Mercurial > hg > truffle
annotate src/share/vm/opto/loopopts.cpp @ 39:76256d272075
6667612: (Escape Analysis) disable loop cloning if it has a scalar replaceable allocation
Summary: Cloning an allocation will not allow scalar replacement since memory operations could not be associated with one allocation.
Reviewed-by: rasbold
author | kvn |
---|---|
date | Thu, 06 Mar 2008 10:53:33 -0800 |
parents | e2ae28d2ce91 |
children | b8f5ba577b02 |
rev | line source |
---|---|
0 | 1 /* |
2 * Copyright 1999-2006 Sun Microsystems, Inc. All Rights Reserved. | |
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
6 * under the terms of the GNU General Public License version 2 only, as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
14 * | |
15 * You should have received a copy of the GNU General Public License version | |
16 * 2 along with this work; if not, write to the Free Software Foundation, | |
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 * | |
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
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 ) { | |
32 int wins = 0; | |
33 assert( !n->is_CFG(), "" ); | |
34 assert( region->is_Region(), "" ); | |
35 Node *phi = new (C, region->req()) PhiNode( region, n->bottom_type() ); | |
36 uint old_unique = C->unique(); | |
37 for( uint i = 1; i < region->req(); i++ ) { | |
38 Node *x; | |
39 Node* the_clone = NULL; | |
40 if( region->in(i) == C->top() ) { | |
41 x = C->top(); // Dead path? Use a dead data op | |
42 } else { | |
43 x = n->clone(); // Else clone up the data op | |
44 the_clone = x; // Remember for possible deletion. | |
45 // Alter data node to use pre-phi inputs | |
46 if( n->in(0) == region ) | |
47 x->set_req( 0, region->in(i) ); | |
48 for( uint j = 1; j < n->req(); j++ ) { | |
49 Node *in = n->in(j); | |
50 if( in->is_Phi() && in->in(0) == region ) | |
51 x->set_req( j, in->in(i) ); // Use pre-Phi input for the clone | |
52 } | |
53 } | |
54 // Check for a 'win' on some paths | |
55 const Type *t = x->Value(&_igvn); | |
56 | |
57 bool singleton = t->singleton(); | |
58 | |
59 // A TOP singleton indicates that there are no possible values incoming | |
60 // along a particular edge. In most cases, this is OK, and the Phi will | |
61 // be eliminated later in an Ideal call. However, we can't allow this to | |
62 // happen if the singleton occurs on loop entry, as the elimination of | |
63 // the PhiNode may cause the resulting node to migrate back to a previous | |
64 // loop iteration. | |
65 if( singleton && t == Type::TOP ) { | |
66 // Is_Loop() == false does not confirm the absence of a loop (e.g., an | |
67 // irreducible loop may not be indicated by an affirmative is_Loop()); | |
68 // therefore, the only top we can split thru a phi is on a backedge of | |
69 // a loop. | |
70 singleton &= region->is_Loop() && (i != LoopNode::EntryControl); | |
71 } | |
72 | |
73 if( singleton ) { | |
74 wins++; | |
75 x = ((PhaseGVN&)_igvn).makecon(t); | |
76 } else { | |
77 // We now call Identity to try to simplify the cloned node. | |
78 // Note that some Identity methods call phase->type(this). | |
79 // Make sure that the type array is big enough for | |
80 // our new node, even though we may throw the node away. | |
81 // (Note: This tweaking with igvn only works because x is a new node.) | |
82 _igvn.set_type(x, t); | |
83 Node *y = x->Identity(&_igvn); | |
84 if( y != x ) { | |
85 wins++; | |
86 x = y; | |
87 } else { | |
88 y = _igvn.hash_find(x); | |
89 if( y ) { | |
90 wins++; | |
91 x = y; | |
92 } else { | |
93 // Else x is a new node we are keeping | |
94 // We do not need register_new_node_with_optimizer | |
95 // because set_type has already been called. | |
96 _igvn._worklist.push(x); | |
97 } | |
98 } | |
99 } | |
100 if (x != the_clone && the_clone != NULL) | |
101 _igvn.remove_dead_node(the_clone); | |
102 phi->set_req( i, x ); | |
103 } | |
104 // Too few wins? | |
105 if( wins <= policy ) { | |
106 _igvn.remove_dead_node(phi); | |
107 return NULL; | |
108 } | |
109 | |
110 // Record Phi | |
111 register_new_node( phi, region ); | |
112 | |
113 for( uint i2 = 1; i2 < phi->req(); i2++ ) { | |
114 Node *x = phi->in(i2); | |
115 // If we commoned up the cloned 'x' with another existing Node, | |
116 // the existing Node picks up a new use. We need to make the | |
117 // existing Node occur higher up so it dominates its uses. | |
118 Node *old_ctrl; | |
119 IdealLoopTree *old_loop; | |
120 | |
121 // The occasional new node | |
122 if( x->_idx >= old_unique ) { // Found a new, unplaced node? | |
123 old_ctrl = x->is_Con() ? C->root() : NULL; | |
124 old_loop = NULL; // Not in any prior loop | |
125 } else { | |
126 old_ctrl = x->is_Con() ? C->root() : get_ctrl(x); | |
127 old_loop = get_loop(old_ctrl); // Get prior loop | |
128 } | |
129 // New late point must dominate new use | |
130 Node *new_ctrl = dom_lca( old_ctrl, region->in(i2) ); | |
131 // Set new location | |
132 set_ctrl(x, new_ctrl); | |
133 IdealLoopTree *new_loop = get_loop( new_ctrl ); | |
134 // If changing loop bodies, see if we need to collect into new body | |
135 if( old_loop != new_loop ) { | |
136 if( old_loop && !old_loop->_child ) | |
137 old_loop->_body.yank(x); | |
138 if( !new_loop->_child ) | |
139 new_loop->_body.push(x); // Collect body info | |
140 } | |
141 } | |
142 | |
143 return phi; | |
144 } | |
145 | |
146 //------------------------------dominated_by------------------------------------ | |
147 // Replace the dominated test with an obvious true or false. Place it on the | |
148 // IGVN worklist for later cleanup. Move control-dependent data Nodes on the | |
149 // live path up to the dominating control. | |
150 void PhaseIdealLoop::dominated_by( Node *prevdom, Node *iff ) { | |
151 #ifndef PRODUCT | |
152 if( VerifyLoopOptimizations && PrintOpto ) tty->print_cr("dominating test"); | |
153 #endif | |
154 | |
155 | |
156 // prevdom is the dominating projection of the dominating test. | |
157 assert( iff->is_If(), "" ); | |
158 assert( iff->Opcode() == Op_If || iff->Opcode() == Op_CountedLoopEnd, "Check this code when new subtype is added"); | |
159 int pop = prevdom->Opcode(); | |
160 assert( pop == Op_IfFalse || pop == Op_IfTrue, "" ); | |
161 // 'con' is set to true or false to kill the dominated test. | |
162 Node *con = _igvn.makecon(pop == Op_IfTrue ? TypeInt::ONE : TypeInt::ZERO); | |
163 set_ctrl(con, C->root()); // Constant gets a new use | |
164 // Hack the dominated test | |
165 _igvn.hash_delete(iff); | |
166 iff->set_req(1, con); | |
167 _igvn._worklist.push(iff); | |
168 | |
169 // If I dont have a reachable TRUE and FALSE path following the IfNode then | |
170 // I can assume this path reaches an infinite loop. In this case it's not | |
171 // important to optimize the data Nodes - either the whole compilation will | |
172 // be tossed or this path (and all data Nodes) will go dead. | |
173 if( iff->outcnt() != 2 ) return; | |
174 | |
175 // Make control-dependent data Nodes on the live path (path that will remain | |
176 // once the dominated IF is removed) become control-dependent on the | |
177 // dominating projection. | |
178 Node* dp = ((IfNode*)iff)->proj_out(pop == Op_IfTrue); | |
179 IdealLoopTree *old_loop = get_loop(dp); | |
180 | |
181 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) { | |
182 Node* cd = dp->fast_out(i); // Control-dependent node | |
183 if( cd->depends_only_on_test() ) { | |
184 assert( cd->in(0) == dp, "" ); | |
185 _igvn.hash_delete( cd ); | |
186 cd->set_req(0, prevdom); | |
187 set_early_ctrl( cd ); | |
188 _igvn._worklist.push(cd); | |
189 IdealLoopTree *new_loop = get_loop(get_ctrl(cd)); | |
190 if( old_loop != new_loop ) { | |
191 if( !old_loop->_child ) old_loop->_body.yank(cd); | |
192 if( !new_loop->_child ) new_loop->_body.push(cd); | |
193 } | |
194 --i; | |
195 --imax; | |
196 } | |
197 } | |
198 } | |
199 | |
200 //------------------------------has_local_phi_input---------------------------- | |
201 // Return TRUE if 'n' has Phi inputs from its local block and no other | |
202 // block-local inputs (all non-local-phi inputs come from earlier blocks) | |
203 Node *PhaseIdealLoop::has_local_phi_input( Node *n ) { | |
204 Node *n_ctrl = get_ctrl(n); | |
205 // See if some inputs come from a Phi in this block, or from before | |
206 // this block. | |
207 uint i; | |
208 for( i = 1; i < n->req(); i++ ) { | |
209 Node *phi = n->in(i); | |
210 if( phi->is_Phi() && phi->in(0) == n_ctrl ) | |
211 break; | |
212 } | |
213 if( i >= n->req() ) | |
214 return NULL; // No Phi inputs; nowhere to clone thru | |
215 | |
216 // Check for inputs created between 'n' and the Phi input. These | |
217 // must split as well; they have already been given the chance | |
218 // (courtesy of a post-order visit) and since they did not we must | |
219 // recover the 'cost' of splitting them by being very profitable | |
220 // when splitting 'n'. Since this is unlikely we simply give up. | |
221 for( i = 1; i < n->req(); i++ ) { | |
222 Node *m = n->in(i); | |
223 if( get_ctrl(m) == n_ctrl && !m->is_Phi() ) { | |
224 // We allow the special case of AddP's with no local inputs. | |
225 // This allows us to split-up address expressions. | |
226 if (m->is_AddP() && | |
227 get_ctrl(m->in(2)) != n_ctrl && | |
228 get_ctrl(m->in(3)) != n_ctrl) { | |
229 // Move the AddP up to dominating point | |
230 set_ctrl_and_loop(m, find_non_split_ctrl(idom(n_ctrl))); | |
231 continue; | |
232 } | |
233 return NULL; | |
234 } | |
235 } | |
236 | |
237 return n_ctrl; | |
238 } | |
239 | |
240 //------------------------------remix_address_expressions---------------------- | |
241 // Rework addressing expressions to get the most loop-invariant stuff | |
242 // moved out. We'd like to do all associative operators, but it's especially | |
243 // important (common) to do address expressions. | |
244 Node *PhaseIdealLoop::remix_address_expressions( Node *n ) { | |
245 if (!has_ctrl(n)) return NULL; | |
246 Node *n_ctrl = get_ctrl(n); | |
247 IdealLoopTree *n_loop = get_loop(n_ctrl); | |
248 | |
249 // See if 'n' mixes loop-varying and loop-invariant inputs and | |
250 // itself is loop-varying. | |
251 | |
252 // Only interested in binary ops (and AddP) | |
253 if( n->req() < 3 || n->req() > 4 ) return NULL; | |
254 | |
255 Node *n1_ctrl = get_ctrl(n->in( 1)); | |
256 Node *n2_ctrl = get_ctrl(n->in( 2)); | |
257 Node *n3_ctrl = get_ctrl(n->in(n->req() == 3 ? 2 : 3)); | |
258 IdealLoopTree *n1_loop = get_loop( n1_ctrl ); | |
259 IdealLoopTree *n2_loop = get_loop( n2_ctrl ); | |
260 IdealLoopTree *n3_loop = get_loop( n3_ctrl ); | |
261 | |
262 // Does one of my inputs spin in a tighter loop than self? | |
263 if( (n_loop->is_member( n1_loop ) && n_loop != n1_loop) || | |
264 (n_loop->is_member( n2_loop ) && n_loop != n2_loop) || | |
265 (n_loop->is_member( n3_loop ) && n_loop != n3_loop) ) | |
266 return NULL; // Leave well enough alone | |
267 | |
268 // Is at least one of my inputs loop-invariant? | |
269 if( n1_loop == n_loop && | |
270 n2_loop == n_loop && | |
271 n3_loop == n_loop ) | |
272 return NULL; // No loop-invariant inputs | |
273 | |
274 | |
275 int n_op = n->Opcode(); | |
276 | |
277 // Replace expressions like ((V+I) << 2) with (V<<2 + I<<2). | |
278 if( n_op == Op_LShiftI ) { | |
279 // Scale is loop invariant | |
280 Node *scale = n->in(2); | |
281 Node *scale_ctrl = get_ctrl(scale); | |
282 IdealLoopTree *scale_loop = get_loop(scale_ctrl ); | |
283 if( n_loop == scale_loop || !scale_loop->is_member( n_loop ) ) | |
284 return NULL; | |
285 const TypeInt *scale_t = scale->bottom_type()->isa_int(); | |
286 if( scale_t && scale_t->is_con() && scale_t->get_con() >= 16 ) | |
287 return NULL; // Dont bother with byte/short masking | |
288 // Add must vary with loop (else shift would be loop-invariant) | |
289 Node *add = n->in(1); | |
290 Node *add_ctrl = get_ctrl(add); | |
291 IdealLoopTree *add_loop = get_loop(add_ctrl); | |
292 //assert( n_loop == add_loop, "" ); | |
293 if( n_loop != add_loop ) return NULL; // happens w/ evil ZKM loops | |
294 | |
295 // Convert I-V into I+ (0-V); same for V-I | |
296 if( add->Opcode() == Op_SubI && | |
297 _igvn.type( add->in(1) ) != TypeInt::ZERO ) { | |
