262 _igvn.replace_input_of(region, i, new_lb->proj_out(LoadBarrierNode::Control));
1263 } else {
1264 Node* iff = region->in(i)->in(0);
1265 Node* out_ctrl = new_lb->proj_out(LoadBarrierNode::Control);
1266 _igvn.replace_input_of(iff, 0, out_ctrl);
1267 set_idom(iff, out_ctrl, dom_depth(out_ctrl)+1);
1268 }
1269 phi->set_req(i, new_lb->proj_out(LoadBarrierNode::Oop));
1270 }
1271 }
1272 register_new_node(phi, region);
1273
1274 replace_barrier(lb, phi);
1275
1276 if (region->is_Loop()) {
1277 // Load barrier moved to the back edge of the Loop may now
1278 // have a safepoint on the path to the barrier on the Similar
1279 // edge
1280 _igvn.replace_input_of(phi->in(LoopNode::LoopBackControl)->in(0), LoadBarrierNode::Similar, C->top());
1281 Node* head = region->in(LoopNode::EntryControl);
1282 set_idom(region, head, dom_depth(head)+1);
1283 recompute_dom_depth();
1284 if (head->is_CountedLoop() && head->as_CountedLoop()->is_main_loop()) {
1285 head->as_CountedLoop()->set_normal_loop();
1286 }
1287 }
1288 return true;
1289 }
1290 }
1291 return false;
1292 }
1293
1294 bool PhaseIdealLoop::move_out_of_loop(LoadBarrierNode* lb) {
1295 IdealLoopTree *lb_loop = get_loop(lb->in(0));
1296 if (lb_loop != _ltree_root && !lb_loop->_irreducible) {
1297 Node* oop_ctrl = get_ctrl(lb->in(LoadBarrierNode::Oop));
1298 IdealLoopTree *oop_loop = get_loop(oop_ctrl);
1299 IdealLoopTree* adr_loop = get_loop(get_ctrl(lb->in(LoadBarrierNode::Address)));
1300 if (!lb_loop->is_member(oop_loop) && !lb_loop->is_member(adr_loop)) {
1301 // That transformation may cause the Similar edge on dominated load barriers to be invalid
1302 lb->fix_similar_in_uses(&_igvn);
1303
1304 Node* head = lb_loop->_head;
1305 assert(head->is_Loop(), "");
1306
1307 if (is_dominator(head, oop_ctrl)) {
1308 assert(oop_ctrl->Opcode() == Op_CProj && oop_ctrl->in(0)->Opcode() == Op_NeverBranch, "");
1309 assert(lb_loop->is_member(get_loop(oop_ctrl->in(0)->in(0))), "");
1310 return false;
1311 }
1312
1313 if (head->is_CountedLoop() && head->as_CountedLoop()->is_main_loop()) {
1314 head->as_CountedLoop()->set_normal_loop();
1315 }
1316
1317 Node* mem = lb->in(LoadBarrierNode::Memory);
1318 Node* m = find_dominating_memory(mem, head);
1319
1320 LoadBarrierNode* new_lb = clone_load_barrier(lb, head->in(LoopNode::EntryControl), m, NULL);
1321
1322 assert(idom(head) == head->in(LoopNode::EntryControl), "");
1323 Node* proj_ctl = new_lb->proj_out(LoadBarrierNode::Control);
1324 _igvn.replace_input_of(head, LoopNode::EntryControl, proj_ctl);
1325 set_idom(head, proj_ctl, dom_depth(proj_ctl)+1);
1326
1327 replace_barrier(lb, new_lb->proj_out(LoadBarrierNode::Oop));
1328
1329 recompute_dom_depth();
1330
1331 return true;
1332 }
1333 }
1334 return false;
1335 }
1336
1337 bool PhaseIdealLoop::common_barriers(LoadBarrierNode* lb) {
1338 Node* in_val = lb->in(LoadBarrierNode::Oop);
1339 for (DUIterator_Fast imax, i = in_val->fast_outs(imax); i < imax; i++) {
1340 Node* u = in_val->fast_out(i);
1341 if (u != lb && u->is_LoadBarrier() && u->as_LoadBarrier()->has_true_uses()) {
1342 Node* this_ctrl = lb->in(LoadBarrierNode::Control);
1343 Node* other_ctrl = u->in(LoadBarrierNode::Control);
1344
1345 Node* lca = dom_lca(this_ctrl, other_ctrl);
1346 bool ok = true;
1347
1348 Node* proj1 = NULL;
1349 Node* proj2 = NULL;
1350
1351 while (this_ctrl != lca && ok) {
1352 if (this_ctrl->in(0) != NULL &&
1353 this_ctrl->in(0)->is_MultiBranch()) {
1354 if (this_ctrl->in(0)->in(0) == lca) {
1355 assert(proj1 == NULL, "");
1356 assert(this_ctrl->is_Proj(), "");
1357 proj1 = this_ctrl;
1358 } else if (!(this_ctrl->in(0)->is_If() && this_ctrl->as_Proj()->is_uncommon_trap_if_pattern(Deoptimization::Reason_none))) {
1359 ok = false;
1360 }
1361 }
1362 this_ctrl = idom(this_ctrl);
1363 }
1364 while (other_ctrl != lca && ok) {
1365 if (other_ctrl->in(0) != NULL &&
1366 other_ctrl->in(0)->is_MultiBranch()) {
1367 if (other_ctrl->in(0)->in(0) == lca) {
1368 assert(other_ctrl->is_Proj(), "");
1369 assert(proj2 == NULL, "");
1370 proj2 = other_ctrl;
1371 } else if (!(other_ctrl->in(0)->is_If() && other_ctrl->as_Proj()->is_uncommon_trap_if_pattern(Deoptimization::Reason_none))) {
1372 ok = false;
1373 }
1374 }
1375 other_ctrl = idom(other_ctrl);
1376 }
1377 assert(proj1 == NULL || proj2 == NULL || proj1->in(0) == proj2->in(0), "");
1378 if (ok && proj1 && proj2 && proj1 != proj2 && proj1->in(0)->is_If()) {
1379 // That transformation may cause the Similar edge on dominated load barriers to be invalid
1380 lb->fix_similar_in_uses(&_igvn);
1381 u->as_LoadBarrier()->fix_similar_in_uses(&_igvn);
1382
1383 Node* split = lca->unique_ctrl_out();
1384 assert(split->in(0) == lca, "");
1385
1386 Node* mem = lb->in(LoadBarrierNode::Memory);
1387 Node* m = find_dominating_memory(mem, split);
1388 LoadBarrierNode* new_lb = clone_load_barrier(lb, lca, m, NULL);
1389
1390 Node* proj_ctl = new_lb->proj_out(LoadBarrierNode::Control);
1391 _igvn.replace_input_of(split, 0, new_lb->proj_out(LoadBarrierNode::Control));
1392 set_idom(split, proj_ctl, dom_depth(proj_ctl)+1);
1393
1394 Node* proj_oop = new_lb->proj_out(LoadBarrierNode::Oop);
1395 replace_barrier(lb, proj_oop);
1396 replace_barrier(u->as_LoadBarrier(), proj_oop);
1397
1398 recompute_dom_depth();
1399
1400 return true;
1401 }
1402 }
1403 }
1404 return false;
1405 }
1406
1407 void PhaseIdealLoop::optimize_load_barrier(LoadBarrierNode* lb, bool last_round) {
1408 if (!C->directive()->OptimizeLoadBarriersOption) {
1409 return;
1410 }
1411
1412 if (lb->has_true_uses()) {
1413
1414 if (replace_with_dominating_barrier(lb, last_round)) {
1415 return;
1416 }
1417
1418 if (split_barrier_thru_phi(lb)) {
1419 return;
1420 }
1421
1422 if (move_out_of_loop(lb)) {
1423 return;
1424 }
1425
1426 if (common_barriers(lb)) {
1427 return;
1428 }
1429 }
1430 }
1431
1432 //------------------------------split_if_with_blocks_post----------------------
1433 // Do the real work in a non-recursive function. CFG hackery wants to be
1434 // in the post-order, so it can dirty the I-DOM info and not use the dirtied
1435 // info.
1436 void PhaseIdealLoop::split_if_with_blocks_post(Node *n, bool last_round) {
1437
1438 // Cloning Cmp through Phi's involves the split-if transform.
1439 // FastLock is not used by an If
1440 if (n->is_Cmp() && !n->is_FastLock() && !last_round) {
1441 Node *n_ctrl = get_ctrl(n);
1442 // Determine if the Node has inputs from some local Phi.
1443 // Returns the block to clone thru.
1444 Node *n_blk = has_local_phi_input(n);
1445 if (n_blk != n_ctrl) {
1446 return;
1447 }
1448
1449 if (!can_split_if(n_ctrl)) {
1450 return;
1451 }
1452
1453 if (n->outcnt() != 1) {
1454 return; // Multiple bool's from 1 compare?
1455 }
1456 Node *bol = n->unique_out();
1457 assert(bol->is_Bool(), "expect a bool here");
1458 if (bol->outcnt() != 1) {
1459 return;// Multiple branches from 1 compare?
1460 }
1461 Node *iff = bol->unique_out();
1462
1463 // Check some safety conditions
1464 if (iff->is_If()) { // Classic split-if?
1465 if (iff->in(0) != n_ctrl) {
1466 return; // Compare must be in same blk as if
1467 }
1468 } else if (iff->is_CMove()) { // Trying to split-up a CMOVE
1469 // Can't split CMove with different control edge.
1470 if (iff->in(0) != NULL && iff->in(0) != n_ctrl ) {
1471 return;
1472 }
1473 if (get_ctrl(iff->in(2)) == n_ctrl ||
1474 get_ctrl(iff->in(3)) == n_ctrl) {
1475 return; // Inputs not yet split-up
1476 }
1477 if (get_loop(n_ctrl) != get_loop(get_ctrl(iff))) {
1478 return; // Loop-invar test gates loop-varying CMOVE
1479 }
1480 } else {
1481 return; // some other kind of node, such as an Allocate
1482 }
1483
1484 // When is split-if profitable? Every 'win' on means some control flow
1485 // goes dead, so it's almost always a win.
1486 int policy = 0;
1487 // Split compare 'n' through the merge point if it is profitable
1488 Node *phi = split_thru_phi( n, n_ctrl, policy);
1489 if (!phi) {
1490 return;
1491 }
1492
1493 // Found a Phi to split thru!
1494 // Replace 'n' with the new phi
1495 _igvn.replace_node(n, phi);
1496
1497 // Now split the bool up thru the phi
1498 Node *bolphi = split_thru_phi(bol, n_ctrl, -1);
1499 guarantee(bolphi != NULL, "null boolean phi node");
1500
1501 _igvn.replace_node(bol, bolphi);
1502 assert(iff->in(1) == bolphi, "");
1503
1504 if (bolphi->Value(&_igvn)->singleton()) {
1505 return;
1506 }
1507
1508 // Conditional-move? Must split up now
1509 if (!iff->is_If()) {
1510 Node *cmovphi = split_thru_phi(iff, n_ctrl, -1);
1511 _igvn.replace_node(iff, cmovphi);
1512 return;
1513 }
1514
1515 // Now split the IF
1516 do_split_if(iff);
1517 return;
1518 }
1519
1520 // Two identical ifs back to back can be merged
1521 if (identical_backtoback_ifs(n) && can_split_if(n->in(0))) {
1522 Node *n_ctrl = n->in(0);
1523 PhiNode* bolphi = PhiNode::make_blank(n_ctrl, n->in(1));
1524 IfNode* dom_if = idom(n_ctrl)->as_If();
1525 Node* proj_true = dom_if->proj_out(1);
1526 Node* proj_false = dom_if->proj_out(0);
1527 Node* con_true = _igvn.makecon(TypeInt::ONE);
1528 Node* con_false = _igvn.makecon(TypeInt::ZERO);
1529
1530 for (uint i = 1; i < n_ctrl->req(); i++) {
1531 if (is_dominator(proj_true, n_ctrl->in(i))) {
1532 bolphi->init_req(i, con_true);
1533 } else {
1534 assert(is_dominator(proj_false, n_ctrl->in(i)), "bad if");
1535 bolphi->init_req(i, con_false);
1536 }
1537 }
1538 register_new_node(bolphi, n_ctrl);
1539 _igvn.replace_input_of(n, 1, bolphi);
1540
1541 // Now split the IF
1542 do_split_if(n);
1543 return;
1544 }
1545
1546 // Check for an IF ready to split; one that has its
1547 // condition codes input coming from a Phi at the block start.
