1 /*
2 * Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
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23 */
24
25 #include "precompiled.hpp"
26 #include "gc/shared/barrierSet.hpp"
27 #include "gc/shared/c2/barrierSetC2.hpp"
28 #include "memory/allocation.inline.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "opto/addnode.hpp"
31 #include "opto/callnode.hpp"
32 #include "opto/castnode.hpp"
33 #include "opto/connode.hpp"
34 #include "opto/castnode.hpp"
35 #include "opto/divnode.hpp"
36 #include "opto/loopnode.hpp"
37 #include "opto/matcher.hpp"
38 #include "opto/mulnode.hpp"
39 #include "opto/movenode.hpp"
40 #include "opto/opaquenode.hpp"
41 #include "opto/rootnode.hpp"
42 #include "opto/subnode.hpp"
43 #include "opto/subtypenode.hpp"
44 #include "utilities/macros.hpp"
45
46 //=============================================================================
47 //------------------------------split_thru_phi---------------------------------
48 // Split Node 'n' through merge point if there is enough win.
49 Node* PhaseIdealLoop::split_thru_phi(Node* n, Node* region, int policy) {
50 if (n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::LONG) {
51 // ConvI2L may have type information on it which is unsafe to push up
52 // so disable this for now
53 return NULL;
54 }
55
56 // Splitting range check CastIIs through a loop induction Phi can
57 // cause new Phis to be created that are left unrelated to the loop
58 // induction Phi and prevent optimizations (vectorization)
59 if (n->Opcode() == Op_CastII && n->as_CastII()->has_range_check() &&
60 region->is_CountedLoop() && n->in(1) == region->as_CountedLoop()->phi()) {
61 return NULL;
62 }
63
64 // Bail out if 'n' is a Div or Mod node whose zero check was removed earlier (i.e. control is NULL) and its divisor is an induction variable
65 // phi p of a trip-counted (integer) loop whose inputs could be zero (include zero in their type range). p could have a more precise type
66 // range that does not necessarily include all values of its inputs. Since each of these inputs will be a divisor of the newly cloned nodes
67 // of 'n', we need to bail out of one of these divisors could be zero (zero in its type range).
68 if ((n->Opcode() == Op_DivI || n->Opcode() == Op_ModI) && n->in(0) == NULL
69 && region->is_CountedLoop() && n->in(2) == region->as_CountedLoop()->phi()) {
70 Node* phi = region->as_CountedLoop()->phi();
71 for (uint i = 1; i < phi->req(); i++) {
72 if (_igvn.type(phi->in(i))->filter_speculative(TypeInt::ZERO) != Type::TOP) {
73 // Zero could be a possible value but we already removed the zero check. Bail out to avoid a possible division by zero at a later point.
74 return NULL;
75 }
76 }
77 }
78
79 int wins = 0;
80 assert(!n->is_CFG(), "");
81 assert(region->is_Region(), "");
82
83 const Type* type = n->bottom_type();
84 const TypeOopPtr* t_oop = _igvn.type(n)->isa_oopptr();
85 Node* phi;
86 if (t_oop != NULL && t_oop->is_known_instance_field()) {
87 int iid = t_oop->instance_id();
88 int index = C->get_alias_index(t_oop);
89 int offset = t_oop->offset();
90 phi = new PhiNode(region, type, NULL, iid, index, offset);
91 } else {
92 phi = PhiNode::make_blank(region, n);
93 }
94 uint old_unique = C->unique();
95 for (uint i = 1; i < region->req(); i++) {
96 Node* x;
97 Node* the_clone = NULL;
98 if (region->in(i) == C->top()) {
99 x = C->top(); // Dead path? Use a dead data op
100 } else {
101 x = n->clone(); // Else clone up the data op
102 the_clone = x; // Remember for possible deletion.
103 // Alter data node to use pre-phi inputs
104 if (n->in(0) == region)
105 x->set_req( 0, region->in(i) );
106 for (uint j = 1; j < n->req(); j++) {
107 Node* in = n->in(j);
108 if (in->is_Phi() && in->in(0) == region)
109 x->set_req(j, in->in(i)); // Use pre-Phi input for the clone
110 }
111 }
112 // Check for a 'win' on some paths
113 const Type* t = x->Value(&_igvn);
114
115 bool singleton = t->singleton();
116
117 // A TOP singleton indicates that there are no possible values incoming
118 // along a particular edge. In most cases, this is OK, and the Phi will
119 // be eliminated later in an Ideal call. However, we can't allow this to
120 // happen if the singleton occurs on loop entry, as the elimination of
121 // the PhiNode may cause the resulting node to migrate back to a previous
122 // loop iteration.
123 if (singleton && t == Type::TOP) {
124 // Is_Loop() == false does not confirm the absence of a loop (e.g., an
125 // irreducible loop may not be indicated by an affirmative is_Loop());
126 // therefore, the only top we can split thru a phi is on a backedge of
127 // a loop.
128 singleton &= region->is_Loop() && (i != LoopNode::EntryControl);
129 }
130
131 if (singleton) {
132 wins++;
133 x = ((PhaseGVN&)_igvn).makecon(t);
134 } else {
135 // We now call Identity to try to simplify the cloned node.
136 // Note that some Identity methods call phase->type(this).
137 // Make sure that the type array is big enough for
138 // our new node, even though we may throw the node away.
139 // (Note: This tweaking with igvn only works because x is a new node.)
140 _igvn.set_type(x, t);
141 // If x is a TypeNode, capture any more-precise type permanently into Node
142 // otherwise it will be not updated during igvn->transform since
143 // igvn->type(x) is set to x->Value() already.
144 x->raise_bottom_type(t);
145 Node* y = x->Identity(&_igvn);
146 if (y != x) {
147 wins++;
148 x = y;
149 } else {
150 y = _igvn.hash_find(x);
151 if (y) {
152 wins++;
153 x = y;
154 } else {
155 // Else x is a new node we are keeping
156 // We do not need register_new_node_with_optimizer
157 // because set_type has already been called.
158 _igvn._worklist.push(x);
159 }
160 }
161 }
162 if (x != the_clone && the_clone != NULL)
163 _igvn.remove_dead_node(the_clone);
164 phi->set_req( i, x );
165 }
166 // Too few wins?
167 if (wins <= policy) {
168 _igvn.remove_dead_node(phi);
169 return NULL;
170 }
171
172 // Record Phi
173 register_new_node( phi, region );
174
175 for (uint i2 = 1; i2 < phi->req(); i2++) {
176 Node *x = phi->in(i2);
177 // If we commoned up the cloned 'x' with another existing Node,
178 // the existing Node picks up a new use. We need to make the
179 // existing Node occur higher up so it dominates its uses.
180 Node *old_ctrl;
181 IdealLoopTree *old_loop;
182
183 if (x->is_Con()) {
184 // Constant's control is always root.
185 set_ctrl(x, C->root());
186 continue;
187 }
188 // The occasional new node
189 if (x->_idx >= old_unique) { // Found a new, unplaced node?
190 old_ctrl = NULL;
191 old_loop = NULL; // Not in any prior loop
192 } else {
193 old_ctrl = get_ctrl(x);
194 old_loop = get_loop(old_ctrl); // Get prior loop
195 }
196 // New late point must dominate new use
197 Node *new_ctrl = dom_lca(old_ctrl, region->in(i2));
198 if (new_ctrl == old_ctrl) // Nothing is changed
199 continue;
200
201 IdealLoopTree *new_loop = get_loop(new_ctrl);
202
203 // Don't move x into a loop if its uses are
204 // outside of loop. Otherwise x will be cloned
205 // for each use outside of this loop.
206 IdealLoopTree *use_loop = get_loop(region);
207 if (!new_loop->is_member(use_loop) &&
208 (old_loop == NULL || !new_loop->is_member(old_loop))) {
209 // Take early control, later control will be recalculated
210 // during next iteration of loop optimizations.
211 new_ctrl = get_early_ctrl(x);
212 new_loop = get_loop(new_ctrl);
213 }
214 // Set new location
215 set_ctrl(x, new_ctrl);
216 // If changing loop bodies, see if we need to collect into new body
217 if (old_loop != new_loop) {
218 if (old_loop && !old_loop->_child)
219 old_loop->_body.yank(x);
220 if (!new_loop->_child)
221 new_loop->_body.push(x); // Collect body info
222 }
223 }
224
225 return phi;
226 }
227
228 //------------------------------dominated_by------------------------------------
229 // Replace the dominated test with an obvious true or false. Place it on the
230 // IGVN worklist for later cleanup. Move control-dependent data Nodes on the
231 // live path up to the dominating control.
232 void PhaseIdealLoop::dominated_by( Node *prevdom, Node *iff, bool flip, bool exclude_loop_predicate ) {
233 if (VerifyLoopOptimizations && PrintOpto) { tty->print_cr("dominating test"); }
234
235 // prevdom is the dominating projection of the dominating test.
236 assert( iff->is_If(), "" );
237 assert(iff->Opcode() == Op_If || iff->Opcode() == Op_CountedLoopEnd || iff->Opcode() == Op_RangeCheck, "Check this code when new subtype is added");
238 int pop = prevdom->Opcode();
239 assert( pop == Op_IfFalse || pop == Op_IfTrue, "" );
240 if (flip) {
241 if (pop == Op_IfTrue)
242 pop = Op_IfFalse;
243 else
244 pop = Op_IfTrue;
245 }
246 // 'con' is set to true or false to kill the dominated test.
247 Node *con = _igvn.makecon(pop == Op_IfTrue ? TypeInt::ONE : TypeInt::ZERO);
248 set_ctrl(con, C->root()); // Constant gets a new use
249 // Hack the dominated test
250 _igvn.replace_input_of(iff, 1, con);
251
252 // If I dont have a reachable TRUE and FALSE path following the IfNode then
253 // I can assume this path reaches an infinite loop. In this case it's not
254 // important to optimize the data Nodes - either the whole compilation will
255 // be tossed or this path (and all data Nodes) will go dead.
256 if (iff->outcnt() != 2) return;
257
258 // Make control-dependent data Nodes on the live path (path that will remain
259 // once the dominated IF is removed) become control-dependent on the
260 // dominating projection.
261 Node* dp = iff->as_If()->proj_out_or_null(pop == Op_IfTrue);
262
263 // Loop predicates may have depending checks which should not
264 // be skipped. For example, range check predicate has two checks
265 // for lower and upper bounds.
266 if (dp == NULL)
267 return;
268
269 ProjNode* dp_proj = dp->as_Proj();
270 ProjNode* unc_proj = iff->as_If()->proj_out(1 - dp_proj->_con)->as_Proj();
271 if (exclude_loop_predicate &&
272 (unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_predicate) != NULL ||
273 unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_profile_predicate) != NULL ||
274 unc_proj->is_uncommon_trap_proj(Deoptimization::Reason_range_check) != NULL)) {
275 // If this is a range check (IfNode::is_range_check), do not
276 // reorder because Compile::allow_range_check_smearing might have
277 // changed the check.
278 return; // Let IGVN transformation change control dependence.
279 }
280
281 IdealLoopTree *old_loop = get_loop(dp);
282
283 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) {
284 Node* cd = dp->fast_out(i); // Control-dependent node
285 if (cd->depends_only_on_test()) {
286 assert(cd->in(0) == dp, "");
287 _igvn.replace_input_of(cd, 0, prevdom);
288 set_early_ctrl(cd);
289 IdealLoopTree *new_loop = get_loop(get_ctrl(cd));
290 if (old_loop != new_loop) {
291 if (!old_loop->_child) old_loop->_body.yank(cd);
292 if (!new_loop->_child) new_loop->_body.push(cd);
293 }
294 --i;
295 --imax;
296 }
297 }
298 }
299
300 //------------------------------has_local_phi_input----------------------------
301 // Return TRUE if 'n' has Phi inputs from its local block and no other
302 // block-local inputs (all non-local-phi inputs come from earlier blocks)
303 Node *PhaseIdealLoop::has_local_phi_input( Node *n ) {
304 Node *n_ctrl = get_ctrl(n);
305 // See if some inputs come from a Phi in this block, or from before
306 // this block.
307 uint i;
308 for( i = 1; i < n->req(); i++ ) {
309 Node *phi = n->in(i);
310 if( phi->is_Phi() && phi->in(0) == n_ctrl )
311 break;
312 }
313 if( i >= n->req() )
314 return NULL; // No Phi inputs; nowhere to clone thru
315
316 // Check for inputs created between 'n' and the Phi input. These
317 // must split as well; they have already been given the chance
318 // (courtesy of a post-order visit) and since they did not we must
319 // recover the 'cost' of splitting them by being very profitable
320 // when splitting 'n'. Since this is unlikely we simply give up.
321 for( i = 1; i < n->req(); i++ ) {
322 Node *m = n->in(i);
323 if( get_ctrl(m) == n_ctrl && !m->is_Phi() ) {
324 // We allow the special case of AddP's with no local inputs.
325 // This allows us to split-up address expressions.
326 if (m->is_AddP() &&
327 get_ctrl(m->in(2)) != n_ctrl &&
328 get_ctrl(m->in(3)) != n_ctrl) {
329 // Move the AddP up to dominating point
330 Node* c = find_non_split_ctrl(idom(n_ctrl));
331 if (c->is_OuterStripMinedLoop()) {
332 c->as_Loop()->verify_strip_mined(1);
333 c = c->in(LoopNode::EntryControl);
334 }
335 set_ctrl_and_loop(m, c);
336 continue;
337 }
338 return NULL;
339 }
340 assert(n->is_Phi() || m->is_Phi() || is_dominator(get_ctrl(m), n_ctrl), "m has strange control");
341 }
342
343 return n_ctrl;
344 }
345
346 //------------------------------remix_address_expressions----------------------
347 // Rework addressing expressions to get the most loop-invariant stuff
348 // moved out. We'd like to do all associative operators, but it's especially
349 // important (common) to do address expressions.
350 Node *PhaseIdealLoop::remix_address_expressions( Node *n ) {
351 if (!has_ctrl(n)) return NULL;
352 Node *n_ctrl = get_ctrl(n);
353 IdealLoopTree *n_loop = get_loop(n_ctrl);
354
355 // See if 'n' mixes loop-varying and loop-invariant inputs and
356 // itself is loop-varying.
357
358 // Only interested in binary ops (and AddP)
359 if( n->req() < 3 || n->req() > 4 ) return NULL;
360
361 Node *n1_ctrl = get_ctrl(n->in( 1));
362 Node *n2_ctrl = get_ctrl(n->in( 2));
363 Node *n3_ctrl = get_ctrl(n->in(n->req() == 3 ? 2 : 3));
364 IdealLoopTree *n1_loop = get_loop( n1_ctrl );
365 IdealLoopTree *n2_loop = get_loop( n2_ctrl );
366 IdealLoopTree *n3_loop = get_loop( n3_ctrl );
367
368 // Does one of my inputs spin in a tighter loop than self?
369 if( (n_loop->is_member( n1_loop ) && n_loop != n1_loop) ||
370 (n_loop->is_member( n2_loop ) && n_loop != n2_loop) ||
371 (n_loop->is_member( n3_loop ) && n_loop != n3_loop) )
372 return NULL; // Leave well enough alone
373
374 // Is at least one of my inputs loop-invariant?
375 if( n1_loop == n_loop &&
376 n2_loop == n_loop &&
377 n3_loop == n_loop )
378 return NULL; // No loop-invariant inputs
379
380
381 int n_op = n->Opcode();
382
383 // Replace expressions like ((V+I) << 2) with (V<<2 + I<<2).
384 if( n_op == Op_LShiftI ) {
385 // Scale is loop invariant
386 Node *scale = n->in(2);
387 Node *scale_ctrl = get_ctrl(scale);
388 IdealLoopTree *scale_loop = get_loop(scale_ctrl );
389 if( n_loop == scale_loop || !scale_loop->is_member( n_loop ) )
390 return NULL;
391 const TypeInt *scale_t = scale->bottom_type()->isa_int();
392 if( scale_t && scale_t->is_con() && scale_t->get_con() >= 16 )
393 return NULL; // Dont bother with byte/short masking
394 // Add must vary with loop (else shift would be loop-invariant)
395 Node *add = n->in(1);
396 Node *add_ctrl = get_ctrl(add);
397 IdealLoopTree *add_loop = get_loop(add_ctrl);
398 //assert( n_loop == add_loop, "" );
399 if( n_loop != add_loop ) return NULL; // happens w/ evil ZKM loops
400
401 // Convert I-V into I+ (0-V); same for V-I
402 if( add->Opcode() == Op_SubI &&
403 _igvn.type( add->in(1) ) != TypeInt::ZERO ) {
404 Node *zero = _igvn.intcon(0);
405 set_ctrl(zero, C->root());
406 Node *neg = new SubINode( _igvn.intcon(0), add->in(2) );
407 register_new_node( neg, get_ctrl(add->in(2) ) );
408 add = new AddINode( add->in(1), neg );
409 register_new_node( add, add_ctrl );
410 }
411 if( add->Opcode() != Op_AddI ) return NULL;
412 // See if one add input is loop invariant
413 Node *add_var = add->in(1);
414 Node *add_var_ctrl = get_ctrl(add_var);
415 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl );
416 Node *add_invar = add->in(2);
417 Node *add_invar_ctrl = get_ctrl(add_invar);
418 IdealLoopTree *add_invar_loop = get_loop(add_invar_ctrl );
419 if( add_var_loop == n_loop ) {
420 } else if( add_invar_loop == n_loop ) {
421 // Swap to find the invariant part
422 add_invar = add_var;
423 add_invar_ctrl = add_var_ctrl;
424 add_invar_loop = add_var_loop;
425 add_var = add->in(2);
426 Node *add_var_ctrl = get_ctrl(add_var);
427 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl );
428 } else // Else neither input is loop invariant
429 return NULL;
430 if( n_loop == add_invar_loop || !add_invar_loop->is_member( n_loop ) )
431 return NULL; // No invariant part of the add?
432
433 // Yes! Reshape address expression!
434 Node *inv_scale = new LShiftINode( add_invar, scale );
435 Node *inv_scale_ctrl =
436 dom_depth(add_invar_ctrl) > dom_depth(scale_ctrl) ?
