Mercurial > hg > truffle
annotate src/share/vm/opto/loopopts.cpp @ 1959:9eecf81a02fb
7000578: CMS: assert(SafepointSynchronize::is_at_safepoint()) failed: Else races are possible
Summary: Weakened assert in onj_is_alive() to allow its use at initialization time when is_at_safepoint() normally reports false; added some related asserts to check order of is_init_completed() after Universe::is_fully_initialized().
Reviewed-by: jcoomes
author | ysr |
---|---|
date | Tue, 16 Nov 2010 13:58:48 -0800 |
parents | 6027dddc26c6 |
children | f95d63e2154a |
rev | line source |
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0 | 1 /* |
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2 * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved. |
0 | 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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
25 #include "incls/_precompiled.incl" | |
26 #include "incls/_loopopts.cpp.incl" | |
27 | |
28 //============================================================================= | |
29 //------------------------------split_thru_phi--------------------------------- | |
30 // Split Node 'n' through merge point if there is enough win. | |
31 Node *PhaseIdealLoop::split_thru_phi( Node *n, Node *region, int policy ) { | |
69 | 32 if (n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::LONG) { |
33 // ConvI2L may have type information on it which is unsafe to push up | |
34 // so disable this for now | |
35 return NULL; | |
36 } | |
0 | 37 int wins = 0; |
38 assert( !n->is_CFG(), "" ); | |
39 assert( region->is_Region(), "" ); | |
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40 |
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41 const Type* type = n->bottom_type(); |
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42 const TypeOopPtr *t_oop = _igvn.type(n)->isa_oopptr(); |
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43 Node *phi; |
223 | 44 if( t_oop != NULL && t_oop->is_known_instance_field() ) { |
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45 int iid = t_oop->instance_id(); |
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46 int index = C->get_alias_index(t_oop); |
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47 int offset = t_oop->offset(); |
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48 phi = new (C,region->req()) PhiNode(region, type, NULL, iid, index, offset); |
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49 } else { |
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50 phi = PhiNode::make_blank(region, n); |
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51 } |
0 | 52 uint old_unique = C->unique(); |
53 for( uint i = 1; i < region->req(); i++ ) { | |
54 Node *x; | |
55 Node* the_clone = NULL; | |
56 if( region->in(i) == C->top() ) { | |
57 x = C->top(); // Dead path? Use a dead data op | |
58 } else { | |
59 x = n->clone(); // Else clone up the data op | |
60 the_clone = x; // Remember for possible deletion. | |
61 // Alter data node to use pre-phi inputs | |
62 if( n->in(0) == region ) | |
63 x->set_req( 0, region->in(i) ); | |
64 for( uint j = 1; j < n->req(); j++ ) { | |
65 Node *in = n->in(j); | |
66 if( in->is_Phi() && in->in(0) == region ) | |
67 x->set_req( j, in->in(i) ); // Use pre-Phi input for the clone | |
68 } | |
69 } | |
70 // Check for a 'win' on some paths | |
71 const Type *t = x->Value(&_igvn); | |
72 | |
73 bool singleton = t->singleton(); | |
74 | |
75 // A TOP singleton indicates that there are no possible values incoming | |
76 // along a particular edge. In most cases, this is OK, and the Phi will | |
77 // be eliminated later in an Ideal call. However, we can't allow this to | |
78 // happen if the singleton occurs on loop entry, as the elimination of | |
79 // the PhiNode may cause the resulting node to migrate back to a previous | |
80 // loop iteration. | |
81 if( singleton && t == Type::TOP ) { | |
82 // Is_Loop() == false does not confirm the absence of a loop (e.g., an | |
83 // irreducible loop may not be indicated by an affirmative is_Loop()); | |
84 // therefore, the only top we can split thru a phi is on a backedge of | |
85 // a loop. | |
86 singleton &= region->is_Loop() && (i != LoopNode::EntryControl); | |
87 } | |
88 | |
89 if( singleton ) { | |
90 wins++; | |
91 x = ((PhaseGVN&)_igvn).makecon(t); | |
92 } else { | |
93 // We now call Identity to try to simplify the cloned node. | |
94 // Note that some Identity methods call phase->type(this). | |
95 // Make sure that the type array is big enough for | |
96 // our new node, even though we may throw the node away. | |
97 // (Note: This tweaking with igvn only works because x is a new node.) | |
98 _igvn.set_type(x, t); | |
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99 // If x is a TypeNode, capture any more-precise type permanently into Node |
605 | 100 // otherwise it will be not updated during igvn->transform since |
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101 // igvn->type(x) is set to x->Value() already. |
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102 x->raise_bottom_type(t); |
0 | 103 Node *y = x->Identity(&_igvn); |
104 if( y != x ) { | |
105 wins++; | |
106 x = y; | |
107 } else { | |
108 y = _igvn.hash_find(x); | |
109 if( y ) { | |
110 wins++; | |
111 x = y; | |
112 } else { | |
113 // Else x is a new node we are keeping | |
114 // We do not need register_new_node_with_optimizer | |
115 // because set_type has already been called. | |
116 _igvn._worklist.push(x); | |
117 } | |
118 } | |
119 } | |
120 if (x != the_clone && the_clone != NULL) | |
121 _igvn.remove_dead_node(the_clone); | |
122 phi->set_req( i, x ); | |
123 } | |
124 // Too few wins? | |
125 if( wins <= policy ) { | |
126 _igvn.remove_dead_node(phi); | |
127 return NULL; | |
128 } | |
129 | |
130 // Record Phi | |
131 register_new_node( phi, region ); | |
132 | |
133 for( uint i2 = 1; i2 < phi->req(); i2++ ) { | |
134 Node *x = phi->in(i2); | |
135 // If we commoned up the cloned 'x' with another existing Node, | |
136 // the existing Node picks up a new use. We need to make the | |
137 // existing Node occur higher up so it dominates its uses. | |
138 Node *old_ctrl; | |
139 IdealLoopTree *old_loop; | |
140 | |
141 // The occasional new node | |
142 if( x->_idx >= old_unique ) { // Found a new, unplaced node? | |
143 old_ctrl = x->is_Con() ? C->root() : NULL; | |
144 old_loop = NULL; // Not in any prior loop | |
145 } else { | |
146 old_ctrl = x->is_Con() ? C->root() : get_ctrl(x); | |
147 old_loop = get_loop(old_ctrl); // Get prior loop | |
148 } | |
149 // New late point must dominate new use | |
150 Node *new_ctrl = dom_lca( old_ctrl, region->in(i2) ); | |
151 // Set new location | |
152 set_ctrl(x, new_ctrl); | |
153 IdealLoopTree *new_loop = get_loop( new_ctrl ); | |
154 // If changing loop bodies, see if we need to collect into new body | |
155 if( old_loop != new_loop ) { | |
156 if( old_loop && !old_loop->_child ) | |
157 old_loop->_body.yank(x); | |
158 if( !new_loop->_child ) | |
159 new_loop->_body.push(x); // Collect body info | |
160 } | |
161 } | |
162 | |
163 return phi; | |
164 } | |
165 | |
166 //------------------------------dominated_by------------------------------------ | |
167 // Replace the dominated test with an obvious true or false. Place it on the | |
168 // IGVN worklist for later cleanup. Move control-dependent data Nodes on the | |
169 // live path up to the dominating control. | |
170 void PhaseIdealLoop::dominated_by( Node *prevdom, Node *iff ) { | |
171 #ifndef PRODUCT | |
172 if( VerifyLoopOptimizations && PrintOpto ) tty->print_cr("dominating test"); | |
173 #endif | |
174 | |
175 | |
176 // prevdom is the dominating projection of the dominating test. | |
177 assert( iff->is_If(), "" ); | |
178 assert( iff->Opcode() == Op_If || iff->Opcode() == Op_CountedLoopEnd, "Check this code when new subtype is added"); | |
179 int pop = prevdom->Opcode(); | |
180 assert( pop == Op_IfFalse || pop == Op_IfTrue, "" ); | |
181 // 'con' is set to true or false to kill the dominated test. | |
182 Node *con = _igvn.makecon(pop == Op_IfTrue ? TypeInt::ONE : TypeInt::ZERO); | |
183 set_ctrl(con, C->root()); // Constant gets a new use | |
184 // Hack the dominated test | |
185 _igvn.hash_delete(iff); | |
186 iff->set_req(1, con); | |
187 _igvn._worklist.push(iff); | |
188 | |
189 // If I dont have a reachable TRUE and FALSE path following the IfNode then | |
190 // I can assume this path reaches an infinite loop. In this case it's not | |
191 // important to optimize the data Nodes - either the whole compilation will | |
192 // be tossed or this path (and all data Nodes) will go dead. | |
193 if( iff->outcnt() != 2 ) return; | |
194 | |
195 // Make control-dependent data Nodes on the live path (path that will remain | |
196 // once the dominated IF is removed) become control-dependent on the | |
197 // dominating projection. | |
198 Node* dp = ((IfNode*)iff)->proj_out(pop == Op_IfTrue); | |
199 IdealLoopTree *old_loop = get_loop(dp); | |
200 | |
201 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) { | |
202 Node* cd = dp->fast_out(i); // Control-dependent node | |
203 if( cd->depends_only_on_test() ) { | |
204 assert( cd->in(0) == dp, "" ); | |
205 _igvn.hash_delete( cd ); | |
206 cd->set_req(0, prevdom); | |
207 set_early_ctrl( cd ); | |
208 _igvn._worklist.push(cd); | |
209 IdealLoopTree *new_loop = get_loop(get_ctrl(cd)); | |
210 if( old_loop != new_loop ) { | |
211 if( !old_loop->_child ) old_loop->_body.yank(cd); | |
212 if( !new_loop->_child ) new_loop->_body.push(cd); | |
213 } | |
214 --i; | |
215 --imax; | |
216 } | |
217 } | |
218 } | |
219 | |
220 //------------------------------has_local_phi_input---------------------------- | |
221 // Return TRUE if 'n' has Phi inputs from its local block and no other | |
222 // block-local inputs (all non-local-phi inputs come from earlier blocks) | |
223 Node *PhaseIdealLoop::has_local_phi_input( Node *n ) { | |
224 Node *n_ctrl = get_ctrl(n); | |
225 // See if some inputs come from a Phi in this block, or from before | |
226 // this block. | |
227 uint i; | |
228 for( i = 1; i < n->req(); i++ ) { | |
229 Node *phi = n->in(i); | |
230 if( phi->is_Phi() && phi->in(0) == n_ctrl ) | |
231 break; | |
232 } | |
233 if( i >= n->req() ) | |
234 return NULL; // No Phi inputs; nowhere to clone thru | |
235 | |
236 // Check for inputs created between 'n' and the Phi input. These | |
237 // must split as well; they have already been given the chance | |
238 // (courtesy of a post-order visit) and since they did not we must | |
239 // recover the 'cost' of splitting them by being very profitable | |
240 // when splitting 'n'. Since this is unlikely we simply give up. | |
241 for( i = 1; i < n->req(); i++ ) { | |
242 Node *m = n->in(i); | |
243 if( get_ctrl(m) == n_ctrl && !m->is_Phi() ) { | |
244 // We allow the special case of AddP's with no local inputs. | |
245 // This allows us to split-up address expressions. | |
246 if (m->is_AddP() && | |
247 get_ctrl(m->in(2)) != n_ctrl && | |
248 get_ctrl(m->in(3)) != n_ctrl) { | |
249 // Move the AddP up to dominating point | |
250 set_ctrl_and_loop(m, find_non_split_ctrl(idom(n_ctrl))); | |
251 continue; | |
252 } | |
253 return NULL; | |
254 } | |
255 } | |
256 | |
257 return n_ctrl; | |
258 } | |
259 | |
260 //------------------------------remix_address_expressions---------------------- | |
261 // Rework addressing expressions to get the most loop-invariant stuff | |
262 // moved out. We'd like to do all associative operators, but it's especially | |
263 // important (common) to do address expressions. | |
264 Node *PhaseIdealLoop::remix_address_expressions( Node *n ) { | |
265 if (!has_ctrl(n)) return NULL; | |
266 Node *n_ctrl = get_ctrl(n); | |
267 IdealLoopTree *n_loop = get_loop(n_ctrl); | |
268 | |
269 // See if 'n' mixes loop-varying and loop-invariant inputs and | |
270 // itself is loop-varying. | |
271 | |
272 // Only interested in binary ops (and AddP) | |
273 if( n->req() < 3 || n->req() > 4 ) return NULL; | |
274 | |
275 Node *n1_ctrl = get_ctrl(n->in( 1)); | |
276 Node *n2_ctrl = get_ctrl(n->in( 2)); | |
277 Node *n3_ctrl = get_ctrl(n->in(n->req() == 3 ? 2 : 3)); | |
278 IdealLoopTree *n1_loop = get_loop( n1_ctrl ); | |
279 IdealLoopTree *n2_loop = get_loop( n2_ctrl ); | |
280 IdealLoopTree *n3_loop = get_loop( n3_ctrl ); | |
281 | |
282 // Does one of my inputs spin in a tighter loop than self? | |
283 if( (n_loop->is_member( n1_loop ) && n_loop != n1_loop) || | |
284 (n_loop->is_member( n2_loop ) && n_loop != n2_loop) || | |
285 (n_loop->is_member( n3_loop ) && n_loop != n3_loop) ) | |
286 return NULL; // Leave well enough alone | |
287 | |
288 // Is at least one of my inputs loop-invariant? | |
289 if( n1_loop == n_loop && | |
290 n2_loop == n_loop && | |
291 n3_loop == n_loop ) | |
292 return NULL; // No loop-invariant inputs | |
293 | |
294 | |
295 int n_op = n->Opcode(); | |
296 | |
297 // Replace expressions like ((V+I) << 2) with (V<<2 + I<<2). | |
298 if( n_op == Op_LShiftI ) { | |
299 // Scale is loop invariant | |
300 Node *scale = n->in(2); | |
301 Node *scale_ctrl = get_ctrl(scale); | |
302 IdealLoopTree *scale_loop = get_loop(scale_ctrl ); | |
303 if( n_loop == scale_loop || !scale_loop->is_member( n_loop ) ) | |
304 return NULL; | |
305 const TypeInt *scale_t = scale->bottom_type()->isa_int(); | |
306 if( scale_t && scale_t->is_con() && scale_t->get_con() >= 16 ) | |
307 return NULL; // Dont bother with byte/short masking | |
308 // Add must vary with loop (else shift would be loop-invariant) | |