1548 int n_op = n->Opcode();
1549
1550 // Check for an IF being dominated by another IF same test
1551 if (n_op == Op_If ||
1552 n_op == Op_RangeCheck) {
1553 Node *bol = n->in(1);
1554 uint max = bol->outcnt();
1555 // Check for same test used more than once?
1556 if (max > 1 && bol->is_Bool()) {
1557 // Search up IDOMs to see if this IF is dominated.
1558 Node *cutoff = get_ctrl(bol);
1559
1560 // Now search up IDOMs till cutoff, looking for a dominating test
1561 Node *prevdom = n;
1562 Node *dom = idom(prevdom);
1563 while (dom != cutoff) {
1564 if (dom->req() > 1 && dom->in(1) == bol && prevdom->in(0) == dom) {
1565 // Replace the dominated test with an obvious true or false.
1566 // Place it on the IGVN worklist for later cleanup.
1567 C->set_major_progress();
1568 dominated_by(prevdom, n, false, true);
1569 #ifndef PRODUCT
1570 if( VerifyLoopOptimizations ) verify();
1571 #endif
1572 return;
1573 }
1574 prevdom = dom;
1575 dom = idom(prevdom);
1576 }
1577 }
1578 }
1579
1580 // See if a shared loop-varying computation has no loop-varying uses.
1581 // Happens if something is only used for JVM state in uncommon trap exits,
1582 // like various versions of induction variable+offset. Clone the
1583 // computation per usage to allow it to sink out of the loop.
1584 if (has_ctrl(n) && !n->in(0)) {// n not dead and has no control edge (can float about)
1585 Node *n_ctrl = get_ctrl(n);
1586 IdealLoopTree *n_loop = get_loop(n_ctrl);
1587 if( n_loop != _ltree_root ) {
1588 DUIterator_Fast imax, i = n->fast_outs(imax);
1589 for (; i < imax; i++) {
1590 Node* u = n->fast_out(i);
1591 if( !has_ctrl(u) ) break; // Found control user
1592 IdealLoopTree *u_loop = get_loop(get_ctrl(u));
1593 if( u_loop == n_loop ) break; // Found loop-varying use
1594 if( n_loop->is_member( u_loop ) ) break; // Found use in inner loop
1595 if( u->Opcode() == Op_Opaque1 ) break; // Found loop limit, bugfix for 4677003
1596 }
1597 bool did_break = (i < imax); // Did we break out of the previous loop?
1598 if (!did_break && n->outcnt() > 1) { // All uses in outer loops!
1599 Node *late_load_ctrl = NULL;
1600 if (n->is_Load()) {
1601 // If n is a load, get and save the result from get_late_ctrl(),
1602 // to be later used in calculating the control for n's clones.
1603 clear_dom_lca_tags();
1604 late_load_ctrl = get_late_ctrl(n, n_ctrl);
1605 }
1606 // If n is a load, and the late control is the same as the current
1607 // control, then the cloning of n is a pointless exercise, because
1608 // GVN will ensure that we end up where we started.
1609 if (!n->is_Load() || late_load_ctrl != n_ctrl) {
1610 for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin; ) {
1611 Node *u = n->last_out(j); // Clone private computation per use
1612 _igvn.rehash_node_delayed(u);
1613 Node *x = n->clone(); // Clone computation
1614 Node *x_ctrl = NULL;
1615 if( u->is_Phi() ) {
1616 // Replace all uses of normal nodes. Replace Phi uses
1617 // individually, so the separate Nodes can sink down
1618 // different paths.
1619 uint k = 1;
1620 while( u->in(k) != n ) k++;
1621 u->set_req( k, x );
1622 // x goes next to Phi input path
1623 x_ctrl = u->in(0)->in(k);
1624 --j;
1625 } else { // Normal use
1626 // Replace all uses
1627 for( uint k = 0; k < u->req(); k++ ) {
1628 if( u->in(k) == n ) {
1629 u->set_req( k, x );
1630 --j;
1631 }
1632 }
1633 x_ctrl = get_ctrl(u);
1634 }
1635
1636 // Find control for 'x' next to use but not inside inner loops.
1637 // For inner loop uses get the preheader area.
1638 x_ctrl = place_near_use(x_ctrl);
1639
1640 if (n->is_Load()) {
1641 // For loads, add a control edge to a CFG node outside of the loop
1642 // to force them to not combine and return back inside the loop
1643 // during GVN optimization (4641526).
1644 //
1645 // Because we are setting the actual control input, factor in
1646 // the result from get_late_ctrl() so we respect any
1647 // anti-dependences. (6233005).
1648 x_ctrl = dom_lca(late_load_ctrl, x_ctrl);
1649
1650 // Don't allow the control input to be a CFG splitting node.
1651 // Such nodes should only have ProjNodes as outs, e.g. IfNode
1652 // should only have IfTrueNode and IfFalseNode (4985384).
1653 x_ctrl = find_non_split_ctrl(x_ctrl);
1654 assert(dom_depth(n_ctrl) <= dom_depth(x_ctrl), "n is later than its clone");
1655
1656 x->set_req(0, x_ctrl);
1657 }
1658 register_new_node(x, x_ctrl);
1659
1660 // Some institutional knowledge is needed here: 'x' is
1661 // yanked because if the optimizer runs GVN on it all the
1662 // cloned x's will common up and undo this optimization and
1663 // be forced back in the loop. This is annoying because it
1664 // makes +VerifyOpto report false-positives on progress. I
1665 // tried setting control edges on the x's to force them to
1666 // not combine, but the matching gets worried when it tries
1667 // to fold a StoreP and an AddP together (as part of an
1668 // address expression) and the AddP and StoreP have
1669 // different controls.
1670 if (!x->is_Load() && !x->is_DecodeNarrowPtr()) _igvn._worklist.yank(x);
1671 }
1672 _igvn.remove_dead_node(n);
1673 }
1674 }
1675 }
1676 }
1677
1678 try_move_store_after_loop(n);
1679
1680 // Check for Opaque2's who's loop has disappeared - who's input is in the
1681 // same loop nest as their output. Remove 'em, they are no longer useful.
1682 if( n_op == Op_Opaque2 &&
1683 n->in(1) != NULL &&
1684 get_loop(get_ctrl(n)) == get_loop(get_ctrl(n->in(1))) ) {
1685 _igvn.replace_node( n, n->in(1) );
1686 }
1687
1688 if (n->is_LoadBarrier()) {
1689 optimize_load_barrier(n->as_LoadBarrier(), last_round);
1690 }
1691 }
1692
1693 //------------------------------split_if_with_blocks---------------------------
1694 // Check for aggressive application of 'split-if' optimization,
1695 // using basic block level info.
1696 void PhaseIdealLoop::split_if_with_blocks(VectorSet &visited, Node_Stack &nstack, bool last_round) {
1697 Node *n = C->root();
1698 visited.set(n->_idx); // first, mark node as visited
1699 // Do pre-visit work for root
1700 n = split_if_with_blocks_pre( n );
1701 uint cnt = n->outcnt();
1702 uint i = 0;
1703 while (true) {
1704 // Visit all children
1705 if (i < cnt) {
1706 Node* use = n->raw_out(i);
1707 ++i;
1708 if (use->outcnt() != 0 && !visited.test_set(use->_idx)) {
1709 // Now do pre-visit work for this use
1710 use = split_if_with_blocks_pre( use );
1711 nstack.push(n, i); // Save parent and next use's index.
1712 n = use; // Process all children of current use.
1713 cnt = use->outcnt();
1714 i = 0;
1715 }
1716 }
1717 else {
1718 // All of n's children have been processed, complete post-processing.
1719 if (cnt != 0 && !n->is_Con()) {
1720 assert(has_node(n), "no dead nodes");
1721 split_if_with_blocks_post(n, last_round);
1722 }
1723 if (nstack.is_empty()) {
1724 // Finished all nodes on stack.
1725 break;
1726 }
1727 // Get saved parent node and next use's index. Visit the rest of uses.
1728 n = nstack.node();
1729 cnt = n->outcnt();
1730 i = nstack.index();
1731 nstack.pop();
1732 }
1733 }
1734 }
1735
1736
1737 //=============================================================================
1738 //
1739 // C L O N E A L O O P B O D Y
1740 //
1741
1742 //------------------------------clone_iff--------------------------------------
1743 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps.
1744 // "Nearly" because all Nodes have been cloned from the original in the loop,
1745 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs
1746 // through the Phi recursively, and return a Bool.
1747 Node* PhaseIdealLoop::clone_iff(PhiNode *phi, IdealLoopTree *loop) {
1748
1749 // Convert this Phi into a Phi merging Bools
1750 uint i;
1751 for (i = 1; i < phi->req(); i++) {
1752 Node *b = phi->in(i);
1753 if (b->is_Phi()) {
1754 _igvn.replace_input_of(phi, i, clone_iff(b->as_Phi(), loop));
1755 } else {
1756 assert(b->is_Bool() || b->Opcode() == Op_Opaque4, "");
1757 }
1758 }
1759
1760 Node* n = phi->in(1);
1761 Node* sample_opaque = NULL;
1762 Node *sample_bool = NULL;
1763 if (n->Opcode() == Op_Opaque4) {
1764 sample_opaque = n;
1765 sample_bool = n->in(1);
1766 assert(sample_bool->is_Bool(), "wrong type");
1767 } else {
1768 sample_bool = n;
1769 }
1770 Node *sample_cmp = sample_bool->in(1);
1771
1772 // Make Phis to merge the Cmp's inputs.
1773 PhiNode *phi1 = new PhiNode(phi->in(0), Type::TOP);
1774 PhiNode *phi2 = new PhiNode(phi->in(0), Type::TOP);
1775 for (i = 1; i < phi->req(); i++) {
1776 Node *n1 = sample_opaque == NULL ? phi->in(i)->in(1)->in(1) : phi->in(i)->in(1)->in(1)->in(1);
1777 Node *n2 = sample_opaque == NULL ? phi->in(i)->in(1)->in(2) : phi->in(i)->in(1)->in(1)->in(2);
1778 phi1->set_req(i, n1);
1779 phi2->set_req(i, n2);
1780 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type()));
1781 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type()));
1782 }
1783 // See if these Phis have been made before.
1784 // Register with optimizer
1785 Node *hit1 = _igvn.hash_find_insert(phi1);
1786 if (hit1) { // Hit, toss just made Phi
1787 _igvn.remove_dead_node(phi1); // Remove new phi
1788 assert(hit1->is_Phi(), "" );
1789 phi1 = (PhiNode*)hit1; // Use existing phi
1790 } else { // Miss
1791 _igvn.register_new_node_with_optimizer(phi1);
1792 }
1793 Node *hit2 = _igvn.hash_find_insert(phi2);
1794 if (hit2) { // Hit, toss just made Phi
1795 _igvn.remove_dead_node(phi2); // Remove new phi
1796 assert(hit2->is_Phi(), "" );
1797 phi2 = (PhiNode*)hit2; // Use existing phi
1798 } else { // Miss
1799 _igvn.register_new_node_with_optimizer(phi2);
1800 }
1801 // Register Phis with loop/block info
1802 set_ctrl(phi1, phi->in(0));
1803 set_ctrl(phi2, phi->in(0));
1804 // Make a new Cmp
1805 Node *cmp = sample_cmp->clone();
1806 cmp->set_req(1, phi1);
1807 cmp->set_req(2, phi2);
1808 _igvn.register_new_node_with_optimizer(cmp);
1809 set_ctrl(cmp, phi->in(0));
1810
1811 // Make a new Bool
1812 Node *b = sample_bool->clone();
1813 b->set_req(1,cmp);
1814 _igvn.register_new_node_with_optimizer(b);
1815 set_ctrl(b, phi->in(0));
1816
1817 if (sample_opaque != NULL) {
1818 Node* opaque = sample_opaque->clone();
1819 opaque->set_req(1, b);
1820 _igvn.register_new_node_with_optimizer(opaque);
1821 set_ctrl(opaque, phi->in(0));
1822 return opaque;
1823 }
1824
1825 assert(b->is_Bool(), "");
1826 return b;
1827 }
1828
1829 //------------------------------clone_bool-------------------------------------
1830 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps.
1831 // "Nearly" because all Nodes have been cloned from the original in the loop,
1832 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs
1833 // through the Phi recursively, and return a Bool.