437 add_invar_ctrl : scale_ctrl;
438 register_new_node( inv_scale, inv_scale_ctrl );
439 Node *var_scale = new LShiftINode( add_var, scale );
440 register_new_node( var_scale, n_ctrl );
441 Node *var_add = new AddINode( var_scale, inv_scale );
442 register_new_node( var_add, n_ctrl );
443 _igvn.replace_node( n, var_add );
444 return var_add;
445 }
446
447 // Replace (I+V) with (V+I)
448 if( n_op == Op_AddI ||
449 n_op == Op_AddL ||
450 n_op == Op_AddF ||
451 n_op == Op_AddD ||
452 n_op == Op_MulI ||
453 n_op == Op_MulL ||
454 n_op == Op_MulF ||
455 n_op == Op_MulD ) {
456 if( n2_loop == n_loop ) {
457 assert( n1_loop != n_loop, "" );
458 n->swap_edges(1, 2);
459 }
460 }
461
462 // Replace ((I1 +p V) +p I2) with ((I1 +p I2) +p V),
463 // but not if I2 is a constant.
464 if( n_op == Op_AddP ) {
465 if( n2_loop == n_loop && n3_loop != n_loop ) {
466 if( n->in(2)->Opcode() == Op_AddP && !n->in(3)->is_Con() ) {
467 Node *n22_ctrl = get_ctrl(n->in(2)->in(2));
468 Node *n23_ctrl = get_ctrl(n->in(2)->in(3));
469 IdealLoopTree *n22loop = get_loop( n22_ctrl );
470 IdealLoopTree *n23_loop = get_loop( n23_ctrl );
471 if( n22loop != n_loop && n22loop->is_member(n_loop) &&
472 n23_loop == n_loop ) {
473 Node *add1 = new AddPNode( n->in(1), n->in(2)->in(2), n->in(3) );
474 // Stuff new AddP in the loop preheader
475 register_new_node( add1, n_loop->_head->in(LoopNode::EntryControl) );
476 Node *add2 = new AddPNode( n->in(1), add1, n->in(2)->in(3) );
477 register_new_node( add2, n_ctrl );
478 _igvn.replace_node( n, add2 );
479 return add2;
480 }
481 }
482 }
483
484 // Replace (I1 +p (I2 + V)) with ((I1 +p I2) +p V)
485 if (n2_loop != n_loop && n3_loop == n_loop) {
486 if (n->in(3)->Opcode() == Op_AddX) {
487 Node *V = n->in(3)->in(1);
488 Node *I = n->in(3)->in(2);
489 if (is_member(n_loop,get_ctrl(V))) {
490 } else {
491 Node *tmp = V; V = I; I = tmp;
492 }
493 if (!is_member(n_loop,get_ctrl(I))) {
494 Node *add1 = new AddPNode(n->in(1), n->in(2), I);
495 // Stuff new AddP in the loop preheader
496 register_new_node(add1, n_loop->_head->in(LoopNode::EntryControl));
497 Node *add2 = new AddPNode(n->in(1), add1, V);
498 register_new_node(add2, n_ctrl);
499 _igvn.replace_node(n, add2);
500 return add2;
501 }
502 }
503 }
504 }
505
506 return NULL;
507 }
508
509 // Optimize ((in1[2*i] * in2[2*i]) + (in1[2*i+1] * in2[2*i+1]))
510 Node *PhaseIdealLoop::convert_add_to_muladd(Node* n) {
511 assert(n->Opcode() == Op_AddI, "sanity");
512 Node * nn = NULL;
513 Node * in1 = n->in(1);
514 Node * in2 = n->in(2);
515 if (in1->Opcode() == Op_MulI && in2->Opcode() == Op_MulI) {
516 IdealLoopTree* loop_n = get_loop(get_ctrl(n));
517 if (loop_n->is_counted() &&
518 loop_n->_head->as_Loop()->is_valid_counted_loop() &&
519 Matcher::match_rule_supported(Op_MulAddVS2VI) &&
520 Matcher::match_rule_supported(Op_MulAddS2I)) {
521 Node* mul_in1 = in1->in(1);
522 Node* mul_in2 = in1->in(2);
523 Node* mul_in3 = in2->in(1);
524 Node* mul_in4 = in2->in(2);
525 if (mul_in1->Opcode() == Op_LoadS &&
526 mul_in2->Opcode() == Op_LoadS &&
527 mul_in3->Opcode() == Op_LoadS &&
528 mul_in4->Opcode() == Op_LoadS) {
529 IdealLoopTree* loop1 = get_loop(get_ctrl(mul_in1));
530 IdealLoopTree* loop2 = get_loop(get_ctrl(mul_in2));
531 IdealLoopTree* loop3 = get_loop(get_ctrl(mul_in3));
532 IdealLoopTree* loop4 = get_loop(get_ctrl(mul_in4));
533 IdealLoopTree* loop5 = get_loop(get_ctrl(in1));
534 IdealLoopTree* loop6 = get_loop(get_ctrl(in2));
535 // All nodes should be in the same counted loop.
536 if (loop_n == loop1 && loop_n == loop2 && loop_n == loop3 &&
537 loop_n == loop4 && loop_n == loop5 && loop_n == loop6) {
538 Node* adr1 = mul_in1->in(MemNode::Address);
539 Node* adr2 = mul_in2->in(MemNode::Address);
540 Node* adr3 = mul_in3->in(MemNode::Address);
541 Node* adr4 = mul_in4->in(MemNode::Address);
542 if (adr1->is_AddP() && adr2->is_AddP() && adr3->is_AddP() && adr4->is_AddP()) {
543 if ((adr1->in(AddPNode::Base) == adr3->in(AddPNode::Base)) &&
544 (adr2->in(AddPNode::Base) == adr4->in(AddPNode::Base))) {
545 nn = new MulAddS2INode(mul_in1, mul_in2, mul_in3, mul_in4);
546 register_new_node(nn, get_ctrl(n));
547 _igvn.replace_node(n, nn);
548 return nn;
549 } else if ((adr1->in(AddPNode::Base) == adr4->in(AddPNode::Base)) &&
550 (adr2->in(AddPNode::Base) == adr3->in(AddPNode::Base))) {
551 nn = new MulAddS2INode(mul_in1, mul_in2, mul_in4, mul_in3);
552 register_new_node(nn, get_ctrl(n));
553 _igvn.replace_node(n, nn);
554 return nn;
555 }
556 }
557 }
558 }
559 }
560 }
561 return nn;
562 }
563
564 //------------------------------conditional_move-------------------------------
565 // Attempt to replace a Phi with a conditional move. We have some pretty
566 // strict profitability requirements. All Phis at the merge point must
567 // be converted, so we can remove the control flow. We need to limit the
568 // number of c-moves to a small handful. All code that was in the side-arms
569 // of the CFG diamond is now speculatively executed. This code has to be
570 // "cheap enough". We are pretty much limited to CFG diamonds that merge
571 // 1 or 2 items with a total of 1 or 2 ops executed speculatively.
572 Node *PhaseIdealLoop::conditional_move( Node *region ) {
573
574 assert(region->is_Region(), "sanity check");
575 if (region->req() != 3) return NULL;
576
577 // Check for CFG diamond
578 Node *lp = region->in(1);
579 Node *rp = region->in(2);
580 if (!lp || !rp) return NULL;
581 Node *lp_c = lp->in(0);
582 if (lp_c == NULL || lp_c != rp->in(0) || !lp_c->is_If()) return NULL;
583 IfNode *iff = lp_c->as_If();
584
585 // Check for ops pinned in an arm of the diamond.
586 // Can't remove the control flow in this case
587 if (lp->outcnt() > 1) return NULL;
588 if (rp->outcnt() > 1) return NULL;
589
590 IdealLoopTree* r_loop = get_loop(region);
591 assert(r_loop == get_loop(iff), "sanity");
592 // Always convert to CMOVE if all results are used only outside this loop.
593 bool used_inside_loop = (r_loop == _ltree_root);
594
595 // Check profitability
596 int cost = 0;
597 int phis = 0;
598 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
599 Node *out = region->fast_out(i);
600 if (!out->is_Phi()) continue; // Ignore other control edges, etc
601 phis++;
602 PhiNode* phi = out->as_Phi();
603 BasicType bt = phi->type()->basic_type();
604 switch (bt) {
605 case T_DOUBLE:
606 case T_FLOAT:
607 if (C->use_cmove()) {
608 continue; //TODO: maybe we want to add some cost
609 }
610 cost += Matcher::float_cmove_cost(); // Could be very expensive
611 break;
612 case T_LONG: {
613 cost += Matcher::long_cmove_cost(); // May encodes as 2 CMOV's
614 }
615 case T_INT: // These all CMOV fine
616 case T_ADDRESS: { // (RawPtr)
617 cost++;
618 break;
619 }
620 case T_NARROWOOP: // Fall through
621 case T_OBJECT: { // Base oops are OK, but not derived oops
622 const TypeOopPtr *tp = phi->type()->make_ptr()->isa_oopptr();
623 // Derived pointers are Bad (tm): what's the Base (for GC purposes) of a
624 // CMOVE'd derived pointer? It's a CMOVE'd derived base. Thus
625 // CMOVE'ing a derived pointer requires we also CMOVE the base. If we
626 // have a Phi for the base here that we convert to a CMOVE all is well
627 // and good. But if the base is dead, we'll not make a CMOVE. Later
628 // the allocator will have to produce a base by creating a CMOVE of the
629 // relevant bases. This puts the allocator in the business of
630 // manufacturing expensive instructions, generally a bad plan.
631 // Just Say No to Conditionally-Moved Derived Pointers.
632 if (tp && tp->offset() != 0)
633 return NULL;
634 cost++;
635 break;
636 }
637 default:
638 return NULL; // In particular, can't do memory or I/O
639 }
640 // Add in cost any speculative ops
641 for (uint j = 1; j < region->req(); j++) {
642 Node *proj = region->in(j);
643 Node *inp = phi->in(j);
644 if (get_ctrl(inp) == proj) { // Found local op
645 cost++;
646 // Check for a chain of dependent ops; these will all become
647 // speculative in a CMOV.
648 for (uint k = 1; k < inp->req(); k++)
649 if (get_ctrl(inp->in(k)) == proj)
650 cost += ConditionalMoveLimit; // Too much speculative goo
651 }
652 }
653 // See if the Phi is used by a Cmp or Narrow oop Decode/Encode.
654 // This will likely Split-If, a higher-payoff operation.
655 for (DUIterator_Fast kmax, k = phi->fast_outs(kmax); k < kmax; k++) {
656 Node* use = phi->fast_out(k);
657 if (use->is_Cmp() || use->is_DecodeNarrowPtr() || use->is_EncodeNarrowPtr())
658 cost += ConditionalMoveLimit;
659 // Is there a use inside the loop?
660 // Note: check only basic types since CMoveP is pinned.
661 if (!used_inside_loop && is_java_primitive(bt)) {
662 IdealLoopTree* u_loop = get_loop(has_ctrl(use) ? get_ctrl(use) : use);
663 if (r_loop == u_loop || r_loop->is_member(u_loop)) {
664 used_inside_loop = true;
665 }
666 }
667 }
668 }//for
669 Node* bol = iff->in(1);
670 if (bol->Opcode() == Op_Opaque4) {
671 return NULL; // Ignore loop predicate checks (the Opaque4 ensures they will go away)
672 }
673 assert(bol->Opcode() == Op_Bool, "Unexpected node");
674 int cmp_op = bol->in(1)->Opcode();
675 if (cmp_op == Op_SubTypeCheck) { // SubTypeCheck expansion expects an IfNode
676 return NULL;
677 }
678 // It is expensive to generate flags from a float compare.
679 // Avoid duplicated float compare.
680 if (phis > 1 && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) return NULL;
681
682 float infrequent_prob = PROB_UNLIKELY_MAG(3);
683 // Ignore cost and blocks frequency if CMOVE can be moved outside the loop.
684 if (used_inside_loop) {
685 if (cost >= ConditionalMoveLimit) return NULL; // Too much goo
686
687 // BlockLayoutByFrequency optimization moves infrequent branch
688 // from hot path. No point in CMOV'ing in such case (110 is used
689 // instead of 100 to take into account not exactness of float value).
690 if (BlockLayoutByFrequency) {
691 infrequent_prob = MAX2(infrequent_prob, (float)BlockLayoutMinDiamondPercentage/110.0f);
692 }
693 }
694 // Check for highly predictable branch. No point in CMOV'ing if
695 // we are going to predict accurately all the time.
696 if (C->use_cmove() && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) {
697 //keep going
698 } else if (iff->_prob < infrequent_prob ||
699 iff->_prob > (1.0f - infrequent_prob))
700 return NULL;
701
702 // --------------
703 // Now replace all Phis with CMOV's
704 Node *cmov_ctrl = iff->in(0);
705 uint flip = (lp->Opcode() == Op_IfTrue);
706 Node_List wq;
707 while (1) {
708 PhiNode* phi = NULL;
709 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
710 Node *out = region->fast_out(i);
711 if (out->is_Phi()) {
712 phi = out->as_Phi();
713 break;
714 }
715 }
716 if (phi == NULL) break;
717 if (PrintOpto && VerifyLoopOptimizations) { tty->print_cr("CMOV"); }
718 // Move speculative ops
719 wq.push(phi);
720 while (wq.size() > 0) {
721 Node *n = wq.pop();
722 for (uint j = 1; j < n->req(); j++) {
723 Node* m = n->in(j);
724 if (m != NULL && !is_dominator(get_ctrl(m), cmov_ctrl)) {
725 #ifndef PRODUCT
726 if (PrintOpto && VerifyLoopOptimizations) {
727 tty->print(" speculate: ");
728 m->dump();
729 }
730 #endif
731 set_ctrl(m, cmov_ctrl);
732 wq.push(m);
733 }
734 }
735 }
736 Node *cmov = CMoveNode::make(cmov_ctrl, iff->in(1), phi->in(1+flip), phi->in(2-flip), _igvn.type(phi));
737 register_new_node( cmov, cmov_ctrl );
738 _igvn.replace_node( phi, cmov );
739 #ifndef PRODUCT
740 if (TraceLoopOpts) {
741 tty->print("CMOV ");
742 r_loop->dump_head();
743 if (Verbose) {
744 bol->in(1)->dump(1);
745 cmov->dump(1);
746 }
747 }
748 if (VerifyLoopOptimizations) verify();
749 #endif
750 }
751
752 // The useless CFG diamond will fold up later; see the optimization in
753 // RegionNode::Ideal.
754 _igvn._worklist.push(region);
755
756 return iff->in(1);
757 }
758
759 static void enqueue_cfg_uses(Node* m, Unique_Node_List& wq) {
760 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax; i++) {
761 Node* u = m->fast_out(i);
762 if (u->is_CFG()) {
763 if (u->Opcode() == Op_NeverBranch) {
764 u = ((NeverBranchNode*)u)->proj_out(0);
765 enqueue_cfg_uses(u, wq);
766 } else {
767 wq.push(u);
768 }
769 }
770 }
771 }
772
773 // Try moving a store out of a loop, right before the loop
774 Node* PhaseIdealLoop::try_move_store_before_loop(Node* n, Node *n_ctrl) {
775 // Store has to be first in the loop body
776 IdealLoopTree *n_loop = get_loop(n_ctrl);
777 if (n->is_Store() && n_loop != _ltree_root &&
778 n_loop->is_loop() && n_loop->_head->is_Loop() &&
779 n->in(0) != NULL) {
780 Node* address = n->in(MemNode::Address);
781 Node* value = n->in(MemNode::ValueIn);
782 Node* mem = n->in(MemNode::Memory);
783 IdealLoopTree* address_loop = get_loop(get_ctrl(address));
784 IdealLoopTree* value_loop = get_loop(get_ctrl(value));
785
786 // - address and value must be loop invariant
787 // - memory must be a memory Phi for the loop
788 // - Store must be the only store on this memory slice in the
789 // loop: if there's another store following this one then value
790 // written at iteration i by the second store could be overwritten
791 // at iteration i+n by the first store: it's not safe to move the
792 // first store out of the loop
793 // - nothing must observe the memory Phi: it guarantees no read
794 // before the store, we are also guaranteed the store post
795 // dominates the loop head (ignoring a possible early
796 // exit). Otherwise there would be extra Phi involved between the
797 // loop's Phi and the store.
798 // - there must be no early exit from the loop before the Store
799 // (such an exit most of the time would be an extra use of the
800 // memory Phi but sometimes is a bottom memory Phi that takes the
801 // store as input).
802
803 if (!n_loop->is_member(address_loop) &&
804 !n_loop->is_member(value_loop) &&
805 mem->is_Phi() && mem->in(0) == n_loop->_head &&
806 mem->outcnt() == 1 &&
807 mem->in(LoopNode::LoopBackControl) == n) {
808
809 assert(n_loop->_tail != NULL, "need a tail");
810 assert(is_dominator(n_ctrl, n_loop->_tail), "store control must not be in a branch in the loop");
811
812 // Verify that there's no early exit of the loop before the store.
813 bool ctrl_ok = false;
814 {
815 // Follow control from loop head until n, we exit the loop or
816 // we reach the tail
817 ResourceMark rm;
818 Unique_Node_List wq;
819 wq.push(n_loop->_head);
820
821 for (uint next = 0; next < wq.size(); ++next) {
822 Node *m = wq.at(next);
823 if (m == n->in(0)) {
824 ctrl_ok = true;
825 continue;
826 }
827 assert(!has_ctrl(m), "should be CFG");
828 if (!n_loop->is_member(get_loop(m)) || m == n_loop->_tail) {
829 ctrl_ok = false;
830 break;
831 }
832 enqueue_cfg_uses(m, wq);
833 if (wq.size() > 10) {
834 ctrl_ok = false;
835 break;
836 }
837 }
838 }
839 if (ctrl_ok) {
840 // move the Store
841 _igvn.replace_input_of(mem, LoopNode::LoopBackControl, mem);
842 _igvn.replace_input_of(n, 0, n_loop->_head->as_Loop()->skip_strip_mined()->in(LoopNode::EntryControl));
843 _igvn.replace_input_of(n, MemNode::Memory, mem->in(LoopNode::EntryControl));
844 // Disconnect the phi now. An empty phi can confuse other
845 // optimizations in this pass of loop opts.