309 Node *add = n->in(1); | |
310 Node *add_ctrl = get_ctrl(add); | |
311 IdealLoopTree *add_loop = get_loop(add_ctrl); | |
312 //assert( n_loop == add_loop, "" ); | |
313 if( n_loop != add_loop ) return NULL; // happens w/ evil ZKM loops | |
314 | |
315 // Convert I-V into I+ (0-V); same for V-I | |
316 if( add->Opcode() == Op_SubI && | |
317 _igvn.type( add->in(1) ) != TypeInt::ZERO ) { | |
318 Node *zero = _igvn.intcon(0); | |
319 set_ctrl(zero, C->root()); | |
320 Node *neg = new (C, 3) SubINode( _igvn.intcon(0), add->in(2) ); | |
321 register_new_node( neg, get_ctrl(add->in(2) ) ); | |
322 add = new (C, 3) AddINode( add->in(1), neg ); | |
323 register_new_node( add, add_ctrl ); | |
324 } | |
325 if( add->Opcode() != Op_AddI ) return NULL; | |
326 // See if one add input is loop invariant | |
327 Node *add_var = add->in(1); | |
328 Node *add_var_ctrl = get_ctrl(add_var); | |
329 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl ); | |
330 Node *add_invar = add->in(2); | |
331 Node *add_invar_ctrl = get_ctrl(add_invar); | |
332 IdealLoopTree *add_invar_loop = get_loop(add_invar_ctrl ); | |
333 if( add_var_loop == n_loop ) { | |
334 } else if( add_invar_loop == n_loop ) { | |
335 // Swap to find the invariant part | |
336 add_invar = add_var; | |
337 add_invar_ctrl = add_var_ctrl; | |
338 add_invar_loop = add_var_loop; | |
339 add_var = add->in(2); | |
340 Node *add_var_ctrl = get_ctrl(add_var); | |
341 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl ); | |
342 } else // Else neither input is loop invariant | |
343 return NULL; | |
344 if( n_loop == add_invar_loop || !add_invar_loop->is_member( n_loop ) ) | |
345 return NULL; // No invariant part of the add? | |
346 | |
347 // Yes! Reshape address expression! | |
348 Node *inv_scale = new (C, 3) LShiftINode( add_invar, scale ); | |
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349 Node *inv_scale_ctrl = |
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350 dom_depth(add_invar_ctrl) > dom_depth(scale_ctrl) ? |
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351 add_invar_ctrl : scale_ctrl; |
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352 register_new_node( inv_scale, inv_scale_ctrl ); |
0 | 353 Node *var_scale = new (C, 3) LShiftINode( add_var, scale ); |
354 register_new_node( var_scale, n_ctrl ); | |
355 Node *var_add = new (C, 3) AddINode( var_scale, inv_scale ); | |
356 register_new_node( var_add, n_ctrl ); | |
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357 _igvn.replace_node( n, var_add ); |
0 | 358 return var_add; |
359 } | |
360 | |
361 // Replace (I+V) with (V+I) | |
362 if( n_op == Op_AddI || | |
363 n_op == Op_AddL || | |
364 n_op == Op_AddF || | |
365 n_op == Op_AddD || | |
366 n_op == Op_MulI || | |
367 n_op == Op_MulL || | |
368 n_op == Op_MulF || | |
369 n_op == Op_MulD ) { | |
370 if( n2_loop == n_loop ) { | |
371 assert( n1_loop != n_loop, "" ); | |
372 n->swap_edges(1, 2); | |
373 } | |
374 } | |
375 | |
376 // Replace ((I1 +p V) +p I2) with ((I1 +p I2) +p V), | |
377 // but not if I2 is a constant. | |
378 if( n_op == Op_AddP ) { | |
379 if( n2_loop == n_loop && n3_loop != n_loop ) { | |
380 if( n->in(2)->Opcode() == Op_AddP && !n->in(3)->is_Con() ) { | |
381 Node *n22_ctrl = get_ctrl(n->in(2)->in(2)); | |
382 Node *n23_ctrl = get_ctrl(n->in(2)->in(3)); | |
383 IdealLoopTree *n22loop = get_loop( n22_ctrl ); | |
384 IdealLoopTree *n23_loop = get_loop( n23_ctrl ); | |
385 if( n22loop != n_loop && n22loop->is_member(n_loop) && | |
386 n23_loop == n_loop ) { | |
387 Node *add1 = new (C, 4) AddPNode( n->in(1), n->in(2)->in(2), n->in(3) ); | |
388 // Stuff new AddP in the loop preheader | |
389 register_new_node( add1, n_loop->_head->in(LoopNode::EntryControl) ); | |
390 Node *add2 = new (C, 4) AddPNode( n->in(1), add1, n->in(2)->in(3) ); | |
391 register_new_node( add2, n_ctrl ); | |
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392 _igvn.replace_node( n, add2 ); |
0 | 393 return add2; |
394 } | |
395 } | |
396 } | |
397 | |
398 // Replace (I1 +p (I2 + V)) with ((I1 +p I2) +p V) | |
399 if( n2_loop != n_loop && n3_loop == n_loop ) { | |
400 if( n->in(3)->Opcode() == Op_AddI ) { | |
401 Node *V = n->in(3)->in(1); | |
402 Node *I = n->in(3)->in(2); | |
403 if( is_member(n_loop,get_ctrl(V)) ) { | |
404 } else { | |
405 Node *tmp = V; V = I; I = tmp; | |
406 } | |
407 if( !is_member(n_loop,get_ctrl(I)) ) { | |
408 Node *add1 = new (C, 4) AddPNode( n->in(1), n->in(2), I ); | |
409 // Stuff new AddP in the loop preheader | |
410 register_new_node( add1, n_loop->_head->in(LoopNode::EntryControl) ); | |
411 Node *add2 = new (C, 4) AddPNode( n->in(1), add1, V ); | |
412 register_new_node( add2, n_ctrl ); | |
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413 _igvn.replace_node( n, add2 ); |
0 | 414 return add2; |
415 } | |
416 } | |
417 } | |
418 } | |
419 | |
420 return NULL; | |
421 } | |
422 | |
423 //------------------------------conditional_move------------------------------- | |
424 // Attempt to replace a Phi with a conditional move. We have some pretty | |
425 // strict profitability requirements. All Phis at the merge point must | |
426 // be converted, so we can remove the control flow. We need to limit the | |
427 // number of c-moves to a small handful. All code that was in the side-arms | |
428 // of the CFG diamond is now speculatively executed. This code has to be | |
429 // "cheap enough". We are pretty much limited to CFG diamonds that merge | |
430 // 1 or 2 items with a total of 1 or 2 ops executed speculatively. | |
431 Node *PhaseIdealLoop::conditional_move( Node *region ) { | |
432 | |
433 assert( region->is_Region(), "sanity check" ); | |
434 if( region->req() != 3 ) return NULL; | |
435 | |
436 // Check for CFG diamond | |
437 Node *lp = region->in(1); | |
438 Node *rp = region->in(2); | |
439 if( !lp || !rp ) return NULL; | |
440 Node *lp_c = lp->in(0); | |
441 if( lp_c == NULL || lp_c != rp->in(0) || !lp_c->is_If() ) return NULL; | |
442 IfNode *iff = lp_c->as_If(); | |
443 | |
444 // Check for highly predictable branch. No point in CMOV'ing if | |
445 // we are going to predict accurately all the time. | |
446 // %%% This hides patterns produced by utility methods like Math.min. | |
447 if( iff->_prob < PROB_UNLIKELY_MAG(3) || | |
448 iff->_prob > PROB_LIKELY_MAG(3) ) | |
449 return NULL; | |
450 | |
451 // Check for ops pinned in an arm of the diamond. | |
452 // Can't remove the control flow in this case | |
453 if( lp->outcnt() > 1 ) return NULL; | |
454 if( rp->outcnt() > 1 ) return NULL; | |
455 | |
456 // Check profitability | |
457 int cost = 0; | |
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458 int phis = 0; |
0 | 459 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { |
460 Node *out = region->fast_out(i); | |
461 if( !out->is_Phi() ) continue; // Ignore other control edges, etc | |
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462 phis++; |
0 | 463 PhiNode* phi = out->as_Phi(); |
464 switch (phi->type()->basic_type()) { | |
465 case T_LONG: | |
466 cost++; // Probably encodes as 2 CMOV's | |
467 case T_INT: // These all CMOV fine | |
468 case T_FLOAT: | |
469 case T_DOUBLE: | |
470 case T_ADDRESS: // (RawPtr) | |
471 cost++; | |
472 break; | |
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473 case T_NARROWOOP: // Fall through |
0 | 474 case T_OBJECT: { // Base oops are OK, but not derived oops |
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475 const TypeOopPtr *tp = phi->type()->make_ptr()->isa_oopptr(); |
0 | 476 // Derived pointers are Bad (tm): what's the Base (for GC purposes) of a |
477 // CMOVE'd derived pointer? It's a CMOVE'd derived base. Thus | |
478 // CMOVE'ing a derived pointer requires we also CMOVE the base. If we | |
479 // have a Phi for the base here that we convert to a CMOVE all is well | |
480 // and good. But if the base is dead, we'll not make a CMOVE. Later | |
481 // the allocator will have to produce a base by creating a CMOVE of the | |
482 // relevant bases. This puts the allocator in the business of | |
483 // manufacturing expensive instructions, generally a bad plan. | |
484 // Just Say No to Conditionally-Moved Derived Pointers. | |
485 if( tp && tp->offset() != 0 ) | |
486 return NULL; | |
487 cost++; | |
488 break; | |
489 } | |
490 default: | |
491 return NULL; // In particular, can't do memory or I/O | |
492 } | |
493 // Add in cost any speculative ops | |
494 for( uint j = 1; j < region->req(); j++ ) { | |
495 Node *proj = region->in(j); | |
496 Node *inp = phi->in(j); | |
497 if (get_ctrl(inp) == proj) { // Found local op | |
498 cost++; | |
499 // Check for a chain of dependent ops; these will all become | |
500 // speculative in a CMOV. | |
501 for( uint k = 1; k < inp->req(); k++ ) | |
502 if (get_ctrl(inp->in(k)) == proj) | |
503 return NULL; // Too much speculative goo | |
504 } | |
505 } | |
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506 // See if the Phi is used by a Cmp or Narrow oop Decode/Encode. |
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507 // This will likely Split-If, a higher-payoff operation. |
0 | 508 for (DUIterator_Fast kmax, k = phi->fast_outs(kmax); k < kmax; k++) { |
509 Node* use = phi->fast_out(k); | |
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510 if( use->is_Cmp() || use->is_DecodeN() || use->is_EncodeP() ) |
0 | 511 return NULL; |
512 } | |
513 } | |
514 if( cost >= ConditionalMoveLimit ) return NULL; // Too much goo | |
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515 Node* bol = iff->in(1); |
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516 assert( bol->Opcode() == Op_Bool, "" ); |
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517 int cmp_op = bol->in(1)->Opcode(); |
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518 // It is expensive to generate flags from a float compare. |
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519 // Avoid duplicated float compare. |
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520 if( phis > 1 && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) return NULL; |
0 | 521 |
522 // -------------- | |
523 // Now replace all Phis with CMOV's | |
524 Node *cmov_ctrl = iff->in(0); | |
525 uint flip = (lp->Opcode() == Op_IfTrue); | |
526 while( 1 ) { | |
527 PhiNode* phi = NULL; | |
528 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { | |
529 Node *out = region->fast_out(i); | |
530 if (out->is_Phi()) { | |
531 phi = out->as_Phi(); | |
532 break; | |
533 } | |
534 } | |
535 if (phi == NULL) break; | |
536 #ifndef PRODUCT | |
537 if( PrintOpto && VerifyLoopOptimizations ) tty->print_cr("CMOV"); | |
538 #endif | |
539 // Move speculative ops | |
540 for( uint j = 1; j < region->req(); j++ ) { | |
541 Node *proj = region->in(j); | |
542 Node *inp = phi->in(j); | |
543 if (get_ctrl(inp) == proj) { // Found local op | |
544 #ifndef PRODUCT | |
545 if( PrintOpto && VerifyLoopOptimizations ) { | |
546 tty->print(" speculate: "); | |
547 inp->dump(); | |
548 } | |
549 #endif | |
550 set_ctrl(inp, cmov_ctrl); | |
551 } | |
552 } | |
553 Node *cmov = CMoveNode::make( C, cmov_ctrl, iff->in(1), phi->in(1+flip), phi->in(2-flip), _igvn.type(phi) ); | |
554 register_new_node( cmov, cmov_ctrl ); | |
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555 _igvn.replace_node( phi, cmov ); |
0 | 556 #ifndef PRODUCT |
557 if( VerifyLoopOptimizations ) verify(); | |
558 #endif | |
559 } | |
560 | |
561 // The useless CFG diamond will fold up later; see the optimization in | |
562 // RegionNode::Ideal. | |
563 _igvn._worklist.push(region); | |
564 | |
565 return iff->in(1); | |
566 } | |
567 | |
568 //------------------------------split_if_with_blocks_pre----------------------- | |
569 // Do the real work in a non-recursive function. Data nodes want to be | |
570 // cloned in the pre-order so they can feed each other nicely. | |
571 Node *PhaseIdealLoop::split_if_with_blocks_pre( Node *n ) { | |
572 // Cloning these guys is unlikely to win | |
573 int n_op = n->Opcode(); | |
574 if( n_op == Op_MergeMem ) return n; | |
575 if( n->is_Proj() ) return n; | |
576 // Do not clone-up CmpFXXX variations, as these are always | |
577 // followed by a CmpI | |
578 if( n->is_Cmp() ) return n; | |
579 // Attempt to use a conditional move instead of a phi/branch | |
580 if( ConditionalMoveLimit > 0 && n_op == Op_Region ) { | |
581 Node *cmov = conditional_move( n ); | |
582 if( cmov ) return cmov; | |
583 } | |
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584 if( n->is_CFG() || n->is_LoadStore() ) |
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585 return n; |
0 | 586 if( n_op == Op_Opaque1 || // Opaque nodes cannot be mod'd |
587 n_op == Op_Opaque2 ) { | |
588 if( !C->major_progress() ) // If chance of no more loop opts... | |
589 _igvn._worklist.push(n); // maybe we'll remove them | |
590 return n; | |
591 } | |
592 | |
593 if( n->is_Con() ) return n; // No cloning for Con nodes | |
594 | |
595 Node *n_ctrl = get_ctrl(n); | |
596 if( !n_ctrl ) return n; // Dead node | |
597 | |
598 // Attempt to remix address expressions for loop invariants | |
599 Node *m = remix_address_expressions( n ); | |
600 if( m ) return m; | |
601 | |
602 // Determine if the Node has inputs from some local Phi. | |
603 // Returns the block to clone thru. | |
604 Node *n_blk = has_local_phi_input( n ); | |
605 if( !n_blk ) return n; | |
606 // Do not clone the trip counter through on a CountedLoop | |
607 // (messes up the canonical shape). | |
608 if( n_blk->is_CountedLoop() && n->Opcode() == Op_AddI ) return n; | |
609 | |
