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 "gc/shared/barrierSet.hpp"
27 #include "gc/shared/c2/barrierSetC2.hpp"
28 #include "memory/allocation.inline.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "opto/addnode.hpp"
31 #include "opto/callnode.hpp"
32 #include "opto/castnode.hpp"
33 #include "opto/connode.hpp"
34 #include "opto/castnode.hpp"
35 #include "opto/divnode.hpp"
36 #include "opto/loopnode.hpp"
37 #include "opto/matcher.hpp"
38 #include "opto/mulnode.hpp"
39 #include "opto/movenode.hpp"
40 #include "opto/opaquenode.hpp"
41 #include "opto/rootnode.hpp"
42 #include "opto/subnode.hpp"
43
44 //=============================================================================
45 //------------------------------split_thru_phi---------------------------------
46 // Split Node 'n' through merge point if there is enough win.
47 Node *PhaseIdealLoop::split_thru_phi( Node *n, Node *region, int policy ) {
48 if (n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::LONG) {
49 // ConvI2L may have type information on it which is unsafe to push up
50 // so disable this for now
51 return NULL;
52 }
53
54 // Splitting range check CastIIs through a loop induction Phi can
55 // cause new Phis to be created that are left unrelated to the loop
56 // induction Phi and prevent optimizations (vectorization)
57 if (n->Opcode() == Op_CastII && n->as_CastII()->has_range_check() &&
58 region->is_CountedLoop() && n->in(1) == region->as_CountedLoop()->phi()) {
59 return NULL;
60 }
61
62 int wins = 0;
63 assert(!n->is_CFG(), "");
64 assert(region->is_Region(), "");
65
66 const Type* type = n->bottom_type();
67 const TypeOopPtr *t_oop = _igvn.type(n)->isa_oopptr();
68 Node *phi;
69 if (t_oop != NULL && t_oop->is_known_instance_field()) {
70 int iid = t_oop->instance_id();
71 int index = C->get_alias_index(t_oop);
72 int offset = t_oop->offset();
73 phi = new PhiNode(region, type, NULL, iid, index, offset);
74 } else {
75 phi = PhiNode::make_blank(region, n);
76 }
77 uint old_unique = C->unique();
78 for (uint i = 1; i < region->req(); i++) {
79 Node *x;
80 Node* the_clone = NULL;
81 if (region->in(i) == C->top()) {
82 x = C->top(); // Dead path? Use a dead data op
83 } else {
84 x = n->clone(); // Else clone up the data op
85 the_clone = x; // Remember for possible deletion.
86 // Alter data node to use pre-phi inputs
87 if (n->in(0) == region)
88 x->set_req( 0, region->in(i) );
89 for (uint j = 1; j < n->req(); j++) {
90 Node *in = n->in(j);
91 if (in->is_Phi() && in->in(0) == region)
92 x->set_req( j, in->in(i) ); // Use pre-Phi input for the clone
93 }
94 }
95 // Check for a 'win' on some paths
96 const Type *t = x->Value(&_igvn);
97
98 bool singleton = t->singleton();
99
100 // A TOP singleton indicates that there are no possible values incoming
101 // along a particular edge. In most cases, this is OK, and the Phi will
102 // be eliminated later in an Ideal call. However, we can't allow this to
103 // happen if the singleton occurs on loop entry, as the elimination of
104 // the PhiNode may cause the resulting node to migrate back to a previous
105 // loop iteration.
106 if (singleton && t == Type::TOP) {
107 // Is_Loop() == false does not confirm the absence of a loop (e.g., an
108 // irreducible loop may not be indicated by an affirmative is_Loop());
109 // therefore, the only top we can split thru a phi is on a backedge of
110 // a loop.
111 singleton &= region->is_Loop() && (i != LoopNode::EntryControl);
112 }
113
114 if (singleton) {
115 wins++;
116 x = ((PhaseGVN&)_igvn).makecon(t);
117 } else {
118 // We now call Identity to try to simplify the cloned node.
119 // Note that some Identity methods call phase->type(this).
120 // Make sure that the type array is big enough for
121 // our new node, even though we may throw the node away.
122 // (Note: This tweaking with igvn only works because x is a new node.)
123 _igvn.set_type(x, t);
124 // If x is a TypeNode, capture any more-precise type permanently into Node
125 // otherwise it will be not updated during igvn->transform since
126 // igvn->type(x) is set to x->Value() already.
127 x->raise_bottom_type(t);
128 Node *y = x->Identity(&_igvn);
129 if (y != x) {
130 wins++;
131 x = y;
132 } else {
133 y = _igvn.hash_find(x);
134 if (y) {
135 wins++;
136 x = y;
137 } else {
138 // Else x is a new node we are keeping
139 // We do not need register_new_node_with_optimizer
140 // because set_type has already been called.
141 _igvn._worklist.push(x);
142 }
143 }
144 }
145 if (x != the_clone && the_clone != NULL)
146 _igvn.remove_dead_node(the_clone);
147 phi->set_req( i, x );
148 }
149 // Too few wins?
150 if (wins <= policy) {
151 _igvn.remove_dead_node(phi);
152 return NULL;
153 }
154
155 // Record Phi
156 register_new_node( phi, region );
157
158 for (uint i2 = 1; i2 < phi->req(); i2++) {
159 Node *x = phi->in(i2);
160 // If we commoned up the cloned 'x' with another existing Node,
161 // the existing Node picks up a new use. We need to make the
162 // existing Node occur higher up so it dominates its uses.
163 Node *old_ctrl;
164 IdealLoopTree *old_loop;
165
166 if (x->is_Con()) {
167 // Constant's control is always root.
168 set_ctrl(x, C->root());
169 continue;
170 }
171 // The occasional new node
172 if (x->_idx >= old_unique) { // Found a new, unplaced node?
173 old_ctrl = NULL;
174 old_loop = NULL; // Not in any prior loop
175 } else {
176 old_ctrl = get_ctrl(x);
177 old_loop = get_loop(old_ctrl); // Get prior loop
178 }
179 // New late point must dominate new use
180 Node *new_ctrl = dom_lca(old_ctrl, region->in(i2));
181 if (new_ctrl == old_ctrl) // Nothing is changed
182 continue;
183
184 IdealLoopTree *new_loop = get_loop(new_ctrl);
185
186 // Don't move x into a loop if its uses are
187 // outside of loop. Otherwise x will be cloned
188 // for each use outside of this loop.
189 IdealLoopTree *use_loop = get_loop(region);
190 if (!new_loop->is_member(use_loop) &&
191 (old_loop == NULL || !new_loop->is_member(old_loop))) {
192 // Take early control, later control will be recalculated
193 // during next iteration of loop optimizations.
194 new_ctrl = get_early_ctrl(x);
195 new_loop = get_loop(new_ctrl);
196 }
197 // Set new location
198 set_ctrl(x, new_ctrl);
199 // If changing loop bodies, see if we need to collect into new body
200 if (old_loop != new_loop) {
201 if (old_loop && !old_loop->_child)
202 old_loop->_body.yank(x);
203 if (!new_loop->_child)
204 new_loop->_body.push(x); // Collect body info
205 }
206 }
207
208 return phi;
209 }
210
211 //------------------------------dominated_by------------------------------------
212 // Replace the dominated test with an obvious true or false. Place it on the
213 // IGVN worklist for later cleanup. Move control-dependent data Nodes on the
214 // live path up to the dominating control.
215 void PhaseIdealLoop::dominated_by( Node *prevdom, Node *iff, bool flip, bool exclude_loop_predicate ) {
216 if (VerifyLoopOptimizations && PrintOpto) { tty->print_cr("dominating test"); }
217
218 // prevdom is the dominating projection of the dominating test.
219 assert( iff->is_If(), "" );
220 assert(iff->Opcode() == Op_If || iff->Opcode() == Op_CountedLoopEnd || iff->Opcode() == Op_RangeCheck, "Check this code when new subtype is added");
221 int pop = prevdom->Opcode();
222 assert( pop == Op_IfFalse || pop == Op_IfTrue, "" );
223 if (flip) {
224 if (pop == Op_IfTrue)
225 pop = Op_IfFalse;
226 else
227 pop = Op_IfTrue;
228 }
229 // 'con' is set to true or false to kill the dominated test.
230 Node *con = _igvn.makecon(pop == Op_IfTrue ? TypeInt::ONE : TypeInt::ZERO);
231 set_ctrl(con, C->root()); // Constant gets a new use
232 // Hack the dominated test
233 _igvn.replace_input_of(iff, 1, con);
234
235 // If I dont have a reachable TRUE and FALSE path following the IfNode then
236 // I can assume this path reaches an infinite loop. In this case it's not
237 // important to optimize the data Nodes - either the whole compilation will
238 // be tossed or this path (and all data Nodes) will go dead.
239 if (iff->outcnt() != 2) return;
240
241 // Make control-dependent data Nodes on the live path (path that will remain
242 // once the dominated IF is removed) become control-dependent on the
243 // dominating projection.
244 Node* dp = iff->as_If()->proj_out_or_null(pop == Op_IfTrue);
245
246 // Loop predicates may have depending checks which should not
247 // be skipped. For example, range check predicate has two checks
248 // for lower and upper bounds.
249 if (dp == NULL)
250 return;
251
252 ProjNode* dp_proj = dp->as_Proj();
253 ProjNode* unc_proj = iff->as_If()->proj_out(1 - dp_proj->_con)->as_Proj();
254 if (exclude_loop_predicate &&
255 (unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_predicate) != NULL ||
256 unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_range_check) != NULL)) {
257 // If this is a range check (IfNode::is_range_check), do not
258 // reorder because Compile::allow_range_check_smearing might have
259 // changed the check.
260 return; // Let IGVN transformation change control dependence.
261 }
262
263 IdealLoopTree *old_loop = get_loop(dp);
264
265 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) {
266 Node* cd = dp->fast_out(i); // Control-dependent node
267 if (cd->depends_only_on_test()) {
268 assert(cd->in(0) == dp, "");
269 _igvn.replace_input_of(cd, 0, prevdom);
270 set_early_ctrl(cd);
271 IdealLoopTree *new_loop = get_loop(get_ctrl(cd));
272 if (old_loop != new_loop) {
273 if (!old_loop->_child) old_loop->_body.yank(cd);
274 if (!new_loop->_child) new_loop->_body.push(cd);
275 }
276 --i;
277 --imax;
278 }
279 }
280 }
281
282 //------------------------------has_local_phi_input----------------------------
283 // Return TRUE if 'n' has Phi inputs from its local block and no other
284 // block-local inputs (all non-local-phi inputs come from earlier blocks)
285 Node *PhaseIdealLoop::has_local_phi_input( Node *n ) {
286 Node *n_ctrl = get_ctrl(n);
287 // See if some inputs come from a Phi in this block, or from before
288 // this block.
289 uint i;
290 for( i = 1; i < n->req(); i++ ) {
291 Node *phi = n->in(i);
292 if( phi->is_Phi() && phi->in(0) == n_ctrl )
293 break;
294 }
295 if( i >= n->req() )
296 return NULL; // No Phi inputs; nowhere to clone thru
297
298 // Check for inputs created between 'n' and the Phi input. These
299 // must split as well; they have already been given the chance
300 // (courtesy of a post-order visit) and since they did not we must
301 // recover the 'cost' of splitting them by being very profitable
302 // when splitting 'n'. Since this is unlikely we simply give up.
303 for( i = 1; i < n->req(); i++ ) {
304 Node *m = n->in(i);
305 if( get_ctrl(m) == n_ctrl && !m->is_Phi() ) {
306 // We allow the special case of AddP's with no local inputs.
307 // This allows us to split-up address expressions.
308 if (m->is_AddP() &&
309 get_ctrl(m->in(2)) != n_ctrl &&
310 get_ctrl(m->in(3)) != n_ctrl) {
311 // Move the AddP up to dominating point
312 Node* c = find_non_split_ctrl(idom(n_ctrl));
313 if (c->is_OuterStripMinedLoop()) {
314 c->as_Loop()->verify_strip_mined(1);
315 c = c->in(LoopNode::EntryControl);
316 }
317 set_ctrl_and_loop(m, c);
318 continue;
319 }
320 return NULL;
321 }
322 assert(m->is_Phi() || is_dominator(get_ctrl(m), n_ctrl), "m has strange control");
323 }
324
325 return n_ctrl;
326 }
327
328 //------------------------------remix_address_expressions----------------------
329 // Rework addressing expressions to get the most loop-invariant stuff
330 // moved out. We'd like to do all associative operators, but it's especially
331 // important (common) to do address expressions.
332 Node *PhaseIdealLoop::remix_address_expressions( Node *n ) {
333 if (!has_ctrl(n)) return NULL;
334 Node *n_ctrl = get_ctrl(n);
335 IdealLoopTree *n_loop = get_loop(n_ctrl);
336
337 // See if 'n' mixes loop-varying and loop-invariant inputs and
338 // itself is loop-varying.
339
340 // Only interested in binary ops (and AddP)
341 if( n->req() < 3 || n->req() > 4 ) return NULL;
342
343 Node *n1_ctrl = get_ctrl(n->in( 1));
344 Node *n2_ctrl = get_ctrl(n->in( 2));
345 Node *n3_ctrl = get_ctrl(n->in(n->req() == 3 ? 2 : 3));
346 IdealLoopTree *n1_loop = get_loop( n1_ctrl );
347 IdealLoopTree *n2_loop = get_loop( n2_ctrl );
348 IdealLoopTree *n3_loop = get_loop( n3_ctrl );
349
350 // Does one of my inputs spin in a tighter loop than self?
351 if( (n_loop->is_member( n1_loop ) && n_loop != n1_loop) ||
352 (n_loop->is_member( n2_loop ) && n_loop != n2_loop) ||
353 (n_loop->is_member( n3_loop ) && n_loop != n3_loop) )
354 return NULL; // Leave well enough alone
355
356 // Is at least one of my inputs loop-invariant?
357 if( n1_loop == n_loop &&
358 n2_loop == n_loop &&
359 n3_loop == n_loop )
360 return NULL; // No loop-invariant inputs
361
362
363 int n_op = n->Opcode();
364
365 // Replace expressions like ((V+I) << 2) with (V<<2 + I<<2).
366 if( n_op == Op_LShiftI ) {
367 // Scale is loop invariant
368 Node *scale = n->in(2);
369 Node *scale_ctrl = get_ctrl(scale);
370 IdealLoopTree *scale_loop = get_loop(scale_ctrl );
371 if( n_loop == scale_loop || !scale_loop->is_member( n_loop ) )
372 return NULL;
373 const TypeInt *scale_t = scale->bottom_type()->isa_int();
374 if( scale_t && scale_t->is_con() && scale_t->get_con() >= 16 )
375 return NULL; // Dont bother with byte/short masking
376 // Add must vary with loop (else shift would be loop-invariant)
377 Node *add = n->in(1);
378 Node *add_ctrl = get_ctrl(add);
379 IdealLoopTree *add_loop = get_loop(add_ctrl);
380 //assert( n_loop == add_loop, "" );
381 if( n_loop != add_loop ) return NULL; // happens w/ evil ZKM loops
382
383 // Convert I-V into I+ (0-V); same for V-I
384 if( add->Opcode() == Op_SubI &&
385 _igvn.type( add->in(1) ) != TypeInt::ZERO ) {
386 Node *zero = _igvn.intcon(0);
387 set_ctrl(zero, C->root());
388 Node *neg = new SubINode( _igvn.intcon(0), add->in(2) );
389 register_new_node( neg, get_ctrl(add->in(2) ) );
390 add = new AddINode( add->in(1), neg );
391 register_new_node( add, add_ctrl );
392 }
393 if( add->Opcode() != Op_AddI ) return NULL;
394 // See if one add input is loop invariant
395 Node *add_var = add->in(1);
396 Node *add_var_ctrl = get_ctrl(add_var);
397 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl );
398 Node *add_invar = add->in(2);
399 Node *add_invar_ctrl = get_ctrl(add_invar);
400 IdealLoopTree *add_invar_loop = get_loop(add_invar_ctrl );
401 if( add_var_loop == n_loop ) {
402 } else if( add_invar_loop == n_loop ) {
403 // Swap to find the invariant part
404 add_invar = add_var;
405 add_invar_ctrl = add_var_ctrl;
406 add_invar_loop = add_var_loop;
407 add_var = add->in(2);
408 Node *add_var_ctrl = get_ctrl(add_var);
409 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl );
410 } else // Else neither input is loop invariant
411 return NULL;
412 if( n_loop == add_invar_loop || !add_invar_loop->is_member( n_loop ) )
413 return NULL; // No invariant part of the add?
414
415 // Yes! Reshape address expression!
416 Node *inv_scale = new LShiftINode( add_invar, scale );
417 Node *inv_scale_ctrl =
418 dom_depth(add_invar_ctrl) > dom_depth(scale_ctrl) ?