846 _igvn.replace_node(mem, mem->in(LoopNode::EntryControl));
847 n_loop->_body.yank(mem);
848
849 set_ctrl_and_loop(n, n->in(0));
850
851 return n;
852 }
853 }
854 }
855 return NULL;
856 }
857
858 // Try moving a store out of a loop, right after the loop
859 void PhaseIdealLoop::try_move_store_after_loop(Node* n) {
860 if (n->is_Store() && n->in(0) != NULL) {
861 Node *n_ctrl = get_ctrl(n);
862 IdealLoopTree *n_loop = get_loop(n_ctrl);
863 // Store must be in a loop
864 if (n_loop != _ltree_root && !n_loop->_irreducible) {
865 Node* address = n->in(MemNode::Address);
866 Node* value = n->in(MemNode::ValueIn);
867 IdealLoopTree* address_loop = get_loop(get_ctrl(address));
868 // address must be loop invariant
869 if (!n_loop->is_member(address_loop)) {
870 // Store must be last on this memory slice in the loop and
871 // nothing in the loop must observe it
872 Node* phi = NULL;
873 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
874 Node* u = n->fast_out(i);
875 if (has_ctrl(u)) { // control use?
876 IdealLoopTree *u_loop = get_loop(get_ctrl(u));
877 if (!n_loop->is_member(u_loop)) {
878 continue;
879 }
880 if (u->is_Phi() && u->in(0) == n_loop->_head) {
881 assert(_igvn.type(u) == Type::MEMORY, "bad phi");
882 // multiple phis on the same slice are possible
883 if (phi != NULL) {
884 return;
885 }
886 phi = u;
887 continue;
888 }
889 }
890 return;
891 }
892 if (phi != NULL) {
893 // Nothing in the loop before the store (next iteration)
894 // must observe the stored value
895 bool mem_ok = true;
896 {
897 ResourceMark rm;
898 Unique_Node_List wq;
899 wq.push(phi);
900 for (uint next = 0; next < wq.size() && mem_ok; ++next) {
901 Node *m = wq.at(next);
902 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax && mem_ok; i++) {
903 Node* u = m->fast_out(i);
904 if (u->is_Store() || u->is_Phi()) {
905 if (u != n) {
906 wq.push(u);
907 mem_ok = (wq.size() <= 10);
908 }
909 } else {
910 mem_ok = false;
911 break;
912 }
913 }
914 }
915 }
916 if (mem_ok) {
917 // Move the store out of the loop if the LCA of all
918 // users (except for the phi) is outside the loop.
919 Node* hook = new Node(1);
920 hook->init_req(0, n_ctrl); // Add an input to prevent hook from being dead
921 _igvn.rehash_node_delayed(phi);
922 int count = phi->replace_edge(n, hook);
923 assert(count > 0, "inconsistent phi");
924
925 // Compute latest point this store can go
926 Node* lca = get_late_ctrl(n, get_ctrl(n));
927 if (lca->is_OuterStripMinedLoop()) {
928 lca = lca->in(LoopNode::EntryControl);
929 }
930 if (n_loop->is_member(get_loop(lca))) {
931 // LCA is in the loop - bail out
932 _igvn.replace_node(hook, n);
933 return;
934 }
935 #ifdef ASSERT
936 if (n_loop->_head->is_Loop() && n_loop->_head->as_Loop()->is_strip_mined()) {
937 assert(n_loop->_head->Opcode() == Op_CountedLoop, "outer loop is a strip mined");
938 n_loop->_head->as_Loop()->verify_strip_mined(1);
939 Node* outer = n_loop->_head->as_CountedLoop()->outer_loop();
940 IdealLoopTree* outer_loop = get_loop(outer);
941 assert(n_loop->_parent == outer_loop, "broken loop tree");
942 assert(get_loop(lca) == outer_loop, "safepoint in outer loop consume all memory state");
943 }
944 #endif
945
946 // Move store out of the loop
947 _igvn.replace_node(hook, n->in(MemNode::Memory));
948 _igvn.replace_input_of(n, 0, lca);
949 set_ctrl_and_loop(n, lca);
950
951 // Disconnect the phi now. An empty phi can confuse other
952 // optimizations in this pass of loop opts..
953 if (phi->in(LoopNode::LoopBackControl) == phi) {
954 _igvn.replace_node(phi, phi->in(LoopNode::EntryControl));
955 n_loop->_body.yank(phi);
956 }
957 }
958 }
959 }
960 }
961 }
962 }
963
964 //------------------------------split_if_with_blocks_pre-----------------------
965 // Do the real work in a non-recursive function. Data nodes want to be
966 // cloned in the pre-order so they can feed each other nicely.
967 Node *PhaseIdealLoop::split_if_with_blocks_pre( Node *n ) {
968 // Cloning these guys is unlikely to win
969 int n_op = n->Opcode();
970 if (n_op == Op_MergeMem) {
971 return n;
972 }
973 if (n->is_Proj()) {
974 return n;
975 }
976 // Do not clone-up CmpFXXX variations, as these are always
977 // followed by a CmpI
978 if (n->is_Cmp()) {
979 return n;
980 }
981 // Attempt to use a conditional move instead of a phi/branch
982 if (ConditionalMoveLimit > 0 && n_op == Op_Region) {
983 Node *cmov = conditional_move( n );
984 if (cmov) {
985 return cmov;
986 }
987 }
988 if (n->is_CFG() || n->is_LoadStore()) {
989 return n;
990 }
991 if (n->is_Opaque1() || // Opaque nodes cannot be mod'd
992 n_op == Op_Opaque2) {
993 if (!C->major_progress()) { // If chance of no more loop opts...
994 _igvn._worklist.push(n); // maybe we'll remove them
995 }
996 return n;
997 }
998
999 if (n->is_Con()) {
1000 return n; // No cloning for Con nodes
1001 }
1002
1003 Node *n_ctrl = get_ctrl(n);
1004 if (!n_ctrl) {
1005 return n; // Dead node
1006 }
1007
1008 Node* res = try_move_store_before_loop(n, n_ctrl);
1009 if (res != NULL) {
1010 return n;
1011 }
1012
1013 // Attempt to remix address expressions for loop invariants
1014 Node *m = remix_address_expressions( n );
1015 if( m ) return m;
1016
1017 if (n_op == Op_AddI) {
1018 Node *nn = convert_add_to_muladd( n );
1019 if ( nn ) return nn;
1020 }
1021
1022 if (n->is_ConstraintCast()) {
1023 Node* dom_cast = n->as_ConstraintCast()->dominating_cast(&_igvn, this);
1024 // ConstraintCastNode::dominating_cast() uses node control input to determine domination.
1025 // Node control inputs don't necessarily agree with loop control info (due to
1026 // transformations happened in between), thus additional dominance check is needed
1027 // to keep loop info valid.
1028 if (dom_cast != NULL && is_dominator(get_ctrl(dom_cast), get_ctrl(n))) {
1029 _igvn.replace_node(n, dom_cast);
1030 return dom_cast;
1031 }
1032 }
1033
1034 // Determine if the Node has inputs from some local Phi.
1035 // Returns the block to clone thru.
1036 Node *n_blk = has_local_phi_input( n );
1037 if( !n_blk ) return n;
1038
1039 // Do not clone the trip counter through on a CountedLoop
1040 // (messes up the canonical shape).
1041 if( n_blk->is_CountedLoop() && n->Opcode() == Op_AddI ) return n;
1042
1043 // Check for having no control input; not pinned. Allow
1044 // dominating control.
1045 if (n->in(0)) {
1046 Node *dom = idom(n_blk);
1047 if (dom_lca(n->in(0), dom) != n->in(0)) {
1048 return n;
1049 }
1050 }
1051 // Policy: when is it profitable. You must get more wins than
1052 // policy before it is considered profitable. Policy is usually 0,
1053 // so 1 win is considered profitable. Big merges will require big
1054 // cloning, so get a larger policy.
1055 int policy = n_blk->req() >> 2;
1056
1057 // If the loop is a candidate for range check elimination,
1058 // delay splitting through it's phi until a later loop optimization
1059 if (n_blk->is_CountedLoop()) {
1060 IdealLoopTree *lp = get_loop(n_blk);
1061 if (lp && lp->_rce_candidate) {
1062 return n;
1063 }
1064 }
1065
1066 if (must_throttle_split_if()) return n;
1067
1068 // Split 'n' through the merge point if it is profitable
1069 Node *phi = split_thru_phi( n, n_blk, policy );
1070 if (!phi) return n;
1071
1072 // Found a Phi to split thru!
1073 // Replace 'n' with the new phi
1074 _igvn.replace_node( n, phi );
1075 // Moved a load around the loop, 'en-registering' something.
1076 if (n_blk->is_Loop() && n->is_Load() &&
1077 !phi->in(LoopNode::LoopBackControl)->is_Load())
1078 C->set_major_progress();
1079
1080 return phi;
1081 }
1082
1083 static bool merge_point_too_heavy(Compile* C, Node* region) {
1084 // Bail out if the region and its phis have too many users.
1085 int weight = 0;
1086 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1087 weight += region->fast_out(i)->outcnt();
1088 }
1089 int nodes_left = C->max_node_limit() - C->live_nodes();
1090 if (weight * 8 > nodes_left) {
1091 if (PrintOpto) {
1092 tty->print_cr("*** Split-if bails out: %d nodes, region weight %d", C->unique(), weight);
1093 }
1094 return true;
1095 } else {
1096 return false;
1097 }
1098 }
1099
1100 static bool merge_point_safe(Node* region) {
1101 // 4799512: Stop split_if_with_blocks from splitting a block with a ConvI2LNode
1102 // having a PhiNode input. This sidesteps the dangerous case where the split
1103 // ConvI2LNode may become TOP if the input Value() does not
1104 // overlap the ConvI2L range, leaving a node which may not dominate its
1105 // uses.
1106 // A better fix for this problem can be found in the BugTraq entry, but
1107 // expediency for Mantis demands this hack.
1108 #ifdef _LP64
1109 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1110 Node* n = region->fast_out(i);
1111 if (n->is_Phi()) {
1112 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
1113 Node* m = n->fast_out(j);
1114 if (m->Opcode() == Op_ConvI2L)
1115 return false;
1116 if (m->is_CastII() && m->isa_CastII()->has_range_check()) {
1117 return false;
1118 }
1119 }
1120 }
1121 }
1122 #endif
1123 return true;
1124 }
1125
1126
1127 //------------------------------place_near_use---------------------------------
1128 // Place some computation next to use but not inside inner loops.
1129 // For inner loop uses move it to the preheader area.
1130 Node *PhaseIdealLoop::place_near_use(Node *useblock) const {
1131 IdealLoopTree *u_loop = get_loop( useblock );
1132 if (u_loop->_irreducible) {
1133 return useblock;
1134 }
1135 if (u_loop->_child) {
1136 if (useblock == u_loop->_head && u_loop->_head->is_OuterStripMinedLoop()) {
1137 return u_loop->_head->in(LoopNode::EntryControl);
1138 }
1139 return useblock;
1140 }
1141 return u_loop->_head->as_Loop()->skip_strip_mined()->in(LoopNode::EntryControl);
1142 }
1143
1144
1145 bool PhaseIdealLoop::identical_backtoback_ifs(Node *n) {
1146 if (!n->is_If() || n->is_CountedLoopEnd()) {
1147 return false;
1148 }
1149 if (!n->in(0)->is_Region()) {
1150 return false;
1151 }
1152 Node* region = n->in(0);
1153 Node* dom = idom(region);
1154 if (!dom->is_If() || dom->in(1) != n->in(1)) {
1155 return false;
1156 }
1157 IfNode* dom_if = dom->as_If();
1158 Node* proj_true = dom_if->proj_out(1);
1159 Node* proj_false = dom_if->proj_out(0);
1160
1161 for (uint i = 1; i < region->req(); i++) {
1162 if (is_dominator(proj_true, region->in(i))) {
1163 continue;
1164 }
1165 if (is_dominator(proj_false, region->in(i))) {
1166 continue;
1167 }
1168 return false;
1169 }
1170
1171 return true;
1172 }
1173
1174
1175 bool PhaseIdealLoop::can_split_if(Node* n_ctrl) {
1176 if (must_throttle_split_if()) {
1177 return false;
1178 }
1179
1180 // Do not do 'split-if' if irreducible loops are present.
1181 if (_has_irreducible_loops) {
1182 return false;
1183 }
1184
1185 if (merge_point_too_heavy(C, n_ctrl)) {
1186 return false;
1187 }
1188
1189 // Do not do 'split-if' if some paths are dead. First do dead code
1190 // elimination and then see if its still profitable.
1191 for (uint i = 1; i < n_ctrl->req(); i++) {
1192 if (n_ctrl->in(i) == C->top()) {
1193 return false;
1194 }
1195 }
1196
1197 // If trying to do a 'Split-If' at the loop head, it is only
1198 // profitable if the cmp folds up on BOTH paths. Otherwise we
1199 // risk peeling a loop forever.
1200
1201 // CNC - Disabled for now. Requires careful handling of loop
1202 // body selection for the cloned code. Also, make sure we check
1203 // for any input path not being in the same loop as n_ctrl. For
1204 // irreducible loops we cannot check for 'n_ctrl->is_Loop()'
1205 // because the alternative loop entry points won't be converted
1206 // into LoopNodes.
1207 IdealLoopTree *n_loop = get_loop(n_ctrl);
1208 for (uint j = 1; j < n_ctrl->req(); j++) {
1209 if (get_loop(n_ctrl->in(j)) != n_loop) {
1210 return false;
1211 }
1212 }
1213
1214 // Check for safety of the merge point.
1215 if (!merge_point_safe(n_ctrl)) {
1216 return false;
1217 }
1218
1219 return true;
1220 }
1221
1222 // Detect if the node is the inner strip-mined loop
1223 // Return: NULL if it's not the case, or the exit of outer strip-mined loop
1224 static Node* is_inner_of_stripmined_loop(const Node* out) {
1225 Node* out_le = NULL;
1226
1227 if (out->is_CountedLoopEnd()) {
1228 const CountedLoopNode* loop = out->as_CountedLoopEnd()->loopnode();
1229
1230 if (loop != NULL && loop->is_strip_mined()) {
1231 out_le = loop->in(LoopNode::EntryControl)->as_OuterStripMinedLoop()->outer_loop_exit();
1232 }
1233 }
1234
1235 return out_le;
1236 }
1237
1238 //------------------------------split_if_with_blocks_post----------------------
1239 // Do the real work in a non-recursive function. CFG hackery wants to be
1240 // in the post-order, so it can dirty the I-DOM info and not use the dirtied
1241 // info.
1242 void PhaseIdealLoop::split_if_with_blocks_post(Node *n) {
1243
1244 // Cloning Cmp through Phi's involves the split-if transform.
1245 // FastLock is not used by an If
1246 if (n->is_Cmp() && !n->is_FastLock()) {
1247 Node *n_ctrl = get_ctrl(n);
1248 // Determine if the Node has inputs from some local Phi.
1249 // Returns the block to clone thru.
1250 Node *n_blk = has_local_phi_input(n);
1251 if (n_blk != n_ctrl) {
1252 return;
1253 }
1254
1255 if (!can_split_if(n_ctrl)) {
1256 return;
1257 }
1258
1259 if (n->outcnt() != 1) {
1260 return; // Multiple bool's from 1 compare?
1261 }
1262 Node *bol = n->unique_out();
1263 assert(bol->is_Bool(), "expect a bool here");
1264 if (bol->outcnt() != 1) {
1265 return;// Multiple branches from 1 compare?
1266 }
1267 Node *iff = bol->unique_out();
1268
1269 // Check some safety conditions
1270 if (iff->is_If()) { // Classic split-if?
1271 if (iff->in(0) != n_ctrl) {
1272 return; // Compare must be in same blk as if
1273 }
1274 } else if (iff->is_CMove()) { // Trying to split-up a CMOVE
1275 // Can't split CMove with different control edge.
1276 if (iff->in(0) != NULL && iff->in(0) != n_ctrl ) {
1277 return;
1278 }
1279 if (get_ctrl(iff->in(2)) == n_ctrl ||
1280 get_ctrl(iff->in(3)) == n_ctrl) {
1281 return; // Inputs not yet split-up
1282 }
1283 if (get_loop(n_ctrl) != get_loop(get_ctrl(iff))) {
1284 return; // Loop-invar test gates loop-varying CMOVE
1285 }
1286 } else {
1287 return; // some other kind of node, such as an Allocate
1288 }
1289
1290 // When is split-if profitable? Every 'win' on means some control flow
1291 // goes dead, so it's almost always a win.
1292 int policy = 0;
1293 // Split compare 'n' through the merge point if it is profitable
1294 Node *phi = split_thru_phi( n, n_ctrl, policy);
1295 if (!phi) {
1296 return;
1297 }
1298
1299 // Found a Phi to split thru!
1300 // Replace 'n' with the new phi
1301 _igvn.replace_node(n, phi);
1302
1303 // Now split the bool up thru the phi
1304 Node *bolphi = split_thru_phi(bol, n_ctrl, -1);
1305 guarantee(bolphi != NULL, "null boolean phi node");
1306
1307 _igvn.replace_node(bol, bolphi);
1308 assert(iff->in(1) == bolphi, "");
1309
1310 if (bolphi->Value(&_igvn)->singleton()) {
1311 return;
1312 }
1313
1314 // Conditional-move? Must split up now
1315 if (!iff->is_If()) {
1316 Node *cmovphi = split_thru_phi(iff, n_ctrl, -1);
1317 _igvn.replace_node(iff, cmovphi);
1318 return;
1319 }
1320
1321 // Now split the IF
1322 do_split_if(iff);
1323 return;
1324 }
1325
1326 // Two identical ifs back to back can be merged
1327 if (identical_backtoback_ifs(n) && can_split_if(n->in(0))) {
1328 Node *n_ctrl = n->in(0);
1329 PhiNode* bolphi = PhiNode::make_blank(n_ctrl, n->in(1));
1330 IfNode* dom_if = idom(n_ctrl)->as_If();
1331 Node* proj_true = dom_if->proj_out(1);
1332 Node* proj_false = dom_if->proj_out(0);
1333 Node* con_true = _igvn.makecon(TypeInt::ONE);
1334 Node* con_false = _igvn.makecon(TypeInt::ZERO);
1335
1336 for (uint i = 1; i < n_ctrl->req(); i++) {
1337 if (is_dominator(proj_true, n_ctrl->in(i))) {
1338 bolphi->init_req(i, con_true);
1339 } else {
1340 assert(is_dominator(proj_false, n_ctrl->in(i)), "bad if");
1341 bolphi->init_req(i, con_false);
1342 }
1343 }
1344 register_new_node(bolphi, n_ctrl);
1345 _igvn.replace_input_of(n, 1, bolphi);
1346
1347 // Now split the IF
1348 do_split_if(n);
1349 return;
1350 }
1351
1352 // Check for an IF ready to split; one that has its
1353 // condition codes input coming from a Phi at the block start.