298 Node *zero = _igvn.intcon(0); | |
299 set_ctrl(zero, C->root()); | |
300 Node *neg = new (C, 3) SubINode( _igvn.intcon(0), add->in(2) ); | |
301 register_new_node( neg, get_ctrl(add->in(2) ) ); | |
302 add = new (C, 3) AddINode( add->in(1), neg ); | |
303 register_new_node( add, add_ctrl ); | |
304 } | |
305 if( add->Opcode() != Op_AddI ) return NULL; | |
306 // See if one add input is loop invariant | |
307 Node *add_var = add->in(1); | |
308 Node *add_var_ctrl = get_ctrl(add_var); | |
309 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl ); | |
310 Node *add_invar = add->in(2); | |
311 Node *add_invar_ctrl = get_ctrl(add_invar); | |
312 IdealLoopTree *add_invar_loop = get_loop(add_invar_ctrl ); | |
313 if( add_var_loop == n_loop ) { | |
314 } else if( add_invar_loop == n_loop ) { | |
315 // Swap to find the invariant part | |
316 add_invar = add_var; | |
317 add_invar_ctrl = add_var_ctrl; | |
318 add_invar_loop = add_var_loop; | |
319 add_var = add->in(2); | |
320 Node *add_var_ctrl = get_ctrl(add_var); | |
321 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl ); | |
322 } else // Else neither input is loop invariant | |
323 return NULL; | |
324 if( n_loop == add_invar_loop || !add_invar_loop->is_member( n_loop ) ) | |
325 return NULL; // No invariant part of the add? | |
326 | |
327 // Yes! Reshape address expression! | |
328 Node *inv_scale = new (C, 3) LShiftINode( add_invar, scale ); | |
329 register_new_node( inv_scale, add_invar_ctrl ); | |
330 Node *var_scale = new (C, 3) LShiftINode( add_var, scale ); | |
331 register_new_node( var_scale, n_ctrl ); | |
332 Node *var_add = new (C, 3) AddINode( var_scale, inv_scale ); | |
333 register_new_node( var_add, n_ctrl ); | |
334 _igvn.hash_delete( n ); | |
335 _igvn.subsume_node( n, var_add ); | |
336 return var_add; | |
337 } | |
338 | |
339 // Replace (I+V) with (V+I) | |
340 if( n_op == Op_AddI || | |
341 n_op == Op_AddL || | |
342 n_op == Op_AddF || | |
343 n_op == Op_AddD || | |
344 n_op == Op_MulI || | |
345 n_op == Op_MulL || | |
346 n_op == Op_MulF || | |
347 n_op == Op_MulD ) { | |
348 if( n2_loop == n_loop ) { | |
349 assert( n1_loop != n_loop, "" ); | |
350 n->swap_edges(1, 2); | |
351 } | |
352 } | |
353 | |
354 // Replace ((I1 +p V) +p I2) with ((I1 +p I2) +p V), | |
355 // but not if I2 is a constant. | |
356 if( n_op == Op_AddP ) { | |
357 if( n2_loop == n_loop && n3_loop != n_loop ) { | |
358 if( n->in(2)->Opcode() == Op_AddP && !n->in(3)->is_Con() ) { | |
359 Node *n22_ctrl = get_ctrl(n->in(2)->in(2)); | |
360 Node *n23_ctrl = get_ctrl(n->in(2)->in(3)); | |
361 IdealLoopTree *n22loop = get_loop( n22_ctrl ); | |
362 IdealLoopTree *n23_loop = get_loop( n23_ctrl ); | |
363 if( n22loop != n_loop && n22loop->is_member(n_loop) && | |
364 n23_loop == n_loop ) { | |
365 Node *add1 = new (C, 4) AddPNode( n->in(1), n->in(2)->in(2), n->in(3) ); | |
366 // Stuff new AddP in the loop preheader | |
367 register_new_node( add1, n_loop->_head->in(LoopNode::EntryControl) ); | |
368 Node *add2 = new (C, 4) AddPNode( n->in(1), add1, n->in(2)->in(3) ); | |
369 register_new_node( add2, n_ctrl ); | |
370 _igvn.hash_delete( n ); | |
371 _igvn.subsume_node( n, add2 ); | |
372 return add2; | |
373 } | |
374 } | |
375 } | |
376 | |
377 // Replace (I1 +p (I2 + V)) with ((I1 +p I2) +p V) | |
378 if( n2_loop != n_loop && n3_loop == n_loop ) { | |
379 if( n->in(3)->Opcode() == Op_AddI ) { | |
380 Node *V = n->in(3)->in(1); | |
381 Node *I = n->in(3)->in(2); | |
382 if( is_member(n_loop,get_ctrl(V)) ) { | |
383 } else { | |
384 Node *tmp = V; V = I; I = tmp; | |
385 } | |
386 if( !is_member(n_loop,get_ctrl(I)) ) { | |
387 Node *add1 = new (C, 4) AddPNode( n->in(1), n->in(2), I ); | |
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, V ); | |
391 register_new_node( add2, n_ctrl ); | |
392 _igvn.hash_delete( n ); | |
393 _igvn.subsume_node( n, add2 ); | |
394 return add2; | |
395 } | |
396 } | |
397 } | |
398 } | |
399 | |
400 return NULL; | |
401 } | |
402 | |
403 //------------------------------conditional_move------------------------------- | |
404 // Attempt to replace a Phi with a conditional move. We have some pretty | |
405 // strict profitability requirements. All Phis at the merge point must | |
406 // be converted, so we can remove the control flow. We need to limit the | |
407 // number of c-moves to a small handful. All code that was in the side-arms | |
408 // of the CFG diamond is now speculatively executed. This code has to be | |
409 // "cheap enough". We are pretty much limited to CFG diamonds that merge | |
410 // 1 or 2 items with a total of 1 or 2 ops executed speculatively. | |
411 Node *PhaseIdealLoop::conditional_move( Node *region ) { | |
412 | |
413 assert( region->is_Region(), "sanity check" ); | |
414 if( region->req() != 3 ) return NULL; | |
415 | |
416 // Check for CFG diamond | |
417 Node *lp = region->in(1); | |
418 Node *rp = region->in(2); | |
419 if( !lp || !rp ) return NULL; | |
420 Node *lp_c = lp->in(0); | |
421 if( lp_c == NULL || lp_c != rp->in(0) || !lp_c->is_If() ) return NULL; | |
422 IfNode *iff = lp_c->as_If(); | |
423 | |
424 // Check for highly predictable branch. No point in CMOV'ing if | |
425 // we are going to predict accurately all the time. | |
426 // %%% This hides patterns produced by utility methods like Math.min. | |
427 if( iff->_prob < PROB_UNLIKELY_MAG(3) || | |
428 iff->_prob > PROB_LIKELY_MAG(3) ) | |
429 return NULL; | |
430 | |
431 // Check for ops pinned in an arm of the diamond. | |
432 // Can't remove the control flow in this case | |
433 if( lp->outcnt() > 1 ) return NULL; | |
434 if( rp->outcnt() > 1 ) return NULL; | |
435 | |
436 // Check profitability | |
437 int cost = 0; | |
35
e2ae28d2ce91
6667588: Don't generate duplicated CMP for float/double values
kvn
parents:
0
diff
changeset
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438 int phis = 0; |
0 | 439 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { |
440 Node *out = region->fast_out(i); | |
441 if( !out->is_Phi() ) continue; // Ignore other control edges, etc | |
35
e2ae28d2ce91
6667588: Don't generate duplicated CMP for float/double values
kvn
parents:
0
diff
changeset
|
442 phis++; |
0 | 443 PhiNode* phi = out->as_Phi(); |
444 switch (phi->type()->basic_type()) { | |
445 case T_LONG: | |
446 cost++; // Probably encodes as 2 CMOV's | |
447 case T_INT: // These all CMOV fine | |
448 case T_FLOAT: | |
449 case T_DOUBLE: | |
450 case T_ADDRESS: // (RawPtr) | |
451 cost++; | |
452 break; | |
453 case T_OBJECT: { // Base oops are OK, but not derived oops | |
454 const TypeOopPtr *tp = phi->type()->isa_oopptr(); | |
455 // Derived pointers are Bad (tm): what's the Base (for GC purposes) of a | |
456 // CMOVE'd derived pointer? It's a CMOVE'd derived base. Thus | |
457 // CMOVE'ing a derived pointer requires we also CMOVE the base. If we | |
458 // have a Phi for the base here that we convert to a CMOVE all is well | |
459 // and good. But if the base is dead, we'll not make a CMOVE. Later | |
460 // the allocator will have to produce a base by creating a CMOVE of the | |
461 // relevant bases. This puts the allocator in the business of | |
462 // manufacturing expensive instructions, generally a bad plan. | |
463 // Just Say No to Conditionally-Moved Derived Pointers. | |
464 if( tp && tp->offset() != 0 ) | |
465 return NULL; | |
466 cost++; | |
467 break; | |
468 } | |
469 default: | |
470 return NULL; // In particular, can't do memory or I/O | |
471 } | |
472 // Add in cost any speculative ops | |
473 for( uint j = 1; j < region->req(); j++ ) { | |
474 Node *proj = region->in(j); | |
475 Node *inp = phi->in(j); | |
476 if (get_ctrl(inp) == proj) { // Found local op | |
477 cost++; | |
478 // Check for a chain of dependent ops; these will all become | |
479 // speculative in a CMOV. | |
480 for( uint k = 1; k < inp->req(); k++ ) | |
481 if (get_ctrl(inp->in(k)) == proj) | |
482 return NULL; // Too much speculative goo | |
483 } | |
484 } | |
485 // See if the Phi is used by a Cmp. This will likely Split-If, a | |
486 // higher-payoff operation. | |
487 for (DUIterator_Fast kmax, k = phi->fast_outs(kmax); k < kmax; k++) { | |
488 Node* use = phi->fast_out(k); | |
489 if( use->is_Cmp() ) | |
490 return NULL; | |
491 } | |
492 } | |
493 if( cost >= ConditionalMoveLimit ) return NULL; // Too much goo | |
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494 Node* bol = iff->in(1); |
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495 assert( bol->Opcode() == Op_Bool, "" ); |
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496 int cmp_op = bol->in(1)->Opcode(); |
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497 // It is expensive to generate flags from a float compare. |
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498 // Avoid duplicated float compare. |
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499 if( phis > 1 && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) return NULL; |
0 | 500 |
501 // -------------- | |
502 // Now replace all Phis with CMOV's | |
503 Node *cmov_ctrl = iff->in(0); | |
504 uint flip = (lp->Opcode() == Op_IfTrue); | |
505 while( 1 ) { | |
506 PhiNode* phi = NULL; | |
507 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { | |
508 Node *out = region->fast_out(i); | |
509 if (out->is_Phi()) { | |
510 phi = out->as_Phi(); | |
511 break; | |
512 } | |
513 } | |
514 if (phi == NULL) break; | |
515 #ifndef PRODUCT | |
516 if( PrintOpto && VerifyLoopOptimizations ) tty->print_cr("CMOV"); | |
517 #endif | |
518 // Move speculative ops | |
519 for( uint j = 1; j < region->req(); j++ ) { | |
520 Node *proj = region->in(j); | |
521 Node *inp = phi->in(j); | |
522 if (get_ctrl(inp) == proj) { // Found local op | |
523 #ifndef PRODUCT | |
524 if( PrintOpto && VerifyLoopOptimizations ) { | |
525 tty->print(" speculate: "); | |
526 inp->dump(); | |
527 } | |
528 #endif | |
529 set_ctrl(inp, cmov_ctrl); | |
530 } | |
531 } | |
532 Node *cmov = CMoveNode::make( C, cmov_ctrl, iff->in(1), phi->in(1+flip), phi->in(2-flip), _igvn.type(phi) ); | |
533 register_new_node( cmov, cmov_ctrl ); | |
534 _igvn.hash_delete(phi); | |
535 _igvn.subsume_node( phi, cmov ); | |
536 #ifndef PRODUCT | |
537 if( VerifyLoopOptimizations ) verify(); | |
538 #endif | |
539 } | |
540 | |
541 // The useless CFG diamond will fold up later; see the optimization in | |
542 // RegionNode::Ideal. | |
543 _igvn._worklist.push(region); | |
544 | |
545 return iff->in(1); | |
546 } | |
547 | |
548 //------------------------------split_if_with_blocks_pre----------------------- | |
549 // Do the real work in a non-recursive function. Data nodes want to be | |
550 // cloned in the pre-order so they can feed each other nicely. | |
551 Node *PhaseIdealLoop::split_if_with_blocks_pre( Node *n ) { | |
552 // Cloning these guys is unlikely to win | |
553 int n_op = n->Opcode(); | |
554 if( n_op == Op_MergeMem ) return n; | |
555 if( n->is_Proj() ) return n; | |
556 // Do not clone-up CmpFXXX variations, as these are always | |
557 // followed by a CmpI | |
558 if( n->is_Cmp() ) return n; | |
559 // Attempt to use a conditional move instead of a phi/branch | |
560 if( ConditionalMoveLimit > 0 && n_op == Op_Region ) { | |
561 Node *cmov = conditional_move( n ); | |
562 if( cmov ) return cmov; | |
563 } | |
564 if( n->is_CFG() || n_op == Op_StorePConditional || n_op == Op_StoreLConditional || n_op == Op_CompareAndSwapI || n_op == Op_CompareAndSwapL ||n_op == Op_CompareAndSwapP) return n; | |
565 if( n_op == Op_Opaque1 || // Opaque nodes cannot be mod'd | |
566 n_op == Op_Opaque2 ) { | |
567 if( !C->major_progress() ) // If chance of no more loop opts... | |
568 _igvn._worklist.push(n); // maybe we'll remove them | |
569 return n; | |
570 } | |
571 | |
572 if( n->is_Con() ) return n; // No cloning for Con nodes | |
573 | |
574 Node *n_ctrl = get_ctrl(n); | |
575 if( !n_ctrl ) return n; // Dead node | |
576 | |
577 // Attempt to remix address expressions for loop invariants | |
578 Node *m = remix_address_expressions( n ); | |
579 if( m ) return m; | |
580 | |
581 // Determine if the Node has inputs from some local Phi. | |
582 // Returns the block to clone thru. | |
583 Node *n_blk = has_local_phi_input( n ); | |