419 add_invar_ctrl : scale_ctrl;
420 register_new_node( inv_scale, inv_scale_ctrl );
421 Node *var_scale = new LShiftINode( add_var, scale );
422 register_new_node( var_scale, n_ctrl );
423 Node *var_add = new AddINode( var_scale, inv_scale );
424 register_new_node( var_add, n_ctrl );
425 _igvn.replace_node( n, var_add );
426 return var_add;
427 }
428
429 // Replace (I+V) with (V+I)
430 if( n_op == Op_AddI ||
431 n_op == Op_AddL ||
432 n_op == Op_AddF ||
433 n_op == Op_AddD ||
434 n_op == Op_MulI ||
435 n_op == Op_MulL ||
436 n_op == Op_MulF ||
437 n_op == Op_MulD ) {
438 if( n2_loop == n_loop ) {
439 assert( n1_loop != n_loop, "" );
440 n->swap_edges(1, 2);
441 }
442 }
443
444 // Replace ((I1 +p V) +p I2) with ((I1 +p I2) +p V),
445 // but not if I2 is a constant.
446 if( n_op == Op_AddP ) {
447 if( n2_loop == n_loop && n3_loop != n_loop ) {
448 if( n->in(2)->Opcode() == Op_AddP && !n->in(3)->is_Con() ) {
449 Node *n22_ctrl = get_ctrl(n->in(2)->in(2));
450 Node *n23_ctrl = get_ctrl(n->in(2)->in(3));
451 IdealLoopTree *n22loop = get_loop( n22_ctrl );
452 IdealLoopTree *n23_loop = get_loop( n23_ctrl );
453 if( n22loop != n_loop && n22loop->is_member(n_loop) &&
454 n23_loop == n_loop ) {
455 Node *add1 = new AddPNode( n->in(1), n->in(2)->in(2), n->in(3) );
456 // Stuff new AddP in the loop preheader
457 register_new_node( add1, n_loop->_head->in(LoopNode::EntryControl) );
458 Node *add2 = new AddPNode( n->in(1), add1, n->in(2)->in(3) );
459 register_new_node( add2, n_ctrl );
460 _igvn.replace_node( n, add2 );
461 return add2;
462 }
463 }
464 }
465
466 // Replace (I1 +p (I2 + V)) with ((I1 +p I2) +p V)
467 if (n2_loop != n_loop && n3_loop == n_loop) {
468 if (n->in(3)->Opcode() == Op_AddX) {
469 Node *V = n->in(3)->in(1);
470 Node *I = n->in(3)->in(2);
471 if (is_member(n_loop,get_ctrl(V))) {
472 } else {
473 Node *tmp = V; V = I; I = tmp;
474 }
475 if (!is_member(n_loop,get_ctrl(I))) {
476 Node *add1 = new AddPNode(n->in(1), n->in(2), I);
477 // Stuff new AddP in the loop preheader
478 register_new_node(add1, n_loop->_head->in(LoopNode::EntryControl));
479 Node *add2 = new AddPNode(n->in(1), add1, V);
480 register_new_node(add2, n_ctrl);
481 _igvn.replace_node(n, add2);
482 return add2;
483 }
484 }
485 }
486 }
487
488 return NULL;
489 }
490
491 //------------------------------conditional_move-------------------------------
492 // Attempt to replace a Phi with a conditional move. We have some pretty
493 // strict profitability requirements. All Phis at the merge point must
494 // be converted, so we can remove the control flow. We need to limit the
495 // number of c-moves to a small handful. All code that was in the side-arms
496 // of the CFG diamond is now speculatively executed. This code has to be
497 // "cheap enough". We are pretty much limited to CFG diamonds that merge
498 // 1 or 2 items with a total of 1 or 2 ops executed speculatively.
499 Node *PhaseIdealLoop::conditional_move( Node *region ) {
500
501 assert(region->is_Region(), "sanity check");
502 if (region->req() != 3) return NULL;
503
504 // Check for CFG diamond
505 Node *lp = region->in(1);
506 Node *rp = region->in(2);
507 if (!lp || !rp) return NULL;
508 Node *lp_c = lp->in(0);
509 if (lp_c == NULL || lp_c != rp->in(0) || !lp_c->is_If()) return NULL;
510 IfNode *iff = lp_c->as_If();
511
512 // Check for ops pinned in an arm of the diamond.
513 // Can't remove the control flow in this case
514 if (lp->outcnt() > 1) return NULL;
515 if (rp->outcnt() > 1) return NULL;
516
517 IdealLoopTree* r_loop = get_loop(region);
518 assert(r_loop == get_loop(iff), "sanity");
519 // Always convert to CMOVE if all results are used only outside this loop.
520 bool used_inside_loop = (r_loop == _ltree_root);
521
522 // Check profitability
523 int cost = 0;
524 int phis = 0;
525 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
526 Node *out = region->fast_out(i);
527 if (!out->is_Phi()) continue; // Ignore other control edges, etc
528 phis++;
529 PhiNode* phi = out->as_Phi();
530 BasicType bt = phi->type()->basic_type();
531 switch (bt) {
532 case T_DOUBLE:
533 case T_FLOAT:
534 if (C->use_cmove()) {
535 continue; //TODO: maybe we want to add some cost
536 }
537 cost += Matcher::float_cmove_cost(); // Could be very expensive
538 break;
539 case T_LONG: {
540 cost += Matcher::long_cmove_cost(); // May encodes as 2 CMOV's
541 }
542 case T_INT: // These all CMOV fine
543 case T_ADDRESS: { // (RawPtr)
544 cost++;
545 break;
546 }
547 case T_NARROWOOP: // Fall through
548 case T_OBJECT: { // Base oops are OK, but not derived oops
549 const TypeOopPtr *tp = phi->type()->make_ptr()->isa_oopptr();
550 // Derived pointers are Bad (tm): what's the Base (for GC purposes) of a
551 // CMOVE'd derived pointer? It's a CMOVE'd derived base. Thus
552 // CMOVE'ing a derived pointer requires we also CMOVE the base. If we
553 // have a Phi for the base here that we convert to a CMOVE all is well
554 // and good. But if the base is dead, we'll not make a CMOVE. Later
555 // the allocator will have to produce a base by creating a CMOVE of the
556 // relevant bases. This puts the allocator in the business of
557 // manufacturing expensive instructions, generally a bad plan.
558 // Just Say No to Conditionally-Moved Derived Pointers.
559 if (tp && tp->offset() != 0)
560 return NULL;
561 cost++;
562 break;
563 }
564 default:
565 return NULL; // In particular, can't do memory or I/O
566 }
567 // Add in cost any speculative ops
568 for (uint j = 1; j < region->req(); j++) {
569 Node *proj = region->in(j);
570 Node *inp = phi->in(j);
571 if (get_ctrl(inp) == proj) { // Found local op
572 cost++;
573 // Check for a chain of dependent ops; these will all become
574 // speculative in a CMOV.
575 for (uint k = 1; k < inp->req(); k++)
576 if (get_ctrl(inp->in(k)) == proj)
577 cost += ConditionalMoveLimit; // Too much speculative goo
578 }
579 }
580 // See if the Phi is used by a Cmp or Narrow oop Decode/Encode.
581 // This will likely Split-If, a higher-payoff operation.
582 for (DUIterator_Fast kmax, k = phi->fast_outs(kmax); k < kmax; k++) {
583 Node* use = phi->fast_out(k);
584 if (use->is_Cmp() || use->is_DecodeNarrowPtr() || use->is_EncodeNarrowPtr())
585 cost += ConditionalMoveLimit;
586 // Is there a use inside the loop?
587 // Note: check only basic types since CMoveP is pinned.
588 if (!used_inside_loop && is_java_primitive(bt)) {
589 IdealLoopTree* u_loop = get_loop(has_ctrl(use) ? get_ctrl(use) : use);
590 if (r_loop == u_loop || r_loop->is_member(u_loop)) {
591 used_inside_loop = true;
592 }
593 }
594 }
595 }//for
596 Node* bol = iff->in(1);
597 assert(bol->Opcode() == Op_Bool, "");
598 int cmp_op = bol->in(1)->Opcode();
599 // It is expensive to generate flags from a float compare.
600 // Avoid duplicated float compare.
601 if (phis > 1 && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) return NULL;
602
603 float infrequent_prob = PROB_UNLIKELY_MAG(3);
604 // Ignore cost and blocks frequency if CMOVE can be moved outside the loop.
605 if (used_inside_loop) {
606 if (cost >= ConditionalMoveLimit) return NULL; // Too much goo
607
608 // BlockLayoutByFrequency optimization moves infrequent branch
609 // from hot path. No point in CMOV'ing in such case (110 is used
610 // instead of 100 to take into account not exactness of float value).
611 if (BlockLayoutByFrequency) {
612 infrequent_prob = MAX2(infrequent_prob, (float)BlockLayoutMinDiamondPercentage/110.0f);
613 }
614 }
615 // Check for highly predictable branch. No point in CMOV'ing if
616 // we are going to predict accurately all the time.
617 if (C->use_cmove() && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) {
618 //keep going
619 } else if (iff->_prob < infrequent_prob ||
620 iff->_prob > (1.0f - infrequent_prob))
621 return NULL;
622
623 // --------------
624 // Now replace all Phis with CMOV's
625 Node *cmov_ctrl = iff->in(0);
626 uint flip = (lp->Opcode() == Op_IfTrue);
627 Node_List wq;
628 while (1) {
629 PhiNode* phi = NULL;
630 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
631 Node *out = region->fast_out(i);
632 if (out->is_Phi()) {
633 phi = out->as_Phi();
634 break;
635 }
636 }
637 if (phi == NULL) break;
638 if (PrintOpto && VerifyLoopOptimizations) { tty->print_cr("CMOV"); }
639 // Move speculative ops
640 wq.push(phi);
641 while (wq.size() > 0) {
642 Node *n = wq.pop();
643 for (uint j = 1; j < n->req(); j++) {
644 Node* m = n->in(j);
645 if (m != NULL && !is_dominator(get_ctrl(m), cmov_ctrl)) {
646 #ifndef PRODUCT
647 if (PrintOpto && VerifyLoopOptimizations) {
648 tty->print(" speculate: ");
649 m->dump();
650 }
651 #endif
652 set_ctrl(m, cmov_ctrl);
653 wq.push(m);
654 }
655 }
656 }
657 Node *cmov = CMoveNode::make(cmov_ctrl, iff->in(1), phi->in(1+flip), phi->in(2-flip), _igvn.type(phi));
658 register_new_node( cmov, cmov_ctrl );
659 _igvn.replace_node( phi, cmov );
660 #ifndef PRODUCT
661 if (TraceLoopOpts) {
662 tty->print("CMOV ");
663 r_loop->dump_head();
664 if (Verbose) {
665 bol->in(1)->dump(1);
666 cmov->dump(1);
667 }
668 }
669 if (VerifyLoopOptimizations) verify();
670 #endif
671 }
672
673 // The useless CFG diamond will fold up later; see the optimization in
674 // RegionNode::Ideal.
675 _igvn._worklist.push(region);
676
677 return iff->in(1);
678 }
679
680 static void enqueue_cfg_uses(Node* m, Unique_Node_List& wq) {
681 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax; i++) {
682 Node* u = m->fast_out(i);
683 if (u->is_CFG()) {
684 if (u->Opcode() == Op_NeverBranch) {
685 u = ((NeverBranchNode*)u)->proj_out(0);
686 enqueue_cfg_uses(u, wq);
687 } else {
688 wq.push(u);
689 }
690 }
691 }
692 }
693
694 // Try moving a store out of a loop, right before the loop
695 Node* PhaseIdealLoop::try_move_store_before_loop(Node* n, Node *n_ctrl) {
696 // Store has to be first in the loop body
697 IdealLoopTree *n_loop = get_loop(n_ctrl);
698 if (n->is_Store() && n_loop != _ltree_root &&
699 n_loop->is_loop() && n_loop->_head->is_Loop() &&
700 n->in(0) != NULL) {
701 Node* address = n->in(MemNode::Address);
702 Node* value = n->in(MemNode::ValueIn);
703 Node* mem = n->in(MemNode::Memory);
704 IdealLoopTree* address_loop = get_loop(get_ctrl(address));
705 IdealLoopTree* value_loop = get_loop(get_ctrl(value));
706
707 // - address and value must be loop invariant
708 // - memory must be a memory Phi for the loop
709 // - Store must be the only store on this memory slice in the
710 // loop: if there's another store following this one then value
711 // written at iteration i by the second store could be overwritten
712 // at iteration i+n by the first store: it's not safe to move the
713 // first store out of the loop
714 // - nothing must observe the memory Phi: it guarantees no read
715 // before the store, we are also guaranteed the store post
716 // dominates the loop head (ignoring a possible early
717 // exit). Otherwise there would be extra Phi involved between the
718 // loop's Phi and the store.
719 // - there must be no early exit from the loop before the Store
720 // (such an exit most of the time would be an extra use of the
721 // memory Phi but sometimes is a bottom memory Phi that takes the
722 // store as input).
723
724 if (!n_loop->is_member(address_loop) &&
725 !n_loop->is_member(value_loop) &&
726 mem->is_Phi() && mem->in(0) == n_loop->_head &&
727 mem->outcnt() == 1 &&
728 mem->in(LoopNode::LoopBackControl) == n) {
729
730 assert(n_loop->_tail != NULL, "need a tail");
731 assert(is_dominator(n_ctrl, n_loop->_tail), "store control must not be in a branch in the loop");
732
733 // Verify that there's no early exit of the loop before the store.
734 bool ctrl_ok = false;
735 {
736 // Follow control from loop head until n, we exit the loop or
737 // we reach the tail
738 ResourceMark rm;
739 Unique_Node_List wq;
740 wq.push(n_loop->_head);
741
742 for (uint next = 0; next < wq.size(); ++next) {
743 Node *m = wq.at(next);
744 if (m == n->in(0)) {
745 ctrl_ok = true;
746 continue;
747 }
748 assert(!has_ctrl(m), "should be CFG");
749 if (!n_loop->is_member(get_loop(m)) || m == n_loop->_tail) {
750 ctrl_ok = false;
751 break;
752 }
753 enqueue_cfg_uses(m, wq);
754 if (wq.size() > 10) {
755 ctrl_ok = false;
756 break;
757 }
758 }
759 }
760 if (ctrl_ok) {
761 // move the Store
762 _igvn.replace_input_of(mem, LoopNode::LoopBackControl, mem);
763 _igvn.replace_input_of(n, 0, n_loop->_head->as_Loop()->skip_strip_mined()->in(LoopNode::EntryControl));
764 _igvn.replace_input_of(n, MemNode::Memory, mem->in(LoopNode::EntryControl));
765 // Disconnect the phi now. An empty phi can confuse other
766 // optimizations in this pass of loop opts.
767 _igvn.replace_node(mem, mem->in(LoopNode::EntryControl));
768 n_loop->_body.yank(mem);
769
770 set_ctrl_and_loop(n, n->in(0));
771
772 return n;
773 }
774 }
775 }
776 return NULL;
777 }
778
779 // Try moving a store out of a loop, right after the loop
780 void PhaseIdealLoop::try_move_store_after_loop(Node* n) {
781 if (n->is_Store() && n->in(0) != NULL) {
782 Node *n_ctrl = get_ctrl(n);
783 IdealLoopTree *n_loop = get_loop(n_ctrl);
784 // Store must be in a loop
785 if (n_loop != _ltree_root && !n_loop->_irreducible) {
786 Node* address = n->in(MemNode::Address);
787 Node* value = n->in(MemNode::ValueIn);
788 IdealLoopTree* address_loop = get_loop(get_ctrl(address));
789 // address must be loop invariant
790 if (!n_loop->is_member(address_loop)) {
791 // Store must be last on this memory slice in the loop and
792 // nothing in the loop must observe it
793 Node* phi = NULL;
794 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
795 Node* u = n->fast_out(i);
796 if (has_ctrl(u)) { // control use?
797 IdealLoopTree *u_loop = get_loop(get_ctrl(u));
798 if (!n_loop->is_member(u_loop)) {
799 continue;
800 }
801 if (u->is_Phi() && u->in(0) == n_loop->_head) {
802 assert(_igvn.type(u) == Type::MEMORY, "bad phi");
803 // multiple phis on the same slice are possible
804 if (phi != NULL) {
805 return;
806 }
807 phi = u;
808 continue;
809 }
810 }
811 return;
812 }
813 if (phi != NULL) {
814 // Nothing in the loop before the store (next iteration)
815 // must observe the stored value
816 bool mem_ok = true;
817 {
818 ResourceMark rm;
819 Unique_Node_List wq;
820 wq.push(phi);
821 for (uint next = 0; next < wq.size() && mem_ok; ++next) {
822 Node *m = wq.at(next);
823 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax && mem_ok; i++) {
824 Node* u = m->fast_out(i);
825 if (u->is_Store() || u->is_Phi()) {
826 if (u != n) {
827 wq.push(u);
828 mem_ok = (wq.size() <= 10);
829 }
830 } else {
831 mem_ok = false;
832 break;
833 }
834 }
835 }
836 }
837 if (mem_ok) {
838 // Move the store out of the loop if the LCA of all
839 // users (except for the phi) is outside the loop.