1354 int n_op = n->Opcode();
1355
1356 // Check for an IF being dominated by another IF same test
1357 if (n_op == Op_If ||
1358 n_op == Op_RangeCheck) {
1359 Node *bol = n->in(1);
1360 uint max = bol->outcnt();
1361 // Check for same test used more than once?
1362 if (max > 1 && bol->is_Bool()) {
1363 // Search up IDOMs to see if this IF is dominated.
1364 Node *cutoff = get_ctrl(bol);
1365
1366 // Now search up IDOMs till cutoff, looking for a dominating test
1367 Node *prevdom = n;
1368 Node *dom = idom(prevdom);
1369 while (dom != cutoff) {
1370 if (dom->req() > 1 && dom->in(1) == bol && prevdom->in(0) == dom) {
1371 // It's invalid to move control dependent data nodes in the inner
1372 // strip-mined loop, because:
1373 // 1) break validation of LoopNode::verify_strip_mined()
1374 // 2) move code with side-effect in strip-mined loop
1375 // Move to the exit of outer strip-mined loop in that case.
1376 Node* out_le = is_inner_of_stripmined_loop(dom);
1377 if (out_le != NULL) {
1378 prevdom = out_le;
1379 }
1380 // Replace the dominated test with an obvious true or false.
1381 // Place it on the IGVN worklist for later cleanup.
1382 C->set_major_progress();
1383 dominated_by(prevdom, n, false, true);
1384 #ifndef PRODUCT
1385 if( VerifyLoopOptimizations ) verify();
1386 #endif
1387 return;
1388 }
1389 prevdom = dom;
1390 dom = idom(prevdom);
1391 }
1392 }
1393 }
1394
1395 // See if a shared loop-varying computation has no loop-varying uses.
1396 // Happens if something is only used for JVM state in uncommon trap exits,
1397 // like various versions of induction variable+offset. Clone the
1398 // computation per usage to allow it to sink out of the loop.
1399 if (has_ctrl(n) && !n->in(0)) {// n not dead and has no control edge (can float about)
1400 Node *n_ctrl = get_ctrl(n);
1401 IdealLoopTree *n_loop = get_loop(n_ctrl);
1402 if( n_loop != _ltree_root ) {
1403 DUIterator_Fast imax, i = n->fast_outs(imax);
1404 for (; i < imax; i++) {
1405 Node* u = n->fast_out(i);
1406 if( !has_ctrl(u) ) break; // Found control user
1407 IdealLoopTree *u_loop = get_loop(get_ctrl(u));
1408 if( u_loop == n_loop ) break; // Found loop-varying use
1409 if( n_loop->is_member( u_loop ) ) break; // Found use in inner loop
1410 if( u->Opcode() == Op_Opaque1 ) break; // Found loop limit, bugfix for 4677003
1411 }
1412 bool did_break = (i < imax); // Did we break out of the previous loop?
1413 if (!did_break && n->outcnt() > 1) { // All uses in outer loops!
1414 Node *late_load_ctrl = NULL;
1415 if (n->is_Load()) {
1416 // If n is a load, get and save the result from get_late_ctrl(),
1417 // to be later used in calculating the control for n's clones.
1418 clear_dom_lca_tags();
1419 late_load_ctrl = get_late_ctrl(n, n_ctrl);
1420 }
1421 // If n is a load, and the late control is the same as the current
1422 // control, then the cloning of n is a pointless exercise, because
1423 // GVN will ensure that we end up where we started.
1424 if (!n->is_Load() || late_load_ctrl != n_ctrl) {
1425 for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin; ) {
1426 Node *u = n->last_out(j); // Clone private computation per use
1427 _igvn.rehash_node_delayed(u);
1428 Node *x = n->clone(); // Clone computation
1429 Node *x_ctrl = NULL;
1430 if( u->is_Phi() ) {
1431 // Replace all uses of normal nodes. Replace Phi uses
1432 // individually, so the separate Nodes can sink down
1433 // different paths.
1434 uint k = 1;
1435 while( u->in(k) != n ) k++;
1436 u->set_req( k, x );
1437 // x goes next to Phi input path
1438 x_ctrl = u->in(0)->in(k);
1439 --j;
1440 } else { // Normal use
1441 // Replace all uses
1442 for( uint k = 0; k < u->req(); k++ ) {
1443 if( u->in(k) == n ) {
1444 u->set_req( k, x );
1445 --j;
1446 }
1447 }
1448 x_ctrl = get_ctrl(u);
1449 }
1450
1451 // Find control for 'x' next to use but not inside inner loops.
1452 // For inner loop uses get the preheader area.
1453 x_ctrl = place_near_use(x_ctrl);
1454
1455 if (n->is_Load()) {
1456 // For loads, add a control edge to a CFG node outside of the loop
1457 // to force them to not combine and return back inside the loop
1458 // during GVN optimization (4641526).
1459 //
1460 // Because we are setting the actual control input, factor in
1461 // the result from get_late_ctrl() so we respect any
1462 // anti-dependences. (6233005).
1463 x_ctrl = dom_lca(late_load_ctrl, x_ctrl);
1464
1465 // Don't allow the control input to be a CFG splitting node.
1466 // Such nodes should only have ProjNodes as outs, e.g. IfNode
1467 // should only have IfTrueNode and IfFalseNode (4985384).
1468 x_ctrl = find_non_split_ctrl(x_ctrl);
1469
1470 IdealLoopTree* x_loop = get_loop(x_ctrl);
1471 Node* x_head = x_loop->_head;
1472 if (x_head->is_Loop() && (x_head->is_OuterStripMinedLoop() || x_head->as_Loop()->is_strip_mined()) && is_dominator(n_ctrl, x_head)) {
1473 // Anti dependence analysis is sometimes too
1474 // conservative: a store in the outer strip mined loop
1475 // can prevent a load from floating out of the outer
1476 // strip mined loop but the load may not be referenced
1477 // from the safepoint: loop strip mining verification
1478 // code reports a problem in that case. Make sure the
1479 // load is not moved in the outer strip mined loop in
1480 // that case.
1481 x_ctrl = x_head->as_Loop()->skip_strip_mined()->in(LoopNode::EntryControl);
1482 }
1483 assert(dom_depth(n_ctrl) <= dom_depth(x_ctrl), "n is later than its clone");
1484
1485 x->set_req(0, x_ctrl);
1486 }
1487 register_new_node(x, x_ctrl);
1488
1489 // Some institutional knowledge is needed here: 'x' is
1490 // yanked because if the optimizer runs GVN on it all the
1491 // cloned x's will common up and undo this optimization and
1492 // be forced back in the loop.
1493 // I tried setting control edges on the x's to force them to
1494 // not combine, but the matching gets worried when it tries
1495 // to fold a StoreP and an AddP together (as part of an
1496 // address expression) and the AddP and StoreP have
1497 // different controls.
1498 if (!x->is_Load() && !x->is_DecodeNarrowPtr()) _igvn._worklist.yank(x);
1499 }
1500 _igvn.remove_dead_node(n);
1501 }
1502 }
1503 }
1504 }
1505
1506 try_move_store_after_loop(n);
1507
1508 // Check for Opaque2's who's loop has disappeared - who's input is in the
1509 // same loop nest as their output. Remove 'em, they are no longer useful.
1510 if( n_op == Op_Opaque2 &&
1511 n->in(1) != NULL &&
1512 get_loop(get_ctrl(n)) == get_loop(get_ctrl(n->in(1))) ) {
1513 _igvn.replace_node( n, n->in(1) );
1514 }
1515 }
1516
1517 //------------------------------split_if_with_blocks---------------------------
1518 // Check for aggressive application of 'split-if' optimization,
1519 // using basic block level info.
1520 void PhaseIdealLoop::split_if_with_blocks(VectorSet &visited, Node_Stack &nstack) {
1521 Node* root = C->root();
1522 visited.set(root->_idx); // first, mark root as visited
1523 // Do pre-visit work for root
1524 Node* n = split_if_with_blocks_pre(root);
1525 uint cnt = n->outcnt();
1526 uint i = 0;
1527
1528 while (true) {
1529 // Visit all children
1530 if (i < cnt) {
1531 Node* use = n->raw_out(i);
1532 ++i;
1533 if (use->outcnt() != 0 && !visited.test_set(use->_idx)) {
1534 // Now do pre-visit work for this use
1535 use = split_if_with_blocks_pre(use);
1536 nstack.push(n, i); // Save parent and next use's index.
1537 n = use; // Process all children of current use.
1538 cnt = use->outcnt();
1539 i = 0;
1540 }
1541 }
1542 else {
1543 // All of n's children have been processed, complete post-processing.
1544 if (cnt != 0 && !n->is_Con()) {
1545 assert(has_node(n), "no dead nodes");
1546 split_if_with_blocks_post(n);
1547 }
1548 if (must_throttle_split_if()) {
1549 nstack.clear();
1550 }
1551 if (nstack.is_empty()) {
1552 // Finished all nodes on stack.
1553 break;
1554 }
1555 // Get saved parent node and next use's index. Visit the rest of uses.
1556 n = nstack.node();
1557 cnt = n->outcnt();
1558 i = nstack.index();
1559 nstack.pop();
1560 }
1561 }
1562 }
1563
1564
1565 //=============================================================================
1566 //
1567 // C L O N E A L O O P B O D Y
1568 //
1569
1570 //------------------------------clone_iff--------------------------------------
1571 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps.
1572 // "Nearly" because all Nodes have been cloned from the original in the loop,
1573 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs
1574 // through the Phi recursively, and return a Bool.
1575 Node* PhaseIdealLoop::clone_iff(PhiNode *phi, IdealLoopTree *loop) {
1576
1577 // Convert this Phi into a Phi merging Bools
1578 uint i;
1579 for (i = 1; i < phi->req(); i++) {
1580 Node *b = phi->in(i);
1581 if (b->is_Phi()) {
1582 _igvn.replace_input_of(phi, i, clone_iff(b->as_Phi(), loop));
1583 } else {
1584 assert(b->is_Bool() || b->Opcode() == Op_Opaque4, "");
1585 }
1586 }
1587
1588 Node* n = phi->in(1);
1589 Node* sample_opaque = NULL;
1590 Node *sample_bool = NULL;
1591 if (n->Opcode() == Op_Opaque4) {
1592 sample_opaque = n;
1593 sample_bool = n->in(1);
1594 assert(sample_bool->is_Bool(), "wrong type");
1595 } else {
1596 sample_bool = n;
1597 }
1598 Node *sample_cmp = sample_bool->in(1);
1599
1600 // Make Phis to merge the Cmp's inputs.
1601 PhiNode *phi1 = new PhiNode(phi->in(0), Type::TOP);
1602 PhiNode *phi2 = new PhiNode(phi->in(0), Type::TOP);
1603 for (i = 1; i < phi->req(); i++) {
1604 Node *n1 = sample_opaque == NULL ? phi->in(i)->in(1)->in(1) : phi->in(i)->in(1)->in(1)->in(1);
1605 Node *n2 = sample_opaque == NULL ? phi->in(i)->in(1)->in(2) : phi->in(i)->in(1)->in(1)->in(2);
1606 phi1->set_req(i, n1);
1607 phi2->set_req(i, n2);
1608 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type()));
1609 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type()));
1610 }
1611 // See if these Phis have been made before.
1612 // Register with optimizer
1613 Node *hit1 = _igvn.hash_find_insert(phi1);
1614 if (hit1) { // Hit, toss just made Phi
1615 _igvn.remove_dead_node(phi1); // Remove new phi
1616 assert(hit1->is_Phi(), "" );
1617 phi1 = (PhiNode*)hit1; // Use existing phi
1618 } else { // Miss
1619 _igvn.register_new_node_with_optimizer(phi1);
1620 }
1621 Node *hit2 = _igvn.hash_find_insert(phi2);
1622 if (hit2) { // Hit, toss just made Phi
1623 _igvn.remove_dead_node(phi2); // Remove new phi
1624 assert(hit2->is_Phi(), "" );
1625 phi2 = (PhiNode*)hit2; // Use existing phi
1626 } else { // Miss
1627 _igvn.register_new_node_with_optimizer(phi2);
1628 }
1629 // Register Phis with loop/block info
1630 set_ctrl(phi1, phi->in(0));
1631 set_ctrl(phi2, phi->in(0));
1632 // Make a new Cmp
1633 Node *cmp = sample_cmp->clone();
1634 cmp->set_req(1, phi1);
1635 cmp->set_req(2, phi2);
1636 _igvn.register_new_node_with_optimizer(cmp);
1637 set_ctrl(cmp, phi->in(0));
1638
1639 // Make a new Bool
1640 Node *b = sample_bool->clone();
1641 b->set_req(1,cmp);
1642 _igvn.register_new_node_with_optimizer(b);
1643 set_ctrl(b, phi->in(0));
1644
1645 if (sample_opaque != NULL) {
1646 Node* opaque = sample_opaque->clone();
1647 opaque->set_req(1, b);
1648 _igvn.register_new_node_with_optimizer(opaque);
1649 set_ctrl(opaque, phi->in(0));
1650 return opaque;
1651 }
1652
1653 assert(b->is_Bool(), "");
1654 return b;
1655 }
1656
1657 //------------------------------clone_bool-------------------------------------
1658 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps.
1659 // "Nearly" because all Nodes have been cloned from the original in the loop,
1660 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs
1661 // through the Phi recursively, and return a Bool.
1662 CmpNode *PhaseIdealLoop::clone_bool( PhiNode *phi, IdealLoopTree *loop ) {
1663 uint i;
1664 // Convert this Phi into a Phi merging Bools
1665 for( i = 1; i < phi->req(); i++ ) {
1666 Node *b = phi->in(i);
1667 if( b->is_Phi() ) {
1668 _igvn.replace_input_of(phi, i, clone_bool( b->as_Phi(), loop ));
1669 } else {
1670 assert( b->is_Cmp() || b->is_top(), "inputs are all Cmp or TOP" );
1671 }
1672 }
1673
1674 Node *sample_cmp = phi->in(1);
1675
1676 // Make Phis to merge the Cmp's inputs.
1677 PhiNode *phi1 = new PhiNode( phi->in(0), Type::TOP );
1678 PhiNode *phi2 = new PhiNode( phi->in(0), Type::TOP );
1679 for( uint j = 1; j < phi->req(); j++ ) {
1680 Node *cmp_top = phi->in(j); // Inputs are all Cmp or TOP
1681 Node *n1, *n2;
1682 if( cmp_top->is_Cmp() ) {
1683 n1 = cmp_top->in(1);
1684 n2 = cmp_top->in(2);
1685 } else {
1686 n1 = n2 = cmp_top;
1687 }
1688 phi1->set_req( j, n1 );
1689 phi2->set_req( j, n2 );
1690 phi1->set_type(phi1->type()->meet_speculative(n1->bottom_type()));
1691 phi2->set_type(phi2->type()->meet_speculative(n2->bottom_type()));
1692 }
1693
1694 // See if these Phis have been made before.
1695 // Register with optimizer
1696 Node *hit1 = _igvn.hash_find_insert(phi1);
1697 if( hit1 ) { // Hit, toss just made Phi
1698 _igvn.remove_dead_node(phi1); // Remove new phi
1699 assert( hit1->is_Phi(), "" );
1700 phi1 = (PhiNode*)hit1; // Use existing phi
1701 } else { // Miss
1702 _igvn.register_new_node_with_optimizer(phi1);
1703 }
1704 Node *hit2 = _igvn.hash_find_insert(phi2);
1705 if( hit2 ) { // Hit, toss just made Phi
1706 _igvn.remove_dead_node(phi2); // Remove new phi
1707 assert( hit2->is_Phi(), "" );
1708 phi2 = (PhiNode*)hit2; // Use existing phi
1709 } else { // Miss
1710 _igvn.register_new_node_with_optimizer(phi2);
1711 }
1712 // Register Phis with loop/block info
1713 set_ctrl(phi1, phi->in(0));
1714 set_ctrl(phi2, phi->in(0));
1715 // Make a new Cmp
1716 Node *cmp = sample_cmp->clone();
1717 cmp->set_req( 1, phi1 );
1718 cmp->set_req( 2, phi2 );
1719 _igvn.register_new_node_with_optimizer(cmp);
1720 set_ctrl(cmp, phi->in(0));
1721
1722 assert( cmp->is_Cmp(), "" );
1723 return (CmpNode*)cmp;
1724 }
1725
1726 //------------------------------sink_use---------------------------------------
1727 // If 'use' was in the loop-exit block, it now needs to be sunk
1728 // below the post-loop merge point.
1729 void PhaseIdealLoop::sink_use( Node *use, Node *post_loop ) {
1730 if (!use->is_CFG() && get_ctrl(use) == post_loop->in(2)) {
1731 set_ctrl(use, post_loop);
1732 for (DUIterator j = use->outs(); use->has_out(j); j++)
1733 sink_use(use->out(j), post_loop);
1734 }
1735 }
1736
1737 void PhaseIdealLoop::clone_loop_handle_data_uses(Node* old, Node_List &old_new,
1738 IdealLoopTree* loop, IdealLoopTree* outer_loop,
1739 Node_List*& split_if_set, Node_List*& split_bool_set,
1740 Node_List*& split_cex_set, Node_List& worklist,
1741 uint new_counter, CloneLoopMode mode) {
1742 Node* nnn = old_new[old->_idx];
1743 // Copy uses to a worklist, so I can munge the def-use info
1744 // with impunity.