584 if( !n_blk ) return n; | |
585 // Do not clone the trip counter through on a CountedLoop | |
586 // (messes up the canonical shape). | |
587 if( n_blk->is_CountedLoop() && n->Opcode() == Op_AddI ) return n; | |
588 | |
589 // Check for having no control input; not pinned. Allow | |
590 // dominating control. | |
591 if( n->in(0) ) { | |
592 Node *dom = idom(n_blk); | |
593 if( dom_lca( n->in(0), dom ) != n->in(0) ) | |
594 return n; | |
595 } | |
596 // Policy: when is it profitable. You must get more wins than | |
597 // policy before it is considered profitable. Policy is usually 0, | |
598 // so 1 win is considered profitable. Big merges will require big | |
599 // cloning, so get a larger policy. | |
600 int policy = n_blk->req() >> 2; | |
601 | |
602 // If the loop is a candidate for range check elimination, | |
603 // delay splitting through it's phi until a later loop optimization | |
604 if (n_blk->is_CountedLoop()) { | |
605 IdealLoopTree *lp = get_loop(n_blk); | |
606 if (lp && lp->_rce_candidate) { | |
607 return n; | |
608 } | |
609 } | |
610 | |
611 // Use same limit as split_if_with_blocks_post | |
612 if( C->unique() > 35000 ) return n; // Method too big | |
613 | |
614 // Split 'n' through the merge point if it is profitable | |
615 Node *phi = split_thru_phi( n, n_blk, policy ); | |
616 if( !phi ) return n; | |
617 | |
618 // Found a Phi to split thru! | |
619 // Replace 'n' with the new phi | |
620 _igvn.hash_delete(n); | |
621 _igvn.subsume_node( n, phi ); | |
622 // Moved a load around the loop, 'en-registering' something. | |
623 if( n_blk->Opcode() == Op_Loop && n->is_Load() && | |
624 !phi->in(LoopNode::LoopBackControl)->is_Load() ) | |
625 C->set_major_progress(); | |
626 | |
627 return phi; | |
628 } | |
629 | |
630 static bool merge_point_too_heavy(Compile* C, Node* region) { | |
631 // Bail out if the region and its phis have too many users. | |
632 int weight = 0; | |
633 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { | |
634 weight += region->fast_out(i)->outcnt(); | |
635 } | |
636 int nodes_left = MaxNodeLimit - C->unique(); | |
637 if (weight * 8 > nodes_left) { | |
638 #ifndef PRODUCT | |
639 if (PrintOpto) | |
640 tty->print_cr("*** Split-if bails out: %d nodes, region weight %d", C->unique(), weight); | |
641 #endif | |
642 return true; | |
643 } else { | |
644 return false; | |
645 } | |
646 } | |
647 | |
648 #ifdef _LP64 | |
649 static bool merge_point_safe(Node* region) { | |
650 // 4799512: Stop split_if_with_blocks from splitting a block with a ConvI2LNode | |
651 // having a PhiNode input. This sidesteps the dangerous case where the split | |
652 // ConvI2LNode may become TOP if the input Value() does not | |
653 // overlap the ConvI2L range, leaving a node which may not dominate its | |
654 // uses. | |
655 // A better fix for this problem can be found in the BugTraq entry, but | |
656 // expediency for Mantis demands this hack. | |
657 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { | |
658 Node* n = region->fast_out(i); | |
659 if (n->is_Phi()) { | |
660 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
661 Node* m = n->fast_out(j); | |
662 if (m->Opcode() == Op_ConvI2L) { | |
663 return false; | |
664 } | |
665 } | |
666 } | |
667 } | |
668 return true; | |
669 } | |
670 #endif | |
671 | |
672 | |
673 //------------------------------place_near_use--------------------------------- | |
674 // Place some computation next to use but not inside inner loops. | |
675 // For inner loop uses move it to the preheader area. | |
676 Node *PhaseIdealLoop::place_near_use( Node *useblock ) const { | |
677 IdealLoopTree *u_loop = get_loop( useblock ); | |
678 return (u_loop->_irreducible || u_loop->_child) | |
679 ? useblock | |
680 : u_loop->_head->in(LoopNode::EntryControl); | |
681 } | |
682 | |
683 | |
684 //------------------------------split_if_with_blocks_post---------------------- | |
685 // Do the real work in a non-recursive function. CFG hackery wants to be | |
686 // in the post-order, so it can dirty the I-DOM info and not use the dirtied | |
687 // info. | |
688 void PhaseIdealLoop::split_if_with_blocks_post( Node *n ) { | |
689 | |
690 // Cloning Cmp through Phi's involves the split-if transform. | |
691 // FastLock is not used by an If | |
692 if( n->is_Cmp() && !n->is_FastLock() ) { | |
693 if( C->unique() > 35000 ) return; // Method too big | |
694 | |
695 // Do not do 'split-if' if irreducible loops are present. | |
696 if( _has_irreducible_loops ) | |
697 return; | |
698 | |
699 Node *n_ctrl = get_ctrl(n); | |
700 // Determine if the Node has inputs from some local Phi. | |
701 // Returns the block to clone thru. | |
702 Node *n_blk = has_local_phi_input( n ); | |
703 if( n_blk != n_ctrl ) return; | |
704 | |
705 if( merge_point_too_heavy(C, n_ctrl) ) | |
706 return; | |
707 | |
708 if( n->outcnt() != 1 ) return; // Multiple bool's from 1 compare? | |
709 Node *bol = n->unique_out(); | |
710 assert( bol->is_Bool(), "expect a bool here" ); | |
711 if( bol->outcnt() != 1 ) return;// Multiple branches from 1 compare? | |
712 Node *iff = bol->unique_out(); | |
713 | |
714 // Check some safety conditions | |
715 if( iff->is_If() ) { // Classic split-if? | |
716 if( iff->in(0) != n_ctrl ) return; // Compare must be in same blk as if | |
717 } else if (iff->is_CMove()) { // Trying to split-up a CMOVE | |
718 if( get_ctrl(iff->in(2)) == n_ctrl || | |
719 get_ctrl(iff->in(3)) == n_ctrl ) | |
720 return; // Inputs not yet split-up | |
721 if ( get_loop(n_ctrl) != get_loop(get_ctrl(iff)) ) { | |
722 return; // Loop-invar test gates loop-varying CMOVE | |
723 } | |
724 } else { | |
725 return; // some other kind of node, such as an Allocate | |
726 } | |
727 | |
728 // Do not do 'split-if' if some paths are dead. First do dead code | |
729 // elimination and then see if its still profitable. | |
730 for( uint i = 1; i < n_ctrl->req(); i++ ) | |
731 if( n_ctrl->in(i) == C->top() ) | |
732 return; | |
733 | |
734 // When is split-if profitable? Every 'win' on means some control flow | |
735 // goes dead, so it's almost always a win. | |
736 int policy = 0; | |
737 // If trying to do a 'Split-If' at the loop head, it is only | |
738 // profitable if the cmp folds up on BOTH paths. Otherwise we | |
739 // risk peeling a loop forever. | |
740 | |
741 // CNC - Disabled for now. Requires careful handling of loop | |
742 // body selection for the cloned code. Also, make sure we check | |
743 // for any input path not being in the same loop as n_ctrl. For | |
744 // irreducible loops we cannot check for 'n_ctrl->is_Loop()' | |
745 // because the alternative loop entry points won't be converted | |
746 // into LoopNodes. | |
747 IdealLoopTree *n_loop = get_loop(n_ctrl); | |
748 for( uint j = 1; j < n_ctrl->req(); j++ ) | |
749 if( get_loop(n_ctrl->in(j)) != n_loop ) | |
750 return; | |
751 | |
752 #ifdef _LP64 | |
753 // Check for safety of the merge point. | |
754 if( !merge_point_safe(n_ctrl) ) { | |
755 return; | |
756 } | |
757 #endif | |
758 | |
759 // Split compare 'n' through the merge point if it is profitable | |
760 Node *phi = split_thru_phi( n, n_ctrl, policy ); | |
761 if( !phi ) return; | |
762 | |
763 // Found a Phi to split thru! | |
764 // Replace 'n' with the new phi | |
765 _igvn.hash_delete(n); | |
766 _igvn.subsume_node( n, phi ); | |
767 | |
768 // Now split the bool up thru the phi | |
769 Node *bolphi = split_thru_phi( bol, n_ctrl, -1 ); | |
770 _igvn.hash_delete(bol); | |
771 _igvn.subsume_node( bol, bolphi ); | |
772 assert( iff->in(1) == bolphi, "" ); | |
773 if( bolphi->Value(&_igvn)->singleton() ) | |
774 return; | |
775 | |
776 // Conditional-move? Must split up now | |
777 if( !iff->is_If() ) { | |
778 Node *cmovphi = split_thru_phi( iff, n_ctrl, -1 ); | |
779 _igvn.hash_delete(iff); | |
780 _igvn.subsume_node( iff, cmovphi ); | |
781 return; | |
782 } | |
783 | |
784 // Now split the IF | |
785 do_split_if( iff ); | |
786 return; | |
787 } | |
788 | |
789 // Check for an IF ready to split; one that has its | |
790 // condition codes input coming from a Phi at the block start. | |
791 int n_op = n->Opcode(); | |
792 | |
793 // Check for an IF being dominated by another IF same test | |
794 if( n_op == Op_If ) { | |
795 Node *bol = n->in(1); | |
796 uint max = bol->outcnt(); | |
797 // Check for same test used more than once? | |
798 if( n_op == Op_If && max > 1 && bol->is_Bool() ) { | |
799 // Search up IDOMs to see if this IF is dominated. | |
800 Node *cutoff = get_ctrl(bol); | |
801 | |
802 // Now search up IDOMs till cutoff, looking for a dominating test | |
803 Node *prevdom = n; | |
804 Node *dom = idom(prevdom); | |
805 while( dom != cutoff ) { | |
806 if( dom->req() > 1 && dom->in(1) == bol && prevdom->in(0) == dom ) { | |
807 // Replace the dominated test with an obvious true or false. | |
808 // Place it on the IGVN worklist for later cleanup. | |
809 C->set_major_progress(); | |
810 dominated_by( prevdom, n ); | |
811 #ifndef PRODUCT | |
812 if( VerifyLoopOptimizations ) verify(); | |
813 #endif | |
814 return; | |
815 } | |
816 prevdom = dom; | |
817 dom = idom(prevdom); | |
818 } | |
819 } | |
820 } | |
821 | |
822 // See if a shared loop-varying computation has no loop-varying uses. | |
823 // Happens if something is only used for JVM state in uncommon trap exits, | |
824 // like various versions of induction variable+offset. Clone the | |
825 // computation per usage to allow it to sink out of the loop. | |
826 if (has_ctrl(n) && !n->in(0)) {// n not dead and has no control edge (can float about) | |
827 Node *n_ctrl = get_ctrl(n); | |
828 IdealLoopTree *n_loop = get_loop(n_ctrl); | |
829 if( n_loop != _ltree_root ) { | |
830 DUIterator_Fast imax, i = n->fast_outs(imax); | |
831 for (; i < imax; i++) { | |
832 Node* u = n->fast_out(i); | |
833 if( !has_ctrl(u) ) break; // Found control user | |
834 IdealLoopTree *u_loop = get_loop(get_ctrl(u)); | |
835 if( u_loop == n_loop ) break; // Found loop-varying use | |
836 if( n_loop->is_member( u_loop ) ) break; // Found use in inner loop | |
837 if( u->Opcode() == Op_Opaque1 ) break; // Found loop limit, bugfix for 4677003 | |
838 } | |
839 bool did_break = (i < imax); // Did we break out of the previous loop? | |
840 if (!did_break && n->outcnt() > 1) { // All uses in outer loops! | |
841 Node *late_load_ctrl; | |
842 if (n->is_Load()) { | |
843 // If n is a load, get and save the result from get_late_ctrl(), | |
844 // to be later used in calculating the control for n's clones. | |
845 clear_dom_lca_tags(); | |
846 late_load_ctrl = get_late_ctrl(n, n_ctrl); | |
847 } | |
848 // If n is a load, and the late control is the same as the current | |
849 // control, then the cloning of n is a pointless exercise, because | |
850 // GVN will ensure that we end up where we started. | |
851 if (!n->is_Load() || late_load_ctrl != n_ctrl) { | |
852 for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin; ) { | |
853 Node *u = n->last_out(j); // Clone private computation per use | |
854 _igvn.hash_delete(u); | |
855 _igvn._worklist.push(u); | |
856 Node *x = n->clone(); // Clone computation | |
857 Node *x_ctrl = NULL; | |
858 if( u->is_Phi() ) { | |
859 // Replace all uses of normal nodes. Replace Phi uses | |
860 // individually, so the seperate Nodes can sink down | |
861 // different paths. | |
862 uint k = 1; | |
863 while( u->in(k) != n ) k++; | |
864 u->set_req( k, x ); | |
865 // x goes next to Phi input path | |
866 x_ctrl = u->in(0)->in(k); | |
867 --j; | |
868 } else { // Normal use | |
869 // Replace all uses | |
870 for( uint k = 0; k < u->req(); k++ ) { | |
871 if( u->in(k) == n ) { | |
872 u->set_req( k, x ); | |
873 --j; | |
874 } | |
875 } | |
876 x_ctrl = get_ctrl(u); | |
877 } | |
878 | |
879 // Find control for 'x' next to use but not inside inner loops. | |
880 // For inner loop uses get the preheader area. | |
881 x_ctrl = place_near_use(x_ctrl); | |
882 | |
883 if (n->is_Load()) { | |
884 // For loads, add a control edge to a CFG node outside of the loop | |
885 // to force them to not combine and return back inside the loop | |
886 // during GVN optimization (4641526). | |
887 // | |
888 // Because we are setting the actual control input, factor in | |