610 // Check for having no control input; not pinned. Allow | |
611 // dominating control. | |
612 if( n->in(0) ) { | |
613 Node *dom = idom(n_blk); | |
614 if( dom_lca( n->in(0), dom ) != n->in(0) ) | |
615 return n; | |
616 } | |
617 // Policy: when is it profitable. You must get more wins than | |
618 // policy before it is considered profitable. Policy is usually 0, | |
619 // so 1 win is considered profitable. Big merges will require big | |
620 // cloning, so get a larger policy. | |
621 int policy = n_blk->req() >> 2; | |
622 | |
623 // If the loop is a candidate for range check elimination, | |
624 // delay splitting through it's phi until a later loop optimization | |
625 if (n_blk->is_CountedLoop()) { | |
626 IdealLoopTree *lp = get_loop(n_blk); | |
627 if (lp && lp->_rce_candidate) { | |
628 return n; | |
629 } | |
630 } | |
631 | |
632 // Use same limit as split_if_with_blocks_post | |
633 if( C->unique() > 35000 ) return n; // Method too big | |
634 | |
635 // Split 'n' through the merge point if it is profitable | |
636 Node *phi = split_thru_phi( n, n_blk, policy ); | |
637 if( !phi ) return n; | |
638 | |
639 // Found a Phi to split thru! | |
640 // Replace 'n' with the new phi | |
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641 _igvn.replace_node( n, phi ); |
0 | 642 // Moved a load around the loop, 'en-registering' something. |
643 if( n_blk->Opcode() == Op_Loop && n->is_Load() && | |
644 !phi->in(LoopNode::LoopBackControl)->is_Load() ) | |
645 C->set_major_progress(); | |
646 | |
647 return phi; | |
648 } | |
649 | |
650 static bool merge_point_too_heavy(Compile* C, Node* region) { | |
651 // Bail out if the region and its phis have too many users. | |
652 int weight = 0; | |
653 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { | |
654 weight += region->fast_out(i)->outcnt(); | |
655 } | |
656 int nodes_left = MaxNodeLimit - C->unique(); | |
657 if (weight * 8 > nodes_left) { | |
658 #ifndef PRODUCT | |
659 if (PrintOpto) | |
660 tty->print_cr("*** Split-if bails out: %d nodes, region weight %d", C->unique(), weight); | |
661 #endif | |
662 return true; | |
663 } else { | |
664 return false; | |
665 } | |
666 } | |
667 | |
668 static bool merge_point_safe(Node* region) { | |
669 // 4799512: Stop split_if_with_blocks from splitting a block with a ConvI2LNode | |
670 // having a PhiNode input. This sidesteps the dangerous case where the split | |
671 // ConvI2LNode may become TOP if the input Value() does not | |
672 // overlap the ConvI2L range, leaving a node which may not dominate its | |
673 // uses. | |
674 // A better fix for this problem can be found in the BugTraq entry, but | |
675 // expediency for Mantis demands this hack. | |
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676 // 6855164: If the merge point has a FastLockNode with a PhiNode input, we stop |
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677 // split_if_with_blocks from splitting a block because we could not move around |
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678 // the FastLockNode. |
0 | 679 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { |
680 Node* n = region->fast_out(i); | |
681 if (n->is_Phi()) { | |
682 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
683 Node* m = n->fast_out(j); | |
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684 if (m->is_FastLock()) |
0 | 685 return false; |
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686 #ifdef _LP64 |
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687 if (m->Opcode() == Op_ConvI2L) |
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688 return false; |
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689 #endif |
0 | 690 } |
691 } | |
692 } | |
693 return true; | |
694 } | |
695 | |
696 | |
697 //------------------------------place_near_use--------------------------------- | |
698 // Place some computation next to use but not inside inner loops. | |
699 // For inner loop uses move it to the preheader area. | |
700 Node *PhaseIdealLoop::place_near_use( Node *useblock ) const { | |
701 IdealLoopTree *u_loop = get_loop( useblock ); | |
702 return (u_loop->_irreducible || u_loop->_child) | |
703 ? useblock | |
704 : u_loop->_head->in(LoopNode::EntryControl); | |
705 } | |
706 | |
707 | |
708 //------------------------------split_if_with_blocks_post---------------------- | |
709 // Do the real work in a non-recursive function. CFG hackery wants to be | |
710 // in the post-order, so it can dirty the I-DOM info and not use the dirtied | |
711 // info. | |
712 void PhaseIdealLoop::split_if_with_blocks_post( Node *n ) { | |
713 | |
714 // Cloning Cmp through Phi's involves the split-if transform. | |
715 // FastLock is not used by an If | |
716 if( n->is_Cmp() && !n->is_FastLock() ) { | |
717 if( C->unique() > 35000 ) return; // Method too big | |
718 | |
719 // Do not do 'split-if' if irreducible loops are present. | |
720 if( _has_irreducible_loops ) | |
721 return; | |
722 | |
723 Node *n_ctrl = get_ctrl(n); | |
724 // Determine if the Node has inputs from some local Phi. | |
725 // Returns the block to clone thru. | |
726 Node *n_blk = has_local_phi_input( n ); | |
727 if( n_blk != n_ctrl ) return; | |
728 | |
729 if( merge_point_too_heavy(C, n_ctrl) ) | |
730 return; | |
731 | |
732 if( n->outcnt() != 1 ) return; // Multiple bool's from 1 compare? | |
733 Node *bol = n->unique_out(); | |
734 assert( bol->is_Bool(), "expect a bool here" ); | |
735 if( bol->outcnt() != 1 ) return;// Multiple branches from 1 compare? | |
736 Node *iff = bol->unique_out(); | |
737 | |
738 // Check some safety conditions | |
739 if( iff->is_If() ) { // Classic split-if? | |
740 if( iff->in(0) != n_ctrl ) return; // Compare must be in same blk as if | |
741 } else if (iff->is_CMove()) { // Trying to split-up a CMOVE | |
742 if( get_ctrl(iff->in(2)) == n_ctrl || | |
743 get_ctrl(iff->in(3)) == n_ctrl ) | |
744 return; // Inputs not yet split-up | |
745 if ( get_loop(n_ctrl) != get_loop(get_ctrl(iff)) ) { | |
746 return; // Loop-invar test gates loop-varying CMOVE | |
747 } | |
748 } else { | |
749 return; // some other kind of node, such as an Allocate | |
750 } | |
751 | |
752 // Do not do 'split-if' if some paths are dead. First do dead code | |
753 // elimination and then see if its still profitable. | |
754 for( uint i = 1; i < n_ctrl->req(); i++ ) | |
755 if( n_ctrl->in(i) == C->top() ) | |
756 return; | |
757 | |
758 // When is split-if profitable? Every 'win' on means some control flow | |
759 // goes dead, so it's almost always a win. | |
760 int policy = 0; | |
761 // If trying to do a 'Split-If' at the loop head, it is only | |
762 // profitable if the cmp folds up on BOTH paths. Otherwise we | |
763 // risk peeling a loop forever. | |
764 | |
765 // CNC - Disabled for now. Requires careful handling of loop | |
766 // body selection for the cloned code. Also, make sure we check | |
767 // for any input path not being in the same loop as n_ctrl. For | |
768 // irreducible loops we cannot check for 'n_ctrl->is_Loop()' | |
769 // because the alternative loop entry points won't be converted | |
770 // into LoopNodes. | |
771 IdealLoopTree *n_loop = get_loop(n_ctrl); | |
772 for( uint j = 1; j < n_ctrl->req(); j++ ) | |
773 if( get_loop(n_ctrl->in(j)) != n_loop ) | |
774 return; | |
775 | |
776 // Check for safety of the merge point. | |
777 if( !merge_point_safe(n_ctrl) ) { | |
778 return; | |
779 } | |
780 | |
781 // Split compare 'n' through the merge point if it is profitable | |
782 Node *phi = split_thru_phi( n, n_ctrl, policy ); | |
783 if( !phi ) return; | |
784 | |
785 // Found a Phi to split thru! | |
786 // Replace 'n' with the new phi | |
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787 _igvn.replace_node( n, phi ); |
0 | 788 |
789 // Now split the bool up thru the phi | |
790 Node *bolphi = split_thru_phi( bol, n_ctrl, -1 ); | |
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791 _igvn.replace_node( bol, bolphi ); |
0 | 792 assert( iff->in(1) == bolphi, "" ); |
793 if( bolphi->Value(&_igvn)->singleton() ) | |
794 return; | |
795 | |
796 // Conditional-move? Must split up now | |
797 if( !iff->is_If() ) { | |
798 Node *cmovphi = split_thru_phi( iff, n_ctrl, -1 ); | |
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799 _igvn.replace_node( iff, cmovphi ); |
0 | 800 return; |
801 } | |
802 | |
803 // Now split the IF | |
804 do_split_if( iff ); | |
805 return; | |
806 } | |
807 | |
808 // Check for an IF ready to split; one that has its | |
809 // condition codes input coming from a Phi at the block start. | |
810 int n_op = n->Opcode(); | |
811 | |
812 // Check for an IF being dominated by another IF same test | |
813 if( n_op == Op_If ) { | |
814 Node *bol = n->in(1); | |
815 uint max = bol->outcnt(); | |
816 // Check for same test used more than once? | |
817 if( n_op == Op_If && max > 1 && bol->is_Bool() ) { | |
818 // Search up IDOMs to see if this IF is dominated. | |
819 Node *cutoff = get_ctrl(bol); | |
820 | |
821 // Now search up IDOMs till cutoff, looking for a dominating test | |
822 Node *prevdom = n; | |
823 Node *dom = idom(prevdom); | |
824 while( dom != cutoff ) { | |
825 if( dom->req() > 1 && dom->in(1) == bol && prevdom->in(0) == dom ) { | |
826 // Replace the dominated test with an obvious true or false. | |
827 // Place it on the IGVN worklist for later cleanup. | |
828 C->set_major_progress(); | |
829 dominated_by( prevdom, n ); | |
830 #ifndef PRODUCT | |
831 if( VerifyLoopOptimizations ) verify(); | |
832 #endif | |
833 return; | |
834 } | |
835 prevdom = dom; | |
836 dom = idom(prevdom); | |
837 } | |
838 } | |
839 } | |
840 | |
841 // See if a shared loop-varying computation has no loop-varying uses. | |
842 // Happens if something is only used for JVM state in uncommon trap exits, | |
843 // like various versions of induction variable+offset. Clone the | |
844 // computation per usage to allow it to sink out of the loop. | |
845 if (has_ctrl(n) && !n->in(0)) {// n not dead and has no control edge (can float about) | |
846 Node *n_ctrl = get_ctrl(n); | |
847 IdealLoopTree *n_loop = get_loop(n_ctrl); | |
848 if( n_loop != _ltree_root ) { | |
849 DUIterator_Fast imax, i = n->fast_outs(imax); | |
850 for (; i < imax; i++) { | |
851 Node* u = n->fast_out(i); | |
852 if( !has_ctrl(u) ) break; // Found control user | |
853 IdealLoopTree *u_loop = get_loop(get_ctrl(u)); | |
854 if( u_loop == n_loop ) break; // Found loop-varying use | |
855 if( n_loop->is_member( u_loop ) ) break; // Found use in inner loop | |
856 if( u->Opcode() == Op_Opaque1 ) break; // Found loop limit, bugfix for 4677003 | |
857 } | |
858 bool did_break = (i < imax); // Did we break out of the previous loop? | |
859 if (!did_break && n->outcnt() > 1) { // All uses in outer loops! | |
860 Node *late_load_ctrl; | |
861 if (n->is_Load()) { | |
862 // If n is a load, get and save the result from get_late_ctrl(), | |
863 // to be later used in calculating the control for n's clones. | |
864 clear_dom_lca_tags(); | |
865 late_load_ctrl = get_late_ctrl(n, n_ctrl); | |
866 } | |
867 // If n is a load, and the late control is the same as the current | |
868 // control, then the cloning of n is a pointless exercise, because | |
869 // GVN will ensure that we end up where we started. | |
870 if (!n->is_Load() || late_load_ctrl != n_ctrl) { | |
871 for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin; ) { | |
872 Node *u = n->last_out(j); // Clone private computation per use | |
873 _igvn.hash_delete(u); | |
874 _igvn._worklist.push(u); | |
875 Node *x = n->clone(); // Clone computation | |
876 Node *x_ctrl = NULL; | |
877 if( u->is_Phi() ) { | |
878 // Replace all uses of normal nodes. Replace Phi uses | |
605 | 879 // individually, so the separate Nodes can sink down |
0 | 880 // different paths. |
881 uint k = 1; | |
882 while( u->in(k) != n ) k++; | |
883 u->set_req( k, x ); | |
884 // x goes next to Phi input path | |
885 x_ctrl = u->in(0)->in(k); | |
886 --j; | |
887 } else { // Normal use | |
888 // Replace all uses | |
889 for( uint k = 0; k < u->req(); k++ ) { | |
890 if( u->in(k) == n ) { | |
891 u->set_req( k, x ); | |
892 --j; | |
893 } | |
894 } | |
895 x_ctrl = get_ctrl(u); | |
896 } | |
897 | |
898 // Find control for 'x' next to use but not inside inner loops. | |
899 // For inner loop uses get the preheader area. | |
900 x_ctrl = place_near_use(x_ctrl); | |
901 | |
902 if (n->is_Load()) { | |
903 // For loads, add a control edge to a CFG node outside of the loop | |
904 // to force them to not combine and return back inside the loop | |
905 // during GVN optimization (4641526). | |
906 // | |
907 // Because we are setting the actual control input, factor in | |
908 // the result from get_late_ctrl() so we respect any | |
909 // anti-dependences. (6233005). | |
910 x_ctrl = dom_lca(late_load_ctrl, x_ctrl); | |
911 | |
912 // Don't allow the control input to be a CFG splitting node. | |
913 // Such nodes should only have ProjNodes as outs, e.g. IfNode | |
914 // should only have IfTrueNode and IfFalseNode (4985384). | |
915 x_ctrl = find_non_split_ctrl(x_ctrl); | |
916 assert(dom_depth(n_ctrl) <= dom_depth(x_ctrl), "n is later than its clone"); | |
917 | |
918 x->set_req(0, x_ctrl); | |
919 } | |
920 register_new_node(x, x_ctrl); | |
921 | |
922 // Some institutional knowledge is needed here: 'x' is | |
923 // yanked because if the optimizer runs GVN on it all the | |
924 // cloned x's will common up and undo this optimization and | |
925 // be forced back in the loop. This is annoying because it | |
926 // makes +VerifyOpto report false-positives on progress. I | |