1745 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++)
1746 worklist.push(old->fast_out(j));
1747
1748 while( worklist.size() ) {
1749 Node *use = worklist.pop();
1750 if (!has_node(use)) continue; // Ignore dead nodes
1751 if (use->in(0) == C->top()) continue;
1752 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use );
1753 // Check for data-use outside of loop - at least one of OLD or USE
1754 // must not be a CFG node.
1755 #ifdef ASSERT
1756 if (loop->_head->as_Loop()->is_strip_mined() && outer_loop->is_member(use_loop) && !loop->is_member(use_loop) && old_new[use->_idx] == NULL) {
1757 Node* sfpt = loop->_head->as_CountedLoop()->outer_safepoint();
1758 assert(mode != IgnoreStripMined, "incorrect cloning mode");
1759 assert((mode == ControlAroundStripMined && use == sfpt) || !use->is_reachable_from_root(), "missed a node");
1760 }
1761 #endif
1762 if (!loop->is_member(use_loop) && !outer_loop->is_member(use_loop) && (!old->is_CFG() || !use->is_CFG())) {
1763
1764 // If the Data use is an IF, that means we have an IF outside of the
1765 // loop that is switching on a condition that is set inside of the
1766 // loop. Happens if people set a loop-exit flag; then test the flag
1767 // in the loop to break the loop, then test is again outside of the
1768 // loop to determine which way the loop exited.
1769 // Loop predicate If node connects to Bool node through Opaque1 node.
1770 if (use->is_If() || use->is_CMove() || C->is_predicate_opaq(use) || use->Opcode() == Op_Opaque4) {
1771 // Since this code is highly unlikely, we lazily build the worklist
1772 // of such Nodes to go split.
1773 if (!split_if_set) {
1774 split_if_set = new Node_List();
1775 }
1776 split_if_set->push(use);
1777 }
1778 if (use->is_Bool()) {
1779 if (!split_bool_set) {
1780 split_bool_set = new Node_List();
1781 }
1782 split_bool_set->push(use);
1783 }
1784 if (use->Opcode() == Op_CreateEx) {
1785 if (!split_cex_set) {
1786 split_cex_set = new Node_List();
1787 }
1788 split_cex_set->push(use);
1789 }
1790
1791
1792 // Get "block" use is in
1793 uint idx = 0;
1794 while( use->in(idx) != old ) idx++;
1795 Node *prev = use->is_CFG() ? use : get_ctrl(use);
1796 assert(!loop->is_member(get_loop(prev)) && !outer_loop->is_member(get_loop(prev)), "" );
1797 Node *cfg = prev->_idx >= new_counter
1798 ? prev->in(2)
1799 : idom(prev);
1800 if( use->is_Phi() ) // Phi use is in prior block
1801 cfg = prev->in(idx); // NOT in block of Phi itself
1802 if (cfg->is_top()) { // Use is dead?
1803 _igvn.replace_input_of(use, idx, C->top());
1804 continue;
1805 }
1806
1807 // If use is referenced through control edge... (idx == 0)
1808 if (mode == IgnoreStripMined && idx == 0) {
1809 LoopNode *head = loop->_head->as_Loop();
1810 if (head->is_strip_mined() && is_dominator(head->outer_loop_exit(), prev)) {
1811 // That node is outside the inner loop, leave it outside the
1812 // outer loop as well to not confuse verification code.
1813 assert(!loop->_parent->is_member(use_loop), "should be out of the outer loop");
1814 _igvn.replace_input_of(use, 0, head->outer_loop_exit());
1815 continue;
1816 }
1817 }
1818
1819 while(!outer_loop->is_member(get_loop(cfg))) {
1820 prev = cfg;
1821 cfg = cfg->_idx >= new_counter ? cfg->in(2) : idom(cfg);
1822 }
1823 // If the use occurs after merging several exits from the loop, then
1824 // old value must have dominated all those exits. Since the same old
1825 // value was used on all those exits we did not need a Phi at this
1826 // merge point. NOW we do need a Phi here. Each loop exit value
1827 // is now merged with the peeled body exit; each exit gets its own
1828 // private Phi and those Phis need to be merged here.
1829 Node *phi;
1830 if( prev->is_Region() ) {
1831 if( idx == 0 ) { // Updating control edge?
1832 phi = prev; // Just use existing control
1833 } else { // Else need a new Phi
1834 phi = PhiNode::make( prev, old );
1835 // Now recursively fix up the new uses of old!
1836 for( uint i = 1; i < prev->req(); i++ ) {
1837 worklist.push(phi); // Onto worklist once for each 'old' input
1838 }
1839 }
1840 } else {
1841 // Get new RegionNode merging old and new loop exits
1842 prev = old_new[prev->_idx];
1843 assert( prev, "just made this in step 7" );
1844 if( idx == 0) { // Updating control edge?
1845 phi = prev; // Just use existing control
1846 } else { // Else need a new Phi
1847 // Make a new Phi merging data values properly
1848 phi = PhiNode::make( prev, old );
1849 phi->set_req( 1, nnn );
1850 }
1851 }
1852 // If inserting a new Phi, check for prior hits
1853 if( idx != 0 ) {
1854 Node *hit = _igvn.hash_find_insert(phi);
1855 if( hit == NULL ) {
1856 _igvn.register_new_node_with_optimizer(phi); // Register new phi
1857 } else { // or
1858 // Remove the new phi from the graph and use the hit
1859 _igvn.remove_dead_node(phi);
1860 phi = hit; // Use existing phi
1861 }
1862 set_ctrl(phi, prev);
1863 }
1864 // Make 'use' use the Phi instead of the old loop body exit value
1865 _igvn.replace_input_of(use, idx, phi);
1866 if( use->_idx >= new_counter ) { // If updating new phis
1867 // Not needed for correctness, but prevents a weak assert
1868 // in AddPNode from tripping (when we end up with different
1869 // base & derived Phis that will become the same after
1870 // IGVN does CSE).
1871 Node *hit = _igvn.hash_find_insert(use);
1872 if( hit ) // Go ahead and re-hash for hits.
1873 _igvn.replace_node( use, hit );
1874 }
1875
1876 // If 'use' was in the loop-exit block, it now needs to be sunk
1877 // below the post-loop merge point.
1878 sink_use( use, prev );
1879 }
1880 }
1881 }
1882
1883 static void clone_outer_loop_helper(Node* n, const IdealLoopTree *loop, const IdealLoopTree* outer_loop,
1884 const Node_List &old_new, Unique_Node_List& wq, PhaseIdealLoop* phase,
1885 bool check_old_new) {
1886 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
1887 Node* u = n->fast_out(j);
1888 assert(check_old_new || old_new[u->_idx] == NULL, "shouldn't have been cloned");
1889 if (!u->is_CFG() && (!check_old_new || old_new[u->_idx] == NULL)) {
1890 Node* c = phase->get_ctrl(u);
1891 IdealLoopTree* u_loop = phase->get_loop(c);
1892 assert(!loop->is_member(u_loop), "can be in outer loop or out of both loops only");
1893 if (outer_loop->is_member(u_loop)) {
1894 wq.push(u);
1895 }
1896 }
1897 }
1898 }
1899
1900 void PhaseIdealLoop::clone_outer_loop(LoopNode* head, CloneLoopMode mode, IdealLoopTree *loop,
1901 IdealLoopTree* outer_loop, int dd, Node_List &old_new,
1902 Node_List& extra_data_nodes) {
1903 if (head->is_strip_mined() && mode != IgnoreStripMined) {
1904 CountedLoopNode* cl = head->as_CountedLoop();
1905 Node* l = cl->outer_loop();
1906 Node* tail = cl->outer_loop_tail();
1907 IfNode* le = cl->outer_loop_end();
1908 Node* sfpt = cl->outer_safepoint();
1909 CountedLoopEndNode* cle = cl->loopexit();
1910 CountedLoopNode* new_cl = old_new[cl->_idx]->as_CountedLoop();
1911 CountedLoopEndNode* new_cle = new_cl->as_CountedLoop()->loopexit_or_null();
1912 Node* cle_out = cle->proj_out(false);
1913
1914 Node* new_sfpt = NULL;
1915 Node* new_cle_out = cle_out->clone();
1916 old_new.map(cle_out->_idx, new_cle_out);
1917 if (mode == CloneIncludesStripMined) {
1918 // clone outer loop body
1919 Node* new_l = l->clone();
1920 Node* new_tail = tail->clone();
1921 IfNode* new_le = le->clone()->as_If();
1922 new_sfpt = sfpt->clone();
1923
1924 set_loop(new_l, outer_loop->_parent);
1925 set_idom(new_l, new_l->in(LoopNode::EntryControl), dd);
1926 set_loop(new_cle_out, outer_loop->_parent);
1927 set_idom(new_cle_out, new_cle, dd);
1928 set_loop(new_sfpt, outer_loop->_parent);
1929 set_idom(new_sfpt, new_cle_out, dd);
1930 set_loop(new_le, outer_loop->_parent);
1931 set_idom(new_le, new_sfpt, dd);
1932 set_loop(new_tail, outer_loop->_parent);
1933 set_idom(new_tail, new_le, dd);
1934 set_idom(new_cl, new_l, dd);
1935
1936 old_new.map(l->_idx, new_l);
1937 old_new.map(tail->_idx, new_tail);
1938 old_new.map(le->_idx, new_le);
1939 old_new.map(sfpt->_idx, new_sfpt);
1940
1941 new_l->set_req(LoopNode::LoopBackControl, new_tail);
1942 new_l->set_req(0, new_l);
1943 new_tail->set_req(0, new_le);
1944 new_le->set_req(0, new_sfpt);
1945 new_sfpt->set_req(0, new_cle_out);
1946 new_cle_out->set_req(0, new_cle);
1947 new_cl->set_req(LoopNode::EntryControl, new_l);
1948
1949 _igvn.register_new_node_with_optimizer(new_l);
1950 _igvn.register_new_node_with_optimizer(new_tail);
1951 _igvn.register_new_node_with_optimizer(new_le);
1952 } else {
1953 Node *newhead = old_new[loop->_head->_idx];
1954 newhead->as_Loop()->clear_strip_mined();
1955 _igvn.replace_input_of(newhead, LoopNode::EntryControl, newhead->in(LoopNode::EntryControl)->in(LoopNode::EntryControl));
1956 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd);
1957 }
1958 // Look at data node that were assigned a control in the outer
1959 // loop: they are kept in the outer loop by the safepoint so start
1960 // from the safepoint node's inputs.
1961 IdealLoopTree* outer_loop = get_loop(l);
1962 Node_Stack stack(2);
1963 stack.push(sfpt, 1);
1964 uint new_counter = C->unique();
1965 while (stack.size() > 0) {
1966 Node* n = stack.node();
1967 uint i = stack.index();
1968 while (i < n->req() &&
1969 (n->in(i) == NULL ||
1970 !has_ctrl(n->in(i)) ||
1971 get_loop(get_ctrl(n->in(i))) != outer_loop ||
1972 (old_new[n->in(i)->_idx] != NULL && old_new[n->in(i)->_idx]->_idx >= new_counter))) {
1973 i++;
1974 }
1975 if (i < n->req()) {
1976 stack.set_index(i+1);
1977 stack.push(n->in(i), 0);
1978 } else {
1979 assert(old_new[n->_idx] == NULL || n == sfpt || old_new[n->_idx]->_idx < new_counter, "no clone yet");
1980 Node* m = n == sfpt ? new_sfpt : n->clone();
1981 if (m != NULL) {
1982 for (uint i = 0; i < n->req(); i++) {
1983 if (m->in(i) != NULL && old_new[m->in(i)->_idx] != NULL) {
1984 m->set_req(i, old_new[m->in(i)->_idx]);
1985 }
1986 }
1987 } else {
1988 assert(n == sfpt && mode != CloneIncludesStripMined, "where's the safepoint clone?");
1989 }
1990 if (n != sfpt) {
1991 extra_data_nodes.push(n);
1992 _igvn.register_new_node_with_optimizer(m);
1993 assert(get_ctrl(n) == cle_out, "what other control?");
1994 set_ctrl(m, new_cle_out);
1995 old_new.map(n->_idx, m);
1996 }
1997 stack.pop();
1998 }
1999 }
2000 if (mode == CloneIncludesStripMined) {
2001 _igvn.register_new_node_with_optimizer(new_sfpt);
2002 _igvn.register_new_node_with_optimizer(new_cle_out);
2003 }
2004 // Some other transformation may have pessimistically assign some
2005 // data nodes to the outer loop. Set their control so they are out
2006 // of the outer loop.
2007 ResourceMark rm;
2008 Unique_Node_List wq;
2009 for (uint i = 0; i < extra_data_nodes.size(); i++) {
2010 Node* old = extra_data_nodes.at(i);
2011 clone_outer_loop_helper(old, loop, outer_loop, old_new, wq, this, true);
2012 }
2013 Node* new_ctrl = cl->outer_loop_exit();
2014 assert(get_loop(new_ctrl) != outer_loop, "must be out of the loop nest");
2015 for (uint i = 0; i < wq.size(); i++) {
2016 Node* n = wq.at(i);
2017 set_ctrl(n, new_ctrl);
2018 clone_outer_loop_helper(n, loop, outer_loop, old_new, wq, this, false);
2019 }
2020 } else {
2021 Node *newhead = old_new[loop->_head->_idx];
2022 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd);
2023 }
2024 }
2025
2026 //------------------------------clone_loop-------------------------------------
2027 //
2028 // C L O N E A L O O P B O D Y
2029 //
2030 // This is the basic building block of the loop optimizations. It clones an
2031 // entire loop body. It makes an old_new loop body mapping; with this mapping
2032 // you can find the new-loop equivalent to an old-loop node. All new-loop
2033 // nodes are exactly equal to their old-loop counterparts, all edges are the
2034 // same. All exits from the old-loop now have a RegionNode that merges the
2035 // equivalent new-loop path. This is true even for the normal "loop-exit"
2036 // condition. All uses of loop-invariant old-loop values now come from (one
2037 // or more) Phis that merge their new-loop equivalents.
2038 //
2039 // This operation leaves the graph in an illegal state: there are two valid
2040 // control edges coming from the loop pre-header to both loop bodies. I'll
2041 // definitely have to hack the graph after running this transform.
2042 //
2043 // From this building block I will further edit edges to perform loop peeling
2044 // or loop unrolling or iteration splitting (Range-Check-Elimination), etc.
2045 //
2046 // Parameter side_by_size_idom:
2047 // When side_by_size_idom is NULL, the dominator tree is constructed for
2048 // the clone loop to dominate the original. Used in construction of
2049 // pre-main-post loop sequence.
2050 // When nonnull, the clone and original are side-by-side, both are
2051 // dominated by the side_by_side_idom node. Used in construction of
2052 // unswitched loops.
2053 void PhaseIdealLoop::clone_loop( IdealLoopTree *loop, Node_List &old_new, int dd,
2054 CloneLoopMode mode, Node* side_by_side_idom) {
2055
2056 LoopNode* head = loop->_head->as_Loop();
2057 head->verify_strip_mined(1);
2058
2059 if (C->do_vector_loop() && PrintOpto) {
2060 const char* mname = C->method()->name()->as_quoted_ascii();
2061 if (mname != NULL) {
2062 tty->print("PhaseIdealLoop::clone_loop: for vectorize method %s\n", mname);
2063 }
2064 }
2065
2066 CloneMap& cm = C->clone_map();
2067 Dict* dict = cm.dict();
2068 if (C->do_vector_loop()) {
2069 cm.set_clone_idx(cm.max_gen()+1);
2070 #ifndef PRODUCT
2071 if (PrintOpto) {
2072 tty->print_cr("PhaseIdealLoop::clone_loop: _clone_idx %d", cm.clone_idx());
2073 loop->dump_head();
2074 }
2075 #endif
2076 }
2077
2078 // Step 1: Clone the loop body. Make the old->new mapping.
2079 uint i;
2080 for( i = 0; i < loop->_body.size(); i++ ) {
2081 Node *old = loop->_body.at(i);
2082 Node *nnn = old->clone();
2083 old_new.map( old->_idx, nnn );
2084 if (C->do_vector_loop()) {
2085 cm.verify_insert_and_clone(old, nnn, cm.clone_idx());
2086 }
2087 _igvn.register_new_node_with_optimizer(nnn);
2088 }
2089
2090 IdealLoopTree* outer_loop = (head->is_strip_mined() && mode != IgnoreStripMined) ? get_loop(head->as_CountedLoop()->outer_loop()) : loop;
2091
2092 // Step 2: Fix the edges in the new body. If the old input is outside the
2093 // loop use it. If the old input is INside the loop, use the corresponding
2094 // new node instead.
2095 for( i = 0; i < loop->_body.size(); i++ ) {
2096 Node *old = loop->_body.at(i);
2097 Node *nnn = old_new[old->_idx];
2098 // Fix CFG/Loop controlling the new node
2099 if (has_ctrl(old)) {
2100 set_ctrl(nnn, old_new[get_ctrl(old)->_idx]);
2101 } else {
2102 set_loop(nnn, outer_loop->_parent);
2103 if (old->outcnt() > 0) {
2104 set_idom( nnn, old_new[idom(old)->_idx], dd );
2105 }
2106 }
2107 // Correct edges to the new node
2108 for( uint j = 0; j < nnn->req(); j++ ) {
2109 Node *n = nnn->in(j);
2110 if( n ) {
2111 IdealLoopTree *old_in_loop = get_loop( has_ctrl(n) ? get_ctrl(n) : n );
2112 if( loop->is_member( old_in_loop ) )
2113 nnn->set_req(j, old_new[n->_idx]);
2114 }
2115 }
2116 _igvn.hash_find_insert(nnn);
2117 }
2118
2119 Node_List extra_data_nodes; // data nodes in the outer strip mined loop
2120 clone_outer_loop(head, mode, loop, outer_loop, dd, old_new, extra_data_nodes);
2121
2122 // Step 3: Now fix control uses. Loop varying control uses have already
2123 // been fixed up (as part of all input edges in Step 2). Loop invariant
2124 // control uses must be either an IfFalse or an IfTrue. Make a merge
2125 // point to merge the old and new IfFalse/IfTrue nodes; make the use
2126 // refer to this.