889 // the result from get_late_ctrl() so we respect any | |
890 // anti-dependences. (6233005). | |
891 x_ctrl = dom_lca(late_load_ctrl, x_ctrl); | |
892 | |
893 // Don't allow the control input to be a CFG splitting node. | |
894 // Such nodes should only have ProjNodes as outs, e.g. IfNode | |
895 // should only have IfTrueNode and IfFalseNode (4985384). | |
896 x_ctrl = find_non_split_ctrl(x_ctrl); | |
897 assert(dom_depth(n_ctrl) <= dom_depth(x_ctrl), "n is later than its clone"); | |
898 | |
899 x->set_req(0, x_ctrl); | |
900 } | |
901 register_new_node(x, x_ctrl); | |
902 | |
903 // Some institutional knowledge is needed here: 'x' is | |
904 // yanked because if the optimizer runs GVN on it all the | |
905 // cloned x's will common up and undo this optimization and | |
906 // be forced back in the loop. This is annoying because it | |
907 // makes +VerifyOpto report false-positives on progress. I | |
908 // tried setting control edges on the x's to force them to | |
909 // not combine, but the matching gets worried when it tries | |
910 // to fold a StoreP and an AddP together (as part of an | |
911 // address expression) and the AddP and StoreP have | |
912 // different controls. | |
913 if( !x->is_Load() ) _igvn._worklist.yank(x); | |
914 } | |
915 _igvn.remove_dead_node(n); | |
916 } | |
917 } | |
918 } | |
919 } | |
920 | |
921 // Check for Opaque2's who's loop has disappeared - who's input is in the | |
922 // same loop nest as their output. Remove 'em, they are no longer useful. | |
923 if( n_op == Op_Opaque2 && | |
924 n->in(1) != NULL && | |
925 get_loop(get_ctrl(n)) == get_loop(get_ctrl(n->in(1))) ) { | |
926 _igvn.add_users_to_worklist(n); | |
927 _igvn.hash_delete(n); | |
928 _igvn.subsume_node( n, n->in(1) ); | |
929 } | |
930 } | |
931 | |
932 //------------------------------split_if_with_blocks--------------------------- | |
933 // Check for aggressive application of 'split-if' optimization, | |
934 // using basic block level info. | |
935 void PhaseIdealLoop::split_if_with_blocks( VectorSet &visited, Node_Stack &nstack ) { | |
936 Node *n = C->root(); | |
937 visited.set(n->_idx); // first, mark node as visited | |
938 // Do pre-visit work for root | |
939 n = split_if_with_blocks_pre( n ); | |
940 uint cnt = n->outcnt(); | |
941 uint i = 0; | |
942 while (true) { | |
943 // Visit all children | |
944 if (i < cnt) { | |
945 Node* use = n->raw_out(i); | |
946 ++i; | |
947 if (use->outcnt() != 0 && !visited.test_set(use->_idx)) { | |
948 // Now do pre-visit work for this use | |
949 use = split_if_with_blocks_pre( use ); | |
950 nstack.push(n, i); // Save parent and next use's index. | |
951 n = use; // Process all children of current use. | |
952 cnt = use->outcnt(); | |
953 i = 0; | |
954 } | |
955 } | |
956 else { | |
957 // All of n's children have been processed, complete post-processing. | |
958 if (cnt != 0 && !n->is_Con()) { | |
959 assert(has_node(n), "no dead nodes"); | |
960 split_if_with_blocks_post( n ); | |
961 } | |
962 if (nstack.is_empty()) { | |
963 // Finished all nodes on stack. | |
964 break; | |
965 } | |
966 // Get saved parent node and next use's index. Visit the rest of uses. | |
967 n = nstack.node(); | |
968 cnt = n->outcnt(); | |
969 i = nstack.index(); | |
970 nstack.pop(); | |
971 } | |
972 } | |
973 } | |
974 | |
975 | |
976 //============================================================================= | |
977 // | |
978 // C L O N E A L O O P B O D Y | |
979 // | |
980 | |
981 //------------------------------clone_iff-------------------------------------- | |
982 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. | |
983 // "Nearly" because all Nodes have been cloned from the original in the loop, | |
984 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs | |
985 // through the Phi recursively, and return a Bool. | |
986 BoolNode *PhaseIdealLoop::clone_iff( PhiNode *phi, IdealLoopTree *loop ) { | |
987 | |
988 // Convert this Phi into a Phi merging Bools | |
989 uint i; | |
990 for( i = 1; i < phi->req(); i++ ) { | |
991 Node *b = phi->in(i); | |
992 if( b->is_Phi() ) { | |
993 _igvn.hash_delete(phi); | |
994 _igvn._worklist.push(phi); | |
995 phi->set_req(i, clone_iff( b->as_Phi(), loop )); | |
996 } else { | |
997 assert( b->is_Bool(), "" ); | |
998 } | |
999 } | |
1000 | |
1001 Node *sample_bool = phi->in(1); | |
1002 Node *sample_cmp = sample_bool->in(1); | |
1003 | |
1004 // Make Phis to merge the Cmp's inputs. | |
1005 int size = phi->in(0)->req(); | |
1006 PhiNode *phi1 = new (C, size) PhiNode( phi->in(0), Type::TOP ); | |
1007 PhiNode *phi2 = new (C, size) PhiNode( phi->in(0), Type::TOP ); | |
1008 for( i = 1; i < phi->req(); i++ ) { | |
1009 Node *n1 = phi->in(i)->in(1)->in(1); | |
1010 Node *n2 = phi->in(i)->in(1)->in(2); | |
1011 phi1->set_req( i, n1 ); | |
1012 phi2->set_req( i, n2 ); | |
1013 phi1->set_type( phi1->type()->meet(n1->bottom_type()) ); | |
1014 phi2->set_type( phi2->type()->meet(n2->bottom_type()) ); | |
1015 } | |
1016 // See if these Phis have been made before. | |
1017 // Register with optimizer | |
1018 Node *hit1 = _igvn.hash_find_insert(phi1); | |
1019 if( hit1 ) { // Hit, toss just made Phi | |
1020 _igvn.remove_dead_node(phi1); // Remove new phi | |
1021 assert( hit1->is_Phi(), "" ); | |
1022 phi1 = (PhiNode*)hit1; // Use existing phi | |
1023 } else { // Miss | |
1024 _igvn.register_new_node_with_optimizer(phi1); | |
1025 } | |
1026 Node *hit2 = _igvn.hash_find_insert(phi2); | |
1027 if( hit2 ) { // Hit, toss just made Phi | |
1028 _igvn.remove_dead_node(phi2); // Remove new phi | |
1029 assert( hit2->is_Phi(), "" ); | |
1030 phi2 = (PhiNode*)hit2; // Use existing phi | |
1031 } else { // Miss | |
1032 _igvn.register_new_node_with_optimizer(phi2); | |
1033 } | |
1034 // Register Phis with loop/block info | |
1035 set_ctrl(phi1, phi->in(0)); | |
1036 set_ctrl(phi2, phi->in(0)); | |
1037 // Make a new Cmp | |
1038 Node *cmp = sample_cmp->clone(); | |
1039 cmp->set_req( 1, phi1 ); | |
1040 cmp->set_req( 2, phi2 ); | |
1041 _igvn.register_new_node_with_optimizer(cmp); | |
1042 set_ctrl(cmp, phi->in(0)); | |
1043 | |
1044 // Make a new Bool | |
1045 Node *b = sample_bool->clone(); | |
1046 b->set_req(1,cmp); | |
1047 _igvn.register_new_node_with_optimizer(b); | |
1048 set_ctrl(b, phi->in(0)); | |
1049 | |
1050 assert( b->is_Bool(), "" ); | |
1051 return (BoolNode*)b; | |
1052 } | |
1053 | |
1054 //------------------------------clone_bool------------------------------------- | |
1055 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. | |
1056 // "Nearly" because all Nodes have been cloned from the original in the loop, | |
1057 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs | |
1058 // through the Phi recursively, and return a Bool. | |
1059 CmpNode *PhaseIdealLoop::clone_bool( PhiNode *phi, IdealLoopTree *loop ) { | |
1060 uint i; | |
1061 // Convert this Phi into a Phi merging Bools | |
1062 for( i = 1; i < phi->req(); i++ ) { | |
1063 Node *b = phi->in(i); | |
1064 if( b->is_Phi() ) { | |
1065 _igvn.hash_delete(phi); | |
1066 _igvn._worklist.push(phi); | |
1067 phi->set_req(i, clone_bool( b->as_Phi(), loop )); | |
1068 } else { | |
1069 assert( b->is_Cmp() || b->is_top(), "inputs are all Cmp or TOP" ); | |
1070 } | |
1071 } | |
1072 | |
1073 Node *sample_cmp = phi->in(1); | |
1074 | |
1075 // Make Phis to merge the Cmp's inputs. | |
1076 int size = phi->in(0)->req(); | |
1077 PhiNode *phi1 = new (C, size) PhiNode( phi->in(0), Type::TOP ); | |
1078 PhiNode *phi2 = new (C, size) PhiNode( phi->in(0), Type::TOP ); | |
1079 for( uint j = 1; j < phi->req(); j++ ) { | |
1080 Node *cmp_top = phi->in(j); // Inputs are all Cmp or TOP | |
1081 Node *n1, *n2; | |
1082 if( cmp_top->is_Cmp() ) { | |
1083 n1 = cmp_top->in(1); | |
1084 n2 = cmp_top->in(2); | |
1085 } else { | |
1086 n1 = n2 = cmp_top; | |
1087 } | |
1088 phi1->set_req( j, n1 ); | |
1089 phi2->set_req( j, n2 ); | |
1090 phi1->set_type( phi1->type()->meet(n1->bottom_type()) ); | |
1091 phi2->set_type( phi2->type()->meet(n2->bottom_type()) ); | |
1092 } | |
1093 | |
1094 // See if these Phis have been made before. | |
1095 // Register with optimizer | |
1096 Node *hit1 = _igvn.hash_find_insert(phi1); | |
1097 if( hit1 ) { // Hit, toss just made Phi | |
1098 _igvn.remove_dead_node(phi1); // Remove new phi | |
1099 assert( hit1->is_Phi(), "" ); | |
1100 phi1 = (PhiNode*)hit1; // Use existing phi | |
1101 } else { // Miss | |
1102 _igvn.register_new_node_with_optimizer(phi1); | |
1103 } | |
1104 Node *hit2 = _igvn.hash_find_insert(phi2); | |
1105 if( hit2 ) { // Hit, toss just made Phi | |
1106 _igvn.remove_dead_node(phi2); // Remove new phi | |
1107 assert( hit2->is_Phi(), "" ); | |
1108 phi2 = (PhiNode*)hit2; // Use existing phi | |
1109 } else { // Miss | |
1110 _igvn.register_new_node_with_optimizer(phi2); | |
1111 } | |
1112 // Register Phis with loop/block info | |
1113 set_ctrl(phi1, phi->in(0)); | |
1114 set_ctrl(phi2, phi->in(0)); | |
1115 // Make a new Cmp | |
1116 Node *cmp = sample_cmp->clone(); | |
1117 cmp->set_req( 1, phi1 ); | |
1118 cmp->set_req( 2, phi2 ); | |
1119 _igvn.register_new_node_with_optimizer(cmp); | |
1120 set_ctrl(cmp, phi->in(0)); | |
1121 | |
1122 assert( cmp->is_Cmp(), "" ); | |
1123 return (CmpNode*)cmp; | |
1124 } | |
1125 | |
1126 //------------------------------sink_use--------------------------------------- | |
1127 // If 'use' was in the loop-exit block, it now needs to be sunk | |
1128 // below the post-loop merge point. | |
1129 void PhaseIdealLoop::sink_use( Node *use, Node *post_loop ) { | |
1130 if (!use->is_CFG() && get_ctrl(use) == post_loop->in(2)) { | |
1131 set_ctrl(use, post_loop); | |
1132 for (DUIterator j = use->outs(); use->has_out(j); j++) | |
1133 sink_use(use->out(j), post_loop); | |
1134 } | |
1135 } | |
1136 | |
1137 //------------------------------clone_loop------------------------------------- | |
1138 // | |
1139 // C L O N E A L O O P B O D Y | |
1140 // | |
1141 // This is the basic building block of the loop optimizations. It clones an | |
1142 // entire loop body. It makes an old_new loop body mapping; with this mapping | |
1143 // you can find the new-loop equivalent to an old-loop node. All new-loop | |
1144 // nodes are exactly equal to their old-loop counterparts, all edges are the | |
1145 // same. All exits from the old-loop now have a RegionNode that merges the | |
1146 // equivalent new-loop path. This is true even for the normal "loop-exit" | |
1147 // condition. All uses of loop-invariant old-loop values now come from (one | |
1148 // or more) Phis that merge their new-loop equivalents. | |
1149 // | |
1150 // This operation leaves the graph in an illegal state: there are two valid | |
1151 // control edges coming from the loop pre-header to both loop bodies. I'll | |
1152 // definitely have to hack the graph after running this transform. | |
1153 // | |
1154 // From this building block I will further edit edges to perform loop peeling | |
1155 // or loop unrolling or iteration splitting (Range-Check-Elimination), etc. | |
1156 // | |
1157 // Parameter side_by_size_idom: | |
1158 // When side_by_size_idom is NULL, the dominator tree is constructed for | |
1159 // the clone loop to dominate the original. Used in construction of | |
1160 // pre-main-post loop sequence. | |
1161 // When nonnull, the clone and original are side-by-side, both are | |
1162 // dominated by the side_by_side_idom node. Used in construction of | |
1163 // unswitched loops. | |
1164 void PhaseIdealLoop::clone_loop( IdealLoopTree *loop, Node_List &old_new, int dd, | |
1165 Node* side_by_side_idom) { | |
1166 | |
1167 // Step 1: Clone the loop body. Make the old->new mapping. | |
1168 uint i; | |
1169 for( i = 0; i < loop->_body.size(); i++ ) { | |
1170 Node *old = loop->_body.at(i); | |
1171 Node *nnn = old->clone(); | |
1172 old_new.map( old->_idx, nnn ); | |
1173 _igvn.register_new_node_with_optimizer(nnn); | |
1174 } | |
1175 | |
1176 | |
1177 // Step 2: Fix the edges in the new body. If the old input is outside the | |
1178 // loop use it. If the old input is INside the loop, use the corresponding | |
1179 // new node instead. | |
1180 for( i = 0; i < loop->_body.size(); i++ ) { | |