1834 CmpNode *PhaseIdealLoop::clone_bool( PhiNode *phi, IdealLoopTree *loop ) {
1835 uint i;
1836 // Convert this Phi into a Phi merging Bools
1837 for( i = 1; i < phi->req(); i++ ) {
1838 Node *b = phi->in(i);
1839 if( b->is_Phi() ) {
1840 _igvn.replace_input_of(phi, i, clone_bool( b->as_Phi(), loop ));
1841 } else {
1842 assert( b->is_Cmp() || b->is_top(), "inputs are all Cmp or TOP" );
1843 }
1844 }
1845
1846 Node *sample_cmp = phi->in(1);
1847
1848 // Make Phis to merge the Cmp's inputs.
1849 PhiNode *phi1 = new PhiNode( phi->in(0), Type::TOP );
1850 PhiNode *phi2 = new PhiNode( phi->in(0), Type::TOP );
1851 for( uint j = 1; j < phi->req(); j++ ) {
1852 Node *cmp_top = phi->in(j); // Inputs are all Cmp or TOP
1853 Node *n1, *n2;
1854 if( cmp_top->is_Cmp() ) {
1855 n1 = cmp_top->in(1);
1856 n2 = cmp_top->in(2);
1857 } else {
1858 n1 = n2 = cmp_top;
1859 }
1860 phi1->set_req( j, n1 );
1861 phi2->set_req( j, n2 );
1862 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type()));
1863 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type()));
1864 }
1865
1866 // See if these Phis have been made before.
1867 // Register with optimizer
1868 Node *hit1 = _igvn.hash_find_insert(phi1);
1869 if( hit1 ) { // Hit, toss just made Phi
1870 _igvn.remove_dead_node(phi1); // Remove new phi
1871 assert( hit1->is_Phi(), "" );
1872 phi1 = (PhiNode*)hit1; // Use existing phi
1873 } else { // Miss
1874 _igvn.register_new_node_with_optimizer(phi1);
1875 }
1876 Node *hit2 = _igvn.hash_find_insert(phi2);
1877 if( hit2 ) { // Hit, toss just made Phi
1878 _igvn.remove_dead_node(phi2); // Remove new phi
1879 assert( hit2->is_Phi(), "" );
1880 phi2 = (PhiNode*)hit2; // Use existing phi
1881 } else { // Miss
1882 _igvn.register_new_node_with_optimizer(phi2);
1883 }
1884 // Register Phis with loop/block info
1885 set_ctrl(phi1, phi->in(0));
1886 set_ctrl(phi2, phi->in(0));
1887 // Make a new Cmp
1888 Node *cmp = sample_cmp->clone();
1889 cmp->set_req( 1, phi1 );
1890 cmp->set_req( 2, phi2 );
1891 _igvn.register_new_node_with_optimizer(cmp);
1892 set_ctrl(cmp, phi->in(0));
1893
1894 assert( cmp->is_Cmp(), "" );
1895 return (CmpNode*)cmp;
1896 }
1897
1898 //------------------------------sink_use---------------------------------------
1899 // If 'use' was in the loop-exit block, it now needs to be sunk
1900 // below the post-loop merge point.
1901 void PhaseIdealLoop::sink_use( Node *use, Node *post_loop ) {
1902 if (!use->is_CFG() && get_ctrl(use) == post_loop->in(2)) {
1903 set_ctrl(use, post_loop);
1904 for (DUIterator j = use->outs(); use->has_out(j); j++)
1905 sink_use(use->out(j), post_loop);
1906 }
1907 }
1908
1909 void PhaseIdealLoop::clone_loop_handle_data_uses(Node* old, Node_List &old_new,
1910 IdealLoopTree* loop, IdealLoopTree* outer_loop,
1911 Node_List*& split_if_set, Node_List*& split_bool_set,
1912 Node_List*& split_cex_set, Node_List& worklist,
1913 uint new_counter, CloneLoopMode mode) {
1914 Node* nnn = old_new[old->_idx];
1915 // Copy uses to a worklist, so I can munge the def-use info
1916 // with impunity.
1917 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++)
1918 worklist.push(old->fast_out(j));
1919
1920 while( worklist.size() ) {
1921 Node *use = worklist.pop();
1922 if (!has_node(use)) continue; // Ignore dead nodes
1923 if (use->in(0) == C->top()) continue;
1924 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use );
1925 // Check for data-use outside of loop - at least one of OLD or USE
1926 // must not be a CFG node.
1927 #ifdef ASSERT
1928 if (loop->_head->as_Loop()->is_strip_mined() && outer_loop->is_member(use_loop) && !loop->is_member(use_loop) && old_new[use->_idx] == NULL) {
1929 Node* sfpt = loop->_head->as_CountedLoop()->outer_safepoint();
1930 assert(mode == ControlAroundStripMined && use == sfpt, "missed a node");
1931 }
1932 #endif
1933 if (!loop->is_member(use_loop) && !outer_loop->is_member(use_loop) && (!old->is_CFG() || !use->is_CFG())) {
1934
1935 // If the Data use is an IF, that means we have an IF outside of the
1936 // loop that is switching on a condition that is set inside of the
1937 // loop. Happens if people set a loop-exit flag; then test the flag
1938 // in the loop to break the loop, then test is again outside of the
1939 // loop to determine which way the loop exited.
1940 // Loop predicate If node connects to Bool node through Opaque1 node.
1941 if (use->is_If() || use->is_CMove() || C->is_predicate_opaq(use) || use->Opcode() == Op_Opaque4) {
1942 // Since this code is highly unlikely, we lazily build the worklist
1943 // of such Nodes to go split.
1944 if (!split_if_set) {
1945 ResourceArea *area = Thread::current()->resource_area();
1946 split_if_set = new Node_List(area);
1947 }
1948 split_if_set->push(use);
1949 }
1950 if (use->is_Bool()) {
1951 if (!split_bool_set) {
1952 ResourceArea *area = Thread::current()->resource_area();
1953 split_bool_set = new Node_List(area);
1954 }
1955 split_bool_set->push(use);
1956 }
1957 if (use->Opcode() == Op_CreateEx) {
1958 if (!split_cex_set) {
1959 ResourceArea *area = Thread::current()->resource_area();
1960 split_cex_set = new Node_List(area);
1961 }
1962 split_cex_set->push(use);
1963 }
1964
1965
1966 // Get "block" use is in
1967 uint idx = 0;
1968 while( use->in(idx) != old ) idx++;
1969 Node *prev = use->is_CFG() ? use : get_ctrl(use);
1970 assert(!loop->is_member(get_loop(prev)) && !outer_loop->is_member(get_loop(prev)), "" );
1971 Node *cfg = prev->_idx >= new_counter
1972 ? prev->in(2)
1973 : idom(prev);
1974 if( use->is_Phi() ) // Phi use is in prior block
1975 cfg = prev->in(idx); // NOT in block of Phi itself
1976 if (cfg->is_top()) { // Use is dead?
1977 _igvn.replace_input_of(use, idx, C->top());
1978 continue;
1979 }
1980
1981 while(!outer_loop->is_member(get_loop(cfg))) {
1982 prev = cfg;
1983 cfg = cfg->_idx >= new_counter ? cfg->in(2) : idom(cfg);
1984 }
1985 // If the use occurs after merging several exits from the loop, then
1986 // old value must have dominated all those exits. Since the same old
1987 // value was used on all those exits we did not need a Phi at this
1988 // merge point. NOW we do need a Phi here. Each loop exit value
1989 // is now merged with the peeled body exit; each exit gets its own
1990 // private Phi and those Phis need to be merged here.
1991 Node *phi;
1992 if( prev->is_Region() ) {
1993 if( idx == 0 ) { // Updating control edge?
1994 phi = prev; // Just use existing control
1995 } else { // Else need a new Phi
1996 phi = PhiNode::make( prev, old );
1997 // Now recursively fix up the new uses of old!
1998 for( uint i = 1; i < prev->req(); i++ ) {
1999 worklist.push(phi); // Onto worklist once for each 'old' input
2000 }
2001 }
2002 } else {
2003 // Get new RegionNode merging old and new loop exits
2004 prev = old_new[prev->_idx];
2005 assert( prev, "just made this in step 7" );
2006 if( idx == 0) { // Updating control edge?
2007 phi = prev; // Just use existing control
2008 } else { // Else need a new Phi
2009 // Make a new Phi merging data values properly
2010 phi = PhiNode::make( prev, old );
2011 phi->set_req( 1, nnn );
2012 }
2013 }
2014 // If inserting a new Phi, check for prior hits
2015 if( idx != 0 ) {
2016 Node *hit = _igvn.hash_find_insert(phi);
2017 if( hit == NULL ) {
2018 _igvn.register_new_node_with_optimizer(phi); // Register new phi
2019 } else { // or
2020 // Remove the new phi from the graph and use the hit
2021 _igvn.remove_dead_node(phi);
2022 phi = hit; // Use existing phi
2023 }
2024 set_ctrl(phi, prev);
2025 }
2026 // Make 'use' use the Phi instead of the old loop body exit value
2027 _igvn.replace_input_of(use, idx, phi);
2028 if( use->_idx >= new_counter ) { // If updating new phis
2029 // Not needed for correctness, but prevents a weak assert
2030 // in AddPNode from tripping (when we end up with different
2031 // base & derived Phis that will become the same after
2032 // IGVN does CSE).
2033 Node *hit = _igvn.hash_find_insert(use);
2034 if( hit ) // Go ahead and re-hash for hits.
2035 _igvn.replace_node( use, hit );
2036 }
2037
2038 // If 'use' was in the loop-exit block, it now needs to be sunk
2039 // below the post-loop merge point.
2040 sink_use( use, prev );
2041 }
2042 }
2043 }
2044
2045 void PhaseIdealLoop::clone_outer_loop(LoopNode* head, CloneLoopMode mode, IdealLoopTree *loop,
2046 IdealLoopTree* outer_loop, int dd, Node_List &old_new,
2047 Node_List& extra_data_nodes) {
2048 if (head->is_strip_mined() && mode != IgnoreStripMined) {
2049 CountedLoopNode* cl = head->as_CountedLoop();
2050 Node* l = cl->outer_loop();
2051 Node* tail = cl->outer_loop_tail();
2052 IfNode* le = cl->outer_loop_end();
2053 Node* sfpt = cl->outer_safepoint();
2054 CountedLoopEndNode* cle = cl->loopexit();
2055 CountedLoopNode* new_cl = old_new[cl->_idx]->as_CountedLoop();
2056 CountedLoopEndNode* new_cle = new_cl->as_CountedLoop()->loopexit_or_null();
2057 Node* cle_out = cle->proj_out(false);
2058
2059 Node* new_sfpt = NULL;
2060 Node* new_cle_out = cle_out->clone();
2061 old_new.map(cle_out->_idx, new_cle_out);
2062 if (mode == CloneIncludesStripMined) {
2063 // clone outer loop body
2064 Node* new_l = l->clone();
2065 Node* new_tail = tail->clone();
2066 IfNode* new_le = le->clone()->as_If();
2067 new_sfpt = sfpt->clone();
2068
2069 set_loop(new_l, outer_loop->_parent);
2070 set_idom(new_l, new_l->in(LoopNode::EntryControl), dd);
2071 set_loop(new_cle_out, outer_loop->_parent);
2072 set_idom(new_cle_out, new_cle, dd);
2073 set_loop(new_sfpt, outer_loop->_parent);
2074 set_idom(new_sfpt, new_cle_out, dd);
2075 set_loop(new_le, outer_loop->_parent);
2076 set_idom(new_le, new_sfpt, dd);
2077 set_loop(new_tail, outer_loop->_parent);
2078 set_idom(new_tail, new_le, dd);
2079 set_idom(new_cl, new_l, dd);
2080
2081 old_new.map(l->_idx, new_l);
2082 old_new.map(tail->_idx, new_tail);
2083 old_new.map(le->_idx, new_le);
2084 old_new.map(sfpt->_idx, new_sfpt);
2085
2086 new_l->set_req(LoopNode::LoopBackControl, new_tail);
2087 new_l->set_req(0, new_l);
2088 new_tail->set_req(0, new_le);
2089 new_le->set_req(0, new_sfpt);
2090 new_sfpt->set_req(0, new_cle_out);
2091 new_cle_out->set_req(0, new_cle);
2092 new_cl->set_req(LoopNode::EntryControl, new_l);
2093
2094 _igvn.register_new_node_with_optimizer(new_l);
2095 _igvn.register_new_node_with_optimizer(new_tail);
2096 _igvn.register_new_node_with_optimizer(new_le);
2097 } else {
2098 Node *newhead = old_new[loop->_head->_idx];
2099 newhead->as_Loop()->clear_strip_mined();
2100 _igvn.replace_input_of(newhead, LoopNode::EntryControl, newhead->in(LoopNode::EntryControl)->in(LoopNode::EntryControl));
2101 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd);
2102 }
2103 // Look at data node that were assigned a control in the outer
2104 // loop: they are kept in the outer loop by the safepoint so start
2105 // from the safepoint node's inputs.