2127 Node_List worklist;
2128 uint new_counter = C->unique();
2129 for( i = 0; i < loop->_body.size(); i++ ) {
2130 Node* old = loop->_body.at(i);
2131 if( !old->is_CFG() ) continue;
2132
2133 // Copy uses to a worklist, so I can munge the def-use info
2134 // with impunity.
2135 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++)
2136 worklist.push(old->fast_out(j));
2137
2138 while( worklist.size() ) { // Visit all uses
2139 Node *use = worklist.pop();
2140 if (!has_node(use)) continue; // Ignore dead nodes
2141 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use );
2142 if( !loop->is_member( use_loop ) && use->is_CFG() ) {
2143 // Both OLD and USE are CFG nodes here.
2144 assert( use->is_Proj(), "" );
2145 Node* nnn = old_new[old->_idx];
2146
2147 Node* newuse = NULL;
2148 if (head->is_strip_mined() && mode != IgnoreStripMined) {
2149 CountedLoopNode* cl = head->as_CountedLoop();
2150 CountedLoopEndNode* cle = cl->loopexit();
2151 Node* cle_out = cle->proj_out_or_null(false);
2152 if (use == cle_out) {
2153 IfNode* le = cl->outer_loop_end();
2154 use = le->proj_out(false);
2155 use_loop = get_loop(use);
2156 if (mode == CloneIncludesStripMined) {
2157 nnn = old_new[le->_idx];
2158 } else {
2159 newuse = old_new[cle_out->_idx];
2160 }
2161 }
2162 }
2163 if (newuse == NULL) {
2164 newuse = use->clone();
2165 }
2166
2167 // Clone the loop exit control projection
2168 if (C->do_vector_loop()) {
2169 cm.verify_insert_and_clone(use, newuse, cm.clone_idx());
2170 }
2171 newuse->set_req(0,nnn);
2172 _igvn.register_new_node_with_optimizer(newuse);
2173 set_loop(newuse, use_loop);
2174 set_idom(newuse, nnn, dom_depth(nnn) + 1 );
2175
2176 // We need a Region to merge the exit from the peeled body and the
2177 // exit from the old loop body.
2178 RegionNode *r = new RegionNode(3);
2179 // Map the old use to the new merge point
2180 old_new.map( use->_idx, r );
2181 uint dd_r = MIN2(dom_depth(newuse),dom_depth(use));
2182 assert( dd_r >= dom_depth(dom_lca(newuse,use)), "" );
2183
2184 // The original user of 'use' uses 'r' instead.
2185 for (DUIterator_Last lmin, l = use->last_outs(lmin); l >= lmin;) {
2186 Node* useuse = use->last_out(l);
2187 _igvn.rehash_node_delayed(useuse);
2188 uint uses_found = 0;
2189 if( useuse->in(0) == use ) {
2190 useuse->set_req(0, r);
2191 uses_found++;
2192 if( useuse->is_CFG() ) {
2193 // This is not a dom_depth > dd_r because when new
2194 // control flow is constructed by a loop opt, a node and
2195 // its dominator can end up at the same dom_depth
2196 assert(dom_depth(useuse) >= dd_r, "");
2197 set_idom(useuse, r, dom_depth(useuse));
2198 }
2199 }
2200 for( uint k = 1; k < useuse->req(); k++ ) {
2201 if( useuse->in(k) == use ) {
2202 useuse->set_req(k, r);
2203 uses_found++;
2204 if (useuse->is_Loop() && k == LoopNode::EntryControl) {
2205 // This is not a dom_depth > dd_r because when new
2206 // control flow is constructed by a loop opt, a node
2207 // and its dominator can end up at the same dom_depth
2208 assert(dom_depth(useuse) >= dd_r , "");
2209 set_idom(useuse, r, dom_depth(useuse));
2210 }
2211 }
2212 }
2213 l -= uses_found; // we deleted 1 or more copies of this edge
2214 }
2215
2216 // Now finish up 'r'
2217 r->set_req( 1, newuse );
2218 r->set_req( 2, use );
2219 _igvn.register_new_node_with_optimizer(r);
2220 set_loop(r, use_loop);
2221 set_idom(r, !side_by_side_idom ? newuse->in(0) : side_by_side_idom, dd_r);
2222 } // End of if a loop-exit test
2223 }
2224 }
2225
2226 // Step 4: If loop-invariant use is not control, it must be dominated by a
2227 // loop exit IfFalse/IfTrue. Find "proper" loop exit. Make a Region
2228 // there if needed. Make a Phi there merging old and new used values.
2229 Node_List *split_if_set = NULL;
2230 Node_List *split_bool_set = NULL;
2231 Node_List *split_cex_set = NULL;
2232 for( i = 0; i < loop->_body.size(); i++ ) {
2233 Node* old = loop->_body.at(i);
2234 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set,
2235 split_bool_set, split_cex_set, worklist, new_counter,
2236 mode);
2237 }
2238
2239 for (i = 0; i < extra_data_nodes.size(); i++) {
2240 Node* old = extra_data_nodes.at(i);
2241 clone_loop_handle_data_uses(old, old_new, loop, outer_loop, split_if_set,
2242 split_bool_set, split_cex_set, worklist, new_counter,
2243 mode);
2244 }
2245
2246 // Check for IFs that need splitting/cloning. Happens if an IF outside of
2247 // the loop uses a condition set in the loop. The original IF probably
2248 // takes control from one or more OLD Regions (which in turn get from NEW
2249 // Regions). In any case, there will be a set of Phis for each merge point
2250 // from the IF up to where the original BOOL def exists the loop.
2251 if (split_if_set) {
2252 while (split_if_set->size()) {
2253 Node *iff = split_if_set->pop();
2254 if (iff->in(1)->is_Phi()) {
2255 Node *b = clone_iff(iff->in(1)->as_Phi(), loop);
2256 _igvn.replace_input_of(iff, 1, b);
2257 }
2258 }
2259 }
2260 if (split_bool_set) {
2261 while (split_bool_set->size()) {
2262 Node *b = split_bool_set->pop();
2263 Node *phi = b->in(1);
2264 assert(phi->is_Phi(), "");
2265 CmpNode *cmp = clone_bool((PhiNode*)phi, loop);
2266 _igvn.replace_input_of(b, 1, cmp);
2267 }
2268 }
2269 if (split_cex_set) {
2270 while (split_cex_set->size()) {
2271 Node *b = split_cex_set->pop();
2272 assert(b->in(0)->is_Region(), "");
2273 assert(b->in(1)->is_Phi(), "");
2274 assert(b->in(0)->in(0) == b->in(1)->in(0), "");
2275 split_up(b, b->in(0), NULL);
2276 }
2277 }
2278
2279 }
2280
2281
2282 //---------------------- stride_of_possible_iv -------------------------------------
2283 // Looks for an iff/bool/comp with one operand of the compare
2284 // being a cycle involving an add and a phi,
2285 // with an optional truncation (left-shift followed by a right-shift)
2286 // of the add. Returns zero if not an iv.
2287 int PhaseIdealLoop::stride_of_possible_iv(Node* iff) {
2288 Node* trunc1 = NULL;
2289 Node* trunc2 = NULL;
2290 const TypeInt* ttype = NULL;
2291 if (!iff->is_If() || iff->in(1) == NULL || !iff->in(1)->is_Bool()) {
2292 return 0;
2293 }
2294 BoolNode* bl = iff->in(1)->as_Bool();
2295 Node* cmp = bl->in(1);
2296 if (!cmp || (cmp->Opcode() != Op_CmpI && cmp->Opcode() != Op_CmpU)) {
2297 return 0;
2298 }
2299 // Must have an invariant operand
2300 if (is_member(get_loop(iff), get_ctrl(cmp->in(2)))) {
2301 return 0;
2302 }
2303 Node* add2 = NULL;
2304 Node* cmp1 = cmp->in(1);
2305 if (cmp1->is_Phi()) {
2306 // (If (Bool (CmpX phi:(Phi ...(Optional-trunc(AddI phi add2))) )))
2307 Node* phi = cmp1;
2308 for (uint i = 1; i < phi->req(); i++) {
2309 Node* in = phi->in(i);
2310 Node* add = CountedLoopNode::match_incr_with_optional_truncation(in,
2311 &trunc1, &trunc2, &ttype);
2312 if (add && add->in(1) == phi) {
2313 add2 = add->in(2);
2314 break;
2315 }
2316 }
2317 } else {
2318 // (If (Bool (CmpX addtrunc:(Optional-trunc((AddI (Phi ...addtrunc...) add2)) )))
2319 Node* addtrunc = cmp1;
2320 Node* add = CountedLoopNode::match_incr_with_optional_truncation(addtrunc,
2321 &trunc1, &trunc2, &ttype);
2322 if (add && add->in(1)->is_Phi()) {
2323 Node* phi = add->in(1);
2324 for (uint i = 1; i < phi->req(); i++) {
2325 if (phi->in(i) == addtrunc) {
2326 add2 = add->in(2);
2327 break;
2328 }
2329 }
2330 }
2331 }
2332 if (add2 != NULL) {
2333 const TypeInt* add2t = _igvn.type(add2)->is_int();
2334 if (add2t->is_con()) {
2335 return add2t->get_con();
2336 }
2337 }
2338 return 0;
2339 }
2340
2341
2342 //---------------------- stay_in_loop -------------------------------------
2343 // Return the (unique) control output node that's in the loop (if it exists.)
2344 Node* PhaseIdealLoop::stay_in_loop( Node* n, IdealLoopTree *loop) {
2345 Node* unique = NULL;
2346 if (!n) return NULL;
2347 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2348 Node* use = n->fast_out(i);
2349 if (!has_ctrl(use) && loop->is_member(get_loop(use))) {
2350 if (unique != NULL) {
2351 return NULL;
2352 }
2353 unique = use;
2354 }
2355 }
2356 return unique;
2357 }
2358
2359 //------------------------------ register_node -------------------------------------
2360 // Utility to register node "n" with PhaseIdealLoop
2361 void PhaseIdealLoop::register_node(Node* n, IdealLoopTree *loop, Node* pred, int ddepth) {
2362 _igvn.register_new_node_with_optimizer(n);
2363 loop->_body.push(n);
2364 if (n->is_CFG()) {
2365 set_loop(n, loop);
2366 set_idom(n, pred, ddepth);
2367 } else {
2368 set_ctrl(n, pred);
2369 }
2370 }
2371
2372 //------------------------------ proj_clone -------------------------------------
2373 // Utility to create an if-projection
2374 ProjNode* PhaseIdealLoop::proj_clone(ProjNode* p, IfNode* iff) {
2375 ProjNode* c = p->clone()->as_Proj();
2376 c->set_req(0, iff);
2377 return c;
2378 }
2379
2380 //------------------------------ short_circuit_if -------------------------------------
2381 // Force the iff control output to be the live_proj
2382 Node* PhaseIdealLoop::short_circuit_if(IfNode* iff, ProjNode* live_proj) {
2383 guarantee(live_proj != NULL, "null projection");
2384 int proj_con = live_proj->_con;
2385 assert(proj_con == 0 || proj_con == 1, "false or true projection");
2386 Node *con = _igvn.intcon(proj_con);
2387 set_ctrl(con, C->root());
2388 if (iff) {
2389 iff->set_req(1, con);
2390 }
2391 return con;
2392 }
2393
2394 //------------------------------ insert_if_before_proj -------------------------------------
2395 // Insert a new if before an if projection (* - new node)
2396 //
2397 // before
2398 // if(test)
2399 // / \
2400 // v v
2401 // other-proj proj (arg)
2402 //
2403 // after
2404 // if(test)
2405 // / \
2406 // / v
2407 // | * proj-clone
2408 // v |
2409 // other-proj v
2410 // * new_if(relop(cmp[IU](left,right)))
2411 // / \
2412 // v v
2413 // * new-proj proj
2414 // (returned)
2415 //
2416 ProjNode* PhaseIdealLoop::insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj) {
2417 IfNode* iff = proj->in(0)->as_If();
2418 IdealLoopTree *loop = get_loop(proj);
2419 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj();
2420 int ddepth = dom_depth(proj);
2421
2422 _igvn.rehash_node_delayed(iff);
2423 _igvn.rehash_node_delayed(proj);
2424
2425 proj->set_req(0, NULL); // temporary disconnect
2426 ProjNode* proj2 = proj_clone(proj, iff);
2427 register_node(proj2, loop, iff, ddepth);
2428
2429 Node* cmp = Signed ? (Node*) new CmpINode(left, right) : (Node*) new CmpUNode(left, right);
2430 register_node(cmp, loop, proj2, ddepth);
2431
2432 BoolNode* bol = new BoolNode(cmp, relop);
2433 register_node(bol, loop, proj2, ddepth);
2434
2435 int opcode = iff->Opcode();
2436 assert(opcode == Op_If || opcode == Op_RangeCheck, "unexpected opcode");
2437 IfNode* new_if = (opcode == Op_If) ? new IfNode(proj2, bol, iff->_prob, iff->_fcnt):
2438 new RangeCheckNode(proj2, bol, iff->_prob, iff->_fcnt);
2439 register_node(new_if, loop, proj2, ddepth);
2440
2441 proj->set_req(0, new_if); // reattach
2442 set_idom(proj, new_if, ddepth);
2443
2444 ProjNode* new_exit = proj_clone(other_proj, new_if)->as_Proj();
2445 guarantee(new_exit != NULL, "null exit node");
2446 register_node(new_exit, get_loop(other_proj), new_if, ddepth);
2447
2448 return new_exit;
2449 }
2450
2451 //------------------------------ insert_region_before_proj -------------------------------------
2452 // Insert a region before an if projection (* - new node)
2453 //
2454 // before
2455 // if(test)
2456 // / |
2457 // v |
2458 // proj v
2459 // other-proj
2460 //
2461 // after
2462 // if(test)
2463 // / |
2464 // v |
2465 // * proj-clone v
2466 // | other-proj
2467 // v
2468 // * new-region
2469 // |
2470 // v
2471 // * dum_if
2472 // / \
2473 // v \
2474 // * dum-proj v
2475 // proj
2476 //
2477 RegionNode* PhaseIdealLoop::insert_region_before_proj(ProjNode* proj) {
2478 IfNode* iff = proj->in(0)->as_If();
2479 IdealLoopTree *loop = get_loop(proj);
2480 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj();
2481 int ddepth = dom_depth(proj);
2482
2483 _igvn.rehash_node_delayed(iff);
2484 _igvn.rehash_node_delayed(proj);
2485
2486 proj->set_req(0, NULL); // temporary disconnect
2487 ProjNode* proj2 = proj_clone(proj, iff);
2488 register_node(proj2, loop, iff, ddepth);
2489
2490 RegionNode* reg = new RegionNode(2);
2491 reg->set_req(1, proj2);
2492 register_node(reg, loop, iff, ddepth);
2493
2494 IfNode* dum_if = new IfNode(reg, short_circuit_if(NULL, proj), iff->_prob, iff->_fcnt);
2495 register_node(dum_if, loop, reg, ddepth);
2496
2497 proj->set_req(0, dum_if); // reattach
2498 set_idom(proj, dum_if, ddepth);
2499
2500 ProjNode* dum_proj = proj_clone(other_proj, dum_if);
2501 register_node(dum_proj, loop, dum_if, ddepth);
2502
2503 return reg;
2504 }
2505
2506 //------------------------------ insert_cmpi_loop_exit -------------------------------------
2507 // Clone a signed compare loop exit from an unsigned compare and
2508 // insert it before the unsigned cmp on the stay-in-loop path.
2509 // All new nodes inserted in the dominator tree between the original
2510 // if and it's projections. The original if test is replaced with
2511 // a constant to force the stay-in-loop path.
2512 //
2513 // This is done to make sure that the original if and it's projections
2514 // still dominate the same set of control nodes, that the ctrl() relation
2515 // from data nodes to them is preserved, and that their loop nesting is
2516 // preserved.
2517 //
2518 // before
2519 // if(i <u limit) unsigned compare loop exit
2520 // / |
2521 // v v
2522 // exit-proj stay-in-loop-proj
2523 //
2524 // after
2525 // if(stay-in-loop-const) original if
2526 // / |
2527 // / v
2528 // / if(i < limit) new signed test
2529 // / / |
2530 // / / v
2531 // / / if(i <u limit) new cloned unsigned test
2532 // / / / |
2533 // v v v |
2534 // region |
2535 // | |
2536 // dum-if |
2537 // / | |
2538 // ether | |
2539 // v v
2540 // exit-proj stay-in-loop-proj
2541 //
2542 IfNode* PhaseIdealLoop::insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *loop) {
2543 const bool Signed = true;
2544 const bool Unsigned = false;
2545
2546 BoolNode* bol = if_cmpu->in(1)->as_Bool();
2547 if (bol->_test._test != BoolTest::lt) return NULL;
2548 CmpNode* cmpu = bol->in(1)->as_Cmp();
2549 if (cmpu->Opcode() != Op_CmpU) return NULL;
2550 int stride = stride_of_possible_iv(if_cmpu);
2551 if (stride == 0) return NULL;
2552
2553 Node* lp_proj = stay_in_loop(if_cmpu, loop);
2554 guarantee(lp_proj != NULL, "null loop node");
2555
2556 ProjNode* lp_continue = lp_proj->as_Proj();
2557 ProjNode* lp_exit = if_cmpu->proj_out(!lp_continue->is_IfTrue())->as_Proj();
2558
2559 Node* limit = NULL;
2560 if (stride > 0) {
2561 limit = cmpu->in(2);
2562 } else {
2563 limit = _igvn.makecon(TypeInt::ZERO);
2564 set_ctrl(limit, C->root());
2565 }
2566 // Create a new region on the exit path
2567 RegionNode* reg = insert_region_before_proj(lp_exit);
2568 guarantee(reg != NULL, "null region node");
2569
2570 // Clone the if-cmpu-true-false using a signed compare
2571 BoolTest::mask rel_i = stride > 0 ? bol->_test._test : BoolTest::ge;
2572 ProjNode* cmpi_exit = insert_if_before_proj(cmpu->in(1), Signed, rel_i, limit, lp_continue);
2573 reg->add_req(cmpi_exit);
2574
2575 // Clone the if-cmpu-true-false
2576 BoolTest::mask rel_u = bol->_test._test;
2577 ProjNode* cmpu_exit = insert_if_before_proj(cmpu->in(1), Unsigned, rel_u, cmpu->in(2), lp_continue);
2578 reg->add_req(cmpu_exit);
2579
2580 // Force original if to stay in loop.