1181 Node *old = loop->_body.at(i); | |
1182 Node *nnn = old_new[old->_idx]; | |
1183 // Fix CFG/Loop controlling the new node | |
1184 if (has_ctrl(old)) { | |
1185 set_ctrl(nnn, old_new[get_ctrl(old)->_idx]); | |
1186 } else { | |
1187 set_loop(nnn, loop->_parent); | |
1188 if (old->outcnt() > 0) { | |
1189 set_idom( nnn, old_new[idom(old)->_idx], dd ); | |
1190 } | |
1191 } | |
1192 // Correct edges to the new node | |
1193 for( uint j = 0; j < nnn->req(); j++ ) { | |
1194 Node *n = nnn->in(j); | |
1195 if( n ) { | |
1196 IdealLoopTree *old_in_loop = get_loop( has_ctrl(n) ? get_ctrl(n) : n ); | |
1197 if( loop->is_member( old_in_loop ) ) | |
1198 nnn->set_req(j, old_new[n->_idx]); | |
1199 } | |
1200 } | |
1201 _igvn.hash_find_insert(nnn); | |
1202 } | |
1203 Node *newhead = old_new[loop->_head->_idx]; | |
1204 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd); | |
1205 | |
1206 | |
1207 // Step 3: Now fix control uses. Loop varying control uses have already | |
1208 // been fixed up (as part of all input edges in Step 2). Loop invariant | |
1209 // control uses must be either an IfFalse or an IfTrue. Make a merge | |
1210 // point to merge the old and new IfFalse/IfTrue nodes; make the use | |
1211 // refer to this. | |
1212 ResourceArea *area = Thread::current()->resource_area(); | |
1213 Node_List worklist(area); | |
1214 uint new_counter = C->unique(); | |
1215 for( i = 0; i < loop->_body.size(); i++ ) { | |
1216 Node* old = loop->_body.at(i); | |
1217 if( !old->is_CFG() ) continue; | |
1218 Node* nnn = old_new[old->_idx]; | |
1219 | |
1220 // Copy uses to a worklist, so I can munge the def-use info | |
1221 // with impunity. | |
1222 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) | |
1223 worklist.push(old->fast_out(j)); | |
1224 | |
1225 while( worklist.size() ) { // Visit all uses | |
1226 Node *use = worklist.pop(); | |
1227 if (!has_node(use)) continue; // Ignore dead nodes | |
1228 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use ); | |
1229 if( !loop->is_member( use_loop ) && use->is_CFG() ) { | |
1230 // Both OLD and USE are CFG nodes here. | |
1231 assert( use->is_Proj(), "" ); | |
1232 | |
1233 // Clone the loop exit control projection | |
1234 Node *newuse = use->clone(); | |
1235 newuse->set_req(0,nnn); | |
1236 _igvn.register_new_node_with_optimizer(newuse); | |
1237 set_loop(newuse, use_loop); | |
1238 set_idom(newuse, nnn, dom_depth(nnn) + 1 ); | |
1239 | |
1240 // We need a Region to merge the exit from the peeled body and the | |
1241 // exit from the old loop body. | |
1242 RegionNode *r = new (C, 3) RegionNode(3); | |
1243 // Map the old use to the new merge point | |
1244 old_new.map( use->_idx, r ); | |
1245 uint dd_r = MIN2(dom_depth(newuse),dom_depth(use)); | |
1246 assert( dd_r >= dom_depth(dom_lca(newuse,use)), "" ); | |
1247 | |
1248 // The original user of 'use' uses 'r' instead. | |
1249 for (DUIterator_Last lmin, l = use->last_outs(lmin); l >= lmin;) { | |
1250 Node* useuse = use->last_out(l); | |
1251 _igvn.hash_delete(useuse); | |
1252 _igvn._worklist.push(useuse); | |
1253 uint uses_found = 0; | |
1254 if( useuse->in(0) == use ) { | |
1255 useuse->set_req(0, r); | |
1256 uses_found++; | |
1257 if( useuse->is_CFG() ) { | |
1258 assert( dom_depth(useuse) > dd_r, "" ); | |
1259 set_idom(useuse, r, dom_depth(useuse)); | |
1260 } | |
1261 } | |
1262 for( uint k = 1; k < useuse->req(); k++ ) { | |
1263 if( useuse->in(k) == use ) { | |
1264 useuse->set_req(k, r); | |
1265 uses_found++; | |
1266 } | |
1267 } | |
1268 l -= uses_found; // we deleted 1 or more copies of this edge | |
1269 } | |
1270 | |
1271 // Now finish up 'r' | |
1272 r->set_req( 1, newuse ); | |
1273 r->set_req( 2, use ); | |
1274 _igvn.register_new_node_with_optimizer(r); | |
1275 set_loop(r, use_loop); | |
1276 set_idom(r, !side_by_side_idom ? newuse->in(0) : side_by_side_idom, dd_r); | |
1277 } // End of if a loop-exit test | |
1278 } | |
1279 } | |
1280 | |
1281 // Step 4: If loop-invariant use is not control, it must be dominated by a | |
1282 // loop exit IfFalse/IfTrue. Find "proper" loop exit. Make a Region | |
1283 // there if needed. Make a Phi there merging old and new used values. | |
1284 Node_List *split_if_set = NULL; | |
1285 Node_List *split_bool_set = NULL; | |
1286 Node_List *split_cex_set = NULL; | |
1287 for( i = 0; i < loop->_body.size(); i++ ) { | |
1288 Node* old = loop->_body.at(i); | |
1289 Node* nnn = old_new[old->_idx]; | |
1290 // Copy uses to a worklist, so I can munge the def-use info | |
1291 // with impunity. | |
1292 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) | |
1293 worklist.push(old->fast_out(j)); | |
1294 | |
1295 while( worklist.size() ) { | |
1296 Node *use = worklist.pop(); | |
1297 if (!has_node(use)) continue; // Ignore dead nodes | |
1298 if (use->in(0) == C->top()) continue; | |
1299 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use ); | |
1300 // Check for data-use outside of loop - at least one of OLD or USE | |
1301 // must not be a CFG node. | |
1302 if( !loop->is_member( use_loop ) && (!old->is_CFG() || !use->is_CFG())) { | |
1303 | |
1304 // If the Data use is an IF, that means we have an IF outside of the | |
1305 // loop that is switching on a condition that is set inside of the | |
1306 // loop. Happens if people set a loop-exit flag; then test the flag | |
1307 // in the loop to break the loop, then test is again outside of the | |
1308 // loop to determine which way the loop exited. | |
1309 if( use->is_If() || use->is_CMove() ) { | |
1310 // Since this code is highly unlikely, we lazily build the worklist | |
1311 // of such Nodes to go split. | |
1312 if( !split_if_set ) | |
1313 split_if_set = new Node_List(area); | |
1314 split_if_set->push(use); | |
1315 } | |
1316 if( use->is_Bool() ) { | |
1317 if( !split_bool_set ) | |
1318 split_bool_set = new Node_List(area); | |
1319 split_bool_set->push(use); | |
1320 } | |
1321 if( use->Opcode() == Op_CreateEx ) { | |
1322 if( !split_cex_set ) | |
1323 split_cex_set = new Node_List(area); | |
1324 split_cex_set->push(use); | |
1325 } | |
1326 | |
1327 | |
1328 // Get "block" use is in | |
1329 uint idx = 0; | |
1330 while( use->in(idx) != old ) idx++; | |
1331 Node *prev = use->is_CFG() ? use : get_ctrl(use); | |
1332 assert( !loop->is_member( get_loop( prev ) ), "" ); | |
1333 Node *cfg = prev->_idx >= new_counter | |
1334 ? prev->in(2) | |
1335 : idom(prev); | |
1336 if( use->is_Phi() ) // Phi use is in prior block | |
1337 cfg = prev->in(idx); // NOT in block of Phi itself | |
1338 if (cfg->is_top()) { // Use is dead? | |
1339 _igvn.hash_delete(use); | |
1340 _igvn._worklist.push(use); | |
1341 use->set_req(idx, C->top()); | |
1342 continue; | |
1343 } | |
1344 | |
1345 while( !loop->is_member( get_loop( cfg ) ) ) { | |
1346 prev = cfg; | |
1347 cfg = cfg->_idx >= new_counter ? cfg->in(2) : idom(cfg); | |
1348 } | |
1349 // If the use occurs after merging several exits from the loop, then | |
1350 // old value must have dominated all those exits. Since the same old | |
1351 // value was used on all those exits we did not need a Phi at this | |
1352 // merge point. NOW we do need a Phi here. Each loop exit value | |
1353 // is now merged with the peeled body exit; each exit gets its own | |
1354 // private Phi and those Phis need to be merged here. | |
1355 Node *phi; | |
1356 if( prev->is_Region() ) { | |
1357 if( idx == 0 ) { // Updating control edge? | |
1358 phi = prev; // Just use existing control | |
1359 } else { // Else need a new Phi | |
1360 phi = PhiNode::make( prev, old ); | |
1361 // Now recursively fix up the new uses of old! | |
1362 for( uint i = 1; i < prev->req(); i++ ) { | |
1363 worklist.push(phi); // Onto worklist once for each 'old' input | |
1364 } | |
1365 } | |
1366 } else { | |
1367 // Get new RegionNode merging old and new loop exits | |
1368 prev = old_new[prev->_idx]; | |
1369 assert( prev, "just made this in step 7" ); | |
1370 if( idx == 0 ) { // Updating control edge? | |
1371 phi = prev; // Just use existing control | |
1372 } else { // Else need a new Phi | |
1373 // Make a new Phi merging data values properly | |
1374 phi = PhiNode::make( prev, old ); | |
1375 phi->set_req( 1, nnn ); | |
1376 } | |
1377 } | |
1378 // If inserting a new Phi, check for prior hits | |
1379 if( idx != 0 ) { | |
1380 Node *hit = _igvn.hash_find_insert(phi); | |
1381 if( hit == NULL ) { | |
1382 _igvn.register_new_node_with_optimizer(phi); // Register new phi | |
1383 } else { // or | |
1384 // Remove the new phi from the graph and use the hit | |
1385 _igvn.remove_dead_node(phi); | |
1386 phi = hit; // Use existing phi | |
1387 } | |
1388 set_ctrl(phi, prev); | |
1389 } | |
1390 // Make 'use' use the Phi instead of the old loop body exit value | |
1391 _igvn.hash_delete(use); | |
1392 _igvn._worklist.push(use); | |
1393 use->set_req(idx, phi); | |
1394 if( use->_idx >= new_counter ) { // If updating new phis | |
1395 // Not needed for correctness, but prevents a weak assert | |
1396 // in AddPNode from tripping (when we end up with different | |
1397 // base & derived Phis that will become the same after | |
1398 // IGVN does CSE). | |
1399 Node *hit = _igvn.hash_find_insert(use); | |
1400 if( hit ) // Go ahead and re-hash for hits. | |
1401 _igvn.subsume_node( use, hit ); | |
1402 } | |
1403 | |
1404 // If 'use' was in the loop-exit block, it now needs to be sunk | |
1405 // below the post-loop merge point. | |
1406 sink_use( use, prev ); | |
1407 } | |
1408 } | |
1409 } | |
1410 | |
1411 // Check for IFs that need splitting/cloning. Happens if an IF outside of | |
1412 // the loop uses a condition set in the loop. The original IF probably | |
1413 // takes control from one or more OLD Regions (which in turn get from NEW | |
1414 // Regions). In any case, there will be a set of Phis for each merge point | |
1415 // from the IF up to where the original BOOL def exists the loop. | |
1416 if( split_if_set ) { | |
1417 while( split_if_set->size() ) { | |
1418 Node *iff = split_if_set->pop(); | |
1419 if( iff->in(1)->is_Phi() ) { | |
1420 BoolNode *b = clone_iff( iff->in(1)->as_Phi(), loop ); | |
1421 _igvn.hash_delete(iff); | |
1422 _igvn._worklist.push(iff); | |
1423 iff->set_req(1, b); | |
1424 } | |
1425 } | |
1426 } | |
1427 if( split_bool_set ) { | |
1428 while( split_bool_set->size() ) { | |
1429 Node *b = split_bool_set->pop(); | |
1430 Node *phi = b->in(1); | |
1431 assert( phi->is_Phi(), "" ); | |
1432 CmpNode *cmp = clone_bool( (PhiNode*)phi, loop ); | |
1433 _igvn.hash_delete(b); | |
1434 _igvn._worklist.push(b); | |
1435 b->set_req(1, cmp); | |
1436 } | |
1437 } | |
1438 if( split_cex_set ) { | |
1439 while( split_cex_set->size() ) { | |
1440 Node *b = split_cex_set->pop(); | |
1441 assert( b->in(0)->is_Region(), "" ); | |
1442 assert( b->in(1)->is_Phi(), "" ); | |
1443 assert( b->in(0)->in(0) == b->in(1)->in(0), "" ); | |
1444 split_up( b, b->in(0), NULL ); | |
1445 } | |
1446 } | |
1447 | |
1448 } | |
1449 | |
1450 | |
1451 //---------------------- stride_of_possible_iv ------------------------------------- | |
1452 // Looks for an iff/bool/comp with one operand of the compare | |
1453 // being a cycle involving an add and a phi, | |
1454 // with an optional truncation (left-shift followed by a right-shift) | |
1455 // of the add. Returns zero if not an iv. | |
1456 int PhaseIdealLoop::stride_of_possible_iv(Node* iff) { | |
1457 Node* trunc1 = NULL; | |
1458 Node* trunc2 = NULL; | |
1459 const TypeInt* ttype = NULL; | |
1460 if (!iff->is_If() || iff->in(1) == NULL || !iff->in(1)->is_Bool()) { | |
1461 return 0; | |
1462 } | |
1463 BoolNode* bl = iff->in(1)->as_Bool(); | |
1464 Node* cmp = bl->in(1); | |
1465 if (!cmp || cmp->Opcode() != Op_CmpI && cmp->Opcode() != Op_CmpU) { | |
1466 return 0; | |
1467 } | |
1468 // Must have an invariant operand | |
1469 if (is_member(get_loop(iff), get_ctrl(cmp->in(2)))) { | |
1470 return 0; | |
1471 } | |
1472 Node* add2 = NULL; | |
1473 Node* cmp1 = cmp->in(1); | |
1474 if (cmp1->is_Phi()) { | |
1475 // (If (Bool (CmpX phi:(Phi ...(Optional-trunc(AddI phi add2))) ))) | |
1476 Node* phi = cmp1; | |
1477 for (uint i = 1; i < phi->req(); i++) { | |
1478 Node* in = phi->in(i); | |