2106 IdealLoopTree* outer_loop = get_loop(l);
2107 Node_Stack stack(2);
2108 stack.push(sfpt, 1);
2109 uint new_counter = C->unique();
2110 while (stack.size() > 0) {
2111 Node* n = stack.node();
2112 uint i = stack.index();
2113 while (i < n->req() &&
2114 (n->in(i) == NULL ||
2115 !has_ctrl(n->in(i)) ||
2116 get_loop(get_ctrl(n->in(i))) != outer_loop ||
2117 (old_new[n->in(i)->_idx] != NULL && old_new[n->in(i)->_idx]->_idx >= new_counter))) {
2118 i++;
2119 }
2120 if (i < n->req()) {
2121 stack.set_index(i+1);
2122 stack.push(n->in(i), 0);
2123 } else {
2124 assert(old_new[n->_idx] == NULL || n == sfpt || old_new[n->_idx]->_idx < new_counter, "no clone yet");
2125 Node* m = n == sfpt ? new_sfpt : n->clone();
2126 if (m != NULL) {
2127 for (uint i = 0; i < n->req(); i++) {
2128 if (m->in(i) != NULL && old_new[m->in(i)->_idx] != NULL) {
2129 m->set_req(i, old_new[m->in(i)->_idx]);
2130 }
2131 }
2132 } else {
2133 assert(n == sfpt && mode != CloneIncludesStripMined, "where's the safepoint clone?");
2134 }
2135 if (n != sfpt) {
2136 extra_data_nodes.push(n);
2137 _igvn.register_new_node_with_optimizer(m);
2138 assert(get_ctrl(n) == cle_out, "what other control?");
2139 set_ctrl(m, new_cle_out);
2140 old_new.map(n->_idx, m);
2141 }
2142 stack.pop();
2143 }
2144 }
2145 if (mode == CloneIncludesStripMined) {
2146 _igvn.register_new_node_with_optimizer(new_sfpt);
2147 _igvn.register_new_node_with_optimizer(new_cle_out);
2148 }
2149 } else {
2150 Node *newhead = old_new[loop->_head->_idx];
2151 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd);
2152 }
2153 }
2154
2155 //------------------------------clone_loop-------------------------------------
2156 //
2157 // C L O N E A L O O P B O D Y
2158 //
2159 // This is the basic building block of the loop optimizations. It clones an
2160 // entire loop body. It makes an old_new loop body mapping; with this mapping
2161 // you can find the new-loop equivalent to an old-loop node. All new-loop
2162 // nodes are exactly equal to their old-loop counterparts, all edges are the
2163 // same. All exits from the old-loop now have a RegionNode that merges the
2164 // equivalent new-loop path. This is true even for the normal "loop-exit"
2165 // condition. All uses of loop-invariant old-loop values now come from (one
2166 // or more) Phis that merge their new-loop equivalents.
2167 //
2168 // This operation leaves the graph in an illegal state: there are two valid
2169 // control edges coming from the loop pre-header to both loop bodies. I'll
2170 // definitely have to hack the graph after running this transform.
2171 //
2172 // From this building block I will further edit edges to perform loop peeling
2173 // or loop unrolling or iteration splitting (Range-Check-Elimination), etc.
2174 //
2175 // Parameter side_by_size_idom:
2176 // When side_by_size_idom is NULL, the dominator tree is constructed for
2177 // the clone loop to dominate the original. Used in construction of
2178 // pre-main-post loop sequence.
2179 // When nonnull, the clone and original are side-by-side, both are
2180 // dominated by the side_by_side_idom node. Used in construction of
2181 // unswitched loops.
2182 void PhaseIdealLoop::clone_loop( IdealLoopTree *loop, Node_List &old_new, int dd,
2183 CloneLoopMode mode, Node* side_by_side_idom) {
2184
2185 LoopNode* head = loop->_head->as_Loop();
2186 head->verify_strip_mined(1);
2187
2188 if (C->do_vector_loop() && PrintOpto) {
2189 const char* mname = C->method()->name()->as_quoted_ascii();
2190 if (mname != NULL) {
2191 tty->print("PhaseIdealLoop::clone_loop: for vectorize method %s\n", mname);
2192 }
2193 }
2194
2195 CloneMap& cm = C->clone_map();
2196 Dict* dict = cm.dict();
2197 if (C->do_vector_loop()) {
2198 cm.set_clone_idx(cm.max_gen()+1);
2199 #ifndef PRODUCT
2200 if (PrintOpto) {
2201 tty->print_cr("PhaseIdealLoop::clone_loop: _clone_idx %d", cm.clone_idx());
2202 loop->dump_head();
2203 }
2204 #endif
2205 }
2206
2207 // Step 1: Clone the loop body. Make the old->new mapping.
2208 uint i;
2209 for( i = 0; i < loop->_body.size(); i++ ) {
2210 Node *old = loop->_body.at(i);
2211 Node *nnn = old->clone();
2212 old_new.map( old->_idx, nnn );
2213 if (C->do_vector_loop()) {
2214 cm.verify_insert_and_clone(old, nnn, cm.clone_idx());
2215 }
2216 _igvn.register_new_node_with_optimizer(nnn);
2217 }
2218
2219 IdealLoopTree* outer_loop = (head->is_strip_mined() && mode != IgnoreStripMined) ? get_loop(head->as_CountedLoop()->outer_loop()) : loop;
2220
2221 // Step 2: Fix the edges in the new body. If the old input is outside the
2222 // loop use it. If the old input is INside the loop, use the corresponding
2223 // new node instead.
2224 for( i = 0; i < loop->_body.size(); i++ ) {
2225 Node *old = loop->_body.at(i);
2226 Node *nnn = old_new[old->_idx];
2227 // Fix CFG/Loop controlling the new node
2228 if (has_ctrl(old)) {
2229 set_ctrl(nnn, old_new[get_ctrl(old)->_idx]);
2230 } else {
2231 set_loop(nnn, outer_loop->_parent);
2232 if (old->outcnt() > 0) {
2233 set_idom( nnn, old_new[idom(old)->_idx], dd );
2234 }
2235 }
2236 // Correct edges to the new node
2237 for( uint j = 0; j < nnn->req(); j++ ) {
2238 Node *n = nnn->in(j);
2239 if( n ) {
2240 IdealLoopTree *old_in_loop = get_loop( has_ctrl(n) ? get_ctrl(n) : n );
2241 if( loop->is_member( old_in_loop ) )
2242 nnn->set_req(j, old_new[n->_idx]);
2243 }
2244 }
2245 _igvn.hash_find_insert(nnn);
2246 }
2247
2248 ResourceArea *area = Thread::current()->resource_area();
2249 Node_List extra_data_nodes(area);
2250 clone_outer_loop(head, mode, loop, outer_loop, dd, old_new, extra_data_nodes);
2251
2252 // Step 3: Now fix control uses. Loop varying control uses have already
2253 // been fixed up (as part of all input edges in Step 2). Loop invariant
2254 // control uses must be either an IfFalse or an IfTrue. Make a merge
2255 // point to merge the old and new IfFalse/IfTrue nodes; make the use
2256 // refer to this.
2257 Node_List worklist(area);
2258 uint new_counter = C->unique();
2259 for( i = 0; i < loop->_body.size(); i++ ) {
2260 Node* old = loop->_body.at(i);
2261 if( !old->is_CFG() ) continue;
2262
2263 // Copy uses to a worklist, so I can munge the def-use info
2264 // with impunity.
2265 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++)
2266 worklist.push(old->fast_out(j));
2267
2268 while( worklist.size() ) { // Visit all uses
2269 Node *use = worklist.pop();
2270 if (!has_node(use)) continue; // Ignore dead nodes
2271 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use );
2272 if( !loop->is_member( use_loop ) && use->is_CFG() ) {
2273 // Both OLD and USE are CFG nodes here.
2274 assert( use->is_Proj(), "" );
2275 Node* nnn = old_new[old->_idx];
2276
2277 Node* newuse = NULL;
2278 if (head->is_strip_mined() && mode != IgnoreStripMined) {
2279 CountedLoopNode* cl = head->as_CountedLoop();
2280 CountedLoopEndNode* cle = cl->loopexit();
2281 Node* cle_out = cle->proj_out_or_null(false);
2282 if (use == cle_out) {
2283 IfNode* le = cl->outer_loop_end();
2284 use = le->proj_out(false);
2285 use_loop = get_loop(use);
2286 if (mode == CloneIncludesStripMined) {
2287 nnn = old_new[le->_idx];
2288 } else {
2289 newuse = old_new[cle_out->_idx];
2290 }
2291 }
2292 }
2293 if (newuse == NULL) {
2294 newuse = use->clone();
2295 }
2296
2297 // Clone the loop exit control projection
2298 if (C->do_vector_loop()) {
2299 cm.verify_insert_and_clone(use, newuse, cm.clone_idx());
2300 }
2301 newuse->set_req(0,nnn);
2302 _igvn.register_new_node_with_optimizer(newuse);
2303 set_loop(newuse, use_loop);
2304 set_idom(newuse, nnn, dom_depth(nnn) + 1 );
2305
2306 // We need a Region to merge the exit from the peeled body and the
2307 // exit from the old loop body.
2308 RegionNode *r = new RegionNode(3);
2309 // Map the old use to the new merge point
2310 old_new.map( use->_idx, r );
2311 uint dd_r = MIN2(dom_depth(newuse),dom_depth(use));
2312 assert( dd_r >= dom_depth(dom_lca(newuse,use)), "" );
2313
2314 // The original user of 'use' uses 'r' instead.
2315 for (DUIterator_Last lmin, l = use->last_outs(lmin); l >= lmin;) {
2316 Node* useuse = use->last_out(l);
2317 _igvn.rehash_node_delayed(useuse);
2318 uint uses_found = 0;
2319 if( useuse->in(0) == use ) {
2320 useuse->set_req(0, r);
2321 uses_found++;
2322 if( useuse->is_CFG() ) {
2323 assert( dom_depth(useuse) > dd_r, "" );
2324 set_idom(useuse, r, dom_depth(useuse));
2325 }
2326 }
2327 for( uint k = 1; k < useuse->req(); k++ ) {
2328 if( useuse->in(k) == use ) {
2329 useuse->set_req(k, r);
2330 uses_found++;
2331 if (useuse->is_Loop() && k == LoopNode::EntryControl) {
2332 assert(dom_depth(useuse) > dd_r , "");
2333 set_idom(useuse, r, dom_depth(useuse));
2334 }
2335 }
2336 }
2337 l -= uses_found; // we deleted 1 or more copies of this edge
2338 }
2339
2340 // Now finish up 'r'
2341 r->set_req( 1, newuse );
2342 r->set_req( 2, use );
2343 _igvn.register_new_node_with_optimizer(r);
2344 set_loop(r, use_loop);
2345 set_idom(r, !side_by_side_idom ? newuse->in(0) : side_by_side_idom, dd_r);
2346 } // End of if a loop-exit test
2347 }
2348 }
2349
2350 // Step 4: If loop-invariant use is not control, it must be dominated by a
2351 // loop exit IfFalse/IfTrue. Find "proper" loop exit. Make a Region
2352 // there if needed. Make a Phi there merging old and new used values.
2353 Node_List *split_if_set = NULL;
2354 Node_List *split_bool_set = NULL;
2355 Node_List *split_cex_set = NULL;
2356 for( i = 0; i < loop->_body.size(); i++ ) {
2357 Node* old = loop->_body.at(i);
2358 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set,
2359 split_bool_set, split_cex_set, worklist, new_counter,
2360 mode);
2361 }
2362
2363 for (i = 0; i < extra_data_nodes.size(); i++) {
2364 Node* old = extra_data_nodes.at(i);
2365 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set,
2366 split_bool_set, split_cex_set, worklist, new_counter,
2367 mode);
2368 }
2369
2370 // Check for IFs that need splitting/cloning. Happens if an IF outside of
2371 // the loop uses a condition set in the loop. The original IF probably
2372 // takes control from one or more OLD Regions (which in turn get from NEW
2373 // Regions). In any case, there will be a set of Phis for each merge point
2374 // from the IF up to where the original BOOL def exists the loop.