2581 short_circuit_if(if_cmpu, lp_continue);
2582
2583 return cmpi_exit->in(0)->as_If();
2584 }
2585
2586 //------------------------------ remove_cmpi_loop_exit -------------------------------------
2587 // Remove a previously inserted signed compare loop exit.
2588 void PhaseIdealLoop::remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop) {
2589 Node* lp_proj = stay_in_loop(if_cmp, loop);
2590 assert(if_cmp->in(1)->in(1)->Opcode() == Op_CmpI &&
2591 stay_in_loop(lp_proj, loop)->is_If() &&
2592 stay_in_loop(lp_proj, loop)->in(1)->in(1)->Opcode() == Op_CmpU, "inserted cmpi before cmpu");
2593 Node *con = _igvn.makecon(lp_proj->is_IfTrue() ? TypeInt::ONE : TypeInt::ZERO);
2594 set_ctrl(con, C->root());
2595 if_cmp->set_req(1, con);
2596 }
2597
2598 //------------------------------ scheduled_nodelist -------------------------------------
2599 // Create a post order schedule of nodes that are in the
2600 // "member" set. The list is returned in "sched".
2601 // The first node in "sched" is the loop head, followed by
2602 // nodes which have no inputs in the "member" set, and then
2603 // followed by the nodes that have an immediate input dependence
2604 // on a node in "sched".
2605 void PhaseIdealLoop::scheduled_nodelist( IdealLoopTree *loop, VectorSet& member, Node_List &sched ) {
2606
2607 assert(member.test(loop->_head->_idx), "loop head must be in member set");
2608 VectorSet visited;
2609 Node_Stack nstack(loop->_body.size());
2610
2611 Node* n = loop->_head; // top of stack is cached in "n"
2612 uint idx = 0;
2613 visited.set(n->_idx);
2614
2615 // Initially push all with no inputs from within member set
2616 for(uint i = 0; i < loop->_body.size(); i++ ) {
2617 Node *elt = loop->_body.at(i);
2618 if (member.test(elt->_idx)) {
2619 bool found = false;
2620 for (uint j = 0; j < elt->req(); j++) {
2621 Node* def = elt->in(j);
2622 if (def && member.test(def->_idx) && def != elt) {
2623 found = true;
2624 break;
2625 }
2626 }
2627 if (!found && elt != loop->_head) {
2628 nstack.push(n, idx);
2629 n = elt;
2630 assert(!visited.test(n->_idx), "not seen yet");
2631 visited.set(n->_idx);
2632 }
2633 }
2634 }
2635
2636 // traverse out's that are in the member set
2637 while (true) {
2638 if (idx < n->outcnt()) {
2639 Node* use = n->raw_out(idx);
2640 idx++;
2641 if (!visited.test_set(use->_idx)) {
2642 if (member.test(use->_idx)) {
2643 nstack.push(n, idx);
2644 n = use;
2645 idx = 0;
2646 }
2647 }
2648 } else {
2649 // All outputs processed
2650 sched.push(n);
2651 if (nstack.is_empty()) break;
2652 n = nstack.node();
2653 idx = nstack.index();
2654 nstack.pop();
2655 }
2656 }
2657 }
2658
2659
2660 //------------------------------ has_use_in_set -------------------------------------
2661 // Has a use in the vector set
2662 bool PhaseIdealLoop::has_use_in_set( Node* n, VectorSet& vset ) {
2663 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2664 Node* use = n->fast_out(j);
2665 if (vset.test(use->_idx)) {
2666 return true;
2667 }
2668 }
2669 return false;
2670 }
2671
2672
2673 //------------------------------ has_use_internal_to_set -------------------------------------
2674 // Has use internal to the vector set (ie. not in a phi at the loop head)
2675 bool PhaseIdealLoop::has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ) {
2676 Node* head = loop->_head;
2677 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2678 Node* use = n->fast_out(j);
2679 if (vset.test(use->_idx) && !(use->is_Phi() && use->in(0) == head)) {
2680 return true;
2681 }
2682 }
2683 return false;
2684 }
2685
2686
2687 //------------------------------ clone_for_use_outside_loop -------------------------------------
2688 // clone "n" for uses that are outside of loop
2689 int PhaseIdealLoop::clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ) {
2690 int cloned = 0;
2691 assert(worklist.size() == 0, "should be empty");
2692 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2693 Node* use = n->fast_out(j);
2694 if( !loop->is_member(get_loop(has_ctrl(use) ? get_ctrl(use) : use)) ) {
2695 worklist.push(use);
2696 }
2697 }
2698 while( worklist.size() ) {
2699 Node *use = worklist.pop();
2700 if (!has_node(use) || use->in(0) == C->top()) continue;
2701 uint j;
2702 for (j = 0; j < use->req(); j++) {
2703 if (use->in(j) == n) break;
2704 }
2705 assert(j < use->req(), "must be there");
2706
2707 // clone "n" and insert it between the inputs of "n" and the use outside the loop
2708 Node* n_clone = n->clone();
2709 _igvn.replace_input_of(use, j, n_clone);
2710 cloned++;
2711 Node* use_c;
2712 if (!use->is_Phi()) {
2713 use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0);
2714 } else {
2715 // Use in a phi is considered a use in the associated predecessor block
2716 use_c = use->in(0)->in(j);
2717 }
2718 set_ctrl(n_clone, use_c);
2719 assert(!loop->is_member(get_loop(use_c)), "should be outside loop");
2720 get_loop(use_c)->_body.push(n_clone);
2721 _igvn.register_new_node_with_optimizer(n_clone);
2722 #ifndef PRODUCT
2723 if (TracePartialPeeling) {
2724 tty->print_cr("loop exit cloning old: %d new: %d newbb: %d", n->_idx, n_clone->_idx, get_ctrl(n_clone)->_idx);
2725 }
2726 #endif
2727 }
2728 return cloned;
2729 }
2730
2731
2732 //------------------------------ clone_for_special_use_inside_loop -------------------------------------
2733 // clone "n" for special uses that are in the not_peeled region.
2734 // If these def-uses occur in separate blocks, the code generator
2735 // marks the method as not compilable. For example, if a "BoolNode"
2736 // is in a different basic block than the "IfNode" that uses it, then
2737 // the compilation is aborted in the code generator.
2738 void PhaseIdealLoop::clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n,
2739 VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ) {
2740 if (n->is_Phi() || n->is_Load()) {
2741 return;
2742 }
2743 assert(worklist.size() == 0, "should be empty");
2744 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
2745 Node* use = n->fast_out(j);
2746 if ( not_peel.test(use->_idx) &&
2747 (use->is_If() || use->is_CMove() || use->is_Bool()) &&
2748 use->in(1) == n) {
2749 worklist.push(use);
2750 }
2751 }
2752 if (worklist.size() > 0) {
2753 // clone "n" and insert it between inputs of "n" and the use
2754 Node* n_clone = n->clone();
2755 loop->_body.push(n_clone);
2756 _igvn.register_new_node_with_optimizer(n_clone);
2757 set_ctrl(n_clone, get_ctrl(n));
2758 sink_list.push(n_clone);
2759 not_peel.set(n_clone->_idx);
2760 #ifndef PRODUCT
2761 if (TracePartialPeeling) {
2762 tty->print_cr("special not_peeled cloning old: %d new: %d", n->_idx, n_clone->_idx);
2763 }
2764 #endif
2765 while( worklist.size() ) {
2766 Node *use = worklist.pop();
2767 _igvn.rehash_node_delayed(use);
2768 for (uint j = 1; j < use->req(); j++) {
2769 if (use->in(j) == n) {
2770 use->set_req(j, n_clone);
2771 }
2772 }
2773 }
2774 }
2775 }
2776
2777
2778 //------------------------------ insert_phi_for_loop -------------------------------------
2779 // Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist
2780 void PhaseIdealLoop::insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ) {
2781 Node *phi = PhiNode::make(lp, back_edge_val);
2782 phi->set_req(LoopNode::EntryControl, lp_entry_val);
2783 // Use existing phi if it already exists
2784 Node *hit = _igvn.hash_find_insert(phi);
2785 if( hit == NULL ) {
2786 _igvn.register_new_node_with_optimizer(phi);
2787 set_ctrl(phi, lp);
2788 } else {
2789 // Remove the new phi from the graph and use the hit
2790 _igvn.remove_dead_node(phi);
2791 phi = hit;
2792 }
2793 _igvn.replace_input_of(use, idx, phi);
2794 }
2795
2796 #ifdef ASSERT
2797 //------------------------------ is_valid_loop_partition -------------------------------------
2798 // Validate the loop partition sets: peel and not_peel
2799 bool PhaseIdealLoop::is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list,
2800 VectorSet& not_peel ) {
2801 uint i;
2802 // Check that peel_list entries are in the peel set
2803 for (i = 0; i < peel_list.size(); i++) {
2804 if (!peel.test(peel_list.at(i)->_idx)) {
2805 return false;
2806 }
2807 }
2808 // Check at loop members are in one of peel set or not_peel set
2809 for (i = 0; i < loop->_body.size(); i++ ) {
2810 Node *def = loop->_body.at(i);
2811 uint di = def->_idx;
2812 // Check that peel set elements are in peel_list
2813 if (peel.test(di)) {
2814 if (not_peel.test(di)) {
2815 return false;
2816 }
2817 // Must be in peel_list also
2818 bool found = false;
2819 for (uint j = 0; j < peel_list.size(); j++) {
2820 if (peel_list.at(j)->_idx == di) {
2821 found = true;
2822 break;
2823 }
2824 }
2825 if (!found) {
2826 return false;
2827 }
2828 } else if (not_peel.test(di)) {
2829 if (peel.test(di)) {
2830 return false;
2831 }
2832 } else {
2833 return false;
2834 }
2835 }
2836 return true;
2837 }
2838
2839 //------------------------------ is_valid_clone_loop_exit_use -------------------------------------
2840 // Ensure a use outside of loop is of the right form
2841 bool PhaseIdealLoop::is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx) {
2842 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use;
2843 return (use->is_Phi() &&
2844 use_c->is_Region() && use_c->req() == 3 &&
2845 (use_c->in(exit_idx)->Opcode() == Op_IfTrue ||
2846 use_c->in(exit_idx)->Opcode() == Op_IfFalse ||
2847 use_c->in(exit_idx)->Opcode() == Op_JumpProj) &&
2848 loop->is_member( get_loop( use_c->in(exit_idx)->in(0) ) ) );
2849 }
2850
2851 //------------------------------ is_valid_clone_loop_form -------------------------------------
2852 // Ensure that all uses outside of loop are of the right form
2853 bool PhaseIdealLoop::is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list,
2854 uint orig_exit_idx, uint clone_exit_idx) {
2855 uint len = peel_list.size();
2856 for (uint i = 0; i < len; i++) {
2857 Node *def = peel_list.at(i);
2858
2859 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
2860 Node *use = def->fast_out(j);
2861 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use;
2862 if (!loop->is_member(get_loop(use_c))) {
2863 // use is not in the loop, check for correct structure
2864 if (use->in(0) == def) {
2865 // Okay
2866 } else if (!is_valid_clone_loop_exit_use(loop, use, orig_exit_idx)) {
2867 return false;
2868 }
2869 }
2870 }
2871 }
2872 return true;
2873 }
2874 #endif
2875
2876 //------------------------------ partial_peel -------------------------------------
2877 // Partially peel (aka loop rotation) the top portion of a loop (called
2878 // the peel section below) by cloning it and placing one copy just before
2879 // the new loop head and the other copy at the bottom of the new loop.
2880 //
2881 // before after where it came from
2882 //
2883 // stmt1 stmt1
2884 // loop: stmt2 clone
2885 // stmt2 if condA goto exitA clone
2886 // if condA goto exitA new_loop: new
2887 // stmt3 stmt3 clone
2888 // if !condB goto loop if condB goto exitB clone
2889 // exitB: stmt2 orig
2890 // stmt4 if !condA goto new_loop orig
2891 // exitA: goto exitA
2892 // exitB:
2893 // stmt4
2894 // exitA:
2895 //
2896 // Step 1: find the cut point: an exit test on probable
2897 // induction variable.
2898 // Step 2: schedule (with cloning) operations in the peel
2899 // section that can be executed after the cut into
2900 // the section that is not peeled. This may need
2901 // to clone operations into exit blocks. For
2902 // instance, a reference to A[i] in the not-peel
2903 // section and a reference to B[i] in an exit block
2904 // may cause a left-shift of i by 2 to be placed
2905 // in the peel block. This step will clone the left
2906 // shift into the exit block and sink the left shift
2907 // from the peel to the not-peel section.
2908 // Step 3: clone the loop, retarget the control, and insert
2909 // phis for values that are live across the new loop
2910 // head. This is very dependent on the graph structure
2911 // from clone_loop. It creates region nodes for
2912 // exit control and associated phi nodes for values
2913 // flow out of the loop through that exit. The region
2914 // node is dominated by the clone's control projection.
2915 // So the clone's peel section is placed before the
2916 // new loop head, and the clone's not-peel section is
2917 // forms the top part of the new loop. The original
2918 // peel section forms the tail of the new loop.
2919 // Step 4: update the dominator tree and recompute the
2920 // dominator depth.
2921 //
2922 // orig
2923 //
2924 // stmt1
2925 // |
2926 // v
2927 // loop predicate
2928 // |
2929 // v
2930 // loop<----+
2931 // | |
2932 // stmt2 |
2933 // | |
2934 // v |
2935 // ifA |
2936 // / | |
2937 // v v |
2938 // false true ^ <-- last_peel
2939 // / | |
2940 // / ===|==cut |
2941 // / stmt3 | <-- first_not_peel
2942 // / | |
2943 // | v |
2944 // v ifB |
2945 // exitA: / \ |
2946 // / \ |
2947 // v v |
2948 // false true |
2949 // / \ |
2950 // / ----+
2951 // |
2952 // v
2953 // exitB:
2954 // stmt4
2955 //
2956 //
2957 // after clone loop
2958 //
2959 // stmt1
2960 // |
2961 // v
2962 // loop predicate
2963 // / \
2964 // clone / \ orig
2965 // / \
2966 // / \
2967 // v v
2968 // +---->loop loop<----+
2969 // | | | |
2970 // | stmt2 stmt2 |
2971 // | | | |
2972 // | v v |
2973 // | ifA ifA |
2974 // | | \ / | |
2975 // | v v v v |
2976 // ^ true false false true ^ <-- last_peel
2977 // | | ^ \ / | |
2978 // | cut==|== \ \ / ===|==cut |
2979 // | stmt3 \ \ / stmt3 | <-- first_not_peel
2980 // | | dom | | | |
2981 // | v \ 1v v2 v |
2982 // | ifB regionA ifB |
2983 // | / \ | / \ |
2984 // | / \ v / \ |
2985 // | v v exitA: v v |
2986 // | true false false true |
2987 // | / ^ \ / \ |
2988 // +---- \ \ / ----+
2989 // dom \ /
2990 // \ 1v v2
2991 // regionB
2992 // |
2993 // v
2994 // exitB:
2995 // stmt4
2996 //
2997 //
2998 // after partial peel
2999 //
3000 // stmt1
3001 // |
3002 // v
3003 // loop predicate
3004 // /
3005 // clone / orig
3006 // / TOP
3007 // / \
3008 // v v
3009 // TOP->loop loop----+
3010 // | | |
3011 // stmt2 stmt2 |
3012 // | | |
3013 // v v |
3014 // ifA ifA |
3015 // | \ / | |
3016 // v v v v |
3017 // true false false true | <-- last_peel
3018 // | ^ \ / +------|---+
3019 // +->newloop \ \ / === ==cut | |
3020 // | stmt3 \ \ / TOP | |
3021 // | | dom | | stmt3 | | <-- first_not_peel
3022 // | v \ 1v v2 v | |
3023 // | ifB regionA ifB ^ v
3024 // | / \ | / \ | |
3025 // | / \ v / \ | |
3026 // | v v exitA: v v | |
3027 // | true false false true | |
3028 // | / ^ \ / \ | |
3029 // | | \ \ / v | |
3030 // | | dom \ / TOP | |
3031 // | | \ 1v v2 | |
3032 // ^ v regionB | |
3033 // | | | | |
3034 // | | v ^ v
3035 // | | exitB: | |
3036 // | | stmt4 | |
3037 // | +------------>-----------------+ |
3038 // | |
3039 // +-----------------<---------------------+
3040 //
3041 //
3042 // final graph
3043 //
3044 // stmt1
3045 // |
3046 // v
3047 // loop predicate
3048 // |
3049 // v
3050 // stmt2 clone
3051 // |
3052 // v
3053 // ........> ifA clone
3054 // : / |
3055 // dom / |
3056 // : v v
3057 // : false true
3058 // : | |
3059 // : | v
3060 // : | newloop<-----+
3061 // : | | |
3062 // : | stmt3 clone |
3063 // : | | |
3064 // : | v |
3065 // : | ifB |
3066 // : | / \ |
3067 // : | v v |
3068 // : | false true |
3069 // : | | | |
3070 // : | v stmt2 |
3071 // : | exitB: | |
3072 // : | stmt4 v |
3073 // : | ifA orig |
3074 // : | / \ |
3075 // : | / \ |
3076 // : | v v |
3077 // : | false true |
3078 // : | / \ |
3079 // : v v -----+
3080 // RegionA
3081 // |
3082 // v
3083 // exitA
3084 //
3085 bool PhaseIdealLoop::partial_peel( IdealLoopTree *loop, Node_List &old_new ) {
3086
3087 assert(!loop->_head->is_CountedLoop(), "Non-counted loop only");
3088 if (!loop->_head->is_Loop()) {
3089 return false;
3090 }
3091 LoopNode *head = loop->_head->as_Loop();
3092
3093 if (head->is_partial_peel_loop() || head->partial_peel_has_failed()) {
3094 return false;
3095 }
3096
3097 // Check for complex exit control
3098 for (uint ii = 0; ii < loop->_body.size(); ii++) {
3099 Node *n = loop->_body.at(ii);
3100 int opc = n->Opcode();
3101 if (n->is_Call() ||
3102 opc == Op_Catch ||
3103 opc == Op_CatchProj ||
3104 opc == Op_Jump ||
3105 opc == Op_JumpProj) {
3106 #ifndef PRODUCT
3107 if (TracePartialPeeling) {
3108 tty->print_cr("\nExit control too complex: lp: %d", head->_idx);
3109 }
3110 #endif
3111 return false;
3112 }
3113 }
3114
3115 int dd = dom_depth(head);
3116
3117 // Step 1: find cut point
3118
3119 // Walk up dominators to loop head looking for first loop exit
3120 // which is executed on every path thru loop.