840 Node* hook = new Node(1);
841 _igvn.rehash_node_delayed(phi);
842 int count = phi->replace_edge(n, hook);
843 assert(count > 0, "inconsistent phi");
844
845 // Compute latest point this store can go
846 Node* lca = get_late_ctrl(n, get_ctrl(n));
847 if (n_loop->is_member(get_loop(lca))) {
848 // LCA is in the loop - bail out
849 _igvn.replace_node(hook, n);
850 return;
851 }
852 #ifdef ASSERT
853 if (n_loop->_head->is_Loop() && n_loop->_head->as_Loop()->is_strip_mined()) {
854 assert(n_loop->_head->Opcode() == Op_CountedLoop, "outer loop is a strip mined");
855 n_loop->_head->as_Loop()->verify_strip_mined(1);
856 Node* outer = n_loop->_head->as_CountedLoop()->outer_loop();
857 IdealLoopTree* outer_loop = get_loop(outer);
858 assert(n_loop->_parent == outer_loop, "broken loop tree");
859 assert(get_loop(lca) == outer_loop, "safepoint in outer loop consume all memory state");
860 }
861 #endif
862
863 // Move store out of the loop
864 _igvn.replace_node(hook, n->in(MemNode::Memory));
865 _igvn.replace_input_of(n, 0, lca);
866 set_ctrl_and_loop(n, lca);
867
868 // Disconnect the phi now. An empty phi can confuse other
869 // optimizations in this pass of loop opts..
870 if (phi->in(LoopNode::LoopBackControl) == phi) {
871 _igvn.replace_node(phi, phi->in(LoopNode::EntryControl));
872 n_loop->_body.yank(phi);
873 }
874 }
875 }
876 }
877 }
878 }
879 }
880
881 //------------------------------split_if_with_blocks_pre-----------------------
882 // Do the real work in a non-recursive function. Data nodes want to be
883 // cloned in the pre-order so they can feed each other nicely.
884 Node *PhaseIdealLoop::split_if_with_blocks_pre( Node *n ) {
885 // Cloning these guys is unlikely to win
886 int n_op = n->Opcode();
887 if( n_op == Op_MergeMem ) return n;
888 if( n->is_Proj() ) return n;
889 // Do not clone-up CmpFXXX variations, as these are always
890 // followed by a CmpI
891 if( n->is_Cmp() ) return n;
892 // Attempt to use a conditional move instead of a phi/branch
893 if( ConditionalMoveLimit > 0 && n_op == Op_Region ) {
894 Node *cmov = conditional_move( n );
895 if( cmov ) return cmov;
896 }
897 if( n->is_CFG() || n->is_LoadStore() )
898 return n;
899 if( n_op == Op_Opaque1 || // Opaque nodes cannot be mod'd
900 n_op == Op_Opaque2 ) {
901 if( !C->major_progress() ) // If chance of no more loop opts...
902 _igvn._worklist.push(n); // maybe we'll remove them
903 return n;
904 }
905
906 if( n->is_Con() ) return n; // No cloning for Con nodes
907
908 Node *n_ctrl = get_ctrl(n);
909 if( !n_ctrl ) return n; // Dead node
910
911 Node* res = try_move_store_before_loop(n, n_ctrl);
912 if (res != NULL) {
913 return n;
914 }
915
916 // Attempt to remix address expressions for loop invariants
917 Node *m = remix_address_expressions( n );
918 if( m ) return m;
919
920 if (n->is_ConstraintCast()) {
921 Node* dom_cast = n->as_ConstraintCast()->dominating_cast(&_igvn, this);
922 // ConstraintCastNode::dominating_cast() uses node control input to determine domination.
923 // Node control inputs don't necessarily agree with loop control info (due to
924 // transformations happened in between), thus additional dominance check is needed
925 // to keep loop info valid.
926 if (dom_cast != NULL && is_dominator(get_ctrl(dom_cast), get_ctrl(n))) {
927 _igvn.replace_node(n, dom_cast);
928 return dom_cast;
929 }
930 }
931
932 // Determine if the Node has inputs from some local Phi.
933 // Returns the block to clone thru.
934 Node *n_blk = has_local_phi_input( n );
935 if( !n_blk ) return n;
936
937 // Do not clone the trip counter through on a CountedLoop
938 // (messes up the canonical shape).
939 if( n_blk->is_CountedLoop() && n->Opcode() == Op_AddI ) return n;
940
941 // Check for having no control input; not pinned. Allow
942 // dominating control.
943 if (n->in(0)) {
944 Node *dom = idom(n_blk);
945 if (dom_lca(n->in(0), dom) != n->in(0)) {
946 return n;
947 }
948 }
949 // Policy: when is it profitable. You must get more wins than
950 // policy before it is considered profitable. Policy is usually 0,
951 // so 1 win is considered profitable. Big merges will require big
952 // cloning, so get a larger policy.
953 int policy = n_blk->req() >> 2;
954
955 // If the loop is a candidate for range check elimination,
956 // delay splitting through it's phi until a later loop optimization
957 if (n_blk->is_CountedLoop()) {
958 IdealLoopTree *lp = get_loop(n_blk);
959 if (lp && lp->_rce_candidate) {
960 return n;
961 }
962 }
963
964 // Use same limit as split_if_with_blocks_post
965 if( C->live_nodes() > 35000 ) return n; // Method too big
966
967 // Split 'n' through the merge point if it is profitable
968 Node *phi = split_thru_phi( n, n_blk, policy );
969 if (!phi) return n;
970
971 // Found a Phi to split thru!
972 // Replace 'n' with the new phi
973 _igvn.replace_node( n, phi );
974 // Moved a load around the loop, 'en-registering' something.
975 if (n_blk->is_Loop() && n->is_Load() &&
976 !phi->in(LoopNode::LoopBackControl)->is_Load())
977 C->set_major_progress();
978
979 return phi;
980 }
981
982 static bool merge_point_too_heavy(Compile* C, Node* region) {
983 // Bail out if the region and its phis have too many users.
984 int weight = 0;
985 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
986 weight += region->fast_out(i)->outcnt();
987 }
988 int nodes_left = C->max_node_limit() - C->live_nodes();
989 if (weight * 8 > nodes_left) {
990 if (PrintOpto) {
991 tty->print_cr("*** Split-if bails out: %d nodes, region weight %d", C->unique(), weight);
992 }
993 return true;
994 } else {
995 return false;
996 }
997 }
998
999 static bool merge_point_safe(Node* region) {
1000 // 4799512: Stop split_if_with_blocks from splitting a block with a ConvI2LNode
1001 // having a PhiNode input. This sidesteps the dangerous case where the split
1002 // ConvI2LNode may become TOP if the input Value() does not
1003 // overlap the ConvI2L range, leaving a node which may not dominate its
1004 // uses.
1005 // A better fix for this problem can be found in the BugTraq entry, but
1006 // expediency for Mantis demands this hack.
1007 // 6855164: If the merge point has a FastLockNode with a PhiNode input, we stop
1008 // split_if_with_blocks from splitting a block because we could not move around
1009 // the FastLockNode.
1010 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1011 Node* n = region->fast_out(i);
1012 if (n->is_Phi()) {
1013 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
1014 Node* m = n->fast_out(j);
1015 if (m->is_FastLock())
1016 return false;
1017 #ifdef _LP64
1018 if (m->Opcode() == Op_ConvI2L)
1019 return false;
1020 if (m->is_CastII() && m->isa_CastII()->has_range_check()) {
1021 return false;
1022 }
1023 #endif
1024 }
1025 }
1026 }
1027 return true;
1028 }
1029
1030
1031 //------------------------------place_near_use---------------------------------
1032 // Place some computation next to use but not inside inner loops.
1033 // For inner loop uses move it to the preheader area.
1034 Node *PhaseIdealLoop::place_near_use(Node *useblock) const {
1035 IdealLoopTree *u_loop = get_loop( useblock );
1036 if (u_loop->_irreducible) {
1037 return useblock;
1038 }
1039 if (u_loop->_child) {
1040 if (useblock == u_loop->_head && u_loop->_head->is_OuterStripMinedLoop()) {
1041 return u_loop->_head->in(LoopNode::EntryControl);
1042 }
1043 return useblock;
1044 }
1045 return u_loop->_head->as_Loop()->skip_strip_mined()->in(LoopNode::EntryControl);
1046 }
1047
1048
1049 bool PhaseIdealLoop::identical_backtoback_ifs(Node *n) {
1050 if (!n->is_If() || n->is_CountedLoopEnd()) {
1051 return false;
1052 }
1053 if (!n->in(0)->is_Region()) {
1054 return false;
1055 }
1056 Node* region = n->in(0);
1057 Node* dom = idom(region);
1058 if (!dom->is_If() || dom->in(1) != n->in(1)) {
1059 return false;
1060 }
1061 IfNode* dom_if = dom->as_If();
1062 Node* proj_true = dom_if->proj_out(1);
1063 Node* proj_false = dom_if->proj_out(0);
1064
1065 for (uint i = 1; i < region->req(); i++) {
1066 if (is_dominator(proj_true, region->in(i))) {
1067 continue;
1068 }
1069 if (is_dominator(proj_false, region->in(i))) {
1070 continue;
1071 }
1072 return false;
1073 }
1074
1075 return true;
1076 }
1077
1078 bool PhaseIdealLoop::can_split_if(Node *n_ctrl) {
1079 if (C->live_nodes() > 35000) {
1080 return false; // Method too big
1081 }
1082
1083 // Do not do 'split-if' if irreducible loops are present.
1084 if (_has_irreducible_loops) {
1085 return false;
1086 }
1087
1088 if (merge_point_too_heavy(C, n_ctrl)) {
1089 return false;
1090 }
1091
1092 // Do not do 'split-if' if some paths are dead. First do dead code
1093 // elimination and then see if its still profitable.
1094 for (uint i = 1; i < n_ctrl->req(); i++) {
1095 if (n_ctrl->in(i) == C->top()) {
1096 return false;
1097 }
1098 }
1099
1100 // If trying to do a 'Split-If' at the loop head, it is only
1101 // profitable if the cmp folds up on BOTH paths. Otherwise we
1102 // risk peeling a loop forever.
1103
1104 // CNC - Disabled for now. Requires careful handling of loop
1105 // body selection for the cloned code. Also, make sure we check
1106 // for any input path not being in the same loop as n_ctrl. For
1107 // irreducible loops we cannot check for 'n_ctrl->is_Loop()'
1108 // because the alternative loop entry points won't be converted
1109 // into LoopNodes.
1110 IdealLoopTree *n_loop = get_loop(n_ctrl);
1111 for (uint j = 1; j < n_ctrl->req(); j++) {
1112 if (get_loop(n_ctrl->in(j)) != n_loop) {
1113 return false;
1114 }
1115 }
1116
1117 // Check for safety of the merge point.
1118 if (!merge_point_safe(n_ctrl)) {
1119 return false;
1120 }
1121
1122 return true;
1123 }
1124
1125 //------------------------------split_if_with_blocks_post----------------------
1126 // Do the real work in a non-recursive function. CFG hackery wants to be
1127 // in the post-order, so it can dirty the I-DOM info and not use the dirtied
1128 // info.
1129 void PhaseIdealLoop::split_if_with_blocks_post(Node *n) {
1130
1131 // Cloning Cmp through Phi's involves the split-if transform.
1132 // FastLock is not used by an If
1133 if (n->is_Cmp() && !n->is_FastLock()) {
1134 Node *n_ctrl = get_ctrl(n);
1135 // Determine if the Node has inputs from some local Phi.
1136 // Returns the block to clone thru.
1137 Node *n_blk = has_local_phi_input(n);
1138 if (n_blk != n_ctrl) {
1139 return;
1140 }
1141
1142 if (!can_split_if(n_ctrl)) {
1143 return;
1144 }
1145
1146 if (n->outcnt() != 1) {
1147 return; // Multiple bool's from 1 compare?
1148 }
1149 Node *bol = n->unique_out();
1150 assert(bol->is_Bool(), "expect a bool here");
1151 if (bol->outcnt() != 1) {
1152 return;// Multiple branches from 1 compare?
1153 }
1154 Node *iff = bol->unique_out();
1155
1156 // Check some safety conditions
1157 if (iff->is_If()) { // Classic split-if?
1158 if (iff->in(0) != n_ctrl) {
1159 return; // Compare must be in same blk as if
1160 }
1161 } else if (iff->is_CMove()) { // Trying to split-up a CMOVE
1162 // Can't split CMove with different control edge.
1163 if (iff->in(0) != NULL && iff->in(0) != n_ctrl ) {
1164 return;
1165 }
1166 if (get_ctrl(iff->in(2)) == n_ctrl ||
1167 get_ctrl(iff->in(3)) == n_ctrl) {
1168 return; // Inputs not yet split-up
1169 }
1170 if (get_loop(n_ctrl) != get_loop(get_ctrl(iff))) {
1171 return; // Loop-invar test gates loop-varying CMOVE
1172 }
1173 } else {
1174 return; // some other kind of node, such as an Allocate
1175 }
1176
1177 // When is split-if profitable? Every 'win' on means some control flow
1178 // goes dead, so it's almost always a win.
1179 int policy = 0;
1180 // Split compare 'n' through the merge point if it is profitable
1181 Node *phi = split_thru_phi( n, n_ctrl, policy);
1182 if (!phi) {
1183 return;
1184 }
1185
1186 // Found a Phi to split thru!
1187 // Replace 'n' with the new phi
1188 _igvn.replace_node(n, phi);
1189
1190 // Now split the bool up thru the phi
1191 Node *bolphi = split_thru_phi(bol, n_ctrl, -1);
1192 guarantee(bolphi != NULL, "null boolean phi node");
1193
1194 _igvn.replace_node(bol, bolphi);
1195 assert(iff->in(1) == bolphi, "");
1196
1197 if (bolphi->Value(&_igvn)->singleton()) {
1198 return;
1199 }
1200
1201 // Conditional-move? Must split up now
1202 if (!iff->is_If()) {
1203 Node *cmovphi = split_thru_phi(iff, n_ctrl, -1);
1204 _igvn.replace_node(iff, cmovphi);
1205 return;
1206 }
1207
1208 // Now split the IF
1209 do_split_if(iff);
1210 return;
1211 }
1212
1213 // Two identical ifs back to back can be merged
1214 if (identical_backtoback_ifs(n) && can_split_if(n->in(0))) {
1215 Node *n_ctrl = n->in(0);
1216 PhiNode* bolphi = PhiNode::make_blank(n_ctrl, n->in(1));
1217 IfNode* dom_if = idom(n_ctrl)->as_If();
1218 Node* proj_true = dom_if->proj_out(1);
1219 Node* proj_false = dom_if->proj_out(0);
1220 Node* con_true = _igvn.makecon(TypeInt::ONE);
1221 Node* con_false = _igvn.makecon(TypeInt::ZERO);
1222
1223 for (uint i = 1; i < n_ctrl->req(); i++) {
1224 if (is_dominator(proj_true, n_ctrl->in(i))) {
1225 bolphi->init_req(i, con_true);
1226 } else {
1227 assert(is_dominator(proj_false, n_ctrl->in(i)), "bad if");
1228 bolphi->init_req(i, con_false);
1229 }
1230 }
1231 register_new_node(bolphi, n_ctrl);
1232 _igvn.replace_input_of(n, 1, bolphi);
1233
1234 // Now split the IF
1235 do_split_if(n);
1236 return;
1237 }
1238
1239 // Check for an IF ready to split; one that has its
1240 // condition codes input coming from a Phi at the block start.
1241 int n_op = n->Opcode();
1242
1243 // Check for an IF being dominated by another IF same test
1244 if (n_op == Op_If ||
1245 n_op == Op_RangeCheck) {
1246 Node *bol = n->in(1);
1247 uint max = bol->outcnt();
1248 // Check for same test used more than once?
1249 if (max > 1 && bol->is_Bool()) {
1250 // Search up IDOMs to see if this IF is dominated.
1251 Node *cutoff = get_ctrl(bol);
1252
1253 // Now search up IDOMs till cutoff, looking for a dominating test
1254 Node *prevdom = n;
1255 Node *dom = idom(prevdom);
1256 while (dom != cutoff) {
1257 if (dom->req() > 1 && dom->in(1) == bol && prevdom->in(0) == dom) {
1258 // Replace the dominated test with an obvious true or false.
1259 // Place it on the IGVN worklist for later cleanup.
1260 C->set_major_progress();
1261 dominated_by(prevdom, n, false, true);
1262 #ifndef PRODUCT
1263 if( VerifyLoopOptimizations ) verify();
1264 #endif
1265 return;
1266 }
1267 prevdom = dom;
1268 dom = idom(prevdom);
1269 }
1270 }
1271 }
1272
1273 // See if a shared loop-varying computation has no loop-varying uses.
1274 // Happens if something is only used for JVM state in uncommon trap exits,
1275 // like various versions of induction variable+offset. Clone the
1276 // computation per usage to allow it to sink out of the loop.