927 // tried setting control edges on the x's to force them to | |
928 // not combine, but the matching gets worried when it tries | |
929 // to fold a StoreP and an AddP together (as part of an | |
930 // address expression) and the AddP and StoreP have | |
931 // different controls. | |
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932 if( !x->is_Load() && !x->is_DecodeN() ) _igvn._worklist.yank(x); |
0 | 933 } |
934 _igvn.remove_dead_node(n); | |
935 } | |
936 } | |
937 } | |
938 } | |
939 | |
940 // Check for Opaque2's who's loop has disappeared - who's input is in the | |
941 // same loop nest as their output. Remove 'em, they are no longer useful. | |
942 if( n_op == Op_Opaque2 && | |
943 n->in(1) != NULL && | |
944 get_loop(get_ctrl(n)) == get_loop(get_ctrl(n->in(1))) ) { | |
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945 _igvn.replace_node( n, n->in(1) ); |
0 | 946 } |
947 } | |
948 | |
949 //------------------------------split_if_with_blocks--------------------------- | |
950 // Check for aggressive application of 'split-if' optimization, | |
951 // using basic block level info. | |
952 void PhaseIdealLoop::split_if_with_blocks( VectorSet &visited, Node_Stack &nstack ) { | |
953 Node *n = C->root(); | |
954 visited.set(n->_idx); // first, mark node as visited | |
955 // Do pre-visit work for root | |
956 n = split_if_with_blocks_pre( n ); | |
957 uint cnt = n->outcnt(); | |
958 uint i = 0; | |
959 while (true) { | |
960 // Visit all children | |
961 if (i < cnt) { | |
962 Node* use = n->raw_out(i); | |
963 ++i; | |
964 if (use->outcnt() != 0 && !visited.test_set(use->_idx)) { | |
965 // Now do pre-visit work for this use | |
966 use = split_if_with_blocks_pre( use ); | |
967 nstack.push(n, i); // Save parent and next use's index. | |
968 n = use; // Process all children of current use. | |
969 cnt = use->outcnt(); | |
970 i = 0; | |
971 } | |
972 } | |
973 else { | |
974 // All of n's children have been processed, complete post-processing. | |
975 if (cnt != 0 && !n->is_Con()) { | |
976 assert(has_node(n), "no dead nodes"); | |
977 split_if_with_blocks_post( n ); | |
978 } | |
979 if (nstack.is_empty()) { | |
980 // Finished all nodes on stack. | |
981 break; | |
982 } | |
983 // Get saved parent node and next use's index. Visit the rest of uses. | |
984 n = nstack.node(); | |
985 cnt = n->outcnt(); | |
986 i = nstack.index(); | |
987 nstack.pop(); | |
988 } | |
989 } | |
990 } | |
991 | |
992 | |
993 //============================================================================= | |
994 // | |
995 // C L O N E A L O O P B O D Y | |
996 // | |
997 | |
998 //------------------------------clone_iff-------------------------------------- | |
999 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. | |
1000 // "Nearly" because all Nodes have been cloned from the original in the loop, | |
1001 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs | |
1002 // through the Phi recursively, and return a Bool. | |
1003 BoolNode *PhaseIdealLoop::clone_iff( PhiNode *phi, IdealLoopTree *loop ) { | |
1004 | |
1005 // Convert this Phi into a Phi merging Bools | |
1006 uint i; | |
1007 for( i = 1; i < phi->req(); i++ ) { | |
1008 Node *b = phi->in(i); | |
1009 if( b->is_Phi() ) { | |
1010 _igvn.hash_delete(phi); | |
1011 _igvn._worklist.push(phi); | |
1012 phi->set_req(i, clone_iff( b->as_Phi(), loop )); | |
1013 } else { | |
1014 assert( b->is_Bool(), "" ); | |
1015 } | |
1016 } | |
1017 | |
1018 Node *sample_bool = phi->in(1); | |
1019 Node *sample_cmp = sample_bool->in(1); | |
1020 | |
1021 // Make Phis to merge the Cmp's inputs. | |
1022 int size = phi->in(0)->req(); | |
1023 PhiNode *phi1 = new (C, size) PhiNode( phi->in(0), Type::TOP ); | |
1024 PhiNode *phi2 = new (C, size) PhiNode( phi->in(0), Type::TOP ); | |
1025 for( i = 1; i < phi->req(); i++ ) { | |
1026 Node *n1 = phi->in(i)->in(1)->in(1); | |
1027 Node *n2 = phi->in(i)->in(1)->in(2); | |
1028 phi1->set_req( i, n1 ); | |
1029 phi2->set_req( i, n2 ); | |
1030 phi1->set_type( phi1->type()->meet(n1->bottom_type()) ); | |
1031 phi2->set_type( phi2->type()->meet(n2->bottom_type()) ); | |
1032 } | |
1033 // See if these Phis have been made before. | |
1034 // Register with optimizer | |
1035 Node *hit1 = _igvn.hash_find_insert(phi1); | |
1036 if( hit1 ) { // Hit, toss just made Phi | |
1037 _igvn.remove_dead_node(phi1); // Remove new phi | |
1038 assert( hit1->is_Phi(), "" ); | |
1039 phi1 = (PhiNode*)hit1; // Use existing phi | |
1040 } else { // Miss | |
1041 _igvn.register_new_node_with_optimizer(phi1); | |
1042 } | |
1043 Node *hit2 = _igvn.hash_find_insert(phi2); | |
1044 if( hit2 ) { // Hit, toss just made Phi | |
1045 _igvn.remove_dead_node(phi2); // Remove new phi | |
1046 assert( hit2->is_Phi(), "" ); | |
1047 phi2 = (PhiNode*)hit2; // Use existing phi | |
1048 } else { // Miss | |
1049 _igvn.register_new_node_with_optimizer(phi2); | |
1050 } | |
1051 // Register Phis with loop/block info | |
1052 set_ctrl(phi1, phi->in(0)); | |
1053 set_ctrl(phi2, phi->in(0)); | |
1054 // Make a new Cmp | |
1055 Node *cmp = sample_cmp->clone(); | |
1056 cmp->set_req( 1, phi1 ); | |
1057 cmp->set_req( 2, phi2 ); | |
1058 _igvn.register_new_node_with_optimizer(cmp); | |
1059 set_ctrl(cmp, phi->in(0)); | |
1060 | |
1061 // Make a new Bool | |
1062 Node *b = sample_bool->clone(); | |
1063 b->set_req(1,cmp); | |
1064 _igvn.register_new_node_with_optimizer(b); | |
1065 set_ctrl(b, phi->in(0)); | |
1066 | |
1067 assert( b->is_Bool(), "" ); | |
1068 return (BoolNode*)b; | |
1069 } | |
1070 | |
1071 //------------------------------clone_bool------------------------------------- | |
1072 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. | |
1073 // "Nearly" because all Nodes have been cloned from the original in the loop, | |
1074 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs | |
1075 // through the Phi recursively, and return a Bool. | |
1076 CmpNode *PhaseIdealLoop::clone_bool( PhiNode *phi, IdealLoopTree *loop ) { | |
1077 uint i; | |
1078 // Convert this Phi into a Phi merging Bools | |
1079 for( i = 1; i < phi->req(); i++ ) { | |
1080 Node *b = phi->in(i); | |
1081 if( b->is_Phi() ) { | |
1082 _igvn.hash_delete(phi); | |
1083 _igvn._worklist.push(phi); | |
1084 phi->set_req(i, clone_bool( b->as_Phi(), loop )); | |
1085 } else { | |
1086 assert( b->is_Cmp() || b->is_top(), "inputs are all Cmp or TOP" ); | |
1087 } | |
1088 } | |
1089 | |
1090 Node *sample_cmp = phi->in(1); | |
1091 | |
1092 // Make Phis to merge the Cmp's inputs. | |
1093 int size = phi->in(0)->req(); | |
1094 PhiNode *phi1 = new (C, size) PhiNode( phi->in(0), Type::TOP ); | |
1095 PhiNode *phi2 = new (C, size) PhiNode( phi->in(0), Type::TOP ); | |
1096 for( uint j = 1; j < phi->req(); j++ ) { | |
1097 Node *cmp_top = phi->in(j); // Inputs are all Cmp or TOP | |
1098 Node *n1, *n2; | |
1099 if( cmp_top->is_Cmp() ) { | |
1100 n1 = cmp_top->in(1); | |
1101 n2 = cmp_top->in(2); | |
1102 } else { | |
1103 n1 = n2 = cmp_top; | |
1104 } | |
1105 phi1->set_req( j, n1 ); | |
1106 phi2->set_req( j, n2 ); | |
1107 phi1->set_type( phi1->type()->meet(n1->bottom_type()) ); | |
1108 phi2->set_type( phi2->type()->meet(n2->bottom_type()) ); | |
1109 } | |
1110 | |
1111 // See if these Phis have been made before. | |
1112 // Register with optimizer | |
1113 Node *hit1 = _igvn.hash_find_insert(phi1); | |
1114 if( hit1 ) { // Hit, toss just made Phi | |
1115 _igvn.remove_dead_node(phi1); // Remove new phi | |
1116 assert( hit1->is_Phi(), "" ); | |
1117 phi1 = (PhiNode*)hit1; // Use existing phi | |
1118 } else { // Miss | |
1119 _igvn.register_new_node_with_optimizer(phi1); | |
1120 } | |
1121 Node *hit2 = _igvn.hash_find_insert(phi2); | |
1122 if( hit2 ) { // Hit, toss just made Phi | |
1123 _igvn.remove_dead_node(phi2); // Remove new phi | |
1124 assert( hit2->is_Phi(), "" ); | |
1125 phi2 = (PhiNode*)hit2; // Use existing phi | |
1126 } else { // Miss | |
1127 _igvn.register_new_node_with_optimizer(phi2); | |
1128 } | |
1129 // Register Phis with loop/block info | |
1130 set_ctrl(phi1, phi->in(0)); | |
1131 set_ctrl(phi2, phi->in(0)); | |
1132 // Make a new Cmp | |
1133 Node *cmp = sample_cmp->clone(); | |
1134 cmp->set_req( 1, phi1 ); | |
1135 cmp->set_req( 2, phi2 ); | |
1136 _igvn.register_new_node_with_optimizer(cmp); | |
1137 set_ctrl(cmp, phi->in(0)); | |
1138 | |
1139 assert( cmp->is_Cmp(), "" ); | |
1140 return (CmpNode*)cmp; | |
1141 } | |
1142 | |
1143 //------------------------------sink_use--------------------------------------- | |
1144 // If 'use' was in the loop-exit block, it now needs to be sunk | |
1145 // below the post-loop merge point. | |
1146 void PhaseIdealLoop::sink_use( Node *use, Node *post_loop ) { | |
1147 if (!use->is_CFG() && get_ctrl(use) == post_loop->in(2)) { | |
1148 set_ctrl(use, post_loop); | |
1149 for (DUIterator j = use->outs(); use->has_out(j); j++) | |
1150 sink_use(use->out(j), post_loop); | |
1151 } | |
1152 } | |
1153 | |
1154 //------------------------------clone_loop------------------------------------- | |
1155 // | |
1156 // C L O N E A L O O P B O D Y | |
1157 // | |
1158 // This is the basic building block of the loop optimizations. It clones an | |
1159 // entire loop body. It makes an old_new loop body mapping; with this mapping | |
1160 // you can find the new-loop equivalent to an old-loop node. All new-loop | |
1161 // nodes are exactly equal to their old-loop counterparts, all edges are the | |
1162 // same. All exits from the old-loop now have a RegionNode that merges the | |
1163 // equivalent new-loop path. This is true even for the normal "loop-exit" | |
1164 // condition. All uses of loop-invariant old-loop values now come from (one | |
1165 // or more) Phis that merge their new-loop equivalents. | |
1166 // | |
1167 // This operation leaves the graph in an illegal state: there are two valid | |
1168 // control edges coming from the loop pre-header to both loop bodies. I'll | |
1169 // definitely have to hack the graph after running this transform. | |
1170 // | |
1171 // From this building block I will further edit edges to perform loop peeling | |
1172 // or loop unrolling or iteration splitting (Range-Check-Elimination), etc. | |
1173 // | |
1174 // Parameter side_by_size_idom: | |
1175 // When side_by_size_idom is NULL, the dominator tree is constructed for | |
1176 // the clone loop to dominate the original. Used in construction of | |
1177 // pre-main-post loop sequence. | |
1178 // When nonnull, the clone and original are side-by-side, both are | |
1179 // dominated by the side_by_side_idom node. Used in construction of | |
1180 // unswitched loops. | |
1181 void PhaseIdealLoop::clone_loop( IdealLoopTree *loop, Node_List &old_new, int dd, | |
1182 Node* side_by_side_idom) { | |
1183 | |
1184 // Step 1: Clone the loop body. Make the old->new mapping. | |
1185 uint i; | |
1186 for( i = 0; i < loop->_body.size(); i++ ) { | |
1187 Node *old = loop->_body.at(i); | |
1188 Node *nnn = old->clone(); | |
1189 old_new.map( old->_idx, nnn ); | |
1190 _igvn.register_new_node_with_optimizer(nnn); | |
1191 } | |
1192 | |
1193 | |
1194 // Step 2: Fix the edges in the new body. If the old input is outside the | |
1195 // loop use it. If the old input is INside the loop, use the corresponding | |
1196 // new node instead. | |
1197 for( i = 0; i < loop->_body.size(); i++ ) { | |
1198 Node *old = loop->_body.at(i); | |
1199 Node *nnn = old_new[old->_idx]; | |
1200 // Fix CFG/Loop controlling the new node | |
1201 if (has_ctrl(old)) { | |
1202 set_ctrl(nnn, old_new[get_ctrl(old)->_idx]); | |
1203 } else { | |
1204 set_loop(nnn, loop->_parent); | |
1205 if (old->outcnt() > 0) { | |
1206 set_idom( nnn, old_new[idom(old)->_idx], dd ); | |
1207 } | |
1208 } | |
1209 // Correct edges to the new node | |
1210 for( uint j = 0; j < nnn->req(); j++ ) { | |
1211 Node *n = nnn->in(j); | |
1212 if( n ) { | |
1213 IdealLoopTree *old_in_loop = get_loop( has_ctrl(n) ? get_ctrl(n) : n ); | |
1214 if( loop->is_member( old_in_loop ) ) | |
1215 nnn->set_req(j, old_new[n->_idx]); | |
1216 } | |
1217 } | |
1218 _igvn.hash_find_insert(nnn); | |
1219 } | |
1220 Node *newhead = old_new[loop->_head->_idx]; | |
1221 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd); | |
1222 | |
1223 | |
1224 // Step 3: Now fix control uses. Loop varying control uses have already | |
1225 // been fixed up (as part of all input edges in Step 2). Loop invariant | |
1226 // control uses must be either an IfFalse or an IfTrue. Make a merge | |
1227 // point to merge the old and new IfFalse/IfTrue nodes; make the use | |
1228 // refer to this. | |
1229 ResourceArea *area = Thread::current()->resource_area(); | |
1230 Node_List worklist(area); | |
1231 uint new_counter = C->unique(); | |
1232 for( i = 0; i < loop->_body.size(); i++ ) { | |
1233 Node* old = loop->_body.at(i); | |
1234 if( !old->is_CFG() ) continue; | |
1235 Node* nnn = old_new[old->_idx]; | |
1236 | |
1237 // Copy uses to a worklist, so I can munge the def-use info | |
1238 // with impunity. | |
1239 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) | |
1240 worklist.push(old->fast_out(j)); | |
1241 | |
1242 while( worklist.size() ) { // Visit all uses | |
1243 Node *use = worklist.pop(); | |
1244 if (!has_node(use)) continue; // Ignore dead nodes | |
1245 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use ); | |
1246 if( !loop->is_member( use_loop ) && use->is_CFG() ) { | |
1247 // Both OLD and USE are CFG nodes here. | |
1248 assert( use->is_Proj(), "" ); | |
1249 | |
1250 // Clone the loop exit control projection | |