3121 IfNode *peel_if = NULL;
3122 IfNode *peel_if_cmpu = NULL;
3123
3124 Node *iff = loop->tail();
3125 while (iff != head) {
3126 if (iff->is_If()) {
3127 Node *ctrl = get_ctrl(iff->in(1));
3128 if (ctrl->is_top()) return false; // Dead test on live IF.
3129 // If loop-varying exit-test, check for induction variable
3130 if (loop->is_member(get_loop(ctrl)) &&
3131 loop->is_loop_exit(iff) &&
3132 is_possible_iv_test(iff)) {
3133 Node* cmp = iff->in(1)->in(1);
3134 if (cmp->Opcode() == Op_CmpI) {
3135 peel_if = iff->as_If();
3136 } else {
3137 assert(cmp->Opcode() == Op_CmpU, "must be CmpI or CmpU");
3138 peel_if_cmpu = iff->as_If();
3139 }
3140 }
3141 }
3142 iff = idom(iff);
3143 }
3144
3145 // Prefer signed compare over unsigned compare.
3146 IfNode* new_peel_if = NULL;
3147 if (peel_if == NULL) {
3148 if (!PartialPeelAtUnsignedTests || peel_if_cmpu == NULL) {
3149 return false; // No peel point found
3150 }
3151 new_peel_if = insert_cmpi_loop_exit(peel_if_cmpu, loop);
3152 if (new_peel_if == NULL) {
3153 return false; // No peel point found
3154 }
3155 peel_if = new_peel_if;
3156 }
3157 Node* last_peel = stay_in_loop(peel_if, loop);
3158 Node* first_not_peeled = stay_in_loop(last_peel, loop);
3159 if (first_not_peeled == NULL || first_not_peeled == head) {
3160 return false;
3161 }
3162
3163 #ifndef PRODUCT
3164 if (TraceLoopOpts) {
3165 tty->print("PartialPeel ");
3166 loop->dump_head();
3167 }
3168
3169 if (TracePartialPeeling) {
3170 tty->print_cr("before partial peel one iteration");
3171 Node_List wl;
3172 Node* t = head->in(2);
3173 while (true) {
3174 wl.push(t);
3175 if (t == head) break;
3176 t = idom(t);
3177 }
3178 while (wl.size() > 0) {
3179 Node* tt = wl.pop();
3180 tt->dump();
3181 if (tt == last_peel) tty->print_cr("-- cut --");
3182 }
3183 }
3184 #endif
3185 VectorSet peel;
3186 VectorSet not_peel;
3187 Node_List peel_list;
3188 Node_List worklist;
3189 Node_List sink_list;
3190
3191 uint estimate = loop->est_loop_clone_sz(1);
3192 if (exceeding_node_budget(estimate)) {
3193 return false;
3194 }
3195
3196 // Set of cfg nodes to peel are those that are executable from
3197 // the head through last_peel.
3198 assert(worklist.size() == 0, "should be empty");
3199 worklist.push(head);
3200 peel.set(head->_idx);
3201 while (worklist.size() > 0) {
3202 Node *n = worklist.pop();
3203 if (n != last_peel) {
3204 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
3205 Node* use = n->fast_out(j);
3206 if (use->is_CFG() &&
3207 loop->is_member(get_loop(use)) &&
3208 !peel.test_set(use->_idx)) {
3209 worklist.push(use);
3210 }
3211 }
3212 }
3213 }
3214
3215 // Set of non-cfg nodes to peel are those that are control
3216 // dependent on the cfg nodes.
3217 for (uint i = 0; i < loop->_body.size(); i++) {
3218 Node *n = loop->_body.at(i);
3219 Node *n_c = has_ctrl(n) ? get_ctrl(n) : n;
3220 if (peel.test(n_c->_idx)) {
3221 peel.set(n->_idx);
3222 } else {
3223 not_peel.set(n->_idx);
3224 }
3225 }
3226
3227 // Step 2: move operations from the peeled section down into the
3228 // not-peeled section
3229
3230 // Get a post order schedule of nodes in the peel region
3231 // Result in right-most operand.
3232 scheduled_nodelist(loop, peel, peel_list);
3233
3234 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition");
3235
3236 // For future check for too many new phis
3237 uint old_phi_cnt = 0;
3238 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) {
3239 Node* use = head->fast_out(j);
3240 if (use->is_Phi()) old_phi_cnt++;
3241 }
3242
3243 #ifndef PRODUCT
3244 if (TracePartialPeeling) {
3245 tty->print_cr("\npeeled list");
3246 }
3247 #endif
3248
3249 // Evacuate nodes in peel region into the not_peeled region if possible
3250 uint new_phi_cnt = 0;
3251 uint cloned_for_outside_use = 0;
3252 for (uint i = 0; i < peel_list.size();) {
3253 Node* n = peel_list.at(i);
3254 #ifndef PRODUCT
3255 if (TracePartialPeeling) n->dump();
3256 #endif
3257 bool incr = true;
3258 if (!n->is_CFG()) {
3259 if (has_use_in_set(n, not_peel)) {
3260 // If not used internal to the peeled region,
3261 // move "n" from peeled to not_peeled region.
3262 if (!has_use_internal_to_set(n, peel, loop)) {
3263 // if not pinned and not a load (which maybe anti-dependent on a store)
3264 // and not a CMove (Matcher expects only bool->cmove).
3265 if (n->in(0) == NULL && !n->is_Load() && !n->is_CMove()) {
3266 cloned_for_outside_use += clone_for_use_outside_loop(loop, n, worklist);
3267 sink_list.push(n);
3268 peel.remove(n->_idx);
3269 not_peel.set(n->_idx);
3270 peel_list.remove(i);
3271 incr = false;
3272 #ifndef PRODUCT
3273 if (TracePartialPeeling) {
3274 tty->print_cr("sink to not_peeled region: %d newbb: %d",
3275 n->_idx, get_ctrl(n)->_idx);
3276 }
3277 #endif
3278 }
3279 } else {
3280 // Otherwise check for special def-use cases that span
3281 // the peel/not_peel boundary such as bool->if
3282 clone_for_special_use_inside_loop(loop, n, not_peel, sink_list, worklist);
3283 new_phi_cnt++;
3284 }
3285 }
3286 }
3287 if (incr) i++;
3288 }
3289
3290 estimate += cloned_for_outside_use + new_phi_cnt;
3291 bool exceed_node_budget = !may_require_nodes(estimate);
3292 bool exceed_phi_limit = new_phi_cnt > old_phi_cnt + PartialPeelNewPhiDelta;
3293
3294 if (exceed_node_budget || exceed_phi_limit) {
3295 #ifndef PRODUCT
3296 if (TracePartialPeeling) {
3297 tty->print_cr("\nToo many new phis: %d old %d new cmpi: %c",
3298 new_phi_cnt, old_phi_cnt, new_peel_if != NULL?'T':'F');
3299 }
3300 #endif
3301 if (new_peel_if != NULL) {
3302 remove_cmpi_loop_exit(new_peel_if, loop);
3303 }
3304 // Inhibit more partial peeling on this loop
3305 assert(!head->is_partial_peel_loop(), "not partial peeled");
3306 head->mark_partial_peel_failed();
3307 if (cloned_for_outside_use > 0) {
3308 // Terminate this round of loop opts because
3309 // the graph outside this loop was changed.
3310 C->set_major_progress();
3311 return true;
3312 }
3313 return false;
3314 }
3315
3316 // Step 3: clone loop, retarget control, and insert new phis
3317
3318 // Create new loop head for new phis and to hang
3319 // the nodes being moved (sinked) from the peel region.
3320 LoopNode* new_head = new LoopNode(last_peel, last_peel);
3321 new_head->set_unswitch_count(head->unswitch_count()); // Preserve
3322 _igvn.register_new_node_with_optimizer(new_head);
3323 assert(first_not_peeled->in(0) == last_peel, "last_peel <- first_not_peeled");
3324 _igvn.replace_input_of(first_not_peeled, 0, new_head);
3325 set_loop(new_head, loop);
3326 loop->_body.push(new_head);
3327 not_peel.set(new_head->_idx);
3328 set_idom(new_head, last_peel, dom_depth(first_not_peeled));
3329 set_idom(first_not_peeled, new_head, dom_depth(first_not_peeled));
3330
3331 while (sink_list.size() > 0) {
3332 Node* n = sink_list.pop();
3333 set_ctrl(n, new_head);
3334 }
3335
3336 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition");
3337
3338 clone_loop(loop, old_new, dd, IgnoreStripMined);
3339
3340 const uint clone_exit_idx = 1;
3341 const uint orig_exit_idx = 2;
3342 assert(is_valid_clone_loop_form(loop, peel_list, orig_exit_idx, clone_exit_idx), "bad clone loop");
3343
3344 Node* head_clone = old_new[head->_idx];
3345 LoopNode* new_head_clone = old_new[new_head->_idx]->as_Loop();
3346 Node* orig_tail_clone = head_clone->in(2);
3347
3348 // Add phi if "def" node is in peel set and "use" is not
3349
3350 for (uint i = 0; i < peel_list.size(); i++) {
3351 Node *def = peel_list.at(i);
3352 if (!def->is_CFG()) {
3353 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) {
3354 Node *use = def->fast_out(j);
3355 if (has_node(use) && use->in(0) != C->top() &&
3356 (!peel.test(use->_idx) ||
3357 (use->is_Phi() && use->in(0) == head)) ) {
3358 worklist.push(use);
3359 }
3360 }
3361 while( worklist.size() ) {
3362 Node *use = worklist.pop();
3363 for (uint j = 1; j < use->req(); j++) {
3364 Node* n = use->in(j);
3365 if (n == def) {
3366
3367 // "def" is in peel set, "use" is not in peel set
3368 // or "use" is in the entry boundary (a phi) of the peel set
3369
3370 Node* use_c = has_ctrl(use) ? get_ctrl(use) : use;
3371
3372 if ( loop->is_member(get_loop( use_c )) ) {
3373 // use is in loop
3374 if (old_new[use->_idx] != NULL) { // null for dead code
3375 Node* use_clone = old_new[use->_idx];
3376 _igvn.replace_input_of(use, j, C->top());
3377 insert_phi_for_loop( use_clone, j, old_new[def->_idx], def, new_head_clone );
3378 }
3379 } else {
3380 assert(is_valid_clone_loop_exit_use(loop, use, orig_exit_idx), "clone loop format");
3381 // use is not in the loop, check if the live range includes the cut
3382 Node* lp_if = use_c->in(orig_exit_idx)->in(0);
3383 if (not_peel.test(lp_if->_idx)) {
3384 assert(j == orig_exit_idx, "use from original loop");
3385 insert_phi_for_loop( use, clone_exit_idx, old_new[def->_idx], def, new_head_clone );
3386 }
3387 }
3388 }
3389 }
3390 }
3391 }
3392 }
3393
3394 // Step 3b: retarget control
3395
3396 // Redirect control to the new loop head if a cloned node in
3397 // the not_peeled region has control that points into the peeled region.
3398 // This necessary because the cloned peeled region will be outside
3399 // the loop.
3400 // from to
3401 // cloned-peeled <---+
3402 // new_head_clone: | <--+
3403 // cloned-not_peeled in(0) in(0)
3404 // orig-peeled
3405
3406 for (uint i = 0; i < loop->_body.size(); i++) {
3407 Node *n = loop->_body.at(i);
3408 if (!n->is_CFG() && n->in(0) != NULL &&
3409 not_peel.test(n->_idx) && peel.test(n->in(0)->_idx)) {
3410 Node* n_clone = old_new[n->_idx];
3411 _igvn.replace_input_of(n_clone, 0, new_head_clone);
3412 }
3413 }
3414
3415 // Backedge of the surviving new_head (the clone) is original last_peel
3416 _igvn.replace_input_of(new_head_clone, LoopNode::LoopBackControl, last_peel);
3417
3418 // Cut first node in original not_peel set
3419 _igvn.rehash_node_delayed(new_head); // Multiple edge updates:
3420 new_head->set_req(LoopNode::EntryControl, C->top()); // use rehash_node_delayed / set_req instead of
3421 new_head->set_req(LoopNode::LoopBackControl, C->top()); // multiple replace_input_of calls
3422
3423 // Copy head_clone back-branch info to original head
3424 // and remove original head's loop entry and
3425 // clone head's back-branch
3426 _igvn.rehash_node_delayed(head); // Multiple edge updates
3427 head->set_req(LoopNode::EntryControl, head_clone->in(LoopNode::LoopBackControl));
3428 head->set_req(LoopNode::LoopBackControl, C->top());
3429 _igvn.replace_input_of(head_clone, LoopNode::LoopBackControl, C->top());
3430
3431 // Similarly modify the phis
3432 for (DUIterator_Fast kmax, k = head->fast_outs(kmax); k < kmax; k++) {
3433 Node* use = head->fast_out(k);
3434 if (use->is_Phi() && use->outcnt() > 0) {
3435 Node* use_clone = old_new[use->_idx];
3436 _igvn.rehash_node_delayed(use); // Multiple edge updates
3437 use->set_req(LoopNode::EntryControl, use_clone->in(LoopNode::LoopBackControl));
3438 use->set_req(LoopNode::LoopBackControl, C->top());
3439 _igvn.replace_input_of(use_clone, LoopNode::LoopBackControl, C->top());
3440 }
3441 }
3442
3443 // Step 4: update dominator tree and dominator depth
3444
3445 set_idom(head, orig_tail_clone, dd);
3446 recompute_dom_depth();
3447
3448 // Inhibit more partial peeling on this loop
3449 new_head_clone->set_partial_peel_loop();
3450 C->set_major_progress();
3451 loop->record_for_igvn();
3452
3453 #ifndef PRODUCT
3454 if (TracePartialPeeling) {
3455 tty->print_cr("\nafter partial peel one iteration");
3456 Node_List wl;
3457 Node* t = last_peel;
3458 while (true) {
3459 wl.push(t);
3460 if (t == head_clone) break;
3461 t = idom(t);
3462 }
3463 while (wl.size() > 0) {
3464 Node* tt = wl.pop();
3465 if (tt == head) tty->print_cr("orig head");
3466 else if (tt == new_head_clone) tty->print_cr("new head");
3467 else if (tt == head_clone) tty->print_cr("clone head");
3468 tt->dump();
3469 }
3470 }
3471 #endif
3472 return true;
3473 }
3474
3475 //------------------------------reorg_offsets----------------------------------
3476 // Reorganize offset computations to lower register pressure. Mostly
3477 // prevent loop-fallout uses of the pre-incremented trip counter (which are
3478 // then alive with the post-incremented trip counter forcing an extra
3479 // register move)
3480 void PhaseIdealLoop::reorg_offsets(IdealLoopTree *loop) {
3481 // Perform it only for canonical counted loops.
3482 // Loop's shape could be messed up by iteration_split_impl.
3483 if (!loop->_head->is_CountedLoop())
3484 return;
3485 if (!loop->_head->as_Loop()->is_valid_counted_loop())
3486 return;
3487
3488 CountedLoopNode *cl = loop->_head->as_CountedLoop();
3489 CountedLoopEndNode *cle = cl->loopexit();
3490 Node *exit = cle->proj_out(false);
3491 Node *phi = cl->phi();
3492
3493 // Check for the special case when using the pre-incremented trip-counter on
3494 // the fall-out path (forces the pre-incremented and post-incremented trip
3495 // counter to be live at the same time). Fix this by adjusting to use the
3496 // post-increment trip counter.
3497
3498 bool progress = true;
3499 while (progress) {
3500 progress = false;
3501 for (DUIterator_Fast imax, i = phi->fast_outs(imax); i < imax; i++) {
3502 Node* use = phi->fast_out(i); // User of trip-counter
3503 if (!has_ctrl(use)) continue;
3504 Node *u_ctrl = get_ctrl(use);
3505 if (use->is_Phi()) {
3506 u_ctrl = NULL;
3507 for (uint j = 1; j < use->req(); j++)
3508 if (use->in(j) == phi)
3509 u_ctrl = dom_lca(u_ctrl, use->in(0)->in(j));
3510 }
3511 IdealLoopTree *u_loop = get_loop(u_ctrl);
3512 // Look for loop-invariant use
3513 if (u_loop == loop) continue;
3514 if (loop->is_member(u_loop)) continue;
3515 // Check that use is live out the bottom. Assuming the trip-counter
3516 // update is right at the bottom, uses of of the loop middle are ok.
3517 if (dom_lca(exit, u_ctrl) != exit) continue;
3518 // Hit! Refactor use to use the post-incremented tripcounter.
3519 // Compute a post-increment tripcounter.
3520 Node* c = exit;
3521 if (cl->is_strip_mined()) {
3522 IdealLoopTree* outer_loop = get_loop(cl->outer_loop());
3523 if (!outer_loop->is_member(u_loop)) {
3524 c = cl->outer_loop_exit();
3525 }
3526 }
3527 Node *opaq = new Opaque2Node(C, cle->incr());
3528 register_new_node(opaq, c);
3529 Node *neg_stride = _igvn.intcon(-cle->stride_con());
3530 set_ctrl(neg_stride, C->root());
3531 Node *post = new AddINode(opaq, neg_stride);
3532 register_new_node(post, c);
3533 _igvn.rehash_node_delayed(use);
3534 for (uint j = 1; j < use->req(); j++) {
3535 if (use->in(j) == phi)
3536 use->set_req(j, post);
3537 }
3538 // Since DU info changed, rerun loop
3539 progress = true;
3540 break;
3541 }
3542 }
3543
3544 }