1277 if (has_ctrl(n) && !n->in(0)) {// n not dead and has no control edge (can float about)
1278 Node *n_ctrl = get_ctrl(n);
1279 IdealLoopTree *n_loop = get_loop(n_ctrl);
1280 if( n_loop != _ltree_root ) {
1281 DUIterator_Fast imax, i = n->fast_outs(imax);
1282 for (; i < imax; i++) {
1283 Node* u = n->fast_out(i);
1284 if( !has_ctrl(u) ) break; // Found control user
1285 IdealLoopTree *u_loop = get_loop(get_ctrl(u));
1286 if( u_loop == n_loop ) break; // Found loop-varying use
1287 if( n_loop->is_member( u_loop ) ) break; // Found use in inner loop
1288 if( u->Opcode() == Op_Opaque1 ) break; // Found loop limit, bugfix for 4677003
1289 }
1290 bool did_break = (i < imax); // Did we break out of the previous loop?
1291 if (!did_break && n->outcnt() > 1) { // All uses in outer loops!
1292 Node *late_load_ctrl = NULL;
1293 if (n->is_Load()) {
1294 // If n is a load, get and save the result from get_late_ctrl(),
1295 // to be later used in calculating the control for n's clones.
1296 clear_dom_lca_tags();
1297 late_load_ctrl = get_late_ctrl(n, n_ctrl);
1298 }
1299 // If n is a load, and the late control is the same as the current
1300 // control, then the cloning of n is a pointless exercise, because
1301 // GVN will ensure that we end up where we started.
1302 if (!n->is_Load() || late_load_ctrl != n_ctrl) {
1303 for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin; ) {
1304 Node *u = n->last_out(j); // Clone private computation per use
1305 _igvn.rehash_node_delayed(u);
1306 Node *x = n->clone(); // Clone computation
1307 Node *x_ctrl = NULL;
1308 if( u->is_Phi() ) {
1309 // Replace all uses of normal nodes. Replace Phi uses
1310 // individually, so the separate Nodes can sink down
1311 // different paths.
1312 uint k = 1;
1313 while( u->in(k) != n ) k++;
1314 u->set_req( k, x );
1315 // x goes next to Phi input path
1316 x_ctrl = u->in(0)->in(k);
1317 --j;
1318 } else { // Normal use
1319 // Replace all uses
1320 for( uint k = 0; k < u->req(); k++ ) {
1321 if( u->in(k) == n ) {
1322 u->set_req( k, x );
1323 --j;
1324 }
1325 }
1326 x_ctrl = get_ctrl(u);
1327 }
1328
1329 // Find control for 'x' next to use but not inside inner loops.
1330 // For inner loop uses get the preheader area.
1331 x_ctrl = place_near_use(x_ctrl);
1332
1333 if (n->is_Load()) {
1334 // For loads, add a control edge to a CFG node outside of the loop
1335 // to force them to not combine and return back inside the loop
1336 // during GVN optimization (4641526).
1337 //
1338 // Because we are setting the actual control input, factor in
1339 // the result from get_late_ctrl() so we respect any
1340 // anti-dependences. (6233005).
1341 x_ctrl = dom_lca(late_load_ctrl, x_ctrl);
1342
1343 // Don't allow the control input to be a CFG splitting node.
1344 // Such nodes should only have ProjNodes as outs, e.g. IfNode
1345 // should only have IfTrueNode and IfFalseNode (4985384).
1346 x_ctrl = find_non_split_ctrl(x_ctrl);
1347 assert(dom_depth(n_ctrl) <= dom_depth(x_ctrl), "n is later than its clone");
1348
1349 x->set_req(0, x_ctrl);
1350 }
1351 register_new_node(x, x_ctrl);
1352
1353 // Some institutional knowledge is needed here: 'x' is
1354 // yanked because if the optimizer runs GVN on it all the
1355 // cloned x's will common up and undo this optimization and
1356 // be forced back in the loop. This is annoying because it
1357 // makes +VerifyOpto report false-positives on progress. I
1358 // tried setting control edges on the x's to force them to
1359 // not combine, but the matching gets worried when it tries
1360 // to fold a StoreP and an AddP together (as part of an
1361 // address expression) and the AddP and StoreP have
1362 // different controls.
1363 if (!x->is_Load() && !x->is_DecodeNarrowPtr()) _igvn._worklist.yank(x);
1364 }
1365 _igvn.remove_dead_node(n);
1366 }
1367 }
1368 }
1369 }
1370
1371 try_move_store_after_loop(n);
1372
1373 // Check for Opaque2's who's loop has disappeared - who's input is in the
1374 // same loop nest as their output. Remove 'em, they are no longer useful.
1375 if( n_op == Op_Opaque2 &&
1376 n->in(1) != NULL &&
1377 get_loop(get_ctrl(n)) == get_loop(get_ctrl(n->in(1))) ) {
1378 _igvn.replace_node( n, n->in(1) );
1379 }
1380 }
1381
1382 //------------------------------split_if_with_blocks---------------------------
1383 // Check for aggressive application of 'split-if' optimization,
1384 // using basic block level info.
1385 void PhaseIdealLoop::split_if_with_blocks( VectorSet &visited, Node_Stack &nstack ) {
1386 Node *n = C->root();
1387 visited.set(n->_idx); // first, mark node as visited
1388 // Do pre-visit work for root
1389 n = split_if_with_blocks_pre( n );
1390 uint cnt = n->outcnt();
1391 uint i = 0;
1392 while (true) {
1393 // Visit all children
1394 if (i < cnt) {
1395 Node* use = n->raw_out(i);
1396 ++i;
1397 if (use->outcnt() != 0 && !visited.test_set(use->_idx)) {
1398 // Now do pre-visit work for this use
1399 use = split_if_with_blocks_pre( use );
1400 nstack.push(n, i); // Save parent and next use's index.
1401 n = use; // Process all children of current use.
1402 cnt = use->outcnt();
1403 i = 0;
1404 }
1405 }
1406 else {
1407 // All of n's children have been processed, complete post-processing.
1408 if (cnt != 0 && !n->is_Con()) {
1409 assert(has_node(n), "no dead nodes");
1410 split_if_with_blocks_post( n );
1411 }
1412 if (nstack.is_empty()) {
1413 // Finished all nodes on stack.
1414 break;
1415 }
1416 // Get saved parent node and next use's index. Visit the rest of uses.
1417 n = nstack.node();
1418 cnt = n->outcnt();
1419 i = nstack.index();
1420 nstack.pop();
1421 }
1422 }
1423 }
1424
1425
1426 //=============================================================================
1427 //
1428 // C L O N E A L O O P B O D Y
1429 //
1430
1431 //------------------------------clone_iff--------------------------------------
1432 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps.
1433 // "Nearly" because all Nodes have been cloned from the original in the loop,
1434 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs
1435 // through the Phi recursively, and return a Bool.
1436 Node* PhaseIdealLoop::clone_iff(PhiNode *phi, IdealLoopTree *loop) {
1437
1438 // Convert this Phi into a Phi merging Bools
1439 uint i;
1440 for (i = 1; i < phi->req(); i++) {
1441 Node *b = phi->in(i);
1442 if (b->is_Phi()) {
1443 _igvn.replace_input_of(phi, i, clone_iff(b->as_Phi(), loop));
1444 } else {
1445 assert(b->is_Bool() || b->Opcode() == Op_Opaque4, "");
1446 }
1447 }
1448
1449 Node* n = phi->in(1);
1450 Node* sample_opaque = NULL;
1451 Node *sample_bool = NULL;
1452 if (n->Opcode() == Op_Opaque4) {
1453 sample_opaque = n;
1454 sample_bool = n->in(1);
1455 assert(sample_bool->is_Bool(), "wrong type");
1456 } else {
1457 sample_bool = n;
1458 }
1459 Node *sample_cmp = sample_bool->in(1);
1460
1461 // Make Phis to merge the Cmp's inputs.
1462 PhiNode *phi1 = new PhiNode(phi->in(0), Type::TOP);
1463 PhiNode *phi2 = new PhiNode(phi->in(0), Type::TOP);
1464 for (i = 1; i < phi->req(); i++) {
1465 Node *n1 = sample_opaque == NULL ? phi->in(i)->in(1)->in(1) : phi->in(i)->in(1)->in(1)->in(1);
1466 Node *n2 = sample_opaque == NULL ? phi->in(i)->in(1)->in(2) : phi->in(i)->in(1)->in(1)->in(2);
1467 phi1->set_req(i, n1);
1468 phi2->set_req(i, n2);
1469 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type()));
1470 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type()));
1471 }
1472 // See if these Phis have been made before.
1473 // Register with optimizer
1474 Node *hit1 = _igvn.hash_find_insert(phi1);
1475 if (hit1) { // Hit, toss just made Phi
1476 _igvn.remove_dead_node(phi1); // Remove new phi
1477 assert(hit1->is_Phi(), "" );
1478 phi1 = (PhiNode*)hit1; // Use existing phi
1479 } else { // Miss
1480 _igvn.register_new_node_with_optimizer(phi1);
1481 }
1482 Node *hit2 = _igvn.hash_find_insert(phi2);
1483 if (hit2) { // Hit, toss just made Phi
1484 _igvn.remove_dead_node(phi2); // Remove new phi
1485 assert(hit2->is_Phi(), "" );
1486 phi2 = (PhiNode*)hit2; // Use existing phi
1487 } else { // Miss
1488 _igvn.register_new_node_with_optimizer(phi2);
1489 }
1490 // Register Phis with loop/block info
1491 set_ctrl(phi1, phi->in(0));
1492 set_ctrl(phi2, phi->in(0));
1493 // Make a new Cmp
1494 Node *cmp = sample_cmp->clone();
1495 cmp->set_req(1, phi1);
1496 cmp->set_req(2, phi2);
1497 _igvn.register_new_node_with_optimizer(cmp);
1498 set_ctrl(cmp, phi->in(0));
1499
1500 // Make a new Bool
1501 Node *b = sample_bool->clone();
1502 b->set_req(1,cmp);
1503 _igvn.register_new_node_with_optimizer(b);
1504 set_ctrl(b, phi->in(0));
1505
1506 if (sample_opaque != NULL) {
1507 Node* opaque = sample_opaque->clone();
1508 opaque->set_req(1, b);
1509 _igvn.register_new_node_with_optimizer(opaque);
1510 set_ctrl(opaque, phi->in(0));
1511 return opaque;
1512 }
1513
1514 assert(b->is_Bool(), "");
1515 return b;
1516 }
1517
1518 //------------------------------clone_bool-------------------------------------
1519 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps.
1520 // "Nearly" because all Nodes have been cloned from the original in the loop,
1521 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs
1522 // through the Phi recursively, and return a Bool.
1523 CmpNode *PhaseIdealLoop::clone_bool( PhiNode *phi, IdealLoopTree *loop ) {
1524 uint i;
1525 // Convert this Phi into a Phi merging Bools
1526 for( i = 1; i < phi->req(); i++ ) {
1527 Node *b = phi->in(i);
1528 if( b->is_Phi() ) {
1529 _igvn.replace_input_of(phi, i, clone_bool( b->as_Phi(), loop ));
1530 } else {
1531 assert( b->is_Cmp() || b->is_top(), "inputs are all Cmp or TOP" );
1532 }
1533 }
1534
1535 Node *sample_cmp = phi->in(1);
1536
1537 // Make Phis to merge the Cmp's inputs.
1538 PhiNode *phi1 = new PhiNode( phi->in(0), Type::TOP );
1539 PhiNode *phi2 = new PhiNode( phi->in(0), Type::TOP );
1540 for( uint j = 1; j < phi->req(); j++ ) {
1541 Node *cmp_top = phi->in(j); // Inputs are all Cmp or TOP
1542 Node *n1, *n2;
1543 if( cmp_top->is_Cmp() ) {
1544 n1 = cmp_top->in(1);
1545 n2 = cmp_top->in(2);
1546 } else {
1547 n1 = n2 = cmp_top;
1548 }
1549 phi1->set_req( j, n1 );
1550 phi2->set_req( j, n2 );
1551 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type()));
1552 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type()));
1553 }
1554
1555 // See if these Phis have been made before.
1556 // Register with optimizer
1557 Node *hit1 = _igvn.hash_find_insert(phi1);
1558 if( hit1 ) { // Hit, toss just made Phi
1559 _igvn.remove_dead_node(phi1); // Remove new phi
1560 assert( hit1->is_Phi(), "" );
1561 phi1 = (PhiNode*)hit1; // Use existing phi
1562 } else { // Miss
1563 _igvn.register_new_node_with_optimizer(phi1);
1564 }
1565 Node *hit2 = _igvn.hash_find_insert(phi2);
1566 if( hit2 ) { // Hit, toss just made Phi
1567 _igvn.remove_dead_node(phi2); // Remove new phi
1568 assert( hit2->is_Phi(), "" );
1569 phi2 = (PhiNode*)hit2; // Use existing phi
1570 } else { // Miss
1571 _igvn.register_new_node_with_optimizer(phi2);
1572 }
1573 // Register Phis with loop/block info
1574 set_ctrl(phi1, phi->in(0));
1575 set_ctrl(phi2, phi->in(0));
1576 // Make a new Cmp
1577 Node *cmp = sample_cmp->clone();
1578 cmp->set_req( 1, phi1 );
1579 cmp->set_req( 2, phi2 );
1580 _igvn.register_new_node_with_optimizer(cmp);
1581 set_ctrl(cmp, phi->in(0));
1582
1583 assert( cmp->is_Cmp(), "" );
1584 return (CmpNode*)cmp;
1585 }
1586
1587 //------------------------------sink_use---------------------------------------
1588 // If 'use' was in the loop-exit block, it now needs to be sunk
1589 // below the post-loop merge point.
1590 void PhaseIdealLoop::sink_use( Node *use, Node *post_loop ) {
1591 if (!use->is_CFG() && get_ctrl(use) == post_loop->in(2)) {
1592 set_ctrl(use, post_loop);
1593 for (DUIterator j = use->outs(); use->has_out(j); j++)
1594 sink_use(use->out(j), post_loop);
1595 }
1596 }
1597
1598 void PhaseIdealLoop::clone_loop_handle_data_uses(Node* old, Node_List &old_new,
1599 IdealLoopTree* loop, IdealLoopTree* outer_loop,
1600 Node_List*& split_if_set, Node_List*& split_bool_set,
1601 Node_List*& split_cex_set, Node_List& worklist,
1602 uint new_counter, CloneLoopMode mode) {
1603 Node* nnn = old_new[old->_idx];
1604 // Copy uses to a worklist, so I can munge the def-use info
1605 // with impunity.
1606 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++)
1607 worklist.push(old->fast_out(j));
1608
1609 while( worklist.size() ) {
1610 Node *use = worklist.pop();
1611 if (!has_node(use)) continue; // Ignore dead nodes
1612 if (use->in(0) == C->top()) continue;
1613 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use );
1614 // Check for data-use outside of loop - at least one of OLD or USE
1615 // must not be a CFG node.
1616 #ifdef ASSERT
1617 if (loop->_head->as_Loop()->is_strip_mined() && outer_loop->is_member(use_loop) && !loop->is_member(use_loop) && old_new[use->_idx] == NULL) {
1618 Node* sfpt = loop->_head->as_CountedLoop()->outer_safepoint();
1619 assert(mode == ControlAroundStripMined && use == sfpt, "missed a node");
1620 }
1621 #endif
1622 if (!loop->is_member(use_loop) && !outer_loop->is_member(use_loop) && (!old->is_CFG() || !use->is_CFG())) {
1623
1624 // If the Data use is an IF, that means we have an IF outside of the
1625 // loop that is switching on a condition that is set inside of the
1626 // loop. Happens if people set a loop-exit flag; then test the flag
1627 // in the loop to break the loop, then test is again outside of the
1628 // loop to determine which way the loop exited.
1629 // Loop predicate If node connects to Bool node through Opaque1 node.
1630 if (use->is_If() || use->is_CMove() || C->is_predicate_opaq(use) || use->Opcode() == Op_Opaque4) {
1631 // Since this code is highly unlikely, we lazily build the worklist
1632 // of such Nodes to go split.
1633 if (!split_if_set) {
1634 ResourceArea *area = Thread::current()->resource_area();
1635 split_if_set = new Node_List(area);
1636 }
1637 split_if_set->push(use);
1638 }
1639 if (use->is_Bool()) {
1640 if (!split_bool_set) {
1641 ResourceArea *area = Thread::current()->resource_area();
1642 split_bool_set = new Node_List(area);
1643 }
1644 split_bool_set->push(use);
1645 }
1646 if (use->Opcode() == Op_CreateEx) {
1647 if (!split_cex_set) {
1648 ResourceArea *area = Thread::current()->resource_area();
1649 split_cex_set = new Node_List(area);
1650 }
1651 split_cex_set->push(use);
1652 }
1653
1654
1655 // Get "block" use is in
1656 uint idx = 0;
1657 while( use->in(idx) != old ) idx++;
1658 Node *prev = use->is_CFG() ? use : get_ctrl(use);
1659 assert(!loop->is_member(get_loop(prev)) && !outer_loop->is_member(get_loop(prev)), "" );
1660 Node *cfg = prev->_idx >= new_counter
1661 ? prev->in(2)
1662 : idom(prev);
1663 if( use->is_Phi() ) // Phi use is in prior block
1664 cfg = prev->in(idx); // NOT in block of Phi itself
1665 if (cfg->is_top()) { // Use is dead?