2375 if (split_if_set) {
2376 while (split_if_set->size()) {
2377 Node *iff = split_if_set->pop();
2378 if (iff->in(1)->is_Phi()) {
2379 Node *b = clone_iff(iff->in(1)->as_Phi(), loop);
2380 _igvn.replace_input_of(iff, 1, b);
2381 }
2382 }
2383 }
2384 if (split_bool_set) {
2385 while (split_bool_set->size()) {
2386 Node *b = split_bool_set->pop();
2387 Node *phi = b->in(1);
2388 assert(phi->is_Phi(), "");
2389 CmpNode *cmp = clone_bool((PhiNode*)phi, loop);
2390 _igvn.replace_input_of(b, 1, cmp);
2391 }
2392 }
2393 if (split_cex_set) {
2394 while (split_cex_set->size()) {
2395 Node *b = split_cex_set->pop();
2396 assert(b->in(0)->is_Region(), "");
2397 assert(b->in(1)->is_Phi(), "");
2398 assert(b->in(0)->in(0) == b->in(1)->in(0), "");
2399 split_up(b, b->in(0), NULL);
2400 }
2401 }
2402
2403 }
2404
2405
2406 //---------------------- stride_of_possible_iv -------------------------------------
2407 // Looks for an iff/bool/comp with one operand of the compare
2408 // being a cycle involving an add and a phi,
2409 // with an optional truncation (left-shift followed by a right-shift)
2410 // of the add. Returns zero if not an iv.
2411 int PhaseIdealLoop::stride_of_possible_iv(Node* iff) {
2412 Node* trunc1 = NULL;
2413 Node* trunc2 = NULL;
2414 const TypeInt* ttype = NULL;
2415 if (!iff->is_If() || iff->in(1) == NULL || !iff->in(1)->is_Bool()) {
2416 return 0;
2417 }
2418 BoolNode* bl = iff->in(1)->as_Bool();
2419 Node* cmp = bl->in(1);
2420 if (!cmp || (cmp->Opcode() != Op_CmpI && cmp->Opcode() != Op_CmpU)) {
2421 return 0;
2422 }
2423 // Must have an invariant operand
2424 if (is_member(get_loop(iff), get_ctrl(cmp->in(2)))) {
2425 return 0;
2426 }
2427 Node* add2 = NULL;
2428 Node* cmp1 = cmp->in(1);
2429 if (cmp1->is_Phi()) {
2430 // (If (Bool (CmpX phi:(Phi ...(Optional-trunc(AddI phi add2))) )))
2431 Node* phi = cmp1;
2432 for (uint i = 1; i < phi->req(); i++) {
2433 Node* in = phi->in(i);
2434 Node* add = CountedLoopNode::match_incr_with_optional_truncation(in,
2435 &trunc1, &trunc2, &ttype);
2436 if (add && add->in(1) == phi) {
2437 add2 = add->in(2);
2438 break;
2439 }
2440 }
2441 } else {
2442 // (If (Bool (CmpX addtrunc:(Optional-trunc((AddI (Phi ...addtrunc...) add2)) )))
2443 Node* addtrunc = cmp1;
2444 Node* add = CountedLoopNode::match_incr_with_optional_truncation(addtrunc,
2445 &trunc1, &trunc2, &ttype);
2446 if (add && add->in(1)->is_Phi()) {
2447 Node* phi = add->in(1);
2448 for (uint i = 1; i < phi->req(); i++) {
2449 if (phi->in(i) == addtrunc) {
2450 add2 = add->in(2);
2451 break;
2452 }
2453 }
2454 }
2455 }
2456 if (add2 != NULL) {
2457 const TypeInt* add2t = _igvn.type(add2)->is_int();
2458 if (add2t->is_con()) {
2459 return add2t->get_con();
2460 }
2461 }
2462 return 0;
2463 }
2464
2465
2466 //---------------------- stay_in_loop -------------------------------------
2467 // Return the (unique) control output node that's in the loop (if it exists.)
2468 Node* PhaseIdealLoop::stay_in_loop( Node* n, IdealLoopTree *loop) {
2469 Node* unique = NULL;
2470 if (!n) return NULL;
2471 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2472 Node* use = n->fast_out(i);
2473 if (!has_ctrl(use) && loop->is_member(get_loop(use))) {
2474 if (unique != NULL) {
2475 return NULL;
2476 }
2477 unique = use;
2478 }
2479 }
2480 return unique;
2481 }
2482
2483 //------------------------------ register_node -------------------------------------
2484 // Utility to register node "n" with PhaseIdealLoop
2485 void PhaseIdealLoop::register_node(Node* n, IdealLoopTree *loop, Node* pred, int ddepth) {
2486 _igvn.register_new_node_with_optimizer(n);
2487 loop->_body.push(n);
2488 if (n->is_CFG()) {
2489 set_loop(n, loop);
2490 set_idom(n, pred, ddepth);
2491 } else {
2492 set_ctrl(n, pred);
2493 }
2494 }
2495
2496 //------------------------------ proj_clone -------------------------------------
2497 // Utility to create an if-projection
2498 ProjNode* PhaseIdealLoop::proj_clone(ProjNode* p, IfNode* iff) {
2499 ProjNode* c = p->clone()->as_Proj();
2500 c->set_req(0, iff);
2501 return c;
2502 }
2503
2504 //------------------------------ short_circuit_if -------------------------------------
2505 // Force the iff control output to be the live_proj
2506 Node* PhaseIdealLoop::short_circuit_if(IfNode* iff, ProjNode* live_proj) {
2507 guarantee(live_proj != NULL, "null projection");
2508 int proj_con = live_proj->_con;
2509 assert(proj_con == 0 || proj_con == 1, "false or true projection");
2510 Node *con = _igvn.intcon(proj_con);
2511 set_ctrl(con, C->root());
2512 if (iff) {
2513 iff->set_req(1, con);
2514 }
2515 return con;
2516 }
2517
2518 //------------------------------ insert_if_before_proj -------------------------------------
2519 // Insert a new if before an if projection (* - new node)
2520 //
2521 // before
2522 // if(test)
2523 // / \
2524 // v v
2525 // other-proj proj (arg)
2526 //
2527 // after
2528 // if(test)
2529 // / \
2530 // / v
2531 // | * proj-clone
2532 // v |
2533 // other-proj v
2534 // * new_if(relop(cmp[IU](left,right)))
2535 // / \
2536 // v v
2537 // * new-proj proj
2538 // (returned)
2539 //
2540 ProjNode* PhaseIdealLoop::insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj) {
2541 IfNode* iff = proj->in(0)->as_If();
2542 IdealLoopTree *loop = get_loop(proj);
2543 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj();
2544 int ddepth = dom_depth(proj);
2545
2546 _igvn.rehash_node_delayed(iff);
2547 _igvn.rehash_node_delayed(proj);
2548
2549 proj->set_req(0, NULL); // temporary disconnect
2550 ProjNode* proj2 = proj_clone(proj, iff);
2551 register_node(proj2, loop, iff, ddepth);
2552
2553 Node* cmp = Signed ? (Node*) new CmpINode(left, right) : (Node*) new CmpUNode(left, right);
2554 register_node(cmp, loop, proj2, ddepth);
2555
2556 BoolNode* bol = new BoolNode(cmp, relop);
2557 register_node(bol, loop, proj2, ddepth);
2558
2559 int opcode = iff->Opcode();
2560 assert(opcode == Op_If || opcode == Op_RangeCheck, "unexpected opcode");
2561 IfNode* new_if = (opcode == Op_If) ? new IfNode(proj2, bol, iff->_prob, iff->_fcnt):
2562 new RangeCheckNode(proj2, bol, iff->_prob, iff->_fcnt);
2563 register_node(new_if, loop, proj2, ddepth);
2564
2565 proj->set_req(0, new_if); // reattach
2566 set_idom(proj, new_if, ddepth);
2567
2568 ProjNode* new_exit = proj_clone(other_proj, new_if)->as_Proj();
2569 guarantee(new_exit != NULL, "null exit node");
2570 register_node(new_exit, get_loop(other_proj), new_if, ddepth);
2571
2572 return new_exit;
2573 }
2574
2575 //------------------------------ insert_region_before_proj -------------------------------------
2576 // Insert a region before an if projection (* - new node)
2577 //
2578 // before
2579 // if(test)
2580 // / |
2581 // v |
2582 // proj v
2583 // other-proj
2584 //
2585 // after
2586 // if(test)
2587 // / |
2588 // v |
2589 // * proj-clone v
2590 // | other-proj
2591 // v
2592 // * new-region
2593 // |
2594 // v
2595 // * dum_if
2596 // / \
2597 // v \
2598 // * dum-proj v
2599 // proj
2600 //
2601 RegionNode* PhaseIdealLoop::insert_region_before_proj(ProjNode* proj) {
2602 IfNode* iff = proj->in(0)->as_If();
2603 IdealLoopTree *loop = get_loop(proj);
2604 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj();
2605 int ddepth = dom_depth(proj);
2606
2607 _igvn.rehash_node_delayed(iff);
2608 _igvn.rehash_node_delayed(proj);
2609
2610 proj->set_req(0, NULL); // temporary disconnect
2611 ProjNode* proj2 = proj_clone(proj, iff);
2612 register_node(proj2, loop, iff, ddepth);
2613
2614 RegionNode* reg = new RegionNode(2);
2615 reg->set_req(1, proj2);
2616 register_node(reg, loop, iff, ddepth);
2617
2618 IfNode* dum_if = new IfNode(reg, short_circuit_if(NULL, proj), iff->_prob, iff->_fcnt);
2619 register_node(dum_if, loop, reg, ddepth);
2620
2621 proj->set_req(0, dum_if); // reattach
2622 set_idom(proj, dum_if, ddepth);
2623
2624 ProjNode* dum_proj = proj_clone(other_proj, dum_if);
2625 register_node(dum_proj, loop, dum_if, ddepth);
2626
2627 return reg;
2628 }
2629
2630 //------------------------------ insert_cmpi_loop_exit -------------------------------------
2631 // Clone a signed compare loop exit from an unsigned compare and
2632 // insert it before the unsigned cmp on the stay-in-loop path.
2633 // All new nodes inserted in the dominator tree between the original
2634 // if and it's projections. The original if test is replaced with
2635 // a constant to force the stay-in-loop path.
2636 //
2637 // This is done to make sure that the original if and it's projections
2638 // still dominate the same set of control nodes, that the ctrl() relation
2639 // from data nodes to them is preserved, and that their loop nesting is
2640 // preserved.
2641 //
2642 // before
2643 // if(i <u limit) unsigned compare loop exit
2644 // / |
2645 // v v
2646 // exit-proj stay-in-loop-proj
2647 //
2648 // after
2649 // if(stay-in-loop-const) original if
2650 // / |
2651 // / v
2652 // / if(i < limit) new signed test
2653 // / / |
2654 // / / v
2655 // / / if(i <u limit) new cloned unsigned test
2656 // / / / |
2657 // v v v |
2658 // region |
2659 // | |
2660 // dum-if |
2661 // / | |
2662 // ether | |
2663 // v v
2664 // exit-proj stay-in-loop-proj
2665 //
2666 IfNode* PhaseIdealLoop::insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *loop) {
2667 const bool Signed = true;
2668 const bool Unsigned = false;
2669
2670 BoolNode* bol = if_cmpu->in(1)->as_Bool();
2671 if (bol->_test._test != BoolTest::lt) return NULL;
2672 CmpNode* cmpu = bol->in(1)->as_Cmp();
2673 if (cmpu->Opcode() != Op_CmpU) return NULL;
2674 int stride = stride_of_possible_iv(if_cmpu);
2675 if (stride == 0) return NULL;
2676
2677 Node* lp_proj = stay_in_loop(if_cmpu, loop);
2678 guarantee(lp_proj != NULL, "null loop node");
2679
2680 ProjNode* lp_continue = lp_proj->as_Proj();
2681 ProjNode* lp_exit = if_cmpu->proj_out(!lp_continue->is_IfTrue())->as_Proj();
2682
2683 Node* limit = NULL;
2684 if (stride > 0) {
2685 limit = cmpu->in(2);
2686 } else {
2687 limit = _igvn.makecon(TypeInt::ZERO);
2688 set_ctrl(limit, C->root());
2689 }
2690 // Create a new region on the exit path
2691 RegionNode* reg = insert_region_before_proj(lp_exit);
2692 guarantee(reg != NULL, "null region node");
2693
2694 // Clone the if-cmpu-true-false using a signed compare
2695 BoolTest::mask rel_i = stride > 0 ? bol->_test._test : BoolTest::ge;
2696 ProjNode* cmpi_exit = insert_if_before_proj(cmpu->in(1), Signed, rel_i, limit, lp_continue);
2697 reg->add_req(cmpi_exit);
2698
2699 // Clone the if-cmpu-true-false
2700 BoolTest::mask rel_u = bol->_test._test;
2701 ProjNode* cmpu_exit = insert_if_before_proj(cmpu->in(1), Unsigned, rel_u, cmpu->in(2), lp_continue);
2702 reg->add_req(cmpu_exit);
2703
2704 // Force original if to stay in loop.