1251 Node *newuse = use->clone(); | |
1252 newuse->set_req(0,nnn); | |
1253 _igvn.register_new_node_with_optimizer(newuse); | |
1254 set_loop(newuse, use_loop); | |
1255 set_idom(newuse, nnn, dom_depth(nnn) + 1 ); | |
1256 | |
1257 // We need a Region to merge the exit from the peeled body and the | |
1258 // exit from the old loop body. | |
1259 RegionNode *r = new (C, 3) RegionNode(3); | |
1260 // Map the old use to the new merge point | |
1261 old_new.map( use->_idx, r ); | |
1262 uint dd_r = MIN2(dom_depth(newuse),dom_depth(use)); | |
1263 assert( dd_r >= dom_depth(dom_lca(newuse,use)), "" ); | |
1264 | |
1265 // The original user of 'use' uses 'r' instead. | |
1266 for (DUIterator_Last lmin, l = use->last_outs(lmin); l >= lmin;) { | |
1267 Node* useuse = use->last_out(l); | |
1268 _igvn.hash_delete(useuse); | |
1269 _igvn._worklist.push(useuse); | |
1270 uint uses_found = 0; | |
1271 if( useuse->in(0) == use ) { | |
1272 useuse->set_req(0, r); | |
1273 uses_found++; | |
1274 if( useuse->is_CFG() ) { | |
1275 assert( dom_depth(useuse) > dd_r, "" ); | |
1276 set_idom(useuse, r, dom_depth(useuse)); | |
1277 } | |
1278 } | |
1279 for( uint k = 1; k < useuse->req(); k++ ) { | |
1280 if( useuse->in(k) == use ) { | |
1281 useuse->set_req(k, r); | |
1282 uses_found++; | |
1283 } | |
1284 } | |
1285 l -= uses_found; // we deleted 1 or more copies of this edge | |
1286 } | |
1287 | |
1288 // Now finish up 'r' | |
1289 r->set_req( 1, newuse ); | |
1290 r->set_req( 2, use ); | |
1291 _igvn.register_new_node_with_optimizer(r); | |
1292 set_loop(r, use_loop); | |
1293 set_idom(r, !side_by_side_idom ? newuse->in(0) : side_by_side_idom, dd_r); | |
1294 } // End of if a loop-exit test | |
1295 } | |
1296 } | |
1297 | |
1298 // Step 4: If loop-invariant use is not control, it must be dominated by a | |
1299 // loop exit IfFalse/IfTrue. Find "proper" loop exit. Make a Region | |
1300 // there if needed. Make a Phi there merging old and new used values. | |
1301 Node_List *split_if_set = NULL; | |
1302 Node_List *split_bool_set = NULL; | |
1303 Node_List *split_cex_set = NULL; | |
1304 for( i = 0; i < loop->_body.size(); i++ ) { | |
1305 Node* old = loop->_body.at(i); | |
1306 Node* nnn = old_new[old->_idx]; | |
1307 // Copy uses to a worklist, so I can munge the def-use info | |
1308 // with impunity. | |
1309 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) | |
1310 worklist.push(old->fast_out(j)); | |
1311 | |
1312 while( worklist.size() ) { | |
1313 Node *use = worklist.pop(); | |
1314 if (!has_node(use)) continue; // Ignore dead nodes | |
1315 if (use->in(0) == C->top()) continue; | |
1316 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use ); | |
1317 // Check for data-use outside of loop - at least one of OLD or USE | |
1318 // must not be a CFG node. | |
1319 if( !loop->is_member( use_loop ) && (!old->is_CFG() || !use->is_CFG())) { | |
1320 | |
1321 // If the Data use is an IF, that means we have an IF outside of the | |
1322 // loop that is switching on a condition that is set inside of the | |
1323 // loop. Happens if people set a loop-exit flag; then test the flag | |
1324 // in the loop to break the loop, then test is again outside of the | |
1325 // loop to determine which way the loop exited. | |
1326 if( use->is_If() || use->is_CMove() ) { | |
1327 // Since this code is highly unlikely, we lazily build the worklist | |
1328 // of such Nodes to go split. | |
1329 if( !split_if_set ) | |
1330 split_if_set = new Node_List(area); | |
1331 split_if_set->push(use); | |
1332 } | |
1333 if( use->is_Bool() ) { | |
1334 if( !split_bool_set ) | |
1335 split_bool_set = new Node_List(area); | |
1336 split_bool_set->push(use); | |
1337 } | |
1338 if( use->Opcode() == Op_CreateEx ) { | |
1339 if( !split_cex_set ) | |
1340 split_cex_set = new Node_List(area); | |
1341 split_cex_set->push(use); | |
1342 } | |
1343 | |
1344 | |
1345 // Get "block" use is in | |
1346 uint idx = 0; | |
1347 while( use->in(idx) != old ) idx++; | |
1348 Node *prev = use->is_CFG() ? use : get_ctrl(use); | |
1349 assert( !loop->is_member( get_loop( prev ) ), "" ); | |
1350 Node *cfg = prev->_idx >= new_counter | |
1351 ? prev->in(2) | |
1352 : idom(prev); | |
1353 if( use->is_Phi() ) // Phi use is in prior block | |
1354 cfg = prev->in(idx); // NOT in block of Phi itself | |
1355 if (cfg->is_top()) { // Use is dead? | |
1356 _igvn.hash_delete(use); | |
1357 _igvn._worklist.push(use); | |
1358 use->set_req(idx, C->top()); | |
1359 continue; | |
1360 } | |
1361 | |
1362 while( !loop->is_member( get_loop( cfg ) ) ) { | |
1363 prev = cfg; | |
1364 cfg = cfg->_idx >= new_counter ? cfg->in(2) : idom(cfg); | |
1365 } | |
1366 // If the use occurs after merging several exits from the loop, then | |
1367 // old value must have dominated all those exits. Since the same old | |
1368 // value was used on all those exits we did not need a Phi at this | |
1369 // merge point. NOW we do need a Phi here. Each loop exit value | |
1370 // is now merged with the peeled body exit; each exit gets its own | |
1371 // private Phi and those Phis need to be merged here. | |
1372 Node *phi; | |
1373 if( prev->is_Region() ) { | |
1374 if( idx == 0 ) { // Updating control edge? | |
1375 phi = prev; // Just use existing control | |
1376 } else { // Else need a new Phi | |
1377 phi = PhiNode::make( prev, old ); | |
1378 // Now recursively fix up the new uses of old! | |
1379 for( uint i = 1; i < prev->req(); i++ ) { | |
1380 worklist.push(phi); // Onto worklist once for each 'old' input | |
1381 } | |
1382 } | |
1383 } else { | |
1384 // Get new RegionNode merging old and new loop exits | |
1385 prev = old_new[prev->_idx]; | |
1386 assert( prev, "just made this in step 7" ); | |
1387 if( idx == 0 ) { // Updating control edge? | |
1388 phi = prev; // Just use existing control | |
1389 } else { // Else need a new Phi | |
1390 // Make a new Phi merging data values properly | |
1391 phi = PhiNode::make( prev, old ); | |
1392 phi->set_req( 1, nnn ); | |
1393 } | |
1394 } | |
1395 // If inserting a new Phi, check for prior hits | |
1396 if( idx != 0 ) { | |
1397 Node *hit = _igvn.hash_find_insert(phi); | |
1398 if( hit == NULL ) { | |
1399 _igvn.register_new_node_with_optimizer(phi); // Register new phi | |
1400 } else { // or | |
1401 // Remove the new phi from the graph and use the hit | |
1402 _igvn.remove_dead_node(phi); | |
1403 phi = hit; // Use existing phi | |
1404 } | |
1405 set_ctrl(phi, prev); | |
1406 } | |
1407 // Make 'use' use the Phi instead of the old loop body exit value | |
1408 _igvn.hash_delete(use); | |
1409 _igvn._worklist.push(use); | |
1410 use->set_req(idx, phi); | |
1411 if( use->_idx >= new_counter ) { // If updating new phis | |
1412 // Not needed for correctness, but prevents a weak assert | |
1413 // in AddPNode from tripping (when we end up with different | |
1414 // base & derived Phis that will become the same after | |
1415 // IGVN does CSE). | |
1416 Node *hit = _igvn.hash_find_insert(use); | |
1417 if( hit ) // Go ahead and re-hash for hits. | |
1621
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1418 _igvn.replace_node( use, hit ); |
0 | 1419 } |
1420 | |
1421 // If 'use' was in the loop-exit block, it now needs to be sunk | |
1422 // below the post-loop merge point. | |
1423 sink_use( use, prev ); | |
1424 } | |
1425 } | |
1426 } | |
1427 | |
1428 // Check for IFs that need splitting/cloning. Happens if an IF outside of | |
1429 // the loop uses a condition set in the loop. The original IF probably | |
1430 // takes control from one or more OLD Regions (which in turn get from NEW | |
1431 // Regions). In any case, there will be a set of Phis for each merge point | |
1432 // from the IF up to where the original BOOL def exists the loop. | |
1433 if( split_if_set ) { | |
1434 while( split_if_set->size() ) { | |
1435 Node *iff = split_if_set->pop(); | |
1436 if( iff->in(1)->is_Phi() ) { | |
1437 BoolNode *b = clone_iff( iff->in(1)->as_Phi(), loop ); | |
1438 _igvn.hash_delete(iff); | |
1439 _igvn._worklist.push(iff); | |
1440 iff->set_req(1, b); | |
1441 } | |
1442 } | |
1443 } | |
1444 if( split_bool_set ) { | |
1445 while( split_bool_set->size() ) { | |
1446 Node *b = split_bool_set->pop(); | |
1447 Node *phi = b->in(1); | |
1448 assert( phi->is_Phi(), "" ); | |
1449 CmpNode *cmp = clone_bool( (PhiNode*)phi, loop ); | |
1450 _igvn.hash_delete(b); | |
1451 _igvn._worklist.push(b); | |
1452 b->set_req(1, cmp); | |
1453 } | |
1454 } | |
1455 if( split_cex_set ) { | |
1456 while( split_cex_set->size() ) { | |
1457 Node *b = split_cex_set->pop(); | |
1458 assert( b->in(0)->is_Region(), "" ); | |
1459 assert( b->in(1)->is_Phi(), "" ); | |
1460 assert( b->in(0)->in(0) == b->in(1)->in(0), "" ); | |
1461 split_up( b, b->in(0), NULL ); | |
1462 } | |
1463 } | |
1464 | |
1465 } | |
1466 | |
1467 | |
1468 //---------------------- stride_of_possible_iv ------------------------------------- | |
1469 // Looks for an iff/bool/comp with one operand of the compare | |
1470 // being a cycle involving an add and a phi, | |
1471 // with an optional truncation (left-shift followed by a right-shift) | |
1472 // of the add. Returns zero if not an iv. | |
1473 int PhaseIdealLoop::stride_of_possible_iv(Node* iff) { | |
1474 Node* trunc1 = NULL; | |
1475 Node* trunc2 = NULL; | |
1476 const TypeInt* ttype = NULL; | |
1477 if (!iff->is_If() || iff->in(1) == NULL || !iff->in(1)->is_Bool()) { | |
1478 return 0; | |
1479 } | |
1480 BoolNode* bl = iff->in(1)->as_Bool(); | |
1481 Node* cmp = bl->in(1); | |
1482 if (!cmp || cmp->Opcode() != Op_CmpI && cmp->Opcode() != Op_CmpU) { | |
1483 return 0; | |
1484 } | |
1485 // Must have an invariant operand | |
1486 if (is_member(get_loop(iff), get_ctrl(cmp->in(2)))) { | |
1487 return 0; | |
1488 } | |
1489 Node* add2 = NULL; | |
1490 Node* cmp1 = cmp->in(1); | |
1491 if (cmp1->is_Phi()) { | |
1492 // (If (Bool (CmpX phi:(Phi ...(Optional-trunc(AddI phi add2))) ))) | |
1493 Node* phi = cmp1; | |
1494 for (uint i = 1; i < phi->req(); i++) { | |
1495 Node* in = phi->in(i); | |
1496 Node* add = CountedLoopNode::match_incr_with_optional_truncation(in, | |
1497 &trunc1, &trunc2, &ttype); | |
1498 if (add && add->in(1) == phi) { | |
1499 add2 = add->in(2); | |
1500 break; | |
1501 } | |
1502 } | |
1503 } else { | |
1504 // (If (Bool (CmpX addtrunc:(Optional-trunc((AddI (Phi ...addtrunc...) add2)) ))) | |
1505 Node* addtrunc = cmp1; | |
1506 Node* add = CountedLoopNode::match_incr_with_optional_truncation(addtrunc, | |
1507 &trunc1, &trunc2, &ttype); | |
1508 if (add && add->in(1)->is_Phi()) { | |
1509 Node* phi = add->in(1); | |
1510 for (uint i = 1; i < phi->req(); i++) { | |
1511 if (phi->in(i) == addtrunc) { | |
1512 add2 = add->in(2); | |
1513 break; | |
1514 } | |
1515 } | |
1516 } | |
1517 } | |
1518 if (add2 != NULL) { | |
1519 const TypeInt* add2t = _igvn.type(add2)->is_int(); | |
1520 if (add2t->is_con()) { | |
1521 return add2t->get_con(); | |
1522 } | |
1523 } | |
1524 return 0; | |
1525 } | |
1526 | |
1527 | |
1528 //---------------------- stay_in_loop ------------------------------------- | |
1529 // Return the (unique) control output node that's in the loop (if it exists.) | |
1530 Node* PhaseIdealLoop::stay_in_loop( Node* n, IdealLoopTree *loop) { | |
1531 Node* unique = NULL; | |
1532 if (!n) return NULL; | |
1533 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { | |
1534 Node* use = n->fast_out(i); | |
1535 if (!has_ctrl(use) && loop->is_member(get_loop(use))) { | |
1536 if (unique != NULL) { | |
1537 return NULL; | |
1538 } | |
1539 unique = use; | |
1540 } | |
1541 } | |
1542 return unique; | |
1543 } | |
1544 | |
1545 //------------------------------ register_node ------------------------------------- | |
1546 // Utility to register node "n" with PhaseIdealLoop | |
1547 void PhaseIdealLoop::register_node(Node* n, IdealLoopTree *loop, Node* pred, int ddepth) { | |
1548 _igvn.register_new_node_with_optimizer(n); | |
1549 loop->_body.push(n); | |
1550 if (n->is_CFG()) { | |
1551 set_loop(n, loop); | |
1552 set_idom(n, pred, ddepth); | |
1553 } else { | |
1554 set_ctrl(n, pred); | |
1555 } | |
1556 } | |
1557 | |
1558 //------------------------------ proj_clone ------------------------------------- | |
1559 // Utility to create an if-projection | |
1560 ProjNode* PhaseIdealLoop::proj_clone(ProjNode* p, IfNode* iff) { | |
1561 ProjNode* c = p->clone()->as_Proj(); | |
1562 c->set_req(0, iff); | |
1563 return c; | |
1564 } | |
1565 | |
1566 //------------------------------ short_circuit_if ------------------------------------- | |
1567 // Force the iff control output to be the live_proj | |
1568 Node* PhaseIdealLoop::short_circuit_if(IfNode* iff, ProjNode* live_proj) { | |
1569 int proj_con = live_proj->_con; | |
1570 assert(proj_con == 0 || proj_con == 1, "false or true projection"); | |
1571 Node *con = _igvn.intcon(proj_con); | |
1572 set_ctrl(con, C->root()); | |
1573 if (iff) { | |
1574 iff->set_req(1, con); | |
1575 } | |
1576 return con; | |
1577 } | |
1578 | |
1579 //------------------------------ insert_if_before_proj ------------------------------------- | |
1580 // Insert a new if before an if projection (* - new node) | |
1581 // | |
1582 // before | |
1583 // if(test) | |
1584 // / \ | |
1585 // v v | |
1586 // other-proj proj (arg) | |
1587 // | |
1588 // after | |
1589 // if(test) | |
1590 // / \ | |
1591 // / v | |
1592 // | * proj-clone | |
1593 // v | | |
1594 // other-proj v | |
1595 // * new_if(relop(cmp[IU](left,right))) | |
1596 // / \ | |
1597 // v v | |
1598 // * new-proj proj | |
1599 // (returned) | |
1600 // | |