1666 _igvn.replace_input_of(use, idx, C->top());
1667 continue;
1668 }
1669
1670 // If use is referenced through control edge... (idx == 0)
1671 if (mode == IgnoreStripMined && idx == 0) {
1672 LoopNode *head = loop->_head->as_Loop();
1673 if (head->is_strip_mined() && is_dominator(head->outer_loop_exit(), prev)) {
1674 // That node is outside the inner loop, leave it outside the
1675 // outer loop as well to not confuse verification code.
1676 assert(!loop->_parent->is_member(use_loop), "should be out of the outer loop");
1677 _igvn.replace_input_of(use, 0, head->outer_loop_exit());
1678 continue;
1679 }
1680 }
1681
1682 while(!outer_loop->is_member(get_loop(cfg))) {
1683 prev = cfg;
1684 cfg = cfg->_idx >= new_counter ? cfg->in(2) : idom(cfg);
1685 }
1686 // If the use occurs after merging several exits from the loop, then
1687 // old value must have dominated all those exits. Since the same old
1688 // value was used on all those exits we did not need a Phi at this
1689 // merge point. NOW we do need a Phi here. Each loop exit value
1690 // is now merged with the peeled body exit; each exit gets its own
1691 // private Phi and those Phis need to be merged here.
1692 Node *phi;
1693 if( prev->is_Region() ) {
1694 if( idx == 0 ) { // Updating control edge?
1695 phi = prev; // Just use existing control
1696 } else { // Else need a new Phi
1697 phi = PhiNode::make( prev, old );
1698 // Now recursively fix up the new uses of old!
1699 for( uint i = 1; i < prev->req(); i++ ) {
1700 worklist.push(phi); // Onto worklist once for each 'old' input
1701 }
1702 }
1703 } else {
1704 // Get new RegionNode merging old and new loop exits
1705 prev = old_new[prev->_idx];
1706 assert( prev, "just made this in step 7" );
1707 if( idx == 0) { // Updating control edge?
1708 phi = prev; // Just use existing control
1709 } else { // Else need a new Phi
1710 // Make a new Phi merging data values properly
1711 phi = PhiNode::make( prev, old );
1712 phi->set_req( 1, nnn );
1713 }
1714 }
1715 // If inserting a new Phi, check for prior hits
1716 if( idx != 0 ) {
1717 Node *hit = _igvn.hash_find_insert(phi);
1718 if( hit == NULL ) {
1719 _igvn.register_new_node_with_optimizer(phi); // Register new phi
1720 } else { // or
1721 // Remove the new phi from the graph and use the hit
1722 _igvn.remove_dead_node(phi);
1723 phi = hit; // Use existing phi
1724 }
1725 set_ctrl(phi, prev);
1726 }
1727 // Make 'use' use the Phi instead of the old loop body exit value
1728 _igvn.replace_input_of(use, idx, phi);
1729 if( use->_idx >= new_counter ) { // If updating new phis
1730 // Not needed for correctness, but prevents a weak assert
1731 // in AddPNode from tripping (when we end up with different
1732 // base & derived Phis that will become the same after
1733 // IGVN does CSE).
1734 Node *hit = _igvn.hash_find_insert(use);
1735 if( hit ) // Go ahead and re-hash for hits.
1736 _igvn.replace_node( use, hit );
1737 }
1738
1739 // If 'use' was in the loop-exit block, it now needs to be sunk
1740 // below the post-loop merge point.
1741 sink_use( use, prev );
1742 }
1743 }
1744 }
1745
1746 void PhaseIdealLoop::clone_outer_loop(LoopNode* head, CloneLoopMode mode, IdealLoopTree *loop,
1747 IdealLoopTree* outer_loop, int dd, Node_List &old_new,
1748 Node_List& extra_data_nodes) {
1749 if (head->is_strip_mined() && mode != IgnoreStripMined) {
1750 CountedLoopNode* cl = head->as_CountedLoop();
1751 Node* l = cl->outer_loop();
1752 Node* tail = cl->outer_loop_tail();
1753 IfNode* le = cl->outer_loop_end();
1754 Node* sfpt = cl->outer_safepoint();
1755 CountedLoopEndNode* cle = cl->loopexit();
1756 CountedLoopNode* new_cl = old_new[cl->_idx]->as_CountedLoop();
1757 CountedLoopEndNode* new_cle = new_cl->as_CountedLoop()->loopexit_or_null();
1758 Node* cle_out = cle->proj_out(false);
1759
1760 Node* new_sfpt = NULL;
1761 Node* new_cle_out = cle_out->clone();
1762 old_new.map(cle_out->_idx, new_cle_out);
1763 if (mode == CloneIncludesStripMined) {
1764 // clone outer loop body
1765 Node* new_l = l->clone();
1766 Node* new_tail = tail->clone();
1767 IfNode* new_le = le->clone()->as_If();
1768 new_sfpt = sfpt->clone();
1769
1770 set_loop(new_l, outer_loop->_parent);
1771 set_idom(new_l, new_l->in(LoopNode::EntryControl), dd);
1772 set_loop(new_cle_out, outer_loop->_parent);
1773 set_idom(new_cle_out, new_cle, dd);
1774 set_loop(new_sfpt, outer_loop->_parent);
1775 set_idom(new_sfpt, new_cle_out, dd);
1776 set_loop(new_le, outer_loop->_parent);
1777 set_idom(new_le, new_sfpt, dd);
1778 set_loop(new_tail, outer_loop->_parent);
1779 set_idom(new_tail, new_le, dd);
1780 set_idom(new_cl, new_l, dd);
1781
1782 old_new.map(l->_idx, new_l);
1783 old_new.map(tail->_idx, new_tail);
1784 old_new.map(le->_idx, new_le);
1785 old_new.map(sfpt->_idx, new_sfpt);
1786
1787 new_l->set_req(LoopNode::LoopBackControl, new_tail);
1788 new_l->set_req(0, new_l);
1789 new_tail->set_req(0, new_le);
1790 new_le->set_req(0, new_sfpt);
1791 new_sfpt->set_req(0, new_cle_out);
1792 new_cle_out->set_req(0, new_cle);
1793 new_cl->set_req(LoopNode::EntryControl, new_l);
1794
1795 _igvn.register_new_node_with_optimizer(new_l);
1796 _igvn.register_new_node_with_optimizer(new_tail);
1797 _igvn.register_new_node_with_optimizer(new_le);
1798 } else {
1799 Node *newhead = old_new[loop->_head->_idx];
1800 newhead->as_Loop()->clear_strip_mined();
1801 _igvn.replace_input_of(newhead, LoopNode::EntryControl, newhead->in(LoopNode::EntryControl)->in(LoopNode::EntryControl));
1802 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd);
1803 }
1804 // Look at data node that were assigned a control in the outer
1805 // loop: they are kept in the outer loop by the safepoint so start
1806 // from the safepoint node's inputs.
1807 IdealLoopTree* outer_loop = get_loop(l);
1808 Node_Stack stack(2);
1809 stack.push(sfpt, 1);
1810 uint new_counter = C->unique();
1811 while (stack.size() > 0) {
1812 Node* n = stack.node();
1813 uint i = stack.index();
1814 while (i < n->req() &&
1815 (n->in(i) == NULL ||
1816 !has_ctrl(n->in(i)) ||
1817 get_loop(get_ctrl(n->in(i))) != outer_loop ||
1818 (old_new[n->in(i)->_idx] != NULL && old_new[n->in(i)->_idx]->_idx >= new_counter))) {
1819 i++;
1820 }
1821 if (i < n->req()) {
1822 stack.set_index(i+1);
1823 stack.push(n->in(i), 0);
1824 } else {
1825 assert(old_new[n->_idx] == NULL || n == sfpt || old_new[n->_idx]->_idx < new_counter, "no clone yet");
1826 Node* m = n == sfpt ? new_sfpt : n->clone();
1827 if (m != NULL) {
1828 for (uint i = 0; i < n->req(); i++) {
1829 if (m->in(i) != NULL && old_new[m->in(i)->_idx] != NULL) {
1830 m->set_req(i, old_new[m->in(i)->_idx]);
1831 }
1832 }
1833 } else {
1834 assert(n == sfpt && mode != CloneIncludesStripMined, "where's the safepoint clone?");
1835 }
1836 if (n != sfpt) {
1837 extra_data_nodes.push(n);
1838 _igvn.register_new_node_with_optimizer(m);
1839 assert(get_ctrl(n) == cle_out, "what other control?");
1840 set_ctrl(m, new_cle_out);
1841 old_new.map(n->_idx, m);
1842 }
1843 stack.pop();
1844 }
1845 }
1846 if (mode == CloneIncludesStripMined) {
1847 _igvn.register_new_node_with_optimizer(new_sfpt);
1848 _igvn.register_new_node_with_optimizer(new_cle_out);
1849 }
1850 } else {
1851 Node *newhead = old_new[loop->_head->_idx];
1852 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd);
1853 }
1854 }
1855
1856 //------------------------------clone_loop-------------------------------------
1857 //
1858 // C L O N E A L O O P B O D Y
1859 //
1860 // This is the basic building block of the loop optimizations. It clones an
1861 // entire loop body. It makes an old_new loop body mapping; with this mapping
1862 // you can find the new-loop equivalent to an old-loop node. All new-loop
1863 // nodes are exactly equal to their old-loop counterparts, all edges are the
1864 // same. All exits from the old-loop now have a RegionNode that merges the
1865 // equivalent new-loop path. This is true even for the normal "loop-exit"
1866 // condition. All uses of loop-invariant old-loop values now come from (one
1867 // or more) Phis that merge their new-loop equivalents.
1868 //
1869 // This operation leaves the graph in an illegal state: there are two valid
1870 // control edges coming from the loop pre-header to both loop bodies. I'll
1871 // definitely have to hack the graph after running this transform.
1872 //
1873 // From this building block I will further edit edges to perform loop peeling
1874 // or loop unrolling or iteration splitting (Range-Check-Elimination), etc.
1875 //
1876 // Parameter side_by_size_idom:
1877 // When side_by_size_idom is NULL, the dominator tree is constructed for
1878 // the clone loop to dominate the original. Used in construction of
1879 // pre-main-post loop sequence.
1880 // When nonnull, the clone and original are side-by-side, both are
1881 // dominated by the side_by_side_idom node. Used in construction of
1882 // unswitched loops.
1883 void PhaseIdealLoop::clone_loop( IdealLoopTree *loop, Node_List &old_new, int dd,
1884 CloneLoopMode mode, Node* side_by_side_idom) {
1885
1886 LoopNode* head = loop->_head->as_Loop();
1887 head->verify_strip_mined(1);
1888
1889 if (C->do_vector_loop() && PrintOpto) {
1890 const char* mname = C->method()->name()->as_quoted_ascii();
1891 if (mname != NULL) {
1892 tty->print("PhaseIdealLoop::clone_loop: for vectorize method %s\n", mname);
1893 }
1894 }
1895
1896 CloneMap& cm = C->clone_map();
1897 Dict* dict = cm.dict();
1898 if (C->do_vector_loop()) {
1899 cm.set_clone_idx(cm.max_gen()+1);
1900 #ifndef PRODUCT
1901 if (PrintOpto) {
1902 tty->print_cr("PhaseIdealLoop::clone_loop: _clone_idx %d", cm.clone_idx());
1903 loop->dump_head();
1904 }
1905 #endif
1906 }
1907
1908 // Step 1: Clone the loop body. Make the old->new mapping.
1909 uint i;
1910 for( i = 0; i < loop->_body.size(); i++ ) {
1911 Node *old = loop->_body.at(i);
1912 Node *nnn = old->clone();
1913 old_new.map( old->_idx, nnn );
1914 if (C->do_vector_loop()) {
1915 cm.verify_insert_and_clone(old, nnn, cm.clone_idx());
1916 }
1917 _igvn.register_new_node_with_optimizer(nnn);
1918 }
1919
1920 IdealLoopTree* outer_loop = (head->is_strip_mined() && mode != IgnoreStripMined) ? get_loop(head->as_CountedLoop()->outer_loop()) : loop;
1921
1922 // Step 2: Fix the edges in the new body. If the old input is outside the
1923 // loop use it. If the old input is INside the loop, use the corresponding
1924 // new node instead.
1925 for( i = 0; i < loop->_body.size(); i++ ) {
1926 Node *old = loop->_body.at(i);
1927 Node *nnn = old_new[old->_idx];
1928 // Fix CFG/Loop controlling the new node
1929 if (has_ctrl(old)) {
1930 set_ctrl(nnn, old_new[get_ctrl(old)->_idx]);
1931 } else {
1932 set_loop(nnn, outer_loop->_parent);
1933 if (old->outcnt() > 0) {
1934 set_idom( nnn, old_new[idom(old)->_idx], dd );
1935 }
1936 }
1937 // Correct edges to the new node
1938 for( uint j = 0; j < nnn->req(); j++ ) {
1939 Node *n = nnn->in(j);
1940 if( n ) {
1941 IdealLoopTree *old_in_loop = get_loop( has_ctrl(n) ? get_ctrl(n) : n );
1942 if( loop->is_member( old_in_loop ) )
1943 nnn->set_req(j, old_new[n->_idx]);
1944 }
1945 }
1946 _igvn.hash_find_insert(nnn);
1947 }
1948
1949 ResourceArea *area = Thread::current()->resource_area();
1950 Node_List extra_data_nodes(area);
1951 clone_outer_loop(head, mode, loop, outer_loop, dd, old_new, extra_data_nodes);
1952
1953 // Step 3: Now fix control uses. Loop varying control uses have already
1954 // been fixed up (as part of all input edges in Step 2). Loop invariant
1955 // control uses must be either an IfFalse or an IfTrue. Make a merge
1956 // point to merge the old and new IfFalse/IfTrue nodes; make the use
1957 // refer to this.
1958 Node_List worklist(area);
1959 uint new_counter = C->unique();
1960 for( i = 0; i < loop->_body.size(); i++ ) {
1961 Node* old = loop->_body.at(i);
1962 if( !old->is_CFG() ) continue;
1963
1964 // Copy uses to a worklist, so I can munge the def-use info
1965 // with impunity.
1966 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++)
1967 worklist.push(old->fast_out(j));
1968
1969 while( worklist.size() ) { // Visit all uses
1970 Node *use = worklist.pop();
1971 if (!has_node(use)) continue; // Ignore dead nodes
1972 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use );
1973 if( !loop->is_member( use_loop ) && use->is_CFG() ) {
1974 // Both OLD and USE are CFG nodes here.
1975 assert( use->is_Proj(), "" );
1976 Node* nnn = old_new[old->_idx];
1977
1978 Node* newuse = NULL;
1979 if (head->is_strip_mined() && mode != IgnoreStripMined) {
1980 CountedLoopNode* cl = head->as_CountedLoop();
1981 CountedLoopEndNode* cle = cl->loopexit();
1982 Node* cle_out = cle->proj_out_or_null(false);
1983 if (use == cle_out) {
1984 IfNode* le = cl->outer_loop_end();
1985 use = le->proj_out(false);
1986 use_loop = get_loop(use);
1987 if (mode == CloneIncludesStripMined) {
1988 nnn = old_new[le->_idx];
1989 } else {
1990 newuse = old_new[cle_out->_idx];
1991 }
1992 }
1993 }
1994 if (newuse == NULL) {
1995 newuse = use->clone();
1996 }
1997
1998 // Clone the loop exit control projection
1999 if (C->do_vector_loop()) {
2000 cm.verify_insert_and_clone(use, newuse, cm.clone_idx());
2001 }
2002 newuse->set_req(0,nnn);
2003 _igvn.register_new_node_with_optimizer(newuse);
2004 set_loop(newuse, use_loop);
2005 set_idom(newuse, nnn, dom_depth(nnn) + 1 );
2006
2007 // We need a Region to merge the exit from the peeled body and the
2008 // exit from the old loop body.
2009 RegionNode *r = new RegionNode(3);
2010 // Map the old use to the new merge point
2011 old_new.map( use->_idx, r );
2012 uint dd_r = MIN2(dom_depth(newuse),dom_depth(use));
2013 assert( dd_r >= dom_depth(dom_lca(newuse,use)), "" );
2014
2015 // The original user of 'use' uses 'r' instead.