1479 Node* add = CountedLoopNode::match_incr_with_optional_truncation(in, | |
1480 &trunc1, &trunc2, &ttype); | |
1481 if (add && add->in(1) == phi) { | |
1482 add2 = add->in(2); | |
1483 break; | |
1484 } | |
1485 } | |
1486 } else { | |
1487 // (If (Bool (CmpX addtrunc:(Optional-trunc((AddI (Phi ...addtrunc...) add2)) ))) | |
1488 Node* addtrunc = cmp1; | |
1489 Node* add = CountedLoopNode::match_incr_with_optional_truncation(addtrunc, | |
1490 &trunc1, &trunc2, &ttype); | |
1491 if (add && add->in(1)->is_Phi()) { | |
1492 Node* phi = add->in(1); | |
1493 for (uint i = 1; i < phi->req(); i++) { | |
1494 if (phi->in(i) == addtrunc) { | |
1495 add2 = add->in(2); | |
1496 break; | |
1497 } | |
1498 } | |
1499 } | |
1500 } | |
1501 if (add2 != NULL) { | |
1502 const TypeInt* add2t = _igvn.type(add2)->is_int(); | |
1503 if (add2t->is_con()) { | |
1504 return add2t->get_con(); | |
1505 } | |
1506 } | |
1507 return 0; | |
1508 } | |
1509 | |
1510 | |
1511 //---------------------- stay_in_loop ------------------------------------- | |
1512 // Return the (unique) control output node that's in the loop (if it exists.) | |
1513 Node* PhaseIdealLoop::stay_in_loop( Node* n, IdealLoopTree *loop) { | |
1514 Node* unique = NULL; | |
1515 if (!n) return NULL; | |
1516 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { | |
1517 Node* use = n->fast_out(i); | |
1518 if (!has_ctrl(use) && loop->is_member(get_loop(use))) { | |
1519 if (unique != NULL) { | |
1520 return NULL; | |
1521 } | |
1522 unique = use; | |
1523 } | |
1524 } | |
1525 return unique; | |
1526 } | |
1527 | |
1528 //------------------------------ register_node ------------------------------------- | |
1529 // Utility to register node "n" with PhaseIdealLoop | |
1530 void PhaseIdealLoop::register_node(Node* n, IdealLoopTree *loop, Node* pred, int ddepth) { | |
1531 _igvn.register_new_node_with_optimizer(n); | |
1532 loop->_body.push(n); | |
1533 if (n->is_CFG()) { | |
1534 set_loop(n, loop); | |
1535 set_idom(n, pred, ddepth); | |
1536 } else { | |
1537 set_ctrl(n, pred); | |
1538 } | |
1539 } | |
1540 | |
1541 //------------------------------ proj_clone ------------------------------------- | |
1542 // Utility to create an if-projection | |
1543 ProjNode* PhaseIdealLoop::proj_clone(ProjNode* p, IfNode* iff) { | |
1544 ProjNode* c = p->clone()->as_Proj(); | |
1545 c->set_req(0, iff); | |
1546 return c; | |
1547 } | |
1548 | |
1549 //------------------------------ short_circuit_if ------------------------------------- | |
1550 // Force the iff control output to be the live_proj | |
1551 Node* PhaseIdealLoop::short_circuit_if(IfNode* iff, ProjNode* live_proj) { | |
1552 int proj_con = live_proj->_con; | |
1553 assert(proj_con == 0 || proj_con == 1, "false or true projection"); | |
1554 Node *con = _igvn.intcon(proj_con); | |
1555 set_ctrl(con, C->root()); | |
1556 if (iff) { | |
1557 iff->set_req(1, con); | |
1558 } | |
1559 return con; | |
1560 } | |
1561 | |
1562 //------------------------------ insert_if_before_proj ------------------------------------- | |
1563 // Insert a new if before an if projection (* - new node) | |
1564 // | |
1565 // before | |
1566 // if(test) | |
1567 // / \ | |
1568 // v v | |
1569 // other-proj proj (arg) | |
1570 // | |
1571 // after | |
1572 // if(test) | |
1573 // / \ | |
1574 // / v | |
1575 // | * proj-clone | |
1576 // v | | |
1577 // other-proj v | |
1578 // * new_if(relop(cmp[IU](left,right))) | |
1579 // / \ | |
1580 // v v | |
1581 // * new-proj proj | |
1582 // (returned) | |
1583 // | |
1584 ProjNode* PhaseIdealLoop::insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj) { | |
1585 IfNode* iff = proj->in(0)->as_If(); | |
1586 IdealLoopTree *loop = get_loop(proj); | |
1587 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); | |
1588 int ddepth = dom_depth(proj); | |
1589 | |
1590 _igvn.hash_delete(iff); | |
1591 _igvn._worklist.push(iff); | |
1592 _igvn.hash_delete(proj); | |
1593 _igvn._worklist.push(proj); | |
1594 | |
1595 proj->set_req(0, NULL); // temporary disconnect | |
1596 ProjNode* proj2 = proj_clone(proj, iff); | |
1597 register_node(proj2, loop, iff, ddepth); | |
1598 | |
1599 Node* cmp = Signed ? (Node*) new (C,3)CmpINode(left, right) : (Node*) new (C,3)CmpUNode(left, right); | |
1600 register_node(cmp, loop, proj2, ddepth); | |
1601 | |
1602 BoolNode* bol = new (C,2)BoolNode(cmp, relop); | |
1603 register_node(bol, loop, proj2, ddepth); | |
1604 | |
1605 IfNode* new_if = new (C,2)IfNode(proj2, bol, iff->_prob, iff->_fcnt); | |
1606 register_node(new_if, loop, proj2, ddepth); | |
1607 | |
1608 proj->set_req(0, new_if); // reattach | |
1609 set_idom(proj, new_if, ddepth); | |
1610 | |
1611 ProjNode* new_exit = proj_clone(other_proj, new_if)->as_Proj(); | |
1612 register_node(new_exit, get_loop(other_proj), new_if, ddepth); | |
1613 | |
1614 return new_exit; | |
1615 } | |
1616 | |
1617 //------------------------------ insert_region_before_proj ------------------------------------- | |
1618 // Insert a region before an if projection (* - new node) | |
1619 // | |
1620 // before | |
1621 // if(test) | |
1622 // / | | |
1623 // v | | |
1624 // proj v | |
1625 // other-proj | |
1626 // | |
1627 // after | |
1628 // if(test) | |
1629 // / | | |
1630 // v | | |
1631 // * proj-clone v | |
1632 // | other-proj | |
1633 // v | |
1634 // * new-region | |
1635 // | | |
1636 // v | |
1637 // * dum_if | |
1638 // / \ | |
1639 // v \ | |
1640 // * dum-proj v | |
1641 // proj | |
1642 // | |
1643 RegionNode* PhaseIdealLoop::insert_region_before_proj(ProjNode* proj) { | |
1644 IfNode* iff = proj->in(0)->as_If(); | |
1645 IdealLoopTree *loop = get_loop(proj); | |
1646 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); | |
1647 int ddepth = dom_depth(proj); | |
1648 | |
1649 _igvn.hash_delete(iff); | |
1650 _igvn._worklist.push(iff); | |
1651 _igvn.hash_delete(proj); | |
1652 _igvn._worklist.push(proj); | |
1653 | |
1654 proj->set_req(0, NULL); // temporary disconnect | |
1655 ProjNode* proj2 = proj_clone(proj, iff); | |
1656 register_node(proj2, loop, iff, ddepth); | |
1657 | |
1658 RegionNode* reg = new (C,2)RegionNode(2); | |
1659 reg->set_req(1, proj2); | |
1660 register_node(reg, loop, iff, ddepth); | |
1661 | |
1662 IfNode* dum_if = new (C,2)IfNode(reg, short_circuit_if(NULL, proj), iff->_prob, iff->_fcnt); | |
1663 register_node(dum_if, loop, reg, ddepth); | |
1664 | |
1665 proj->set_req(0, dum_if); // reattach | |
1666 set_idom(proj, dum_if, ddepth); | |
1667 | |
1668 ProjNode* dum_proj = proj_clone(other_proj, dum_if); | |
1669 register_node(dum_proj, loop, dum_if, ddepth); | |
1670 | |
1671 return reg; | |
1672 } | |
1673 | |
1674 //------------------------------ insert_cmpi_loop_exit ------------------------------------- | |
1675 // Clone a signed compare loop exit from an unsigned compare and | |
1676 // insert it before the unsigned cmp on the stay-in-loop path. | |
1677 // All new nodes inserted in the dominator tree between the original | |
1678 // if and it's projections. The original if test is replaced with | |
1679 // a constant to force the stay-in-loop path. | |
1680 // | |
1681 // This is done to make sure that the original if and it's projections | |
1682 // still dominate the same set of control nodes, that the ctrl() relation | |
1683 // from data nodes to them is preserved, and that their loop nesting is | |
1684 // preserved. | |
1685 // | |
1686 // before | |
1687 // if(i <u limit) unsigned compare loop exit | |
1688 // / | | |
1689 // v v | |
1690 // exit-proj stay-in-loop-proj | |
1691 // | |
1692 // after | |
1693 // if(stay-in-loop-const) original if | |
1694 // / | | |
1695 // / v | |
1696 // / if(i < limit) new signed test | |
1697 // / / | | |
1698 // / / v | |
1699 // / / if(i <u limit) new cloned unsigned test | |
1700 // / / / | | |
1701 // v v v | | |
1702 // region | | |
1703 // | | | |
1704 // dum-if | | |
1705 // / | | | |
1706 // ether | | | |
1707 // v v | |
1708 // exit-proj stay-in-loop-proj | |
1709 // | |
1710 IfNode* PhaseIdealLoop::insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *loop) { | |
1711 const bool Signed = true; | |
1712 const bool Unsigned = false; | |
1713 | |
1714 BoolNode* bol = if_cmpu->in(1)->as_Bool(); | |
1715 if (bol->_test._test != BoolTest::lt) return NULL; | |
1716 CmpNode* cmpu = bol->in(1)->as_Cmp(); | |
1717 if (cmpu->Opcode() != Op_CmpU) return NULL; | |
1718 int stride = stride_of_possible_iv(if_cmpu); | |
1719 if (stride == 0) return NULL; | |
1720 | |
1721 ProjNode* lp_continue = stay_in_loop(if_cmpu, loop)->as_Proj(); | |
1722 ProjNode* lp_exit = if_cmpu->proj_out(!lp_continue->is_IfTrue())->as_Proj(); | |
1723 | |
1724 Node* limit = NULL; | |
1725 if (stride > 0) { | |
1726 limit = cmpu->in(2); | |
1727 } else { | |
1728 limit = _igvn.makecon(TypeInt::ZERO); | |
1729 set_ctrl(limit, C->root()); | |
1730 } | |
1731 // Create a new region on the exit path | |
1732 RegionNode* reg = insert_region_before_proj(lp_exit); | |
1733 | |
1734 // Clone the if-cmpu-true-false using a signed compare | |
1735 BoolTest::mask rel_i = stride > 0 ? bol->_test._test : BoolTest::ge; | |
1736 ProjNode* cmpi_exit = insert_if_before_proj(cmpu->in(1), Signed, rel_i, limit, lp_continue); | |
1737 reg->add_req(cmpi_exit); | |
1738 | |
1739 // Clone the if-cmpu-true-false | |
1740 BoolTest::mask rel_u = bol->_test._test; | |
1741 ProjNode* cmpu_exit = insert_if_before_proj(cmpu->in(1), Unsigned, rel_u, cmpu->in(2), lp_continue); | |
1742 reg->add_req(cmpu_exit); | |
1743 | |
1744 // Force original if to stay in loop. | |
1745 short_circuit_if(if_cmpu, lp_continue); | |
1746 | |
1747 return cmpi_exit->in(0)->as_If(); | |
1748 } | |
1749 | |
1750 //------------------------------ remove_cmpi_loop_exit ------------------------------------- | |
1751 // Remove a previously inserted signed compare loop exit. | |
1752 void PhaseIdealLoop::remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop) { | |
1753 Node* lp_proj = stay_in_loop(if_cmp, loop); | |
1754 assert(if_cmp->in(1)->in(1)->Opcode() == Op_CmpI && | |
1755 stay_in_loop(lp_proj, loop)->is_If() && | |
1756 stay_in_loop(lp_proj, loop)->in(1)->in(1)->Opcode() == Op_CmpU, "inserted cmpi before cmpu"); | |
1757 Node *con = _igvn.makecon(lp_proj->is_IfTrue() ? TypeInt::ONE : TypeInt::ZERO); | |
1758 set_ctrl(con, C->root()); | |
1759 if_cmp->set_req(1, con); | |
1760 } | |
1761 | |
1762 //------------------------------ scheduled_nodelist ------------------------------------- | |
1763 // Create a post order schedule of nodes that are in the | |
1764 // "member" set. The list is returned in "sched". | |
1765 // The first node in "sched" is the loop head, followed by | |
1766 // nodes which have no inputs in the "member" set, and then | |
1767 // followed by the nodes that have an immediate input dependence | |
1768 // on a node in "sched". | |
1769 void PhaseIdealLoop::scheduled_nodelist( IdealLoopTree *loop, VectorSet& member, Node_List &sched ) { | |
1770 | |
1771 assert(member.test(loop->_head->_idx), "loop head must be in member set"); | |
1772 Arena *a = Thread::current()->resource_area(); | |
1773 VectorSet visited(a); | |
1774 Node_Stack nstack(a, loop->_body.size()); | |
1775 | |
1776 Node* n = loop->_head; // top of stack is cached in "n" | |
1777 uint idx = 0; | |
1778 visited.set(n->_idx); | |
1779 | |
1780 // Initially push all with no inputs from within member set | |
1781 for(uint i = 0; i < loop->_body.size(); i++ ) { | |
1782 Node *elt = loop->_body.at(i); | |
1783 if (member.test(elt->_idx)) { | |
1784 bool found = false; | |
1785 for (uint j = 0; j < elt->req(); j++) { | |
1786 Node* def = elt->in(j); | |
1787 if (def && member.test(def->_idx) && def != elt) { | |
1788 found = true; | |
1789 break; | |
1790 } | |
1791 } | |
1792 if (!found && elt != loop->_head) { | |
1793 nstack.push(n, idx); | |
1794 n = elt; | |
1795 assert(!visited.test(n->_idx), "not seen yet"); | |
1796 visited.set(n->_idx); | |
1797 } | |
1798 } | |
1799 } | |
1800 | |
1801 // traverse out's that are in the member set | |
1802 while (true) { | |
1803 if (idx < n->outcnt()) { | |
1804 Node* use = n->raw_out(idx); | |
1805 idx++; | |
1806 if (!visited.test_set(use->_idx)) { | |