1601 ProjNode* PhaseIdealLoop::insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj) { | |
1602 IfNode* iff = proj->in(0)->as_If(); | |
1603 IdealLoopTree *loop = get_loop(proj); | |
1604 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); | |
1605 int ddepth = dom_depth(proj); | |
1606 | |
1607 _igvn.hash_delete(iff); | |
1608 _igvn._worklist.push(iff); | |
1609 _igvn.hash_delete(proj); | |
1610 _igvn._worklist.push(proj); | |
1611 | |
1612 proj->set_req(0, NULL); // temporary disconnect | |
1613 ProjNode* proj2 = proj_clone(proj, iff); | |
1614 register_node(proj2, loop, iff, ddepth); | |
1615 | |
1616 Node* cmp = Signed ? (Node*) new (C,3)CmpINode(left, right) : (Node*) new (C,3)CmpUNode(left, right); | |
1617 register_node(cmp, loop, proj2, ddepth); | |
1618 | |
1619 BoolNode* bol = new (C,2)BoolNode(cmp, relop); | |
1620 register_node(bol, loop, proj2, ddepth); | |
1621 | |
1622 IfNode* new_if = new (C,2)IfNode(proj2, bol, iff->_prob, iff->_fcnt); | |
1623 register_node(new_if, loop, proj2, ddepth); | |
1624 | |
1625 proj->set_req(0, new_if); // reattach | |
1626 set_idom(proj, new_if, ddepth); | |
1627 | |
1628 ProjNode* new_exit = proj_clone(other_proj, new_if)->as_Proj(); | |
1629 register_node(new_exit, get_loop(other_proj), new_if, ddepth); | |
1630 | |
1631 return new_exit; | |
1632 } | |
1633 | |
1634 //------------------------------ insert_region_before_proj ------------------------------------- | |
1635 // Insert a region before an if projection (* - new node) | |
1636 // | |
1637 // before | |
1638 // if(test) | |
1639 // / | | |
1640 // v | | |
1641 // proj v | |
1642 // other-proj | |
1643 // | |
1644 // after | |
1645 // if(test) | |
1646 // / | | |
1647 // v | | |
1648 // * proj-clone v | |
1649 // | other-proj | |
1650 // v | |
1651 // * new-region | |
1652 // | | |
1653 // v | |
1654 // * dum_if | |
1655 // / \ | |
1656 // v \ | |
1657 // * dum-proj v | |
1658 // proj | |
1659 // | |
1660 RegionNode* PhaseIdealLoop::insert_region_before_proj(ProjNode* proj) { | |
1661 IfNode* iff = proj->in(0)->as_If(); | |
1662 IdealLoopTree *loop = get_loop(proj); | |
1663 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); | |
1664 int ddepth = dom_depth(proj); | |
1665 | |
1666 _igvn.hash_delete(iff); | |
1667 _igvn._worklist.push(iff); | |
1668 _igvn.hash_delete(proj); | |
1669 _igvn._worklist.push(proj); | |
1670 | |
1671 proj->set_req(0, NULL); // temporary disconnect | |
1672 ProjNode* proj2 = proj_clone(proj, iff); | |
1673 register_node(proj2, loop, iff, ddepth); | |
1674 | |
1675 RegionNode* reg = new (C,2)RegionNode(2); | |
1676 reg->set_req(1, proj2); | |
1677 register_node(reg, loop, iff, ddepth); | |
1678 | |
1679 IfNode* dum_if = new (C,2)IfNode(reg, short_circuit_if(NULL, proj), iff->_prob, iff->_fcnt); | |
1680 register_node(dum_if, loop, reg, ddepth); | |
1681 | |
1682 proj->set_req(0, dum_if); // reattach | |
1683 set_idom(proj, dum_if, ddepth); | |
1684 | |
1685 ProjNode* dum_proj = proj_clone(other_proj, dum_if); | |
1686 register_node(dum_proj, loop, dum_if, ddepth); | |
1687 | |
1688 return reg; | |
1689 } | |
1690 | |
1691 //------------------------------ insert_cmpi_loop_exit ------------------------------------- | |
1692 // Clone a signed compare loop exit from an unsigned compare and | |
1693 // insert it before the unsigned cmp on the stay-in-loop path. | |
1694 // All new nodes inserted in the dominator tree between the original | |
1695 // if and it's projections. The original if test is replaced with | |
1696 // a constant to force the stay-in-loop path. | |
1697 // | |
1698 // This is done to make sure that the original if and it's projections | |
1699 // still dominate the same set of control nodes, that the ctrl() relation | |
1700 // from data nodes to them is preserved, and that their loop nesting is | |
1701 // preserved. | |
1702 // | |
1703 // before | |
1704 // if(i <u limit) unsigned compare loop exit | |
1705 // / | | |
1706 // v v | |
1707 // exit-proj stay-in-loop-proj | |
1708 // | |
1709 // after | |
1710 // if(stay-in-loop-const) original if | |
1711 // / | | |
1712 // / v | |
1713 // / if(i < limit) new signed test | |
1714 // / / | | |
1715 // / / v | |
1716 // / / if(i <u limit) new cloned unsigned test | |
1717 // / / / | | |
1718 // v v v | | |
1719 // region | | |
1720 // | | | |
1721 // dum-if | | |
1722 // / | | | |
1723 // ether | | | |
1724 // v v | |
1725 // exit-proj stay-in-loop-proj | |
1726 // | |
1727 IfNode* PhaseIdealLoop::insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *loop) { | |
1728 const bool Signed = true; | |
1729 const bool Unsigned = false; | |
1730 | |
1731 BoolNode* bol = if_cmpu->in(1)->as_Bool(); | |
1732 if (bol->_test._test != BoolTest::lt) return NULL; | |
1733 CmpNode* cmpu = bol->in(1)->as_Cmp(); | |
1734 if (cmpu->Opcode() != Op_CmpU) return NULL; | |
1735 int stride = stride_of_possible_iv(if_cmpu); | |
1736 if (stride == 0) return NULL; | |
1737 | |
1738 ProjNode* lp_continue = stay_in_loop(if_cmpu, loop)->as_Proj(); | |
1739 ProjNode* lp_exit = if_cmpu->proj_out(!lp_continue->is_IfTrue())->as_Proj(); | |
1740 | |
1741 Node* limit = NULL; | |
1742 if (stride > 0) { | |
1743 limit = cmpu->in(2); | |
1744 } else { | |
1745 limit = _igvn.makecon(TypeInt::ZERO); | |
1746 set_ctrl(limit, C->root()); | |
1747 } | |
1748 // Create a new region on the exit path | |
1749 RegionNode* reg = insert_region_before_proj(lp_exit); | |
1750 | |
1751 // Clone the if-cmpu-true-false using a signed compare | |
1752 BoolTest::mask rel_i = stride > 0 ? bol->_test._test : BoolTest::ge; | |
1753 ProjNode* cmpi_exit = insert_if_before_proj(cmpu->in(1), Signed, rel_i, limit, lp_continue); | |
1754 reg->add_req(cmpi_exit); | |
1755 | |
1756 // Clone the if-cmpu-true-false | |
1757 BoolTest::mask rel_u = bol->_test._test; | |
1758 ProjNode* cmpu_exit = insert_if_before_proj(cmpu->in(1), Unsigned, rel_u, cmpu->in(2), lp_continue); | |
1759 reg->add_req(cmpu_exit); | |
1760 | |
1761 // Force original if to stay in loop. | |
1762 short_circuit_if(if_cmpu, lp_continue); | |
1763 | |
1764 return cmpi_exit->in(0)->as_If(); | |
1765 } | |
1766 | |
1767 //------------------------------ remove_cmpi_loop_exit ------------------------------------- | |
1768 // Remove a previously inserted signed compare loop exit. | |
1769 void PhaseIdealLoop::remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop) { | |
1770 Node* lp_proj = stay_in_loop(if_cmp, loop); | |
1771 assert(if_cmp->in(1)->in(1)->Opcode() == Op_CmpI && | |
1772 stay_in_loop(lp_proj, loop)->is_If() && | |
1773 stay_in_loop(lp_proj, loop)->in(1)->in(1)->Opcode() == Op_CmpU, "inserted cmpi before cmpu"); | |
1774 Node *con = _igvn.makecon(lp_proj->is_IfTrue() ? TypeInt::ONE : TypeInt::ZERO); | |
1775 set_ctrl(con, C->root()); | |
1776 if_cmp->set_req(1, con); | |
1777 } | |
1778 | |
1779 //------------------------------ scheduled_nodelist ------------------------------------- | |
1780 // Create a post order schedule of nodes that are in the | |
1781 // "member" set. The list is returned in "sched". | |
1782 // The first node in "sched" is the loop head, followed by | |
1783 // nodes which have no inputs in the "member" set, and then | |
1784 // followed by the nodes that have an immediate input dependence | |
1785 // on a node in "sched". | |
1786 void PhaseIdealLoop::scheduled_nodelist( IdealLoopTree *loop, VectorSet& member, Node_List &sched ) { | |
1787 | |
1788 assert(member.test(loop->_head->_idx), "loop head must be in member set"); | |
1789 Arena *a = Thread::current()->resource_area(); | |
1790 VectorSet visited(a); | |
1791 Node_Stack nstack(a, loop->_body.size()); | |
1792 | |
1793 Node* n = loop->_head; // top of stack is cached in "n" | |
1794 uint idx = 0; | |
1795 visited.set(n->_idx); | |
1796 | |
1797 // Initially push all with no inputs from within member set | |
1798 for(uint i = 0; i < loop->_body.size(); i++ ) { | |
1799 Node *elt = loop->_body.at(i); | |
1800 if (member.test(elt->_idx)) { | |
1801 bool found = false; | |
1802 for (uint j = 0; j < elt->req(); j++) { | |
1803 Node* def = elt->in(j); | |
1804 if (def && member.test(def->_idx) && def != elt) { | |
1805 found = true; | |
1806 break; | |
1807 } | |
1808 } | |
1809 if (!found && elt != loop->_head) { | |
1810 nstack.push(n, idx); | |
1811 n = elt; | |
1812 assert(!visited.test(n->_idx), "not seen yet"); | |
1813 visited.set(n->_idx); | |
1814 } | |
1815 } | |
1816 } | |
1817 | |
1818 // traverse out's that are in the member set | |
1819 while (true) { | |
1820 if (idx < n->outcnt()) { | |
1821 Node* use = n->raw_out(idx); | |
1822 idx++; | |
1823 if (!visited.test_set(use->_idx)) { | |
1824 if (member.test(use->_idx)) { | |
1825 nstack.push(n, idx); | |
1826 n = use; | |
1827 idx = 0; | |
1828 } | |
1829 } | |
1830 } else { | |
1831 // All outputs processed | |
1832 sched.push(n); | |
1833 if (nstack.is_empty()) break; | |
1834 n = nstack.node(); | |
1835 idx = nstack.index(); | |
1836 nstack.pop(); | |
1837 } | |
1838 } | |
1839 } | |
1840 | |
1841 | |
1842 //------------------------------ has_use_in_set ------------------------------------- | |
1843 // Has a use in the vector set | |
1844 bool PhaseIdealLoop::has_use_in_set( Node* n, VectorSet& vset ) { | |
1845 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
1846 Node* use = n->fast_out(j); | |
1847 if (vset.test(use->_idx)) { | |
1848 return true; | |
1849 } | |
1850 } | |
1851 return false; | |
1852 } | |
1853 | |
1854 | |
1855 //------------------------------ has_use_internal_to_set ------------------------------------- | |
1856 // Has use internal to the vector set (ie. not in a phi at the loop head) | |
1857 bool PhaseIdealLoop::has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ) { | |
1858 Node* head = loop->_head; | |
1859 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
1860 Node* use = n->fast_out(j); | |
1861 if (vset.test(use->_idx) && !(use->is_Phi() && use->in(0) == head)) { | |
1862 return true; | |
1863 } | |
1864 } | |
1865 return false; | |
1866 } | |
1867 | |
1868 | |
1869 //------------------------------ clone_for_use_outside_loop ------------------------------------- | |
1870 // clone "n" for uses that are outside of loop | |
1871 void PhaseIdealLoop::clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ) { | |
1872 | |
1873 assert(worklist.size() == 0, "should be empty"); | |
1874 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
1875 Node* use = n->fast_out(j); | |
1876 if( !loop->is_member(get_loop(has_ctrl(use) ? get_ctrl(use) : use)) ) { | |
1877 worklist.push(use); | |
1878 } | |
1879 } | |
1880 while( worklist.size() ) { | |
1881 Node *use = worklist.pop(); | |
1882 if (!has_node(use) || use->in(0) == C->top()) continue; | |
1883 uint j; | |
1884 for (j = 0; j < use->req(); j++) { | |
1885 if (use->in(j) == n) break; | |
1886 } | |
1887 assert(j < use->req(), "must be there"); | |
1888 | |
1889 // clone "n" and insert it between the inputs of "n" and the use outside the loop | |
1890 Node* n_clone = n->clone(); | |
1891 _igvn.hash_delete(use); | |
1892 use->set_req(j, n_clone); | |
1893 _igvn._worklist.push(use); | |
251 | 1894 Node* use_c; |
0 | 1895 if (!use->is_Phi()) { |
251 | 1896 use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0); |
0 | 1897 } else { |
1898 // Use in a phi is considered a use in the associated predecessor block | |
251 | 1899 use_c = use->in(0)->in(j); |
0 | 1900 } |
251 | 1901 set_ctrl(n_clone, use_c); |
1902 assert(!loop->is_member(get_loop(use_c)), "should be outside loop"); | |
1903 get_loop(use_c)->_body.push(n_clone); | |
0 | 1904 _igvn.register_new_node_with_optimizer(n_clone); |
1905 #if !defined(PRODUCT) | |
1906 if (TracePartialPeeling) { | |
1907 tty->print_cr("loop exit cloning old: %d new: %d newbb: %d", n->_idx, n_clone->_idx, get_ctrl(n_clone)->_idx); | |
1908 } | |
1909 #endif | |
1910 } | |
1911 } | |
1912 | |
1913 | |
1914 //------------------------------ clone_for_special_use_inside_loop ------------------------------------- | |
1915 // clone "n" for special uses that are in the not_peeled region. | |
1916 // If these def-uses occur in separate blocks, the code generator | |
1917 // marks the method as not compilable. For example, if a "BoolNode" | |
1918 // is in a different basic block than the "IfNode" that uses it, then | |
1919 // the compilation is aborted in the code generator. | |
1920 void PhaseIdealLoop::clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n, | |
1921 VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ) { | |
1922 if (n->is_Phi() || n->is_Load()) { | |
1923 return; | |
1924 } | |
1925 assert(worklist.size() == 0, "should be empty"); | |
1926 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
1927 Node* use = n->fast_out(j); | |
1928 if ( not_peel.test(use->_idx) && | |
1929 (use->is_If() || use->is_CMove() || use->is_Bool()) && | |
1930 use->in(1) == n) { | |
1931 worklist.push(use); | |
1932 } | |
1933 } | |
1934 if (worklist.size() > 0) { | |
1935 // clone "n" and insert it between inputs of "n" and the use | |
1936 Node* n_clone = n->clone(); | |
1937 loop->_body.push(n_clone); | |
1938 _igvn.register_new_node_with_optimizer(n_clone); | |
1939 set_ctrl(n_clone, get_ctrl(n)); | |
1940 sink_list.push(n_clone); | |
1941 not_peel <<= n_clone->_idx; // add n_clone to not_peel set. | |
1942 #if !defined(PRODUCT) | |
1943 if (TracePartialPeeling) { | |
1944 tty->print_cr("special not_peeled cloning old: %d new: %d", n->_idx, n_clone->_idx); | |
1945 } | |
1946 #endif | |
1947 while( worklist.size() ) { | |
1948 Node *use = worklist.pop(); | |
1949 _igvn.hash_delete(use); | |