2016 for (DUIterator_Last lmin, l = use->last_outs(lmin); l >= lmin;) {
2017 Node* useuse = use->last_out(l);
2018 _igvn.rehash_node_delayed(useuse);
2019 uint uses_found = 0;
2020 if( useuse->in(0) == use ) {
2021 useuse->set_req(0, r);
2022 uses_found++;
2023 if( useuse->is_CFG() ) {
2024 assert( dom_depth(useuse) > dd_r, "" );
2025 set_idom(useuse, r, dom_depth(useuse));
2026 }
2027 }
2028 for( uint k = 1; k < useuse->req(); k++ ) {
2029 if( useuse->in(k) == use ) {
2030 useuse->set_req(k, r);
2031 uses_found++;
2032 if (useuse->is_Loop() && k == LoopNode::EntryControl) {
2033 assert(dom_depth(useuse) > dd_r , "");
2034 set_idom(useuse, r, dom_depth(useuse));
2035 }
2036 }
2037 }
2038 l -= uses_found; // we deleted 1 or more copies of this edge
2039 }
2040
2041 // Now finish up 'r'
2042 r->set_req( 1, newuse );
2043 r->set_req( 2, use );
2044 _igvn.register_new_node_with_optimizer(r);
2045 set_loop(r, use_loop);
2046 set_idom(r, !side_by_side_idom ? newuse->in(0) : side_by_side_idom, dd_r);
2047 } // End of if a loop-exit test
2048 }
2049 }
2050
2051 // Step 4: If loop-invariant use is not control, it must be dominated by a
2052 // loop exit IfFalse/IfTrue. Find "proper" loop exit. Make a Region
2053 // there if needed. Make a Phi there merging old and new used values.
2054 Node_List *split_if_set = NULL;
2055 Node_List *split_bool_set = NULL;
2056 Node_List *split_cex_set = NULL;
2057 for( i = 0; i < loop->_body.size(); i++ ) {
2058 Node* old = loop->_body.at(i);
2059 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set,
2060 split_bool_set, split_cex_set, worklist, new_counter,
2061 mode);
2062 }
2063
2064 for (i = 0; i < extra_data_nodes.size(); i++) {
2065 Node* old = extra_data_nodes.at(i);
2066 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set,
2067 split_bool_set, split_cex_set, worklist, new_counter,
2068 mode);
2069 }
2070
2071 // Check for IFs that need splitting/cloning. Happens if an IF outside of
2072 // the loop uses a condition set in the loop. The original IF probably
2073 // takes control from one or more OLD Regions (which in turn get from NEW
2074 // Regions). In any case, there will be a set of Phis for each merge point
2075 // from the IF up to where the original BOOL def exists the loop.
2076 if (split_if_set) {
2077 while (split_if_set->size()) {
2078 Node *iff = split_if_set->pop();
2079 if (iff->in(1)->is_Phi()) {
2080 Node *b = clone_iff(iff->in(1)->as_Phi(), loop);
2081 _igvn.replace_input_of(iff, 1, b);
2082 }
2083 }
2084 }
2085 if (split_bool_set) {
2086 while (split_bool_set->size()) {
2087 Node *b = split_bool_set->pop();
2088 Node *phi = b->in(1);
2089 assert(phi->is_Phi(), "");
2090 CmpNode *cmp = clone_bool((PhiNode*)phi, loop);
2091 _igvn.replace_input_of(b, 1, cmp);
2092 }
2093 }
2094 if (split_cex_set) {
2095 while (split_cex_set->size()) {
2096 Node *b = split_cex_set->pop();
2097 assert(b->in(0)->is_Region(), "");
2098 assert(b->in(1)->is_Phi(), "");
2099 assert(b->in(0)->in(0) == b->in(1)->in(0), "");
2100 split_up(b, b->in(0), NULL);
2101 }
2102 }
2103
2104 }
2105
2106
2107 //---------------------- stride_of_possible_iv -------------------------------------
2108 // Looks for an iff/bool/comp with one operand of the compare
2109 // being a cycle involving an add and a phi,
2110 // with an optional truncation (left-shift followed by a right-shift)
2111 // of the add. Returns zero if not an iv.
2112 int PhaseIdealLoop::stride_of_possible_iv(Node* iff) {
2113 Node* trunc1 = NULL;
2114 Node* trunc2 = NULL;
2115 const TypeInt* ttype = NULL;
2116 if (!iff->is_If() || iff->in(1) == NULL || !iff->in(1)->is_Bool()) {
2117 return 0;
2118 }
2119 BoolNode* bl = iff->in(1)->as_Bool();
2120 Node* cmp = bl->in(1);
2121 if (!cmp || (cmp->Opcode() != Op_CmpI && cmp->Opcode() != Op_CmpU)) {
2122 return 0;
2123 }
2124 // Must have an invariant operand
2125 if (is_member(get_loop(iff), get_ctrl(cmp->in(2)))) {
2126 return 0;
2127 }
2128 Node* add2 = NULL;
2129 Node* cmp1 = cmp->in(1);
2130 if (cmp1->is_Phi()) {
2131 // (If (Bool (CmpX phi:(Phi ...(Optional-trunc(AddI phi add2))) )))
2132 Node* phi = cmp1;
2133 for (uint i = 1; i < phi->req(); i++) {
2134 Node* in = phi->in(i);
2135 Node* add = CountedLoopNode::match_incr_with_optional_truncation(in,
2136 &trunc1, &trunc2, &ttype);
2137 if (add && add->in(1) == phi) {
2138 add2 = add->in(2);
2139 break;
2140 }
2141 }
2142 } else {
2143 // (If (Bool (CmpX addtrunc:(Optional-trunc((AddI (Phi ...addtrunc...) add2)) )))
2144 Node* addtrunc = cmp1;
2145 Node* add = CountedLoopNode::match_incr_with_optional_truncation(addtrunc,
2146 &trunc1, &trunc2, &ttype);
2147 if (add && add->in(1)->is_Phi()) {
2148 Node* phi = add->in(1);
2149 for (uint i = 1; i < phi->req(); i++) {
2150 if (phi->in(i) == addtrunc) {
2151 add2 = add->in(2);
2152 break;
2153 }
2154 }
2155 }
2156 }
2157 if (add2 != NULL) {
2158 const TypeInt* add2t = _igvn.type(add2)->is_int();
2159 if (add2t->is_con()) {
2160 return add2t->get_con();
2161 }
2162 }
2163 return 0;
2164 }
2165
2166
2167 //---------------------- stay_in_loop -------------------------------------
2168 // Return the (unique) control output node that's in the loop (if it exists.)
2169 Node* PhaseIdealLoop::stay_in_loop( Node* n, IdealLoopTree *loop) {
2170 Node* unique = NULL;
2171 if (!n) return NULL;
2172 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2173 Node* use = n->fast_out(i);
2174 if (!has_ctrl(use) && loop->is_member(get_loop(use))) {
2175 if (unique != NULL) {
2176 return NULL;
2177 }
2178 unique = use;
2179 }
2180 }
2181 return unique;
2182 }
2183
2184 //------------------------------ register_node -------------------------------------
2185 // Utility to register node "n" with PhaseIdealLoop
2186 void PhaseIdealLoop::register_node(Node* n, IdealLoopTree *loop, Node* pred, int ddepth) {
2187 _igvn.register_new_node_with_optimizer(n);
2188 loop->_body.push(n);
2189 if (n->is_CFG()) {
2190 set_loop(n, loop);
2191 set_idom(n, pred, ddepth);
2192 } else {
2193 set_ctrl(n, pred);
2194 }
2195 }
2196
2197 //------------------------------ proj_clone -------------------------------------
2198 // Utility to create an if-projection
2199 ProjNode* PhaseIdealLoop::proj_clone(ProjNode* p, IfNode* iff) {
2200 ProjNode* c = p->clone()->as_Proj();
2201 c->set_req(0, iff);
2202 return c;
2203 }
2204
2205 //------------------------------ short_circuit_if -------------------------------------
2206 // Force the iff control output to be the live_proj
2207 Node* PhaseIdealLoop::short_circuit_if(IfNode* iff, ProjNode* live_proj) {
2208 guarantee(live_proj != NULL, "null projection");
2209 int proj_con = live_proj->_con;
2210 assert(proj_con == 0 || proj_con == 1, "false or true projection");
2211 Node *con = _igvn.intcon(proj_con);
2212 set_ctrl(con, C->root());
2213 if (iff) {
2214 iff->set_req(1, con);
2215 }
2216 return con;
2217 }
2218
2219 //------------------------------ insert_if_before_proj -------------------------------------
2220 // Insert a new if before an if projection (* - new node)
2221 //
2222 // before
2223 // if(test)
2224 // / \
2225 // v v
2226 // other-proj proj (arg)
2227 //
2228 // after
2229 // if(test)
2230 // / \
2231 // / v
2232 // | * proj-clone
2233 // v |
2234 // other-proj v
2235 // * new_if(relop(cmp[IU](left,right)))
2236 // / \
2237 // v v
2238 // * new-proj proj
2239 // (returned)
2240 //
2241 ProjNode* PhaseIdealLoop::insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj) {
2242 IfNode* iff = proj->in(0)->as_If();
2243 IdealLoopTree *loop = get_loop(proj);
2244 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj();
2245 int ddepth = dom_depth(proj);
2246
2247 _igvn.rehash_node_delayed(iff);
2248 _igvn.rehash_node_delayed(proj);
2249
2250 proj->set_req(0, NULL); // temporary disconnect
2251 ProjNode* proj2 = proj_clone(proj, iff);
2252 register_node(proj2, loop, iff, ddepth);
2253
2254 Node* cmp = Signed ? (Node*) new CmpINode(left, right) : (Node*) new CmpUNode(left, right);
2255 register_node(cmp, loop, proj2, ddepth);
2256
2257 BoolNode* bol = new BoolNode(cmp, relop);
2258 register_node(bol, loop, proj2, ddepth);
2259
2260 int opcode = iff->Opcode();
2261 assert(opcode == Op_If || opcode == Op_RangeCheck, "unexpected opcode");
2262 IfNode* new_if = (opcode == Op_If) ? new IfNode(proj2, bol, iff->_prob, iff->_fcnt):
2263 new RangeCheckNode(proj2, bol, iff->_prob, iff->_fcnt);
2264 register_node(new_if, loop, proj2, ddepth);
2265
2266 proj->set_req(0, new_if); // reattach
2267 set_idom(proj, new_if, ddepth);
2268
2269 ProjNode* new_exit = proj_clone(other_proj, new_if)->as_Proj();
2270 guarantee(new_exit != NULL, "null exit node");
2271 register_node(new_exit, get_loop(other_proj), new_if, ddepth);
2272
2273 return new_exit;
2274 }
2275
2276 //------------------------------ insert_region_before_proj -------------------------------------
2277 // Insert a region before an if projection (* - new node)
2278 //
2279 // before
2280 // if(test)
2281 // / |
2282 // v |
2283 // proj v
2284 // other-proj
2285 //
2286 // after
2287 // if(test)
2288 // / |
2289 // v |
2290 // * proj-clone v
2291 // | other-proj
2292 // v
2293 // * new-region
2294 // |
2295 // v
2296 // * dum_if
2297 // / \
2298 // v \
2299 // * dum-proj v
2300 // proj
2301 //
2302 RegionNode* PhaseIdealLoop::insert_region_before_proj(ProjNode* proj) {
2303 IfNode* iff = proj->in(0)->as_If();
2304 IdealLoopTree *loop = get_loop(proj);
2305 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj();
2306 int ddepth = dom_depth(proj);
2307
2308 _igvn.rehash_node_delayed(iff);
2309 _igvn.rehash_node_delayed(proj);
2310
2311 proj->set_req(0, NULL); // temporary disconnect
2312 ProjNode* proj2 = proj_clone(proj, iff);
2313 register_node(proj2, loop, iff, ddepth);
2314
2315 RegionNode* reg = new RegionNode(2);
2316 reg->set_req(1, proj2);
2317 register_node(reg, loop, iff, ddepth);
2318
2319 IfNode* dum_if = new IfNode(reg, short_circuit_if(NULL, proj), iff->_prob, iff->_fcnt);
2320 register_node(dum_if, loop, reg, ddepth);
2321
2322 proj->set_req(0, dum_if); // reattach
2323 set_idom(proj, dum_if, ddepth);
2324
2325 ProjNode* dum_proj = proj_clone(other_proj, dum_if);
2326 register_node(dum_proj, loop, dum_if, ddepth);
2327
2328 return reg;
2329 }
2330
2331 //------------------------------ insert_cmpi_loop_exit -------------------------------------
2332 // Clone a signed compare loop exit from an unsigned compare and
2333 // insert it before the unsigned cmp on the stay-in-loop path.
2334 // All new nodes inserted in the dominator tree between the original
2335 // if and it's projections. The original if test is replaced with
2336 // a constant to force the stay-in-loop path.
2337 //
2338 // This is done to make sure that the original if and it's projections
2339 // still dominate the same set of control nodes, that the ctrl() relation
2340 // from data nodes to them is preserved, and that their loop nesting is
2341 // preserved.
2342 //
2343 // before
2344 // if(i <u limit) unsigned compare loop exit
2345 // / |
2346 // v v
2347 // exit-proj stay-in-loop-proj
2348 //
2349 // after
2350 // if(stay-in-loop-const) original if
2351 // / |
2352 // / v
2353 // / if(i < limit) new signed test
2354 // / / |
2355 // / / v
2356 // / / if(i <u limit) new cloned unsigned test
2357 // / / / |
2358 // v v v |
2359 // region |
2360 // | |
2361 // dum-if |
2362 // / | |
2363 // ether | |
2364 // v v
2365 // exit-proj stay-in-loop-proj
2366 //
2367 IfNode* PhaseIdealLoop::insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *loop) {
2368 const bool Signed = true;
2369 const bool Unsigned = false;
2370
2371 BoolNode* bol = if_cmpu->in(1)->as_Bool();
2372 if (bol->_test._test != BoolTest::lt) return NULL;
2373 CmpNode* cmpu = bol->in(1)->as_Cmp();
2374 if (cmpu->Opcode() != Op_CmpU) return NULL;
2375 int stride = stride_of_possible_iv(if_cmpu);
2376 if (stride == 0) return NULL;
2377
2378 Node* lp_proj = stay_in_loop(if_cmpu, loop);
2379 guarantee(lp_proj != NULL, "null loop node");
2380
2381 ProjNode* lp_continue = lp_proj->as_Proj();
2382 ProjNode* lp_exit = if_cmpu->proj_out(!lp_continue->is_IfTrue())->as_Proj();
2383
2384 Node* limit = NULL;
2385 if (stride > 0) {
2386 limit = cmpu->in(2);
2387 } else {
2388 limit = _igvn.makecon(TypeInt::ZERO);
2389 set_ctrl(limit, C->root());
2390 }
2391 // Create a new region on the exit path
2392 RegionNode* reg = insert_region_before_proj(lp_exit);
2393 guarantee(reg != NULL, "null region node");
2394
2395 // Clone the if-cmpu-true-false using a signed compare
2396 BoolTest::mask rel_i = stride > 0 ? bol->_test._test : BoolTest::ge;
2397 ProjNode* cmpi_exit = insert_if_before_proj(cmpu->in(1), Signed, rel_i, limit, lp_continue);
2398 reg->add_req(cmpi_exit);
2399
2400 // Clone the if-cmpu-true-false
2401 BoolTest::mask rel_u = bol->_test._test;
2402 ProjNode* cmpu_exit = insert_if_before_proj(cmpu->in(1), Unsigned, rel_u, cmpu->in(2), lp_continue);
2403 reg->add_req(cmpu_exit);
2404
2405 // Force original if to stay in loop.
2406 short_circuit_if(if_cmpu, lp_continue);
2407
2408 return cmpi_exit->in(0)->as_If();
2409 }
2410
2411 //------------------------------ remove_cmpi_loop_exit -------------------------------------
2412 // Remove a previously inserted signed compare loop exit.
2413 void PhaseIdealLoop::remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop) {
2414 Node* lp_proj = stay_in_loop(if_cmp, loop);
2415 assert(if_cmp->in(1)->in(1)->Opcode() == Op_CmpI &&
2416 stay_in_loop(lp_proj, loop)->is_If() &&
2417 stay_in_loop(lp_proj, loop)->in(1)->in(1)->Opcode() == Op_CmpU, "inserted cmpi before cmpu");
2418 Node *con = _igvn.makecon(lp_proj->is_IfTrue() ? TypeInt::ONE : TypeInt::ZERO);
2419 set_ctrl(con, C->root());
2420 if_cmp->set_req(1, con);
2421 }
2422
2423 //------------------------------ scheduled_nodelist -------------------------------------
2424 // Create a post order schedule of nodes that are in the
2425 // "member" set. The list is returned in "sched".
2426 // The first node in "sched" is the loop head, followed by
2427 // nodes which have no inputs in the "member" set, and then
2428 // followed by the nodes that have an immediate input dependence
2429 // on a node in "sched".