2705 short_circuit_if(if_cmpu, lp_continue);
2706
2707 return cmpi_exit->in(0)->as_If();
2708 }
2709
2710 //------------------------------ remove_cmpi_loop_exit -------------------------------------
2711 // Remove a previously inserted signed compare loop exit.
2712 void PhaseIdealLoop::remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop) {
2713 Node* lp_proj = stay_in_loop(if_cmp, loop);
2714 assert(if_cmp->in(1)->in(1)->Opcode() == Op_CmpI &&
2715 stay_in_loop(lp_proj, loop)->is_If() &&
2716 stay_in_loop(lp_proj, loop)->in(1)->in(1)->Opcode() == Op_CmpU, "inserted cmpi before cmpu");
2717 Node *con = _igvn.makecon(lp_proj->is_IfTrue() ? TypeInt::ONE : TypeInt::ZERO);
2718 set_ctrl(con, C->root());
2719 if_cmp->set_req(1, con);
2720 }
2721
2722 //------------------------------ scheduled_nodelist -------------------------------------
2723 // Create a post order schedule of nodes that are in the
2724 // "member" set. The list is returned in "sched".
2725 // The first node in "sched" is the loop head, followed by
2726 // nodes which have no inputs in the "member" set, and then
2727 // followed by the nodes that have an immediate input dependence
2728 // on a node in "sched".
2729 void PhaseIdealLoop::scheduled_nodelist( IdealLoopTree *loop, VectorSet& member, Node_List &sched ) {
2730
2731 assert(member.test(loop->_head->_idx), "loop head must be in member set");
2732 Arena *a = Thread::current()->resource_area();
2733 VectorSet visited(a);
2734 Node_Stack nstack(a, loop->_body.size());
2735
2736 Node* n = loop->_head; // top of stack is cached in "n"
2737 uint idx = 0;
2738 visited.set(n->_idx);
2739
2740 // Initially push all with no inputs from within member set
2741 for(uint i = 0; i < loop->_body.size(); i++ ) {
2742 Node *elt = loop->_body.at(i);
2743 if (member.test(elt->_idx)) {
2744 bool found = false;
2745 for (uint j = 0; j < elt->req(); j++) {
2746 Node* def = elt->in(j);
2747 if (def && member.test(def->_idx) && def != elt) {
2748 found = true;
2749 break;
2750 }
2751 }
2752 if (!found && elt != loop->_head) {
2753 nstack.push(n, idx);
2754 n = elt;
2755 assert(!visited.test(n->_idx), "not seen yet");
2756 visited.set(n->_idx);
2757 }
2758 }
2759 }
2760
2761 // traverse out's that are in the member set
2762 while (true) {
2763 if (idx < n->outcnt()) {
2764 Node* use = n->raw_out(idx);
2765 idx++;
2766 if (!visited.test_set(use->_idx)) {
2767 if (member.test(use->_idx)) {
2768 nstack.push(n, idx);
2769 n = use;
2770 idx = 0;
2771 }
2772 }
2773 } else {
2774 // All outputs processed
2775 sched.push(n);
2776 if (nstack.is_empty()) break;
2777 n = nstack.node();
2778 idx = nstack.index();
2779 nstack.pop();
2780 }
2781 }
2782 }
2783
2784
2785 //------------------------------ has_use_in_set -------------------------------------
2786 // Has a use in the vector set
2787 bool PhaseIdealLoop::has_use_in_set( Node* n, VectorSet& vset ) {
2788 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2789 Node* use = n->fast_out(j);
2790 if (vset.test(use->_idx)) {
2791 return true;
2792 }
2793 }
2794 return false;
2795 }
2796
2797
2798 //------------------------------ has_use_internal_to_set -------------------------------------
2799 // Has use internal to the vector set (ie. not in a phi at the loop head)
2800 bool PhaseIdealLoop::has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ) {
2801 Node* head = loop->_head;
2802 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2803 Node* use = n->fast_out(j);
2804 if (vset.test(use->_idx) && !(use->is_Phi() && use->in(0) == head)) {
2805 return true;
2806 }
2807 }
2808 return false;
2809 }
2810
2811
2812 //------------------------------ clone_for_use_outside_loop -------------------------------------
2813 // clone "n" for uses that are outside of loop
2814 int PhaseIdealLoop::clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ) {
2815 int cloned = 0;
2816 assert(worklist.size() == 0, "should be empty");
2817 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2818 Node* use = n->fast_out(j);
2819 if( !loop->is_member(get_loop(has_ctrl(use) ? get_ctrl(use) : use)) ) {
2820 worklist.push(use);
2821 }
2822 }
2823 while( worklist.size() ) {
2824 Node *use = worklist.pop();
2825 if (!has_node(use) || use->in(0) == C->top()) continue;
2826 uint j;
2827 for (j = 0; j < use->req(); j++) {
2828 if (use->in(j) == n) break;
2829 }
2830 assert(j < use->req(), "must be there");
2831
2832 // clone "n" and insert it between the inputs of "n" and the use outside the loop
2833 Node* n_clone = n->clone();
2834 _igvn.replace_input_of(use, j, n_clone);
2835 cloned++;
2836 Node* use_c;
2837 if (!use->is_Phi()) {
2838 use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0);
2839 } else {
2840 // Use in a phi is considered a use in the associated predecessor block
2841 use_c = use->in(0)->in(j);
2842 }
2843 set_ctrl(n_clone, use_c);
2844 assert(!loop->is_member(get_loop(use_c)), "should be outside loop");
2845 get_loop(use_c)->_body.push(n_clone);
2846 _igvn.register_new_node_with_optimizer(n_clone);
2847 #if !defined(PRODUCT)
2848 if (TracePartialPeeling) {
2849 tty->print_cr("loop exit cloning old: %d new: %d newbb: %d", n->_idx, n_clone->_idx, get_ctrl(n_clone)->_idx);
2850 }
2851 #endif
2852 }
2853 return cloned;
2854 }
2855
2856
2857 //------------------------------ clone_for_special_use_inside_loop -------------------------------------
2858 // clone "n" for special uses that are in the not_peeled region.
2859 // If these def-uses occur in separate blocks, the code generator
2860 // marks the method as not compilable. For example, if a "BoolNode"
2861 // is in a different basic block than the "IfNode" that uses it, then
2862 // the compilation is aborted in the code generator.
2863 void PhaseIdealLoop::clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n,
2864 VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ) {
2865 if (n->is_Phi() || n->is_Load()) {
2866 return;
2867 }
2868 assert(worklist.size() == 0, "should be empty");
2869 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2870 Node* use = n->fast_out(j);
2871 if ( not_peel.test(use->_idx) &&
2872 (use->is_If() || use->is_CMove() || use->is_Bool()) &&
2873 use->in(1) == n) {
2874 worklist.push(use);
2875 }
2876 }
2877 if (worklist.size() > 0) {
2878 // clone "n" and insert it between inputs of "n" and the use
2879 Node* n_clone = n->clone();
2880 loop->_body.push(n_clone);
2881 _igvn.register_new_node_with_optimizer(n_clone);
2882 set_ctrl(n_clone, get_ctrl(n));
2883 sink_list.push(n_clone);
2884 not_peel <<= n_clone->_idx; // add n_clone to not_peel set.
2885 #if !defined(PRODUCT)
2886 if (TracePartialPeeling) {
2887 tty->print_cr("special not_peeled cloning old: %d new: %d", n->_idx, n_clone->_idx);
2888 }
2889 #endif
2890 while( worklist.size() ) {
2891 Node *use = worklist.pop();
2892 _igvn.rehash_node_delayed(use);
2893 for (uint j = 1; j < use->req(); j++) {
2894 if (use->in(j) == n) {
2895 use->set_req(j, n_clone);
2896 }
2897 }
2898 }
2899 }
2900 }
2901
2902
2903 //------------------------------ insert_phi_for_loop -------------------------------------
2904 // Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist
2905 void PhaseIdealLoop::insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ) {
2906 Node *phi = PhiNode::make(lp, back_edge_val);
2907 phi->set_req(LoopNode::EntryControl, lp_entry_val);
2908 // Use existing phi if it already exists
2909 Node *hit = _igvn.hash_find_insert(phi);
2910 if( hit == NULL ) {
2911 _igvn.register_new_node_with_optimizer(phi);
2912 set_ctrl(phi, lp);
2913 } else {
2914 // Remove the new phi from the graph and use the hit
2915 _igvn.remove_dead_node(phi);
2916 phi = hit;
2917 }
2918 _igvn.replace_input_of(use, idx, phi);
2919 }
2920
2921 #ifdef ASSERT
2922 //------------------------------ is_valid_loop_partition -------------------------------------
2923 // Validate the loop partition sets: peel and not_peel
2924 bool PhaseIdealLoop::is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list,
2925 VectorSet& not_peel ) {
2926 uint i;
2927 // Check that peel_list entries are in the peel set
2928 for (i = 0; i < peel_list.size(); i++) {
2929 if (!peel.test(peel_list.at(i)->_idx)) {
2930 return false;
2931 }
2932 }
2933 // Check at loop members are in one of peel set or not_peel set
2934 for (i = 0; i < loop->_body.size(); i++ ) {
2935 Node *def = loop->_body.at(i);
2936 uint di = def->_idx;
2937 // Check that peel set elements are in peel_list
2938 if (peel.test(di)) {
2939 if (not_peel.test(di)) {
2940 return false;
2941 }
2942 // Must be in peel_list also
2943 bool found = false;
2944 for (uint j = 0; j < peel_list.size(); j++) {
2945 if (peel_list.at(j)->_idx == di) {
2946 found = true;
2947 break;
2948 }
2949 }
2950 if (!found) {
2951 return false;
2952 }
2953 } else if (not_peel.test(di)) {
2954 if (peel.test(di)) {
2955 return false;
2956 }
2957 } else {
2958 return false;
2959 }
2960 }
2961 return true;
2962 }
2963
2964 //------------------------------ is_valid_clone_loop_exit_use -------------------------------------
2965 // Ensure a use outside of loop is of the right form
2966 bool PhaseIdealLoop::is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx) {
2967 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use;
2968 return (use->is_Phi() &&
2969 use_c->is_Region() && use_c->req() == 3 &&
2970 (use_c->in(exit_idx)->Opcode() == Op_IfTrue ||
2971 use_c->in(exit_idx)->Opcode() == Op_IfFalse ||
2972 use_c->in(exit_idx)->Opcode() == Op_JumpProj) &&
2973 loop->is_member( get_loop( use_c->in(exit_idx)->in(0) ) ) );
2974 }
2975
2976 //------------------------------ is_valid_clone_loop_form -------------------------------------
2977 // Ensure that all uses outside of loop are of the right form
2978 bool PhaseIdealLoop::is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list,
2979 uint orig_exit_idx, uint clone_exit_idx) {
2980 uint len = peel_list.size();
2981 for (uint i = 0; i < len; i++) {
2982 Node *def = peel_list.at(i);
2983
2984 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
2985 Node *use = def->fast_out(j);
2986 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use;
2987 if (!loop->is_member(get_loop(use_c))) {
2988 // use is not in the loop, check for correct structure
2989 if (use->in(0) == def) {
2990 // Okay
2991 } else if (!is_valid_clone_loop_exit_use(loop, use, orig_exit_idx)) {
2992 return false;
2993 }
2994 }
2995 }
2996 }
2997 return true;
2998 }
2999 #endif
3000
3001 //------------------------------ partial_peel -------------------------------------
3002 // Partially peel (aka loop rotation) the top portion of a loop (called
3003 // the peel section below) by cloning it and placing one copy just before
3004 // the new loop head and the other copy at the bottom of the new loop.
