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