2430 void PhaseIdealLoop::scheduled_nodelist( IdealLoopTree *loop, VectorSet& member, Node_List &sched ) {
2431
2432 assert(member.test(loop->_head->_idx), "loop head must be in member set");
2433 Arena *a = Thread::current()->resource_area();
2434 VectorSet visited(a);
2435 Node_Stack nstack(a, loop->_body.size());
2436
2437 Node* n = loop->_head; // top of stack is cached in "n"
2438 uint idx = 0;
2439 visited.set(n->_idx);
2440
2441 // Initially push all with no inputs from within member set
2442 for(uint i = 0; i < loop->_body.size(); i++ ) {
2443 Node *elt = loop->_body.at(i);
2444 if (member.test(elt->_idx)) {
2445 bool found = false;
2446 for (uint j = 0; j < elt->req(); j++) {
2447 Node* def = elt->in(j);
2448 if (def && member.test(def->_idx) && def != elt) {
2449 found = true;
2450 break;
2451 }
2452 }
2453 if (!found && elt != loop->_head) {
2454 nstack.push(n, idx);
2455 n = elt;
2456 assert(!visited.test(n->_idx), "not seen yet");
2457 visited.set(n->_idx);
2458 }
2459 }
2460 }
2461
2462 // traverse out's that are in the member set
2463 while (true) {
2464 if (idx < n->outcnt()) {
2465 Node* use = n->raw_out(idx);
2466 idx++;
2467 if (!visited.test_set(use->_idx)) {
2468 if (member.test(use->_idx)) {
2469 nstack.push(n, idx);
2470 n = use;
2471 idx = 0;
2472 }
2473 }
2474 } else {
2475 // All outputs processed
2476 sched.push(n);
2477 if (nstack.is_empty()) break;
2478 n = nstack.node();
2479 idx = nstack.index();
2480 nstack.pop();
2481 }
2482 }
2483 }
2484
2485
2486 //------------------------------ has_use_in_set -------------------------------------
2487 // Has a use in the vector set
2488 bool PhaseIdealLoop::has_use_in_set( Node* n, VectorSet& vset ) {
2489 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2490 Node* use = n->fast_out(j);
2491 if (vset.test(use->_idx)) {
2492 return true;
2493 }
2494 }
2495 return false;
2496 }
2497
2498
2499 //------------------------------ has_use_internal_to_set -------------------------------------
2500 // Has use internal to the vector set (ie. not in a phi at the loop head)
2501 bool PhaseIdealLoop::has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ) {
2502 Node* head = loop->_head;
2503 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2504 Node* use = n->fast_out(j);
2505 if (vset.test(use->_idx) && !(use->is_Phi() && use->in(0) == head)) {
2506 return true;
2507 }
2508 }
2509 return false;
2510 }
2511
2512
2513 //------------------------------ clone_for_use_outside_loop -------------------------------------
2514 // clone "n" for uses that are outside of loop
2515 int PhaseIdealLoop::clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ) {
2516 int cloned = 0;
2517 assert(worklist.size() == 0, "should be empty");
2518 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2519 Node* use = n->fast_out(j);
2520 if( !loop->is_member(get_loop(has_ctrl(use) ? get_ctrl(use) : use)) ) {
2521 worklist.push(use);
2522 }
2523 }
2524 while( worklist.size() ) {
2525 Node *use = worklist.pop();
2526 if (!has_node(use) || use->in(0) == C->top()) continue;
2527 uint j;
2528 for (j = 0; j < use->req(); j++) {
2529 if (use->in(j) == n) break;
2530 }
2531 assert(j < use->req(), "must be there");
2532
2533 // clone "n" and insert it between the inputs of "n" and the use outside the loop
2534 Node* n_clone = n->clone();
2535 _igvn.replace_input_of(use, j, n_clone);
2536 cloned++;
2537 Node* use_c;
2538 if (!use->is_Phi()) {
2539 use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0);
2540 } else {
2541 // Use in a phi is considered a use in the associated predecessor block
2542 use_c = use->in(0)->in(j);
2543 }
2544 set_ctrl(n_clone, use_c);
2545 assert(!loop->is_member(get_loop(use_c)), "should be outside loop");
2546 get_loop(use_c)->_body.push(n_clone);
2547 _igvn.register_new_node_with_optimizer(n_clone);
2548 #if !defined(PRODUCT)
2549 if (TracePartialPeeling) {
2550 tty->print_cr("loop exit cloning old: %d new: %d newbb: %d", n->_idx, n_clone->_idx, get_ctrl(n_clone)->_idx);
2551 }
2552 #endif
2553 }
2554 return cloned;
2555 }
2556
2557
2558 //------------------------------ clone_for_special_use_inside_loop -------------------------------------
2559 // clone "n" for special uses that are in the not_peeled region.
2560 // If these def-uses occur in separate blocks, the code generator
2561 // marks the method as not compilable. For example, if a "BoolNode"
2562 // is in a different basic block than the "IfNode" that uses it, then
2563 // the compilation is aborted in the code generator.
2564 void PhaseIdealLoop::clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n,
2565 VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ) {
2566 if (n->is_Phi() || n->is_Load()) {
2567 return;
2568 }
2569 assert(worklist.size() == 0, "should be empty");
2570 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2571 Node* use = n->fast_out(j);
2572 if ( not_peel.test(use->_idx) &&
2573 (use->is_If() || use->is_CMove() || use->is_Bool()) &&
2574 use->in(1) == n) {
2575 worklist.push(use);
2576 }
2577 }
2578 if (worklist.size() > 0) {
2579 // clone "n" and insert it between inputs of "n" and the use
2580 Node* n_clone = n->clone();
2581 loop->_body.push(n_clone);
2582 _igvn.register_new_node_with_optimizer(n_clone);
2583 set_ctrl(n_clone, get_ctrl(n));
2584 sink_list.push(n_clone);
2585 not_peel <<= n_clone->_idx; // add n_clone to not_peel set.
2586 #if !defined(PRODUCT)
2587 if (TracePartialPeeling) {
2588 tty->print_cr("special not_peeled cloning old: %d new: %d", n->_idx, n_clone->_idx);
2589 }
2590 #endif
2591 while( worklist.size() ) {
2592 Node *use = worklist.pop();
2593 _igvn.rehash_node_delayed(use);
2594 for (uint j = 1; j < use->req(); j++) {
2595 if (use->in(j) == n) {
2596 use->set_req(j, n_clone);
2597 }
2598 }
2599 }
2600 }
2601 }
2602
2603
2604 //------------------------------ insert_phi_for_loop -------------------------------------
2605 // Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist
2606 void PhaseIdealLoop::insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ) {
2607 Node *phi = PhiNode::make(lp, back_edge_val);
2608 phi->set_req(LoopNode::EntryControl, lp_entry_val);
2609 // Use existing phi if it already exists
2610 Node *hit = _igvn.hash_find_insert(phi);
2611 if( hit == NULL ) {
2612 _igvn.register_new_node_with_optimizer(phi);
2613 set_ctrl(phi, lp);
2614 } else {
2615 // Remove the new phi from the graph and use the hit
2616 _igvn.remove_dead_node(phi);
2617 phi = hit;
2618 }
2619 _igvn.replace_input_of(use, idx, phi);
2620 }
2621
2622 #ifdef ASSERT
2623 //------------------------------ is_valid_loop_partition -------------------------------------
2624 // Validate the loop partition sets: peel and not_peel
2625 bool PhaseIdealLoop::is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list,
2626 VectorSet& not_peel ) {
2627 uint i;
2628 // Check that peel_list entries are in the peel set
2629 for (i = 0; i < peel_list.size(); i++) {
2630 if (!peel.test(peel_list.at(i)->_idx)) {
2631 return false;
2632 }
2633 }
2634 // Check at loop members are in one of peel set or not_peel set
2635 for (i = 0; i < loop->_body.size(); i++ ) {
2636 Node *def = loop->_body.at(i);
2637 uint di = def->_idx;
2638 // Check that peel set elements are in peel_list
2639 if (peel.test(di)) {
2640 if (not_peel.test(di)) {
2641 return false;
2642 }
2643 // Must be in peel_list also
2644 bool found = false;
2645 for (uint j = 0; j < peel_list.size(); j++) {
2646 if (peel_list.at(j)->_idx == di) {
2647 found = true;
2648 break;
2649 }
2650 }
2651 if (!found) {
2652 return false;
2653 }
2654 } else if (not_peel.test(di)) {
2655 if (peel.test(di)) {
2656 return false;
2657 }
2658 } else {
2659 return false;
2660 }
2661 }
2662 return true;
2663 }
2664
2665 //------------------------------ is_valid_clone_loop_exit_use -------------------------------------
2666 // Ensure a use outside of loop is of the right form
2667 bool PhaseIdealLoop::is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx) {
2668 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use;
2669 return (use->is_Phi() &&
2670 use_c->is_Region() && use_c->req() == 3 &&
2671 (use_c->in(exit_idx)->Opcode() == Op_IfTrue ||
2672 use_c->in(exit_idx)->Opcode() == Op_IfFalse ||
2673 use_c->in(exit_idx)->Opcode() == Op_JumpProj) &&
2674 loop->is_member( get_loop( use_c->in(exit_idx)->in(0) ) ) );
2675 }
2676
2677 //------------------------------ is_valid_clone_loop_form -------------------------------------
2678 // Ensure that all uses outside of loop are of the right form
2679 bool PhaseIdealLoop::is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list,
2680 uint orig_exit_idx, uint clone_exit_idx) {
2681 uint len = peel_list.size();
2682 for (uint i = 0; i < len; i++) {
2683 Node *def = peel_list.at(i);
2684
2685 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
2686 Node *use = def->fast_out(j);
2687 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use;
2688 if (!loop->is_member(get_loop(use_c))) {
2689 // use is not in the loop, check for correct structure
2690 if (use->in(0) == def) {
2691 // Okay
2692 } else if (!is_valid_clone_loop_exit_use(loop, use, orig_exit_idx)) {
2693 return false;
2694 }
2695 }
2696 }
2697 }
2698 return true;
2699 }
2700 #endif
2701
2702 //------------------------------ partial_peel -------------------------------------
2703 // Partially peel (aka loop rotation) the top portion of a loop (called
2704 // the peel section below) by cloning it and placing one copy just before
2705 // the new loop head and the other copy at the bottom of the new loop.
2706 //
2707 // before after where it came from
2708 //
2709 // stmt1 stmt1
2710 // loop: stmt2 clone
2711 // stmt2 if condA goto exitA clone
2712 // if condA goto exitA new_loop: new
2713 // stmt3 stmt3 clone
2714 // if !condB goto loop if condB goto exitB clone
2715 // exitB: stmt2 orig
2716 // stmt4 if !condA goto new_loop orig
2717 // exitA: goto exitA
2718 // exitB:
2719 // stmt4
2720 // exitA:
2721 //
2722 // Step 1: find the cut point: an exit test on probable
2723 // induction variable.
2724 // Step 2: schedule (with cloning) operations in the peel
2725 // section that can be executed after the cut into
2726 // the section that is not peeled. This may need
2727 // to clone operations into exit blocks. For
2728 // instance, a reference to A[i] in the not-peel
2729 // section and a reference to B[i] in an exit block
2730 // may cause a left-shift of i by 2 to be placed
2731 // in the peel block. This step will clone the left
2732 // shift into the exit block and sink the left shift
2733 // from the peel to the not-peel section.
2734 // Step 3: clone the loop, retarget the control, and insert
2735 // phis for values that are live across the new loop
2736 // head. This is very dependent on the graph structure
2737 // from clone_loop. It creates region nodes for
2738 // exit control and associated phi nodes for values
2739 // flow out of the loop through that exit. The region
2740 // node is dominated by the clone's control projection.
2741 // So the clone's peel section is placed before the
2742 // new loop head, and the clone's not-peel section is
2743 // forms the top part of the new loop. The original
2744 // peel section forms the tail of the new loop.
2745 // Step 4: update the dominator tree and recompute the
2746 // dominator depth.
2747 //
2748 // orig
2749 //
2750 // stmt1
2751 // |
2752 // v
2753 // loop predicate
2754 // |
2755 // v
2756 // loop<----+
2757 // | |
2758 // stmt2 |
2759 // | |
2760 // v |
2761 // ifA |
2762 // / | |
2763 // v v |
2764 // false true ^ <-- last_peel
2765 // / | |
2766 // / ===|==cut |
2767 // / stmt3 | <-- first_not_peel
2768 // / | |
2769 // | v |
2770 // v ifB |
2771 // exitA: / \ |
2772 // / \ |
2773 // v v |
2774 // false true |
2775 // / \ |
2776 // / ----+
2777 // |
2778 // v
2779 // exitB:
2780 // stmt4
2781 //
2782 //
2783 // after clone loop
2784 //
2785 // stmt1
2786 // |
2787 // v
2788 // loop predicate
2789 // / \
2790 // clone / \ orig
2791 // / \
2792 // / \
2793 // v v
2794 // +---->loop loop<----+
2795 // | | | |
2796 // | stmt2 stmt2 |
2797 // | | | |
2798 // | v v |
2799 // | ifA ifA |
2800 // | | \ / | |
2801 // | v v v v |
2802 // ^ true false false true ^ <-- last_peel
2803 // | | ^ \ / | |
2804 // | cut==|== \ \ / ===|==cut |
2805 // | stmt3 \ \ / stmt3 | <-- first_not_peel
2806 // | | dom | | | |
2807 // | v \ 1v v2 v |
2808 // | ifB regionA ifB |
2809 // | / \ | / \ |
2810 // | / \ v / \ |
2811 // | v v exitA: v v |
2812 // | true false false true |
2813 // | / ^ \ / \ |
2814 // +---- \ \ / ----+
2815 // dom \ /
2816 // \ 1v v2
2817 // regionB
2818 // |
2819 // v
2820 // exitB:
2821 // stmt4
2822 //
2823 //
2824 // after partial peel
2825 //
2826 // stmt1
2827 // |
2828 // v
2829 // loop predicate
2830 // /
2831 // clone / orig
2832 // / TOP
2833 // / \
2834 // v v
2835 // TOP->loop loop----+
2836 // | | |
2837 // stmt2 stmt2 |
2838 // | | |
2839 // v v |
2840 // ifA ifA |
2841 // | \ / | |
2842 // v v v v |
2843 // true false false true | <-- last_peel
2844 // | ^ \ / +------|---+
2845 // +->newloop \ \ / === ==cut | |
2846 // | stmt3 \ \ / TOP | |
2847 // | | dom | | stmt3 | | <-- first_not_peel
2848 // | v \ 1v v2 v | |
2849 // | ifB regionA ifB ^ v
2850 // | / \ | / \ | |
2851 // | / \ v / \ | |
2852 // | v v exitA: v v | |
2853 // | true false false true | |
2854 // | / ^ \ / \ | |
2855 // | | \ \ / v | |
2856 // | | dom \ / TOP | |
2857 // | | \ 1v v2 | |
2858 // ^ v regionB | |
2859 // | | | | |
2860 // | | v ^ v
2861 // | | exitB: | |
2862 // | | stmt4 | |
2863 // | +------------>-----------------+ |
2864 // | |
2865 // +-----------------<---------------------+
2866 //
2867 //
2868 // final graph
2869 //
2870 // stmt1
2871 // |
2872 // v
2873 // loop predicate
2874 // |
2875 // v
2876 // stmt2 clone
2877 // |
2878 // v
2879 // ........> ifA clone
2880 // : / |
2881 // dom / |
2882 // : v v
2883 // : false true
2884 // : | |
2885 // : | v
2886 // : | newloop<-----+
2887 // : | | |
2888 // : | stmt3 clone |
2889 // : | | |
2890 // : | v |
2891 // : | ifB |
2892 // : | / \ |
2893 // : | v v |
2894 // : | false true |
2895 // : | | | |
2896 // : | v stmt2 |
2897 // : | exitB: | |
2898 // : | stmt4 v |
2899 // : | ifA orig |
2900 // : | / \ |
2901 // : | / \ |
2902 // : | v v |
2903 // : | false true |
2904 // : | / \ |
2905 // : v v -----+
2906 // RegionA
2907 // |
2908 // v
2909 // exitA
2910 //
2911 bool PhaseIdealLoop::partial_peel( IdealLoopTree *loop, Node_List &old_new ) {
2912
2913 assert(!loop->_head->is_CountedLoop(), "Non-counted loop only");
2914 if (!loop->_head->is_Loop()) {
2915 return false; }
2916
2917 LoopNode *head = loop->_head->as_Loop();
2918
2919 if (head->is_partial_peel_loop() || head->partial_peel_has_failed()) {
2920 return false;
2921 }
2922
2923 // Check for complex exit control
2924 for(uint ii = 0; ii < loop->_body.size(); ii++ ) {
2925 Node *n = loop->_body.at(ii);
2926 int opc = n->Opcode();
2927 if (n->is_Call() ||
2928 opc == Op_Catch ||
2929 opc == Op_CatchProj ||
2930 opc == Op_Jump ||
2931 opc == Op_JumpProj) {
2932 #if !defined(PRODUCT)
2933 if (TracePartialPeeling) {
2934 tty->print_cr("\nExit control too complex: lp: %d", head->_idx);
2935 }
2936 #endif
2937 return false;
2938 }
2939 }
2940
2941 int dd = dom_depth(head);
2942
2943 // Step 1: find cut point
2944
2945 // Walk up dominators to loop head looking for first loop exit
2946 // which is executed on every path thru loop.