3005 //
3006 // before after where it came from
3007 //
3008 // stmt1 stmt1
3009 // loop: stmt2 clone
3010 // stmt2 if condA goto exitA clone
3011 // if condA goto exitA new_loop: new
3012 // stmt3 stmt3 clone
3013 // if !condB goto loop if condB goto exitB clone
3014 // exitB: stmt2 orig
3015 // stmt4 if !condA goto new_loop orig
3016 // exitA: goto exitA
3017 // exitB:
3018 // stmt4
3019 // exitA:
3020 //
3021 // Step 1: find the cut point: an exit test on probable
3022 // induction variable.
3023 // Step 2: schedule (with cloning) operations in the peel
3024 // section that can be executed after the cut into
3025 // the section that is not peeled. This may need
3026 // to clone operations into exit blocks. For
3027 // instance, a reference to A[i] in the not-peel
3028 // section and a reference to B[i] in an exit block
3029 // may cause a left-shift of i by 2 to be placed
3030 // in the peel block. This step will clone the left
3031 // shift into the exit block and sink the left shift
3032 // from the peel to the not-peel section.
3033 // Step 3: clone the loop, retarget the control, and insert
3034 // phis for values that are live across the new loop
3035 // head. This is very dependent on the graph structure
3036 // from clone_loop. It creates region nodes for
3037 // exit control and associated phi nodes for values
3038 // flow out of the loop through that exit. The region
3039 // node is dominated by the clone's control projection.
3040 // So the clone's peel section is placed before the
3041 // new loop head, and the clone's not-peel section is
3042 // forms the top part of the new loop. The original
3043 // peel section forms the tail of the new loop.
3044 // Step 4: update the dominator tree and recompute the
3045 // dominator depth.
3046 //
3047 // orig
3048 //
3049 // stmt1
3050 // |
3051 // v
3052 // loop predicate
3053 // |
3054 // v
3055 // loop<----+
3056 // | |
3057 // stmt2 |
3058 // | |
3059 // v |
3060 // ifA |
3061 // / | |
3062 // v v |
3063 // false true ^ <-- last_peel
3064 // / | |
3065 // / ===|==cut |
3066 // / stmt3 | <-- first_not_peel
3067 // / | |
3068 // | v |
3069 // v ifB |
3070 // exitA: / \ |
3071 // / \ |
3072 // v v |
3073 // false true |
3074 // / \ |
3075 // / ----+
3076 // |
3077 // v
3078 // exitB:
3079 // stmt4
3080 //
3081 //
3082 // after clone loop
3083 //
3084 // stmt1
3085 // |
3086 // v
3087 // loop predicate
3088 // / \
3089 // clone / \ orig
3090 // / \
3091 // / \
3092 // v v
3093 // +---->loop loop<----+
3094 // | | | |
3095 // | stmt2 stmt2 |
3096 // | | | |
3097 // | v v |
3098 // | ifA ifA |
3099 // | | \ / | |
3100 // | v v v v |
3101 // ^ true false false true ^ <-- last_peel
3102 // | | ^ \ / | |
3103 // | cut==|== \ \ / ===|==cut |
3104 // | stmt3 \ \ / stmt3 | <-- first_not_peel
3105 // | | dom | | | |
3106 // | v \ 1v v2 v |
3107 // | ifB regionA ifB |
3108 // | / \ | / \ |
3109 // | / \ v / \ |
3110 // | v v exitA: v v |
3111 // | true false false true |
3112 // | / ^ \ / \ |
3113 // +---- \ \ / ----+
3114 // dom \ /
3115 // \ 1v v2
3116 // regionB
3117 // |
3118 // v
3119 // exitB:
3120 // stmt4
3121 //
3122 //
3123 // after partial peel
3124 //
3125 // stmt1
3126 // |
3127 // v
3128 // loop predicate
3129 // /
3130 // clone / orig
3131 // / TOP
3132 // / \
3133 // v v
3134 // TOP->loop loop----+
3135 // | | |
3136 // stmt2 stmt2 |
3137 // | | |
3138 // v v |
3139 // ifA ifA |
3140 // | \ / | |
3141 // v v v v |
3142 // true false false true | <-- last_peel
3143 // | ^ \ / +------|---+
3144 // +->newloop \ \ / === ==cut | |
3145 // | stmt3 \ \ / TOP | |
3146 // | | dom | | stmt3 | | <-- first_not_peel
3147 // | v \ 1v v2 v | |
3148 // | ifB regionA ifB ^ v
3149 // | / \ | / \ | |
3150 // | / \ v / \ | |
3151 // | v v exitA: v v | |
3152 // | true false false true | |
3153 // | / ^ \ / \ | |
3154 // | | \ \ / v | |
3155 // | | dom \ / TOP | |
3156 // | | \ 1v v2 | |
3157 // ^ v regionB | |
3158 // | | | | |
3159 // | | v ^ v
3160 // | | exitB: | |
3161 // | | stmt4 | |
3162 // | +------------>-----------------+ |
3163 // | |
3164 // +-----------------<---------------------+
3165 //
3166 //
3167 // final graph
3168 //
3169 // stmt1
3170 // |
3171 // v
3172 // loop predicate
3173 // |
3174 // v
3175 // stmt2 clone
3176 // |
3177 // v
3178 // ........> ifA clone
3179 // : / |
3180 // dom / |
3181 // : v v
3182 // : false true
3183 // : | |
3184 // : | v
3185 // : | newloop<-----+
3186 // : | | |
3187 // : | stmt3 clone |
3188 // : | | |
3189 // : | v |
3190 // : | ifB |
3191 // : | / \ |
3192 // : | v v |
3193 // : | false true |
3194 // : | | | |
3195 // : | v stmt2 |
3196 // : | exitB: | |
3197 // : | stmt4 v |
3198 // : | ifA orig |
3199 // : | / \ |
3200 // : | / \ |
3201 // : | v v |
3202 // : | false true |
3203 // : | / \ |
3204 // : v v -----+
3205 // RegionA
3206 // |
3207 // v
3208 // exitA
3209 //
3210 bool PhaseIdealLoop::partial_peel( IdealLoopTree *loop, Node_List &old_new ) {
3211
3212 assert(!loop->_head->is_CountedLoop(), "Non-counted loop only");
3213 if (!loop->_head->is_Loop()) {
3214 return false; }
3215
3216 LoopNode *head = loop->_head->as_Loop();
3217
3218 if (head->is_partial_peel_loop() || head->partial_peel_has_failed()) {
3219 return false;
3220 }
3221
3222 // Check for complex exit control
3223 for(uint ii = 0; ii < loop->_body.size(); ii++ ) {
3224 Node *n = loop->_body.at(ii);
3225 int opc = n->Opcode();
3226 if (n->is_Call() ||
3227 opc == Op_Catch ||
3228 opc == Op_CatchProj ||
3229 opc == Op_Jump ||
3230 opc == Op_JumpProj) {
3231 #if !defined(PRODUCT)
3232 if (TracePartialPeeling) {
3233 tty->print_cr("\nExit control too complex: lp: %d", head->_idx);
3234 }
3235 #endif
3236 return false;
3237 }
3238 }
3239
3240 int dd = dom_depth(head);
3241
3242 // Step 1: find cut point
3243
3244 // Walk up dominators to loop head looking for first loop exit
3245 // which is executed on every path thru loop.
3246 IfNode *peel_if = NULL;
3247 IfNode *peel_if_cmpu = NULL;
3248
3249 Node *iff = loop->tail();
3250 while( iff != head ) {
3251 if( iff->is_If() ) {
3252 Node *ctrl = get_ctrl(iff->in(1));
3253 if (ctrl->is_top()) return false; // Dead test on live IF.
3254 // If loop-varying exit-test, check for induction variable
3255 if( loop->is_member(get_loop(ctrl)) &&
3256 loop->is_loop_exit(iff) &&
3257 is_possible_iv_test(iff)) {
3258 Node* cmp = iff->in(1)->in(1);
3259 if (cmp->Opcode() == Op_CmpI) {
3260 peel_if = iff->as_If();
3261 } else {
3262 assert(cmp->Opcode() == Op_CmpU, "must be CmpI or CmpU");
3263 peel_if_cmpu = iff->as_If();
3264 }
3265 }
3266 }
3267 iff = idom(iff);
3268 }
3269 // Prefer signed compare over unsigned compare.
3270 IfNode* new_peel_if = NULL;
3271 if (peel_if == NULL) {
3272 if (!PartialPeelAtUnsignedTests || peel_if_cmpu == NULL) {
3273 return false; // No peel point found
3274 }
3275 new_peel_if = insert_cmpi_loop_exit(peel_if_cmpu, loop);
3276 if (new_peel_if == NULL) {
3277 return false; // No peel point found
3278 }
3279 peel_if = new_peel_if;
3280 }
3281 Node* last_peel = stay_in_loop(peel_if, loop);
3282 Node* first_not_peeled = stay_in_loop(last_peel, loop);
3283 if (first_not_peeled == NULL || first_not_peeled == head) {
3284 return false;
3285 }
3286
3287 #if !defined(PRODUCT)
3288 if (TraceLoopOpts) {
3289 tty->print("PartialPeel ");
3290 loop->dump_head();
3291 }
3292
3293 if (TracePartialPeeling) {
3294 tty->print_cr("before partial peel one iteration");
3295 Node_List wl;
3296 Node* t = head->in(2);
3297 while (true) {
3298 wl.push(t);
3299 if (t == head) break;
3300 t = idom(t);
3301 }
3302 while (wl.size() > 0) {
3303 Node* tt = wl.pop();
3304 tt->dump();
3305 if (tt == last_peel) tty->print_cr("-- cut --");
3306 }
3307 }
3308 #endif
3309 ResourceArea *area = Thread::current()->resource_area();
3310 VectorSet peel(area);
3311 VectorSet not_peel(area);
3312 Node_List peel_list(area);
3313 Node_List worklist(area);
3314 Node_List sink_list(area);
3315
3316 // Set of cfg nodes to peel are those that are executable from
3317 // the head through last_peel.
3318 assert(worklist.size() == 0, "should be empty");
3319 worklist.push(head);
3320 peel.set(head->_idx);
3321 while (worklist.size() > 0) {
3322 Node *n = worklist.pop();
3323 if (n != last_peel) {
3324 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3325 Node* use = n->fast_out(j);
3326 if (use->is_CFG() &&
3327 loop->is_member(get_loop(use)) &&
3328 !peel.test_set(use->_idx)) {
3329 worklist.push(use);
3330 }
3331 }
3332 }
3333 }
3334
3335 // Set of non-cfg nodes to peel are those that are control
3336 // dependent on the cfg nodes.
3337 uint i;
3338 for(i = 0; i < loop->_body.size(); i++ ) {
3339 Node *n = loop->_body.at(i);
3340 Node *n_c = has_ctrl(n) ? get_ctrl(n) : n;
3341 if (peel.test(n_c->_idx)) {
3342 peel.set(n->_idx);
3343 } else {
3344 not_peel.set(n->_idx);
3345 }
3346 }
3347
3348 // Step 2: move operations from the peeled section down into the
3349 // not-peeled section
3350
3351 // Get a post order schedule of nodes in the peel region
3352 // Result in right-most operand.
3353 scheduled_nodelist(loop, peel, peel_list );
3354
3355 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition");
3356
3357 // For future check for too many new phis
3358 uint old_phi_cnt = 0;
3359 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) {
3360 Node* use = head->fast_out(j);
3361 if (use->is_Phi()) old_phi_cnt++;
3362 }
3363
3364 #if !defined(PRODUCT)
3365 if (TracePartialPeeling) {
3366 tty->print_cr("\npeeled list");
3367 }
3368 #endif
3369
3370 // Evacuate nodes in peel region into the not_peeled region if possible
3371 uint new_phi_cnt = 0;
3372 uint cloned_for_outside_use = 0;
3373 for (i = 0; i < peel_list.size();) {
3374 Node* n = peel_list.at(i);
3375 #if !defined(PRODUCT)
3376 if (TracePartialPeeling) n->dump();
3377 #endif
3378 bool incr = true;
3379 if ( !n->is_CFG() ) {
3380
3381 if ( has_use_in_set(n, not_peel) ) {
3382
3383 // If not used internal to the peeled region,
3384 // move "n" from peeled to not_peeled region.