1950 _igvn._worklist.push(use); | |
1951 for (uint j = 1; j < use->req(); j++) { | |
1952 if (use->in(j) == n) { | |
1953 use->set_req(j, n_clone); | |
1954 } | |
1955 } | |
1956 } | |
1957 } | |
1958 } | |
1959 | |
1960 | |
1961 //------------------------------ insert_phi_for_loop ------------------------------------- | |
1962 // Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist | |
1963 void PhaseIdealLoop::insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ) { | |
1964 Node *phi = PhiNode::make(lp, back_edge_val); | |
1965 phi->set_req(LoopNode::EntryControl, lp_entry_val); | |
1966 // Use existing phi if it already exists | |
1967 Node *hit = _igvn.hash_find_insert(phi); | |
1968 if( hit == NULL ) { | |
1969 _igvn.register_new_node_with_optimizer(phi); | |
1970 set_ctrl(phi, lp); | |
1971 } else { | |
1972 // Remove the new phi from the graph and use the hit | |
1973 _igvn.remove_dead_node(phi); | |
1974 phi = hit; | |
1975 } | |
1976 _igvn.hash_delete(use); | |
1977 _igvn._worklist.push(use); | |
1978 use->set_req(idx, phi); | |
1979 } | |
1980 | |
1981 #ifdef ASSERT | |
1982 //------------------------------ is_valid_loop_partition ------------------------------------- | |
1983 // Validate the loop partition sets: peel and not_peel | |
1984 bool PhaseIdealLoop::is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list, | |
1985 VectorSet& not_peel ) { | |
1986 uint i; | |
1987 // Check that peel_list entries are in the peel set | |
1988 for (i = 0; i < peel_list.size(); i++) { | |
1989 if (!peel.test(peel_list.at(i)->_idx)) { | |
1990 return false; | |
1991 } | |
1992 } | |
1993 // Check at loop members are in one of peel set or not_peel set | |
1994 for (i = 0; i < loop->_body.size(); i++ ) { | |
1995 Node *def = loop->_body.at(i); | |
1996 uint di = def->_idx; | |
1997 // Check that peel set elements are in peel_list | |
1998 if (peel.test(di)) { | |
1999 if (not_peel.test(di)) { | |
2000 return false; | |
2001 } | |
2002 // Must be in peel_list also | |
2003 bool found = false; | |
2004 for (uint j = 0; j < peel_list.size(); j++) { | |
2005 if (peel_list.at(j)->_idx == di) { | |
2006 found = true; | |
2007 break; | |
2008 } | |
2009 } | |
2010 if (!found) { | |
2011 return false; | |
2012 } | |
2013 } else if (not_peel.test(di)) { | |
2014 if (peel.test(di)) { | |
2015 return false; | |
2016 } | |
2017 } else { | |
2018 return false; | |
2019 } | |
2020 } | |
2021 return true; | |
2022 } | |
2023 | |
2024 //------------------------------ is_valid_clone_loop_exit_use ------------------------------------- | |
2025 // Ensure a use outside of loop is of the right form | |
2026 bool PhaseIdealLoop::is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx) { | |
2027 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; | |
2028 return (use->is_Phi() && | |
2029 use_c->is_Region() && use_c->req() == 3 && | |
2030 (use_c->in(exit_idx)->Opcode() == Op_IfTrue || | |
2031 use_c->in(exit_idx)->Opcode() == Op_IfFalse || | |
2032 use_c->in(exit_idx)->Opcode() == Op_JumpProj) && | |
2033 loop->is_member( get_loop( use_c->in(exit_idx)->in(0) ) ) ); | |
2034 } | |
2035 | |
2036 //------------------------------ is_valid_clone_loop_form ------------------------------------- | |
2037 // Ensure that all uses outside of loop are of the right form | |
2038 bool PhaseIdealLoop::is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list, | |
2039 uint orig_exit_idx, uint clone_exit_idx) { | |
2040 uint len = peel_list.size(); | |
2041 for (uint i = 0; i < len; i++) { | |
2042 Node *def = peel_list.at(i); | |
2043 | |
2044 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { | |
2045 Node *use = def->fast_out(j); | |
2046 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; | |
2047 if (!loop->is_member(get_loop(use_c))) { | |
2048 // use is not in the loop, check for correct structure | |
2049 if (use->in(0) == def) { | |
2050 // Okay | |
2051 } else if (!is_valid_clone_loop_exit_use(loop, use, orig_exit_idx)) { | |
2052 return false; | |
2053 } | |
2054 } | |
2055 } | |
2056 } | |
2057 return true; | |
2058 } | |
2059 #endif | |
2060 | |
2061 //------------------------------ partial_peel ------------------------------------- | |
2062 // Partially peel (aka loop rotation) the top portion of a loop (called | |
2063 // the peel section below) by cloning it and placing one copy just before | |
2064 // the new loop head and the other copy at the bottom of the new loop. | |
2065 // | |
2066 // before after where it came from | |
2067 // | |
2068 // stmt1 stmt1 | |
2069 // loop: stmt2 clone | |
2070 // stmt2 if condA goto exitA clone | |
2071 // if condA goto exitA new_loop: new | |
2072 // stmt3 stmt3 clone | |
2073 // if !condB goto loop if condB goto exitB clone | |
2074 // exitB: stmt2 orig | |
2075 // stmt4 if !condA goto new_loop orig | |
2076 // exitA: goto exitA | |
2077 // exitB: | |
2078 // stmt4 | |
2079 // exitA: | |
2080 // | |
2081 // Step 1: find the cut point: an exit test on probable | |
2082 // induction variable. | |
2083 // Step 2: schedule (with cloning) operations in the peel | |
2084 // section that can be executed after the cut into | |
2085 // the section that is not peeled. This may need | |
2086 // to clone operations into exit blocks. For | |
2087 // instance, a reference to A[i] in the not-peel | |
2088 // section and a reference to B[i] in an exit block | |
2089 // may cause a left-shift of i by 2 to be placed | |
2090 // in the peel block. This step will clone the left | |
2091 // shift into the exit block and sink the left shift | |
2092 // from the peel to the not-peel section. | |
2093 // Step 3: clone the loop, retarget the control, and insert | |
2094 // phis for values that are live across the new loop | |
2095 // head. This is very dependent on the graph structure | |
2096 // from clone_loop. It creates region nodes for | |
2097 // exit control and associated phi nodes for values | |
2098 // flow out of the loop through that exit. The region | |
2099 // node is dominated by the clone's control projection. | |
2100 // So the clone's peel section is placed before the | |
2101 // new loop head, and the clone's not-peel section is | |
2102 // forms the top part of the new loop. The original | |
2103 // peel section forms the tail of the new loop. | |
2104 // Step 4: update the dominator tree and recompute the | |
2105 // dominator depth. | |
2106 // | |
2107 // orig | |
2108 // | |
2109 // stmt1 | |
2110 // | | |
2111 // v | |
2112 // loop<----+ | |
2113 // | | | |
2114 // stmt2 | | |
2115 // | | | |
2116 // v | | |
2117 // ifA | | |
2118 // / | | | |
2119 // v v | | |
2120 // false true ^ <-- last_peel | |
2121 // / | | | |
2122 // / ===|==cut | | |
2123 // / stmt3 | <-- first_not_peel | |
2124 // / | | | |
2125 // | v | | |
2126 // v ifB | | |
2127 // exitA: / \ | | |
2128 // / \ | | |
2129 // v v | | |
2130 // false true | | |
2131 // / \ | | |
2132 // / ----+ | |
2133 // | | |
2134 // v | |
2135 // exitB: | |
2136 // stmt4 | |
2137 // | |
2138 // | |
2139 // after clone loop | |
2140 // | |
2141 // stmt1 | |
2142 // / \ | |
2143 // clone / \ orig | |
2144 // / \ | |
2145 // / \ | |
2146 // v v | |
2147 // +---->loop loop<----+ | |
2148 // | | | | | |
2149 // | stmt2 stmt2 | | |
2150 // | | | | | |
2151 // | v v | | |
2152 // | ifA ifA | | |
2153 // | | \ / | | | |
2154 // | v v v v | | |
2155 // ^ true false false true ^ <-- last_peel | |
2156 // | | ^ \ / | | | |
2157 // | cut==|== \ \ / ===|==cut | | |
2158 // | stmt3 \ \ / stmt3 | <-- first_not_peel | |
2159 // | | dom | | | | | |
2160 // | v \ 1v v2 v | | |
2161 // | ifB regionA ifB | | |
2162 // | / \ | / \ | | |
2163 // | / \ v / \ | | |
2164 // | v v exitA: v v | | |
2165 // | true false false true | | |
2166 // | / ^ \ / \ | | |
2167 // +---- \ \ / ----+ | |
2168 // dom \ / | |
2169 // \ 1v v2 | |
2170 // regionB | |
2171 // | | |
2172 // v | |
2173 // exitB: | |
2174 // stmt4 | |
2175 // | |
2176 // | |
2177 // after partial peel | |
2178 // | |
2179 // stmt1 | |
2180 // / | |
2181 // clone / orig | |
2182 // / TOP | |
2183 // / \ | |
2184 // v v | |
2185 // TOP->region region----+ | |
2186 // | | | | |
2187 // stmt2 stmt2 | | |
2188 // | | | | |
2189 // v v | | |
2190 // ifA ifA | | |
2191 // | \ / | | | |
2192 // v v v v | | |
2193 // true false false true | <-- last_peel | |
2194 // | ^ \ / +------|---+ | |
2195 // +->newloop \ \ / === ==cut | | | |
2196 // | stmt3 \ \ / TOP | | | |
2197 // | | dom | | stmt3 | | <-- first_not_peel | |
2198 // | v \ 1v v2 v | | | |
2199 // | ifB regionA ifB ^ v | |
2200 // | / \ | / \ | | | |
2201 // | / \ v / \ | | | |
2202 // | v v exitA: v v | | | |
2203 // | true false false true | | | |
2204 // | / ^ \ / \ | | | |
2205 // | | \ \ / v | | | |
2206 // | | dom \ / TOP | | | |
2207 // | | \ 1v v2 | | | |
2208 // ^ v regionB | | | |
2209 // | | | | | | |
2210 // | | v ^ v | |
2211 // | | exitB: | | | |
2212 // | | stmt4 | | | |
2213 // | +------------>-----------------+ | | |
2214 // | | | |
2215 // +-----------------<---------------------+ | |
2216 // | |
2217 // | |
2218 // final graph | |
2219 // | |
2220 // stmt1 | |
2221 // | | |
2222 // v | |
2223 // ........> ifA clone | |
2224 // : / | | |
2225 // dom / | | |
2226 // : v v | |
2227 // : false true | |
2228 // : | | | |
2229 // : | stmt2 clone | |
2230 // : | | | |
2231 // : | v | |
2232 // : | newloop<-----+ | |
2233 // : | | | | |
2234 // : | stmt3 clone | | |
2235 // : | | | | |
2236 // : | v | | |
2237 // : | ifB | | |
2238 // : | / \ | | |
2239 // : | v v | | |
2240 // : | false true | | |
2241 // : | | | | | |
2242 // : | v stmt2 | | |
2243 // : | exitB: | | | |
2244 // : | stmt4 v | | |
2245 // : | ifA orig | | |
2246 // : | / \ | | |
2247 // : | / \ | | |
2248 // : | v v | | |
2249 // : | false true | | |
2250 // : | / \ | | |
2251 // : v v -----+ | |
2252 // RegionA | |
2253 // | | |
2254 // v | |
2255 // exitA | |
2256 // | |
2257 bool PhaseIdealLoop::partial_peel( IdealLoopTree *loop, Node_List &old_new ) { | |
2258 | |
108 | 2259 if (!loop->_head->is_Loop()) { |
2260 return false; } | |
2261 | |
0 | 2262 LoopNode *head = loop->_head->as_Loop(); |
2263 | |
2264 if (head->is_partial_peel_loop() || head->partial_peel_has_failed()) { | |
2265 return false; | |
2266 } | |
2267 | |
2268 // Check for complex exit control | |
2269 for(uint ii = 0; ii < loop->_body.size(); ii++ ) { | |
2270 Node *n = loop->_body.at(ii); | |
2271 int opc = n->Opcode(); | |
2272 if (n->is_Call() || | |
2273 opc == Op_Catch || | |
2274 opc == Op_CatchProj || | |
2275 opc == Op_Jump || | |
2276 opc == Op_JumpProj) { | |
2277 #if !defined(PRODUCT) | |
2278 if (TracePartialPeeling) { | |
2279 tty->print_cr("\nExit control too complex: lp: %d", head->_idx); | |
2280 } | |
2281 #endif | |
2282 return false; | |
2283 } | |
2284 } | |
2285 | |
2286 int dd = dom_depth(head); | |
2287 | |
2288 // Step 1: find cut point | |
2289 | |
2290 // Walk up dominators to loop head looking for first loop exit | |
2291 // which is executed on every path thru loop. | |
2292 IfNode *peel_if = NULL; | |
2293 IfNode *peel_if_cmpu = NULL; | |
2294 | |
2295 Node *iff = loop->tail(); | |
2296 while( iff != head ) { | |
2297 if( iff->is_If() ) { | |
2298 Node *ctrl = get_ctrl(iff->in(1)); | |
2299 if (ctrl->is_top()) return false; // Dead test on live IF. | |
2300 // If loop-varying exit-test, check for induction variable | |
2301 if( loop->is_member(get_loop(ctrl)) && | |
2302 loop->is_loop_exit(iff) && | |
2303 is_possible_iv_test(iff)) { | |
2304 Node* cmp = iff->in(1)->in(1); | |
2305 if (cmp->Opcode() == Op_CmpI) { | |
2306 peel_if = iff->as_If(); | |
2307 } else { | |
2308 assert(cmp->Opcode() == Op_CmpU, "must be CmpI or CmpU"); | |
2309 peel_if_cmpu = iff->as_If(); | |
2310 } | |
2311 } | |
2312 } | |
2313 iff = idom(iff); | |
2314 } | |
2315 // Prefer signed compare over unsigned compare. | |
2316 IfNode* new_peel_if = NULL; | |
2317 if (peel_if == NULL) { | |
2318 if (!PartialPeelAtUnsignedTests || peel_if_cmpu == NULL) { | |
2319 return false; // No peel point found | |
2320 } | |
2321 new_peel_if = insert_cmpi_loop_exit(peel_if_cmpu, loop); | |
2322 if (new_peel_if == NULL) { | |
2323 return false; // No peel point found | |
2324 } | |
2325 peel_if = new_peel_if; | |
2326 } | |
2327 Node* last_peel = stay_in_loop(peel_if, loop); | |
2328 Node* first_not_peeled = stay_in_loop(last_peel, loop); | |
2329 if (first_not_peeled == NULL || first_not_peeled == head) { | |
2330 return false; | |
2331 } | |
2332 | |
2333 #if !defined(PRODUCT) | |
2334 if (TracePartialPeeling) { | |
2335 tty->print_cr("before partial peel one iteration"); | |
2336 Node_List wl; | |
2337 Node* t = head->in(2); | |
2338 while (true) { | |
2339 wl.push(t); | |
2340 if (t == head) break; | |
2341 t = idom(t); | |
2342 } | |
2343 while (wl.size() > 0) { | |
2344 Node* tt = wl.pop(); | |
2345 tt->dump(); | |
2346 if (tt == last_peel) tty->print_cr("-- cut --"); | |
2347 } | |
2348 } | |
2349 #endif | |
2350 ResourceArea *area = Thread::current()->resource_area(); | |
2351 VectorSet peel(area); | |
2352 VectorSet not_peel(area); | |
2353 Node_List peel_list(area); | |
2354 Node_List worklist(area); | |
2355 Node_List sink_list(area); | |
2356 | |
2357 // Set of cfg nodes to peel are those that are executable from | |
2358 // the head through last_peel. | |
2359 assert(worklist.size() == 0, "should be empty"); | |
2360 worklist.push(head); | |
2361 peel.set(head->_idx); | |
2362 while (worklist.size() > 0) { | |
2363 Node *n = worklist.pop(); | |
2364 if (n != last_peel) { | |
2365 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