1807 if (member.test(use->_idx)) { | |
1808 nstack.push(n, idx); | |
1809 n = use; | |
1810 idx = 0; | |
1811 } | |
1812 } | |
1813 } else { | |
1814 // All outputs processed | |
1815 sched.push(n); | |
1816 if (nstack.is_empty()) break; | |
1817 n = nstack.node(); | |
1818 idx = nstack.index(); | |
1819 nstack.pop(); | |
1820 } | |
1821 } | |
1822 } | |
1823 | |
1824 | |
1825 //------------------------------ has_use_in_set ------------------------------------- | |
1826 // Has a use in the vector set | |
1827 bool PhaseIdealLoop::has_use_in_set( Node* n, VectorSet& vset ) { | |
1828 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
1829 Node* use = n->fast_out(j); | |
1830 if (vset.test(use->_idx)) { | |
1831 return true; | |
1832 } | |
1833 } | |
1834 return false; | |
1835 } | |
1836 | |
1837 | |
1838 //------------------------------ has_use_internal_to_set ------------------------------------- | |
1839 // Has use internal to the vector set (ie. not in a phi at the loop head) | |
1840 bool PhaseIdealLoop::has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ) { | |
1841 Node* head = loop->_head; | |
1842 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
1843 Node* use = n->fast_out(j); | |
1844 if (vset.test(use->_idx) && !(use->is_Phi() && use->in(0) == head)) { | |
1845 return true; | |
1846 } | |
1847 } | |
1848 return false; | |
1849 } | |
1850 | |
1851 | |
1852 //------------------------------ clone_for_use_outside_loop ------------------------------------- | |
1853 // clone "n" for uses that are outside of loop | |
1854 void PhaseIdealLoop::clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ) { | |
1855 | |
1856 assert(worklist.size() == 0, "should be empty"); | |
1857 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
1858 Node* use = n->fast_out(j); | |
1859 if( !loop->is_member(get_loop(has_ctrl(use) ? get_ctrl(use) : use)) ) { | |
1860 worklist.push(use); | |
1861 } | |
1862 } | |
1863 while( worklist.size() ) { | |
1864 Node *use = worklist.pop(); | |
1865 if (!has_node(use) || use->in(0) == C->top()) continue; | |
1866 uint j; | |
1867 for (j = 0; j < use->req(); j++) { | |
1868 if (use->in(j) == n) break; | |
1869 } | |
1870 assert(j < use->req(), "must be there"); | |
1871 | |
1872 // clone "n" and insert it between the inputs of "n" and the use outside the loop | |
1873 Node* n_clone = n->clone(); | |
1874 _igvn.hash_delete(use); | |
1875 use->set_req(j, n_clone); | |
1876 _igvn._worklist.push(use); | |
1877 if (!use->is_Phi()) { | |
1878 Node* use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0); | |
1879 set_ctrl(n_clone, use_c); | |
1880 assert(!loop->is_member(get_loop(use_c)), "should be outside loop"); | |
1881 get_loop(use_c)->_body.push(n_clone); | |
1882 } else { | |
1883 // Use in a phi is considered a use in the associated predecessor block | |
1884 Node *prevbb = use->in(0)->in(j); | |
1885 set_ctrl(n_clone, prevbb); | |
1886 assert(!loop->is_member(get_loop(prevbb)), "should be outside loop"); | |
1887 get_loop(prevbb)->_body.push(n_clone); | |
1888 } | |
1889 _igvn.register_new_node_with_optimizer(n_clone); | |
1890 #if !defined(PRODUCT) | |
1891 if (TracePartialPeeling) { | |
1892 tty->print_cr("loop exit cloning old: %d new: %d newbb: %d", n->_idx, n_clone->_idx, get_ctrl(n_clone)->_idx); | |
1893 } | |
1894 #endif | |
1895 } | |
1896 } | |
1897 | |
1898 | |
1899 //------------------------------ clone_for_special_use_inside_loop ------------------------------------- | |
1900 // clone "n" for special uses that are in the not_peeled region. | |
1901 // If these def-uses occur in separate blocks, the code generator | |
1902 // marks the method as not compilable. For example, if a "BoolNode" | |
1903 // is in a different basic block than the "IfNode" that uses it, then | |
1904 // the compilation is aborted in the code generator. | |
1905 void PhaseIdealLoop::clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n, | |
1906 VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ) { | |
1907 if (n->is_Phi() || n->is_Load()) { | |
1908 return; | |
1909 } | |
1910 assert(worklist.size() == 0, "should be empty"); | |
1911 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
1912 Node* use = n->fast_out(j); | |
1913 if ( not_peel.test(use->_idx) && | |
1914 (use->is_If() || use->is_CMove() || use->is_Bool()) && | |
1915 use->in(1) == n) { | |
1916 worklist.push(use); | |
1917 } | |
1918 } | |
1919 if (worklist.size() > 0) { | |
1920 // clone "n" and insert it between inputs of "n" and the use | |
1921 Node* n_clone = n->clone(); | |
1922 loop->_body.push(n_clone); | |
1923 _igvn.register_new_node_with_optimizer(n_clone); | |
1924 set_ctrl(n_clone, get_ctrl(n)); | |
1925 sink_list.push(n_clone); | |
1926 not_peel <<= n_clone->_idx; // add n_clone to not_peel set. | |
1927 #if !defined(PRODUCT) | |
1928 if (TracePartialPeeling) { | |
1929 tty->print_cr("special not_peeled cloning old: %d new: %d", n->_idx, n_clone->_idx); | |
1930 } | |
1931 #endif | |
1932 while( worklist.size() ) { | |
1933 Node *use = worklist.pop(); | |
1934 _igvn.hash_delete(use); | |
1935 _igvn._worklist.push(use); | |
1936 for (uint j = 1; j < use->req(); j++) { | |
1937 if (use->in(j) == n) { | |
1938 use->set_req(j, n_clone); | |
1939 } | |
1940 } | |
1941 } | |
1942 } | |
1943 } | |
1944 | |
1945 | |
1946 //------------------------------ insert_phi_for_loop ------------------------------------- | |
1947 // Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist | |
1948 void PhaseIdealLoop::insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ) { | |
1949 Node *phi = PhiNode::make(lp, back_edge_val); | |
1950 phi->set_req(LoopNode::EntryControl, lp_entry_val); | |
1951 // Use existing phi if it already exists | |
1952 Node *hit = _igvn.hash_find_insert(phi); | |
1953 if( hit == NULL ) { | |
1954 _igvn.register_new_node_with_optimizer(phi); | |
1955 set_ctrl(phi, lp); | |
1956 } else { | |
1957 // Remove the new phi from the graph and use the hit | |
1958 _igvn.remove_dead_node(phi); | |
1959 phi = hit; | |
1960 } | |
1961 _igvn.hash_delete(use); | |
1962 _igvn._worklist.push(use); | |
1963 use->set_req(idx, phi); | |
1964 } | |
1965 | |
1966 #ifdef ASSERT | |
1967 //------------------------------ is_valid_loop_partition ------------------------------------- | |
1968 // Validate the loop partition sets: peel and not_peel | |
1969 bool PhaseIdealLoop::is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list, | |
1970 VectorSet& not_peel ) { | |
1971 uint i; | |
1972 // Check that peel_list entries are in the peel set | |
1973 for (i = 0; i < peel_list.size(); i++) { | |
1974 if (!peel.test(peel_list.at(i)->_idx)) { | |
1975 return false; | |
1976 } | |
1977 } | |
1978 // Check at loop members are in one of peel set or not_peel set | |
1979 for (i = 0; i < loop->_body.size(); i++ ) { | |
1980 Node *def = loop->_body.at(i); | |
1981 uint di = def->_idx; | |
1982 // Check that peel set elements are in peel_list | |
1983 if (peel.test(di)) { | |
1984 if (not_peel.test(di)) { | |
1985 return false; | |
1986 } | |
1987 // Must be in peel_list also | |
1988 bool found = false; | |
1989 for (uint j = 0; j < peel_list.size(); j++) { | |
1990 if (peel_list.at(j)->_idx == di) { | |
1991 found = true; | |
1992 break; | |
1993 } | |
1994 } | |
1995 if (!found) { | |
1996 return false; | |
1997 } | |
1998 } else if (not_peel.test(di)) { | |
1999 if (peel.test(di)) { | |
2000 return false; | |
2001 } | |
2002 } else { | |
2003 return false; | |
2004 } | |
2005 } | |
2006 return true; | |
2007 } | |
2008 | |
2009 //------------------------------ is_valid_clone_loop_exit_use ------------------------------------- | |
2010 // Ensure a use outside of loop is of the right form | |
2011 bool PhaseIdealLoop::is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx) { | |
2012 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; | |
2013 return (use->is_Phi() && | |
2014 use_c->is_Region() && use_c->req() == 3 && | |
2015 (use_c->in(exit_idx)->Opcode() == Op_IfTrue || | |
2016 use_c->in(exit_idx)->Opcode() == Op_IfFalse || | |
2017 use_c->in(exit_idx)->Opcode() == Op_JumpProj) && | |
2018 loop->is_member( get_loop( use_c->in(exit_idx)->in(0) ) ) ); | |
2019 } | |
2020 | |
2021 //------------------------------ is_valid_clone_loop_form ------------------------------------- | |
2022 // Ensure that all uses outside of loop are of the right form | |
2023 bool PhaseIdealLoop::is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list, | |
2024 uint orig_exit_idx, uint clone_exit_idx) { | |
2025 uint len = peel_list.size(); | |
2026 for (uint i = 0; i < len; i++) { | |
2027 Node *def = peel_list.at(i); | |
2028 | |
2029 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { | |
2030 Node *use = def->fast_out(j); | |
2031 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; | |
2032 if (!loop->is_member(get_loop(use_c))) { | |
2033 // use is not in the loop, check for correct structure | |
2034 if (use->in(0) == def) { | |
2035 // Okay | |
2036 } else if (!is_valid_clone_loop_exit_use(loop, use, orig_exit_idx)) { | |
2037 return false; | |
2038 } | |
2039 } | |
2040 } | |
2041 } | |
2042 return true; | |
2043 } | |
2044 #endif | |
2045 | |
2046 //------------------------------ partial_peel ------------------------------------- | |
2047 // Partially peel (aka loop rotation) the top portion of a loop (called | |
2048 // the peel section below) by cloning it and placing one copy just before | |
2049 // the new loop head and the other copy at the bottom of the new loop. | |
2050 // | |
2051 // before after where it came from | |
2052 // | |
2053 // stmt1 stmt1 | |
2054 // loop: stmt2 clone | |
2055 // stmt2 if condA goto exitA clone | |
2056 // if condA goto exitA new_loop: new | |
2057 // stmt3 stmt3 clone | |
2058 // if !condB goto loop if condB goto exitB clone | |
2059 // exitB: stmt2 orig | |
2060 // stmt4 if !condA goto new_loop orig | |
2061 // exitA: goto exitA | |
2062 // exitB: | |
2063 // stmt4 | |
2064 // exitA: | |
2065 // | |
2066 // Step 1: find the cut point: an exit test on probable | |
2067 // induction variable. | |
2068 // Step 2: schedule (with cloning) operations in the peel | |
2069 // section that can be executed after the cut into | |
2070 // the section that is not peeled. This may need | |
2071 // to clone operations into exit blocks. For | |
2072 // instance, a reference to A[i] in the not-peel | |
2073 // section and a reference to B[i] in an exit block | |
2074 // may cause a left-shift of i by 2 to be placed | |
2075 // in the peel block. This step will clone the left | |
2076 // shift into the exit block and sink the left shift | |
2077 // from the peel to the not-peel section. | |
2078 // Step 3: clone the loop, retarget the control, and insert | |
2079 // phis for values that are live across the new loop | |
2080 // head. This is very dependent on the graph structure | |
2081 // from clone_loop. It creates region nodes for | |
2082 // exit control and associated phi nodes for values | |
2083 // flow out of the loop through that exit. The region | |
2084 // node is dominated by the clone's control projection. | |
2085 // So the clone's peel section is placed before the | |
2086 // new loop head, and the clone's not-peel section is | |
2087 // forms the top part of the new loop. The original | |
2088 // peel section forms the tail of the new loop. | |
2089 // Step 4: update the dominator tree and recompute the | |
2090 // dominator depth. | |
2091 // | |
2092 // orig | |
2093 // | |
2094 // stmt1 | |
2095 // | | |
2096 // v | |
2097 // loop<----+ | |
2098 // | | | |
2099 // stmt2 | | |
2100 // | | | |
2101 // v | | |
2102 // ifA | | |
2103 // / | | | |
2104 // v v | | |
2105 // false true ^ <-- last_peel | |
2106 // / | | | |
2107 // / ===|==cut | | |
2108 // / stmt3 | <-- first_not_peel | |
2109 // / | | | |
2110 // | v | | |
2111 // v ifB | | |
2112 // exitA: / \ | | |
2113 // / \ | | |
2114 // v v | | |
2115 // false true | | |
2116 // / \ | | |
2117 // / ----+ | |
2118 // | | |
2119 // v | |
2120 // exitB: | |
2121 // stmt4 | |
2122 // | |
2123 // | |
2124 // after clone loop | |
2125 // | |
2126 // stmt1 | |
2127 // / \ | |
2128 // clone / \ orig | |