2947 IfNode *peel_if = NULL;
2948 IfNode *peel_if_cmpu = NULL;
2949
2950 Node *iff = loop->tail();
2951 while( iff != head ) {
2952 if( iff->is_If() ) {
2953 Node *ctrl = get_ctrl(iff->in(1));
2954 if (ctrl->is_top()) return false; // Dead test on live IF.
2955 // If loop-varying exit-test, check for induction variable
2956 if( loop->is_member(get_loop(ctrl)) &&
2957 loop->is_loop_exit(iff) &&
2958 is_possible_iv_test(iff)) {
2959 Node* cmp = iff->in(1)->in(1);
2960 if (cmp->Opcode() == Op_CmpI) {
2961 peel_if = iff->as_If();
2962 } else {
2963 assert(cmp->Opcode() == Op_CmpU, "must be CmpI or CmpU");
2964 peel_if_cmpu = iff->as_If();
2965 }
2966 }
2967 }
2968 iff = idom(iff);
2969 }
2970 // Prefer signed compare over unsigned compare.
2971 IfNode* new_peel_if = NULL;
2972 if (peel_if == NULL) {
2973 if (!PartialPeelAtUnsignedTests || peel_if_cmpu == NULL) {
2974 return false; // No peel point found
2975 }
2976 new_peel_if = insert_cmpi_loop_exit(peel_if_cmpu, loop);
2977 if (new_peel_if == NULL) {
2978 return false; // No peel point found
2979 }
2980 peel_if = new_peel_if;
2981 }
2982 Node* last_peel = stay_in_loop(peel_if, loop);
2983 Node* first_not_peeled = stay_in_loop(last_peel, loop);
2984 if (first_not_peeled == NULL || first_not_peeled == head) {
2985 return false;
2986 }
2987
2988 #if !defined(PRODUCT)
2989 if (TraceLoopOpts) {
2990 tty->print("PartialPeel ");
2991 loop->dump_head();
2992 }
2993
2994 if (TracePartialPeeling) {
2995 tty->print_cr("before partial peel one iteration");
2996 Node_List wl;
2997 Node* t = head->in(2);
2998 while (true) {
2999 wl.push(t);
3000 if (t == head) break;
3001 t = idom(t);
3002 }
3003 while (wl.size() > 0) {
3004 Node* tt = wl.pop();
3005 tt->dump();
3006 if (tt == last_peel) tty->print_cr("-- cut --");
3007 }
3008 }
3009 #endif
3010 ResourceArea *area = Thread::current()->resource_area();
3011 VectorSet peel(area);
3012 VectorSet not_peel(area);
3013 Node_List peel_list(area);
3014 Node_List worklist(area);
3015 Node_List sink_list(area);
3016
3017 // Set of cfg nodes to peel are those that are executable from
3018 // the head through last_peel.
3019 assert(worklist.size() == 0, "should be empty");
3020 worklist.push(head);
3021 peel.set(head->_idx);
3022 while (worklist.size() > 0) {
3023 Node *n = worklist.pop();
3024 if (n != last_peel) {
3025 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3026 Node* use = n->fast_out(j);
3027 if (use->is_CFG() &&
3028 loop->is_member(get_loop(use)) &&
3029 !peel.test_set(use->_idx)) {
3030 worklist.push(use);
3031 }
3032 }
3033 }
3034 }
3035
3036 // Set of non-cfg nodes to peel are those that are control
3037 // dependent on the cfg nodes.
3038 uint i;
3039 for(i = 0; i < loop->_body.size(); i++ ) {
3040 Node *n = loop->_body.at(i);
3041 Node *n_c = has_ctrl(n) ? get_ctrl(n) : n;
3042 if (peel.test(n_c->_idx)) {
3043 peel.set(n->_idx);
3044 } else {
3045 not_peel.set(n->_idx);
3046 }
3047 }
3048
3049 // Step 2: move operations from the peeled section down into the
3050 // not-peeled section
3051
3052 // Get a post order schedule of nodes in the peel region
3053 // Result in right-most operand.
3054 scheduled_nodelist(loop, peel, peel_list );
3055
3056 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition");
3057
3058 // For future check for too many new phis
3059 uint old_phi_cnt = 0;
3060 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) {
3061 Node* use = head->fast_out(j);
3062 if (use->is_Phi()) old_phi_cnt++;
3063 }
3064
3065 #if !defined(PRODUCT)
3066 if (TracePartialPeeling) {
3067 tty->print_cr("\npeeled list");
3068 }
3069 #endif
3070
3071 // Evacuate nodes in peel region into the not_peeled region if possible
3072 uint new_phi_cnt = 0;
3073 uint cloned_for_outside_use = 0;
3074 for (i = 0; i < peel_list.size();) {
3075 Node* n = peel_list.at(i);
3076 #if !defined(PRODUCT)
3077 if (TracePartialPeeling) n->dump();
3078 #endif
3079 bool incr = true;
3080 if ( !n->is_CFG() ) {
3081
3082 if ( has_use_in_set(n, not_peel) ) {
3083
3084 // If not used internal to the peeled region,
3085 // move "n" from peeled to not_peeled region.
3086
3087 if ( !has_use_internal_to_set(n, peel, loop) ) {
3088
3089 // if not pinned and not a load (which maybe anti-dependent on a store)
3090 // and not a CMove (Matcher expects only bool->cmove).
3091 if ( n->in(0) == NULL && !n->is_Load() && !n->is_CMove() ) {
3092 cloned_for_outside_use += clone_for_use_outside_loop( loop, n, worklist );
3093 sink_list.push(n);
3094 peel >>= n->_idx; // delete n from peel set.
3095 not_peel <<= n->_idx; // add n to not_peel set.
3096 peel_list.remove(i);
3097 incr = false;
3098 #if !defined(PRODUCT)
3099 if (TracePartialPeeling) {
3100 tty->print_cr("sink to not_peeled region: %d newbb: %d",
3101 n->_idx, get_ctrl(n)->_idx);
3102 }
3103 #endif
3104 }
3105 } else {
3106 // Otherwise check for special def-use cases that span
3107 // the peel/not_peel boundary such as bool->if
3108 clone_for_special_use_inside_loop( loop, n, not_peel, sink_list, worklist );
3109 new_phi_cnt++;
3110 }
3111 }
3112 }
3113 if (incr) i++;
3114 }
3115
3116 if (new_phi_cnt > old_phi_cnt + PartialPeelNewPhiDelta) {
3117 #if !defined(PRODUCT)
3118 if (TracePartialPeeling) {
3119 tty->print_cr("\nToo many new phis: %d old %d new cmpi: %c",
3120 new_phi_cnt, old_phi_cnt, new_peel_if != NULL?'T':'F');
3121 }
3122 #endif
3123 if (new_peel_if != NULL) {
3124 remove_cmpi_loop_exit(new_peel_if, loop);
3125 }
3126 // Inhibit more partial peeling on this loop
3127 assert(!head->is_partial_peel_loop(), "not partial peeled");
3128 head->mark_partial_peel_failed();
3129 if (cloned_for_outside_use > 0) {
3130 // Terminate this round of loop opts because
3131 // the graph outside this loop was changed.
3132 C->set_major_progress();
3133 return true;
3134 }
3135 return false;
3136 }
3137
3138 // Step 3: clone loop, retarget control, and insert new phis
3139
3140 // Create new loop head for new phis and to hang
3141 // the nodes being moved (sinked) from the peel region.
3142 LoopNode* new_head = new LoopNode(last_peel, last_peel);
3143 new_head->set_unswitch_count(head->unswitch_count()); // Preserve
3144 _igvn.register_new_node_with_optimizer(new_head);
3145 assert(first_not_peeled->in(0) == last_peel, "last_peel <- first_not_peeled");
3146 _igvn.replace_input_of(first_not_peeled, 0, new_head);
3147 set_loop(new_head, loop);
3148 loop->_body.push(new_head);
3149 not_peel.set(new_head->_idx);
3150 set_idom(new_head, last_peel, dom_depth(first_not_peeled));
3151 set_idom(first_not_peeled, new_head, dom_depth(first_not_peeled));
3152
3153 while (sink_list.size() > 0) {
3154 Node* n = sink_list.pop();
3155 set_ctrl(n, new_head);
3156 }
3157
3158 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition");
3159
3160 clone_loop(loop, old_new, dd, IgnoreStripMined);
3161
3162 const uint clone_exit_idx = 1;
3163 const uint orig_exit_idx = 2;
3164 assert(is_valid_clone_loop_form( loop, peel_list, orig_exit_idx, clone_exit_idx ), "bad clone loop");
3165
3166 Node* head_clone = old_new[head->_idx];
3167 LoopNode* new_head_clone = old_new[new_head->_idx]->as_Loop();
3168 Node* orig_tail_clone = head_clone->in(2);
3169
3170 // Add phi if "def" node is in peel set and "use" is not
3171
3172 for(i = 0; i < peel_list.size(); i++ ) {
3173 Node *def = peel_list.at(i);
3174 if (!def->is_CFG()) {
3175 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
3176 Node *use = def->fast_out(j);
3177 if (has_node(use) && use->in(0) != C->top() &&
3178 (!peel.test(use->_idx) ||
3179 (use->is_Phi() && use->in(0) == head)) ) {
3180 worklist.push(use);
3181 }
3182 }
3183 while( worklist.size() ) {
3184 Node *use = worklist.pop();
3185 for (uint j = 1; j < use->req(); j++) {
3186 Node* n = use->in(j);
3187 if (n == def) {
3188
3189 // "def" is in peel set, "use" is not in peel set
3190 // or "use" is in the entry boundary (a phi) of the peel set
3191
3192 Node* use_c = has_ctrl(use) ? get_ctrl(use) : use;
3193
3194 if ( loop->is_member(get_loop( use_c )) ) {
3195 // use is in loop
3196 if (old_new[use->_idx] != NULL) { // null for dead code
3197 Node* use_clone = old_new[use->_idx];
3198 _igvn.replace_input_of(use, j, C->top());
3199 insert_phi_for_loop( use_clone, j, old_new[def->_idx], def, new_head_clone );
3200 }
3201 } else {
3202 assert(is_valid_clone_loop_exit_use(loop, use, orig_exit_idx), "clone loop format");
3203 // use is not in the loop, check if the live range includes the cut
3204 Node* lp_if = use_c->in(orig_exit_idx)->in(0);
3205 if (not_peel.test(lp_if->_idx)) {
3206 assert(j == orig_exit_idx, "use from original loop");
3207 insert_phi_for_loop( use, clone_exit_idx, old_new[def->_idx], def, new_head_clone );
3208 }
3209 }
3210 }
3211 }
3212 }
3213 }
3214 }
3215
3216 // Step 3b: retarget control
3217
3218 // Redirect control to the new loop head if a cloned node in
3219 // the not_peeled region has control that points into the peeled region.
3220 // This necessary because the cloned peeled region will be outside
3221 // the loop.
3222 // from to
3223 // cloned-peeled <---+
3224 // new_head_clone: | <--+
3225 // cloned-not_peeled in(0) in(0)
3226 // orig-peeled
3227
3228 for(i = 0; i < loop->_body.size(); i++ ) {
3229 Node *n = loop->_body.at(i);
3230 if (!n->is_CFG() && n->in(0) != NULL &&
3231 not_peel.test(n->_idx) && peel.test(n->in(0)->_idx)) {
3232 Node* n_clone = old_new[n->_idx];
3233 _igvn.replace_input_of(n_clone, 0, new_head_clone);
3234 }
3235 }
3236
3237 // Backedge of the surviving new_head (the clone) is original last_peel
3238 _igvn.replace_input_of(new_head_clone, LoopNode::LoopBackControl, last_peel);
3239
3240 // Cut first node in original not_peel set
3241 _igvn.rehash_node_delayed(new_head); // Multiple edge updates:
3242 new_head->set_req(LoopNode::EntryControl, C->top()); // use rehash_node_delayed / set_req instead of
3243 new_head->set_req(LoopNode::LoopBackControl, C->top()); // multiple replace_input_of calls
3244
3245 // Copy head_clone back-branch info to original head
3246 // and remove original head's loop entry and
3247 // clone head's back-branch
3248 _igvn.rehash_node_delayed(head); // Multiple edge updates
3249 head->set_req(LoopNode::EntryControl, head_clone->in(LoopNode::LoopBackControl));
3250 head->set_req(LoopNode::LoopBackControl, C->top());
3251 _igvn.replace_input_of(head_clone, LoopNode::LoopBackControl, C->top());
3252
3253 // Similarly modify the phis
3254 for (DUIterator_Fast kmax, k = head->fast_outs(kmax); k < kmax; k++) {
3255 Node* use = head->fast_out(k);
3256 if (use->is_Phi() && use->outcnt() > 0) {
3257 Node* use_clone = old_new[use->_idx];
3258 _igvn.rehash_node_delayed(use); // Multiple edge updates
3259 use->set_req(LoopNode::EntryControl, use_clone->in(LoopNode::LoopBackControl));
3260 use->set_req(LoopNode::LoopBackControl, C->top());
3261 _igvn.replace_input_of(use_clone, LoopNode::LoopBackControl, C->top());
3262 }
3263 }
3264
3265 // Step 4: update dominator tree and dominator depth
3266
3267 set_idom(head, orig_tail_clone, dd);
3268 recompute_dom_depth();
3269
3270 // Inhibit more partial peeling on this loop
3271 new_head_clone->set_partial_peel_loop();
3272 C->set_major_progress();
3273 loop->record_for_igvn();
3274
3275 #if !defined(PRODUCT)
3276 if (TracePartialPeeling) {
3277 tty->print_cr("\nafter partial peel one iteration");
3278 Node_List wl(area);
3279 Node* t = last_peel;
3280 while (true) {
3281 wl.push(t);
3282 if (t == head_clone) break;
3283 t = idom(t);
3284 }
3285 while (wl.size() > 0) {
3286 Node* tt = wl.pop();
3287 if (tt == head) tty->print_cr("orig head");
3288 else if (tt == new_head_clone) tty->print_cr("new head");
3289 else if (tt == head_clone) tty->print_cr("clone head");
3290 tt->dump();
3291 }
3292 }
3293 #endif
3294 return true;
3295 }
3296
3297 //------------------------------reorg_offsets----------------------------------
3298 // Reorganize offset computations to lower register pressure. Mostly
3299 // prevent loop-fallout uses of the pre-incremented trip counter (which are
3300 // then alive with the post-incremented trip counter forcing an extra
3301 // register move)
3302 void PhaseIdealLoop::reorg_offsets(IdealLoopTree *loop) {
3303 // Perform it only for canonical counted loops.
3304 // Loop's shape could be messed up by iteration_split_impl.
3305 if (!loop->_head->is_CountedLoop())
3306 return;
3307 if (!loop->_head->as_Loop()->is_valid_counted_loop())
3308 return;
3309
3310 CountedLoopNode *cl = loop->_head->as_CountedLoop();
3311 CountedLoopEndNode *cle = cl->loopexit();
3312 Node *exit = cle->proj_out(false);
3313 Node *phi = cl->phi();
3314
3315 // Check for the special case of folks using the pre-incremented
3316 // trip-counter on the fall-out path (forces the pre-incremented
3317 // and post-incremented trip counter to be live at the same time).
3318 // Fix this by adjusting to use the post-increment trip counter.
3319
3320 bool progress = true;
3321 while (progress) {
3322 progress = false;
3323 for (DUIterator_Fast imax, i = phi->fast_outs(imax); i < imax; i++) {
3324 Node* use = phi->fast_out(i); // User of trip-counter
3325 if (!has_ctrl(use)) continue;
3326 Node *u_ctrl = get_ctrl(use);
3327 if (use->is_Phi()) {
3328 u_ctrl = NULL;
3329 for (uint j = 1; j < use->req(); j++)
3330 if (use->in(j) == phi)
3331 u_ctrl = dom_lca(u_ctrl, use->in(0)->in(j));
3332 }
3333 IdealLoopTree *u_loop = get_loop(u_ctrl);
3334 // Look for loop-invariant use
3335 if (u_loop == loop) continue;
3336 if (loop->is_member(u_loop)) continue;
3337 // Check that use is live out the bottom. Assuming the trip-counter
3338 // update is right at the bottom, uses of of the loop middle are ok.
3339 if (dom_lca(exit, u_ctrl) != exit) continue;
3340 // Hit! Refactor use to use the post-incremented tripcounter.
3341 // Compute a post-increment tripcounter.
3342 Node *opaq = new Opaque2Node( C, cle->incr() );
3343 register_new_node(opaq, exit);
3344 Node *neg_stride = _igvn.intcon(-cle->stride_con());
3345 set_ctrl(neg_stride, C->root());
3346 Node *post = new AddINode( opaq, neg_stride);
3347 register_new_node(post, exit);
3348 _igvn.rehash_node_delayed(use);
3349 for (uint j = 1; j < use->req(); j++) {
3350 if (use->in(j) == phi)
3351 use->set_req(j, post);
3352 }
3353 // Since DU info changed, rerun loop
3354 progress = true;
3355 break;
3356 }
3357 }
3358
3359 }