2366 Node* use = n->fast_out(j); | |
2367 if (use->is_CFG() && | |
2368 loop->is_member(get_loop(use)) && | |
2369 !peel.test_set(use->_idx)) { | |
2370 worklist.push(use); | |
2371 } | |
2372 } | |
2373 } | |
2374 } | |
2375 | |
2376 // Set of non-cfg nodes to peel are those that are control | |
2377 // dependent on the cfg nodes. | |
2378 uint i; | |
2379 for(i = 0; i < loop->_body.size(); i++ ) { | |
2380 Node *n = loop->_body.at(i); | |
2381 Node *n_c = has_ctrl(n) ? get_ctrl(n) : n; | |
2382 if (peel.test(n_c->_idx)) { | |
2383 peel.set(n->_idx); | |
2384 } else { | |
2385 not_peel.set(n->_idx); | |
2386 } | |
2387 } | |
2388 | |
2389 // Step 2: move operations from the peeled section down into the | |
2390 // not-peeled section | |
2391 | |
2392 // Get a post order schedule of nodes in the peel region | |
2393 // Result in right-most operand. | |
2394 scheduled_nodelist(loop, peel, peel_list ); | |
2395 | |
2396 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); | |
2397 | |
2398 // For future check for too many new phis | |
2399 uint old_phi_cnt = 0; | |
2400 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) { | |
2401 Node* use = head->fast_out(j); | |
2402 if (use->is_Phi()) old_phi_cnt++; | |
2403 } | |
2404 | |
2405 #if !defined(PRODUCT) | |
2406 if (TracePartialPeeling) { | |
2407 tty->print_cr("\npeeled list"); | |
2408 } | |
2409 #endif | |
2410 | |
2411 // Evacuate nodes in peel region into the not_peeled region if possible | |
2412 uint new_phi_cnt = 0; | |
2413 for (i = 0; i < peel_list.size();) { | |
2414 Node* n = peel_list.at(i); | |
2415 #if !defined(PRODUCT) | |
2416 if (TracePartialPeeling) n->dump(); | |
2417 #endif | |
2418 bool incr = true; | |
2419 if ( !n->is_CFG() ) { | |
2420 | |
2421 if ( has_use_in_set(n, not_peel) ) { | |
2422 | |
2423 // If not used internal to the peeled region, | |
2424 // move "n" from peeled to not_peeled region. | |
2425 | |
2426 if ( !has_use_internal_to_set(n, peel, loop) ) { | |
2427 | |
2428 // if not pinned and not a load (which maybe anti-dependent on a store) | |
2429 // and not a CMove (Matcher expects only bool->cmove). | |
2430 if ( n->in(0) == NULL && !n->is_Load() && !n->is_CMove() ) { | |
2431 clone_for_use_outside_loop( loop, n, worklist ); | |
2432 | |
2433 sink_list.push(n); | |
2434 peel >>= n->_idx; // delete n from peel set. | |
2435 not_peel <<= n->_idx; // add n to not_peel set. | |
2436 peel_list.remove(i); | |
2437 incr = false; | |
2438 #if !defined(PRODUCT) | |
2439 if (TracePartialPeeling) { | |
2440 tty->print_cr("sink to not_peeled region: %d newbb: %d", | |
2441 n->_idx, get_ctrl(n)->_idx); | |
2442 } | |
2443 #endif | |
2444 } | |
2445 } else { | |
2446 // Otherwise check for special def-use cases that span | |
2447 // the peel/not_peel boundary such as bool->if | |
2448 clone_for_special_use_inside_loop( loop, n, not_peel, sink_list, worklist ); | |
2449 new_phi_cnt++; | |
2450 } | |
2451 } | |
2452 } | |
2453 if (incr) i++; | |
2454 } | |
2455 | |
2456 if (new_phi_cnt > old_phi_cnt + PartialPeelNewPhiDelta) { | |
2457 #if !defined(PRODUCT) | |
2458 if (TracePartialPeeling) { | |
2459 tty->print_cr("\nToo many new phis: %d old %d new cmpi: %c", | |
2460 new_phi_cnt, old_phi_cnt, new_peel_if != NULL?'T':'F'); | |
2461 } | |
2462 #endif | |
2463 if (new_peel_if != NULL) { | |
2464 remove_cmpi_loop_exit(new_peel_if, loop); | |
2465 } | |
2466 // Inhibit more partial peeling on this loop | |
2467 assert(!head->is_partial_peel_loop(), "not partial peeled"); | |
2468 head->mark_partial_peel_failed(); | |
2469 return false; | |
2470 } | |
2471 | |
2472 // Step 3: clone loop, retarget control, and insert new phis | |
2473 | |
2474 // Create new loop head for new phis and to hang | |
2475 // the nodes being moved (sinked) from the peel region. | |
2476 LoopNode* new_head = new (C, 3) LoopNode(last_peel, last_peel); | |
2477 _igvn.register_new_node_with_optimizer(new_head); | |
2478 assert(first_not_peeled->in(0) == last_peel, "last_peel <- first_not_peeled"); | |
2479 first_not_peeled->set_req(0, new_head); | |
2480 set_loop(new_head, loop); | |
2481 loop->_body.push(new_head); | |
2482 not_peel.set(new_head->_idx); | |
2483 set_idom(new_head, last_peel, dom_depth(first_not_peeled)); | |
2484 set_idom(first_not_peeled, new_head, dom_depth(first_not_peeled)); | |
2485 | |
2486 while (sink_list.size() > 0) { | |
2487 Node* n = sink_list.pop(); | |
2488 set_ctrl(n, new_head); | |
2489 } | |
2490 | |
2491 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); | |
2492 | |
2493 clone_loop( loop, old_new, dd ); | |
2494 | |
2495 const uint clone_exit_idx = 1; | |
2496 const uint orig_exit_idx = 2; | |
2497 assert(is_valid_clone_loop_form( loop, peel_list, orig_exit_idx, clone_exit_idx ), "bad clone loop"); | |
2498 | |
2499 Node* head_clone = old_new[head->_idx]; | |
2500 LoopNode* new_head_clone = old_new[new_head->_idx]->as_Loop(); | |
2501 Node* orig_tail_clone = head_clone->in(2); | |
2502 | |
2503 // Add phi if "def" node is in peel set and "use" is not | |
2504 | |
2505 for(i = 0; i < peel_list.size(); i++ ) { | |
2506 Node *def = peel_list.at(i); | |
2507 if (!def->is_CFG()) { | |
2508 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { | |
2509 Node *use = def->fast_out(j); | |
2510 if (has_node(use) && use->in(0) != C->top() && | |
2511 (!peel.test(use->_idx) || | |
2512 (use->is_Phi() && use->in(0) == head)) ) { | |
2513 worklist.push(use); | |
2514 } | |
2515 } | |
2516 while( worklist.size() ) { | |
2517 Node *use = worklist.pop(); | |
2518 for (uint j = 1; j < use->req(); j++) { | |
2519 Node* n = use->in(j); | |
2520 if (n == def) { | |
2521 | |
2522 // "def" is in peel set, "use" is not in peel set | |
2523 // or "use" is in the entry boundary (a phi) of the peel set | |
2524 | |
2525 Node* use_c = has_ctrl(use) ? get_ctrl(use) : use; | |
2526 | |
2527 if ( loop->is_member(get_loop( use_c )) ) { | |
2528 // use is in loop | |
2529 if (old_new[use->_idx] != NULL) { // null for dead code | |
2530 Node* use_clone = old_new[use->_idx]; | |
2531 _igvn.hash_delete(use); | |
2532 use->set_req(j, C->top()); | |
2533 _igvn._worklist.push(use); | |
2534 insert_phi_for_loop( use_clone, j, old_new[def->_idx], def, new_head_clone ); | |
2535 } | |
2536 } else { | |
2537 assert(is_valid_clone_loop_exit_use(loop, use, orig_exit_idx), "clone loop format"); | |
2538 // use is not in the loop, check if the live range includes the cut | |
2539 Node* lp_if = use_c->in(orig_exit_idx)->in(0); | |
2540 if (not_peel.test(lp_if->_idx)) { | |
2541 assert(j == orig_exit_idx, "use from original loop"); | |
2542 insert_phi_for_loop( use, clone_exit_idx, old_new[def->_idx], def, new_head_clone ); | |
2543 } | |
2544 } | |
2545 } | |
2546 } | |
2547 } | |
2548 } | |
2549 } | |
2550 | |
2551 // Step 3b: retarget control | |
2552 | |
2553 // Redirect control to the new loop head if a cloned node in | |
2554 // the not_peeled region has control that points into the peeled region. | |
2555 // This necessary because the cloned peeled region will be outside | |
2556 // the loop. | |
2557 // from to | |
2558 // cloned-peeled <---+ | |
2559 // new_head_clone: | <--+ | |
2560 // cloned-not_peeled in(0) in(0) | |
2561 // orig-peeled | |
2562 | |
2563 for(i = 0; i < loop->_body.size(); i++ ) { | |
2564 Node *n = loop->_body.at(i); | |
2565 if (!n->is_CFG() && n->in(0) != NULL && | |
2566 not_peel.test(n->_idx) && peel.test(n->in(0)->_idx)) { | |
2567 Node* n_clone = old_new[n->_idx]; | |
2568 _igvn.hash_delete(n_clone); | |
2569 n_clone->set_req(0, new_head_clone); | |
2570 _igvn._worklist.push(n_clone); | |
2571 } | |
2572 } | |
2573 | |
2574 // Backedge of the surviving new_head (the clone) is original last_peel | |
2575 _igvn.hash_delete(new_head_clone); | |
2576 new_head_clone->set_req(LoopNode::LoopBackControl, last_peel); | |
2577 _igvn._worklist.push(new_head_clone); | |
2578 | |
2579 // Cut first node in original not_peel set | |
2580 _igvn.hash_delete(new_head); | |
2581 new_head->set_req(LoopNode::EntryControl, C->top()); | |
2582 new_head->set_req(LoopNode::LoopBackControl, C->top()); | |
2583 _igvn._worklist.push(new_head); | |
2584 | |
2585 // Copy head_clone back-branch info to original head | |
2586 // and remove original head's loop entry and | |
2587 // clone head's back-branch | |
2588 _igvn.hash_delete(head); | |
2589 _igvn.hash_delete(head_clone); | |
2590 head->set_req(LoopNode::EntryControl, head_clone->in(LoopNode::LoopBackControl)); | |
2591 head->set_req(LoopNode::LoopBackControl, C->top()); | |
2592 head_clone->set_req(LoopNode::LoopBackControl, C->top()); | |
2593 _igvn._worklist.push(head); | |
2594 _igvn._worklist.push(head_clone); | |
2595 | |
2596 // Similarly modify the phis | |
2597 for (DUIterator_Fast kmax, k = head->fast_outs(kmax); k < kmax; k++) { | |
2598 Node* use = head->fast_out(k); | |
2599 if (use->is_Phi() && use->outcnt() > 0) { | |
2600 Node* use_clone = old_new[use->_idx]; | |
2601 _igvn.hash_delete(use); | |
2602 _igvn.hash_delete(use_clone); | |
2603 use->set_req(LoopNode::EntryControl, use_clone->in(LoopNode::LoopBackControl)); | |
2604 use->set_req(LoopNode::LoopBackControl, C->top()); | |
2605 use_clone->set_req(LoopNode::LoopBackControl, C->top()); | |
2606 _igvn._worklist.push(use); | |
2607 _igvn._worklist.push(use_clone); | |
2608 } | |
2609 } | |
2610 | |
2611 // Step 4: update dominator tree and dominator depth | |
2612 | |
2613 set_idom(head, orig_tail_clone, dd); | |
2614 recompute_dom_depth(); | |
2615 | |
2616 // Inhibit more partial peeling on this loop | |
2617 new_head_clone->set_partial_peel_loop(); | |
2618 C->set_major_progress(); | |
2619 | |
2620 #if !defined(PRODUCT) | |
2621 if (TracePartialPeeling) { | |
2622 tty->print_cr("\nafter partial peel one iteration"); | |
2623 Node_List wl(area); | |
2624 Node* t = last_peel; | |
2625 while (true) { | |
2626 wl.push(t); | |
2627 if (t == head_clone) break; | |
2628 t = idom(t); | |
2629 } | |
2630 while (wl.size() > 0) { | |
2631 Node* tt = wl.pop(); | |
2632 if (tt == head) tty->print_cr("orig head"); | |
2633 else if (tt == new_head_clone) tty->print_cr("new head"); | |
2634 else if (tt == head_clone) tty->print_cr("clone head"); | |
2635 tt->dump(); | |
2636 } | |
2637 } | |
2638 #endif | |
2639 return true; | |
2640 } | |
2641 | |
2642 //------------------------------reorg_offsets---------------------------------- | |
2643 // Reorganize offset computations to lower register pressure. Mostly | |
2644 // prevent loop-fallout uses of the pre-incremented trip counter (which are | |
2645 // then alive with the post-incremented trip counter forcing an extra | |
2646 // register move) | |
2647 void PhaseIdealLoop::reorg_offsets( IdealLoopTree *loop ) { | |
2648 | |
2649 CountedLoopNode *cl = loop->_head->as_CountedLoop(); | |
2650 CountedLoopEndNode *cle = cl->loopexit(); | |
2651 if( !cle ) return; // The occasional dead loop | |
2652 // Find loop exit control | |
2653 Node *exit = cle->proj_out(false); | |
2654 assert( exit->Opcode() == Op_IfFalse, "" ); | |
2655 | |
2656 // Check for the special case of folks using the pre-incremented | |
2657 // trip-counter on the fall-out path (forces the pre-incremented | |
2658 // and post-incremented trip counter to be live at the same time). | |
2659 // Fix this by adjusting to use the post-increment trip counter. | |
2660 Node *phi = cl->phi(); | |
2661 if( !phi ) return; // Dead infinite loop | |
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2662 |
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2663 // Shape messed up, probably by iteration_split_impl |
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2664 if (phi->in(LoopNode::LoopBackControl) != cl->incr()) return; |
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2665 |
0 | 2666 bool progress = true; |
2667 while (progress) { | |
2668 progress = false; | |
2669 for (DUIterator_Fast imax, i = phi->fast_outs(imax); i < imax; i++) { | |
2670 Node* use = phi->fast_out(i); // User of trip-counter | |
2671 if (!has_ctrl(use)) continue; | |
2672 Node *u_ctrl = get_ctrl(use); | |
2673 if( use->is_Phi() ) { | |
2674 u_ctrl = NULL; | |
2675 for( uint j = 1; j < use->req(); j++ ) | |
2676 if( use->in(j) == phi ) | |
2677 u_ctrl = dom_lca( u_ctrl, use->in(0)->in(j) ); | |
2678 } | |
2679 IdealLoopTree *u_loop = get_loop(u_ctrl); | |
2680 // Look for loop-invariant use | |
2681 if( u_loop == loop ) continue; | |
2682 if( loop->is_member( u_loop ) ) continue; | |
2683 // Check that use is live out the bottom. Assuming the trip-counter | |
2684 // update is right at the bottom, uses of of the loop middle are ok. | |
2685 if( dom_lca( exit, u_ctrl ) != exit ) continue; | |
2686 // protect against stride not being a constant | |
2687 if( !cle->stride_is_con() ) continue; | |
2688 // Hit! Refactor use to use the post-incremented tripcounter. | |
2689 // Compute a post-increment tripcounter. | |
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2690 Node *opaq = new (C, 2) Opaque2Node( C, cle->incr() ); |
0 | 2691 register_new_node( opaq, u_ctrl ); |
2692 Node *neg_stride = _igvn.intcon(-cle->stride_con()); | |
2693 set_ctrl(neg_stride, C->root()); | |
2694 Node *post = new (C, 3) AddINode( opaq, neg_stride); | |
2695 register_new_node( post, u_ctrl ); | |
2696 _igvn.hash_delete(use); | |
2697 _igvn._worklist.push(use); | |
2698 for( uint j = 1; j < use->req(); j++ ) | |
2699 if( use->in(j) == phi ) | |
2700 use->set_req(j, post); | |
2701 // Since DU info changed, rerun loop | |
2702 progress = true; | |
2703 break; | |
2704 } | |
2705 } | |
2706 | |
2707 } |