3385
3386 if ( !has_use_internal_to_set(n, peel, loop) ) {
3387
3388 // if not pinned and not a load (which maybe anti-dependent on a store)
3389 // and not a CMove (Matcher expects only bool->cmove).
3390 if ( n->in(0) == NULL && !n->is_Load() && !n->is_CMove() ) {
3391 cloned_for_outside_use += clone_for_use_outside_loop( loop, n, worklist );
3392 sink_list.push(n);
3393 peel >>= n->_idx; // delete n from peel set.
3394 not_peel <<= n->_idx; // add n to not_peel set.
3395 peel_list.remove(i);
3396 incr = false;
3397 #if !defined(PRODUCT)
3398 if (TracePartialPeeling) {
3399 tty->print_cr("sink to not_peeled region: %d newbb: %d",
3400 n->_idx, get_ctrl(n)->_idx);
3401 }
3402 #endif
3403 }
3404 } else {
3405 // Otherwise check for special def-use cases that span
3406 // the peel/not_peel boundary such as bool->if
3407 clone_for_special_use_inside_loop( loop, n, not_peel, sink_list, worklist );
3408 new_phi_cnt++;
3409 }
3410 }
3411 }
3412 if (incr) i++;
3413 }
3414
3415 if (new_phi_cnt > old_phi_cnt + PartialPeelNewPhiDelta) {
3416 #if !defined(PRODUCT)
3417 if (TracePartialPeeling) {
3418 tty->print_cr("\nToo many new phis: %d old %d new cmpi: %c",
3419 new_phi_cnt, old_phi_cnt, new_peel_if != NULL?'T':'F');
3420 }
3421 #endif
3422 if (new_peel_if != NULL) {
3423 remove_cmpi_loop_exit(new_peel_if, loop);
3424 }
3425 // Inhibit more partial peeling on this loop
3426 assert(!head->is_partial_peel_loop(), "not partial peeled");
3427 head->mark_partial_peel_failed();
3428 if (cloned_for_outside_use > 0) {
3429 // Terminate this round of loop opts because
3430 // the graph outside this loop was changed.
3431 C->set_major_progress();
3432 return true;
3433 }
3434 return false;
3435 }
3436
3437 // Step 3: clone loop, retarget control, and insert new phis
3438
3439 // Create new loop head for new phis and to hang
3440 // the nodes being moved (sinked) from the peel region.
3441 LoopNode* new_head = new LoopNode(last_peel, last_peel);
3442 new_head->set_unswitch_count(head->unswitch_count()); // Preserve
3443 _igvn.register_new_node_with_optimizer(new_head);
3444 assert(first_not_peeled->in(0) == last_peel, "last_peel <- first_not_peeled");
3445 _igvn.replace_input_of(first_not_peeled, 0, new_head);
3446 set_loop(new_head, loop);
3447 loop->_body.push(new_head);
3448 not_peel.set(new_head->_idx);
3449 set_idom(new_head, last_peel, dom_depth(first_not_peeled));
3450 set_idom(first_not_peeled, new_head, dom_depth(first_not_peeled));
3451
3452 while (sink_list.size() > 0) {
3453 Node* n = sink_list.pop();
3454 set_ctrl(n, new_head);
3455 }
3456
3457 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition");
3458
3459 clone_loop(loop, old_new, dd, IgnoreStripMined);
3460
3461 const uint clone_exit_idx = 1;
3462 const uint orig_exit_idx = 2;
3463 assert(is_valid_clone_loop_form( loop, peel_list, orig_exit_idx, clone_exit_idx ), "bad clone loop");
3464
3465 Node* head_clone = old_new[head->_idx];
3466 LoopNode* new_head_clone = old_new[new_head->_idx]->as_Loop();
3467 Node* orig_tail_clone = head_clone->in(2);
3468
3469 // Add phi if "def" node is in peel set and "use" is not
3470
3471 for(i = 0; i < peel_list.size(); i++ ) {
3472 Node *def = peel_list.at(i);
3473 if (!def->is_CFG()) {
3474 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
3475 Node *use = def->fast_out(j);
3476 if (has_node(use) && use->in(0) != C->top() &&
3477 (!peel.test(use->_idx) ||
3478 (use->is_Phi() && use->in(0) == head)) ) {
3479 worklist.push(use);
3480 }
3481 }
3482 while( worklist.size() ) {
3483 Node *use = worklist.pop();
3484 for (uint j = 1; j < use->req(); j++) {
3485 Node* n = use->in(j);
3486 if (n == def) {
3487
3488 // "def" is in peel set, "use" is not in peel set
3489 // or "use" is in the entry boundary (a phi) of the peel set
3490
3491 Node* use_c = has_ctrl(use) ? get_ctrl(use) : use;
3492
3493 if ( loop->is_member(get_loop( use_c )) ) {
3494 // use is in loop
3495 if (old_new[use->_idx] != NULL) { // null for dead code
3496 Node* use_clone = old_new[use->_idx];
3497 _igvn.replace_input_of(use, j, C->top());
3498 insert_phi_for_loop( use_clone, j, old_new[def->_idx], def, new_head_clone );
3499 }
3500 } else {
3501 assert(is_valid_clone_loop_exit_use(loop, use, orig_exit_idx), "clone loop format");
3502 // use is not in the loop, check if the live range includes the cut
3503 Node* lp_if = use_c->in(orig_exit_idx)->in(0);
3504 if (not_peel.test(lp_if->_idx)) {
3505 assert(j == orig_exit_idx, "use from original loop");
3506 insert_phi_for_loop( use, clone_exit_idx, old_new[def->_idx], def, new_head_clone );
3507 }
3508 }
3509 }
3510 }
3511 }
3512 }
3513 }
3514
3515 // Step 3b: retarget control
3516
3517 // Redirect control to the new loop head if a cloned node in
3518 // the not_peeled region has control that points into the peeled region.
3519 // This necessary because the cloned peeled region will be outside
3520 // the loop.
3521 // from to
3522 // cloned-peeled <---+
3523 // new_head_clone: | <--+
3524 // cloned-not_peeled in(0) in(0)
3525 // orig-peeled
3526
3527 for(i = 0; i < loop->_body.size(); i++ ) {
3528 Node *n = loop->_body.at(i);
3529 if (!n->is_CFG() && n->in(0) != NULL &&
3530 not_peel.test(n->_idx) && peel.test(n->in(0)->_idx)) {
3531 Node* n_clone = old_new[n->_idx];
3532 _igvn.replace_input_of(n_clone, 0, new_head_clone);
3533 }
3534 }
3535
3536 // Backedge of the surviving new_head (the clone) is original last_peel
3537 _igvn.replace_input_of(new_head_clone, LoopNode::LoopBackControl, last_peel);
3538
3539 // Cut first node in original not_peel set
3540 _igvn.rehash_node_delayed(new_head); // Multiple edge updates:
3541 new_head->set_req(LoopNode::EntryControl, C->top()); // use rehash_node_delayed / set_req instead of
3542 new_head->set_req(LoopNode::LoopBackControl, C->top()); // multiple replace_input_of calls
3543
3544 // Copy head_clone back-branch info to original head
3545 // and remove original head's loop entry and
3546 // clone head's back-branch
3547 _igvn.rehash_node_delayed(head); // Multiple edge updates
3548 head->set_req(LoopNode::EntryControl, head_clone->in(LoopNode::LoopBackControl));
3549 head->set_req(LoopNode::LoopBackControl, C->top());
3550 _igvn.replace_input_of(head_clone, LoopNode::LoopBackControl, C->top());
3551
3552 // Similarly modify the phis
3553 for (DUIterator_Fast kmax, k = head->fast_outs(kmax); k < kmax; k++) {
3554 Node* use = head->fast_out(k);
3555 if (use->is_Phi() && use->outcnt() > 0) {
3556 Node* use_clone = old_new[use->_idx];
3557 _igvn.rehash_node_delayed(use); // Multiple edge updates
3558 use->set_req(LoopNode::EntryControl, use_clone->in(LoopNode::LoopBackControl));
3559 use->set_req(LoopNode::LoopBackControl, C->top());
3560 _igvn.replace_input_of(use_clone, LoopNode::LoopBackControl, C->top());
3561 }
3562 }
3563
3564 // Step 4: update dominator tree and dominator depth
3565
3566 set_idom(head, orig_tail_clone, dd);
3567 recompute_dom_depth();
3568
3569 // Inhibit more partial peeling on this loop
3570 new_head_clone->set_partial_peel_loop();
3571 C->set_major_progress();
3572 loop->record_for_igvn();
3573
3574 #if !defined(PRODUCT)
3575 if (TracePartialPeeling) {
3576 tty->print_cr("\nafter partial peel one iteration");
3577 Node_List wl(area);
3578 Node* t = last_peel;
3579 while (true) {
3580 wl.push(t);
3581 if (t == head_clone) break;
3582 t = idom(t);
3583 }
3584 while (wl.size() > 0) {
3585 Node* tt = wl.pop();
3586 if (tt == head) tty->print_cr("orig head");
3587 else if (tt == new_head_clone) tty->print_cr("new head");
3588 else if (tt == head_clone) tty->print_cr("clone head");
3589 tt->dump();
3590 }
3591 }
3592 #endif
3593 return true;
3594 }
3595
3596 //------------------------------reorg_offsets----------------------------------
3597 // Reorganize offset computations to lower register pressure. Mostly
3598 // prevent loop-fallout uses of the pre-incremented trip counter (which are
3599 // then alive with the post-incremented trip counter forcing an extra
3600 // register move)
3601 void PhaseIdealLoop::reorg_offsets(IdealLoopTree *loop) {
3602 // Perform it only for canonical counted loops.
3603 // Loop's shape could be messed up by iteration_split_impl.
3604 if (!loop->_head->is_CountedLoop())
3605 return;
3606 if (!loop->_head->as_Loop()->is_valid_counted_loop())
3607 return;
3608
3609 CountedLoopNode *cl = loop->_head->as_CountedLoop();
3610 CountedLoopEndNode *cle = cl->loopexit();
3611 Node *exit = cle->proj_out(false);
3612 Node *phi = cl->phi();
3613
3614 // Check for the special case of folks using the pre-incremented
3615 // trip-counter on the fall-out path (forces the pre-incremented
3616 // and post-incremented trip counter to be live at the same time).
3617 // Fix this by adjusting to use the post-increment trip counter.
3618
3619 bool progress = true;
3620 while (progress) {
3621 progress = false;
3622 for (DUIterator_Fast imax, i = phi->fast_outs(imax); i < imax; i++) {
3623 Node* use = phi->fast_out(i); // User of trip-counter
3624 if (!has_ctrl(use)) continue;
3625 Node *u_ctrl = get_ctrl(use);
3626 if (use->is_Phi()) {
3627 u_ctrl = NULL;
3628 for (uint j = 1; j < use->req(); j++)
3629 if (use->in(j) == phi)
3630 u_ctrl = dom_lca(u_ctrl, use->in(0)->in(j));
3631 }
3632 IdealLoopTree *u_loop = get_loop(u_ctrl);
3633 // Look for loop-invariant use
3634 if (u_loop == loop) continue;
3635 if (loop->is_member(u_loop)) continue;
3636 // Check that use is live out the bottom. Assuming the trip-counter
3637 // update is right at the bottom, uses of of the loop middle are ok.
3638 if (dom_lca(exit, u_ctrl) != exit) continue;
3639 // Hit! Refactor use to use the post-incremented tripcounter.
3640 // Compute a post-increment tripcounter.
3641 Node *opaq = new Opaque2Node( C, cle->incr() );
3642 register_new_node(opaq, exit);
3643 Node *neg_stride = _igvn.intcon(-cle->stride_con());
3644 set_ctrl(neg_stride, C->root());
3645 Node *post = new AddINode( opaq, neg_stride);
3646 register_new_node(post, exit);
3647 _igvn.rehash_node_delayed(use);
3648 for (uint j = 1; j < use->req(); j++) {
3649 if (use->in(j) == phi)
3650 use->set_req(j, post);
3651 }
3652 // Since DU info changed, rerun loop
3653 progress = true;
3654 break;
3655 }
3656 }
3657
3658 }