2129 // / \ | |
2130 // / \ | |
2131 // v v | |
2132 // +---->loop loop<----+ | |
2133 // | | | | | |
2134 // | stmt2 stmt2 | | |
2135 // | | | | | |
2136 // | v v | | |
2137 // | ifA ifA | | |
2138 // | | \ / | | | |
2139 // | v v v v | | |
2140 // ^ true false false true ^ <-- last_peel | |
2141 // | | ^ \ / | | | |
2142 // | cut==|== \ \ / ===|==cut | | |
2143 // | stmt3 \ \ / stmt3 | <-- first_not_peel | |
2144 // | | dom | | | | | |
2145 // | v \ 1v v2 v | | |
2146 // | ifB regionA ifB | | |
2147 // | / \ | / \ | | |
2148 // | / \ v / \ | | |
2149 // | v v exitA: v v | | |
2150 // | true false false true | | |
2151 // | / ^ \ / \ | | |
2152 // +---- \ \ / ----+ | |
2153 // dom \ / | |
2154 // \ 1v v2 | |
2155 // regionB | |
2156 // | | |
2157 // v | |
2158 // exitB: | |
2159 // stmt4 | |
2160 // | |
2161 // | |
2162 // after partial peel | |
2163 // | |
2164 // stmt1 | |
2165 // / | |
2166 // clone / orig | |
2167 // / TOP | |
2168 // / \ | |
2169 // v v | |
2170 // TOP->region region----+ | |
2171 // | | | | |
2172 // stmt2 stmt2 | | |
2173 // | | | | |
2174 // v v | | |
2175 // ifA ifA | | |
2176 // | \ / | | | |
2177 // v v v v | | |
2178 // true false false true | <-- last_peel | |
2179 // | ^ \ / +------|---+ | |
2180 // +->newloop \ \ / === ==cut | | | |
2181 // | stmt3 \ \ / TOP | | | |
2182 // | | dom | | stmt3 | | <-- first_not_peel | |
2183 // | v \ 1v v2 v | | | |
2184 // | ifB regionA ifB ^ v | |
2185 // | / \ | / \ | | | |
2186 // | / \ v / \ | | | |
2187 // | v v exitA: v v | | | |
2188 // | true false false true | | | |
2189 // | / ^ \ / \ | | | |
2190 // | | \ \ / v | | | |
2191 // | | dom \ / TOP | | | |
2192 // | | \ 1v v2 | | | |
2193 // ^ v regionB | | | |
2194 // | | | | | | |
2195 // | | v ^ v | |
2196 // | | exitB: | | | |
2197 // | | stmt4 | | | |
2198 // | +------------>-----------------+ | | |
2199 // | | | |
2200 // +-----------------<---------------------+ | |
2201 // | |
2202 // | |
2203 // final graph | |
2204 // | |
2205 // stmt1 | |
2206 // | | |
2207 // v | |
2208 // ........> ifA clone | |
2209 // : / | | |
2210 // dom / | | |
2211 // : v v | |
2212 // : false true | |
2213 // : | | | |
2214 // : | stmt2 clone | |
2215 // : | | | |
2216 // : | v | |
2217 // : | newloop<-----+ | |
2218 // : | | | | |
2219 // : | stmt3 clone | | |
2220 // : | | | | |
2221 // : | v | | |
2222 // : | ifB | | |
2223 // : | / \ | | |
2224 // : | v v | | |
2225 // : | false true | | |
2226 // : | | | | | |
2227 // : | v stmt2 | | |
2228 // : | exitB: | | | |
2229 // : | stmt4 v | | |
2230 // : | ifA orig | | |
2231 // : | / \ | | |
2232 // : | / \ | | |
2233 // : | v v | | |
2234 // : | false true | | |
2235 // : | / \ | | |
2236 // : v v -----+ | |
2237 // RegionA | |
2238 // | | |
2239 // v | |
2240 // exitA | |
2241 // | |
2242 bool PhaseIdealLoop::partial_peel( IdealLoopTree *loop, Node_List &old_new ) { | |
2243 | |
2244 LoopNode *head = loop->_head->as_Loop(); | |
2245 | |
2246 if (head->is_partial_peel_loop() || head->partial_peel_has_failed()) { | |
2247 return false; | |
2248 } | |
2249 | |
2250 // Check for complex exit control | |
2251 for(uint ii = 0; ii < loop->_body.size(); ii++ ) { | |
2252 Node *n = loop->_body.at(ii); | |
2253 int opc = n->Opcode(); | |
2254 if (n->is_Call() || | |
2255 opc == Op_Catch || | |
2256 opc == Op_CatchProj || | |
2257 opc == Op_Jump || | |
2258 opc == Op_JumpProj) { | |
2259 #if !defined(PRODUCT) | |
2260 if (TracePartialPeeling) { | |
2261 tty->print_cr("\nExit control too complex: lp: %d", head->_idx); | |
2262 } | |
2263 #endif | |
2264 return false; | |
2265 } | |
2266 } | |
2267 | |
2268 int dd = dom_depth(head); | |
2269 | |
2270 // Step 1: find cut point | |
2271 | |
2272 // Walk up dominators to loop head looking for first loop exit | |
2273 // which is executed on every path thru loop. | |
2274 IfNode *peel_if = NULL; | |
2275 IfNode *peel_if_cmpu = NULL; | |
2276 | |
2277 Node *iff = loop->tail(); | |
2278 while( iff != head ) { | |
2279 if( iff->is_If() ) { | |
2280 Node *ctrl = get_ctrl(iff->in(1)); | |
2281 if (ctrl->is_top()) return false; // Dead test on live IF. | |
2282 // If loop-varying exit-test, check for induction variable | |
2283 if( loop->is_member(get_loop(ctrl)) && | |
2284 loop->is_loop_exit(iff) && | |
2285 is_possible_iv_test(iff)) { | |
2286 Node* cmp = iff->in(1)->in(1); | |
2287 if (cmp->Opcode() == Op_CmpI) { | |
2288 peel_if = iff->as_If(); | |
2289 } else { | |
2290 assert(cmp->Opcode() == Op_CmpU, "must be CmpI or CmpU"); | |
2291 peel_if_cmpu = iff->as_If(); | |
2292 } | |
2293 } | |
2294 } | |
2295 iff = idom(iff); | |
2296 } | |
2297 // Prefer signed compare over unsigned compare. | |
2298 IfNode* new_peel_if = NULL; | |
2299 if (peel_if == NULL) { | |
2300 if (!PartialPeelAtUnsignedTests || peel_if_cmpu == NULL) { | |
2301 return false; // No peel point found | |
2302 } | |
2303 new_peel_if = insert_cmpi_loop_exit(peel_if_cmpu, loop); | |
2304 if (new_peel_if == NULL) { | |
2305 return false; // No peel point found | |
2306 } | |
2307 peel_if = new_peel_if; | |
2308 } | |
2309 Node* last_peel = stay_in_loop(peel_if, loop); | |
2310 Node* first_not_peeled = stay_in_loop(last_peel, loop); | |
2311 if (first_not_peeled == NULL || first_not_peeled == head) { | |
2312 return false; | |
2313 } | |
2314 | |
2315 #if !defined(PRODUCT) | |
2316 if (TracePartialPeeling) { | |
2317 tty->print_cr("before partial peel one iteration"); | |
2318 Node_List wl; | |
2319 Node* t = head->in(2); | |
2320 while (true) { | |
2321 wl.push(t); | |
2322 if (t == head) break; | |
2323 t = idom(t); | |
2324 } | |
2325 while (wl.size() > 0) { | |
2326 Node* tt = wl.pop(); | |
2327 tt->dump(); | |
2328 if (tt == last_peel) tty->print_cr("-- cut --"); | |
2329 } | |
2330 } | |
2331 #endif | |
2332 ResourceArea *area = Thread::current()->resource_area(); | |
2333 VectorSet peel(area); | |
2334 VectorSet not_peel(area); | |
2335 Node_List peel_list(area); | |
2336 Node_List worklist(area); | |
2337 Node_List sink_list(area); | |
2338 | |
2339 // Set of cfg nodes to peel are those that are executable from | |
2340 // the head through last_peel. | |
2341 assert(worklist.size() == 0, "should be empty"); | |
2342 worklist.push(head); | |
2343 peel.set(head->_idx); | |
2344 while (worklist.size() > 0) { | |
2345 Node *n = worklist.pop(); | |
2346 if (n != last_peel) { | |
2347 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
2348 Node* use = n->fast_out(j); | |
2349 if (use->is_CFG() && | |
2350 loop->is_member(get_loop(use)) && | |
2351 !peel.test_set(use->_idx)) { | |
2352 worklist.push(use); | |
2353 } | |
2354 } | |
2355 } | |
2356 } | |
2357 | |
2358 // Set of non-cfg nodes to peel are those that are control | |
2359 // dependent on the cfg nodes. | |
2360 uint i; | |
2361 for(i = 0; i < loop->_body.size(); i++ ) { | |
2362 Node *n = loop->_body.at(i); | |
2363 Node *n_c = has_ctrl(n) ? get_ctrl(n) : n; | |
2364 if (peel.test(n_c->_idx)) { | |
2365 peel.set(n->_idx); | |
2366 } else { | |
2367 not_peel.set(n->_idx); | |
2368 } | |
2369 } | |
2370 | |
2371 // Step 2: move operations from the peeled section down into the | |
2372 // not-peeled section | |
2373 | |
2374 // Get a post order schedule of nodes in the peel region | |
2375 // Result in right-most operand. | |
2376 scheduled_nodelist(loop, peel, peel_list ); | |
2377 | |
2378 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); | |
2379 | |
2380 // For future check for too many new phis | |
2381 uint old_phi_cnt = 0; | |
2382 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) { | |
2383 Node* use = head->fast_out(j); | |
2384 if (use->is_Phi()) old_phi_cnt++; | |
2385 } | |
2386 | |
2387 #if !defined(PRODUCT) | |
2388 if (TracePartialPeeling) { | |
2389 tty->print_cr("\npeeled list"); | |
2390 } | |
2391 #endif | |
2392 | |
2393 // Evacuate nodes in peel region into the not_peeled region if possible | |
2394 uint new_phi_cnt = 0; | |
2395 for (i = 0; i < peel_list.size();) { | |
2396 Node* n = peel_list.at(i); | |
2397 #if !defined(PRODUCT) | |
2398 if (TracePartialPeeling) n->dump(); | |
2399 #endif | |
2400 bool incr = true; | |
2401 if ( !n->is_CFG() ) { | |
2402 | |
2403 if ( has_use_in_set(n, not_peel) ) { | |
2404 | |
2405 // If not used internal to the peeled region, | |
2406 // move "n" from peeled to not_peeled region. | |
2407 | |
2408 if ( !has_use_internal_to_set(n, peel, loop) ) { | |
2409 | |
2410 // if not pinned and not a load (which maybe anti-dependent on a store) | |
2411 // and not a CMove (Matcher expects only bool->cmove). | |
2412 if ( n->in(0) == NULL && !n->is_Load() && !n->is_CMove() ) { | |
2413 clone_for_use_outside_loop( loop, n, worklist ); | |
2414 | |
2415 sink_list.push(n); | |
2416 peel >>= n->_idx; // delete n from peel set. | |
2417 not_peel <<= n->_idx; // add n to not_peel set. | |
2418 peel_list.remove(i); | |
2419 incr = false; | |
2420 #if !defined(PRODUCT) | |
2421 if (TracePartialPeeling) { | |
2422 tty->print_cr("sink to not_peeled region: %d newbb: %d", | |
2423 n->_idx, get_ctrl(n)->_idx); | |
2424 } | |
2425 #endif | |
2426 } | |
2427 } else { | |
2428 // Otherwise check for special def-use cases that span | |
2429 // the peel/not_peel boundary such as bool->if | |
2430 clone_for_special_use_inside_loop( loop, n, not_peel, sink_list, worklist ); | |
2431 new_phi_cnt++; | |
2432 } | |
2433 } | |
2434 } | |
2435 if (incr) i++; | |
2436 } | |
2437 | |
2438 if (new_phi_cnt > old_phi_cnt + PartialPeelNewPhiDelta) { | |
2439 #if !defined(PRODUCT) | |
2440 if (TracePartialPeeling) { | |
2441 tty->print_cr("\nToo many new phis: %d old %d new cmpi: %c", | |
2442 new_phi_cnt, old_phi_cnt, new_peel_if != NULL?'T':'F'); | |
2443 } | |
2444 #endif | |
2445 if (new_peel_if != NULL) { | |
2446 remove_cmpi_loop_exit(new_peel_if, loop); | |
2447 } | |
2448 // Inhibit more partial peeling on this loop | |
2449 assert(!head->is_partial_peel_loop(), "not partial peeled"); | |
2450 head->mark_partial_peel_failed(); | |
2451 return false; | |
2452 } | |
2453 | |
2454 // Step 3: clone loop, retarget control, and insert new phis | |
2455 | |
2456 // Create new loop head for new phis and to hang | |
2457 // the nodes being moved (sinked) from the peel region. | |
2458 LoopNode* new_head = new (C, 3) LoopNode(last_peel, last_peel); | |
2459 _igvn.register_new_node_with_optimizer(new_head); | |
2460 assert(first_not_peeled->in(0) == last_peel, "last_peel <- first_not_peeled"); | |
2461 first_not_peeled->set_req(0, new_head); | |
2462 set_loop(new_head, loop); | |
2463 loop->_body.push(new_head); | |
2464 not_peel.set(new_head->_idx); | |
2465 set_idom(new_head, last_peel, dom_depth(first_not_peeled)); | |
2466 set_idom(first_not_peeled, new_head, dom_depth(first_not_peeled)); | |
2467 | |
2468 while (sink_list.size() > 0) { | |
2469 Node* n = sink_list.pop(); | |
2470 set_ctrl(n, new_head); | |
2471 } | |
2472 | |
2473 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); | |
2474 | |
2475 clone_loop( loop, old_new, dd ); | |
2476 | |
2477 const uint clone_exit_idx = 1; | |
2478 const uint orig_exit_idx = 2; | |
2479 assert(is_valid_clone_loop_form( loop, peel_list, orig_exit_idx, clone_exit_idx ), "bad clone loop"); | |
2480 | |
2481 Node* head_clone = old_new[head->_idx]; | |
2482 LoopNode* new_head_clone = old_new[new_head->_idx]->as_Loop(); | |
2483 Node* orig_tail_clone = head_clone->in(2); | |
2484 | |
2485 // Add phi if "def" node is in peel set and "use" is not | |
2486 | |
2487 for(i = 0; i < peel_list.size(); i++ ) { | |
2488 Node *def = peel_list.at(i); | |
2489 if (!def->is_CFG()) { | |
2490 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { | |
2491 Node *use = def->fast_out(j); | |
2492 if (has_node(use) && use->in(0) != C->top() && | |
2493 (!peel.test(use->_idx) || | |
2494 (use->is_Phi() && use->in(0) == head)) ) { | |
2495 worklist.push(use); | |
2496 } | |
2497 } | |
2498 while( worklist.size() ) { | |
2499 Node *use = worklist.pop(); | |
2500 for (uint j = 1; j < use->req(); j++) { | |
2501 Node* n = use->in(j); | |
2502 if (n == def) { | |
2503 | |
2504 // "def" is in peel set, "use" is not in peel set | |
2505 // or "use" is in the entry boundary (a phi) of the peel set | |
2506 | |
2507 Node* use_c = has_ctrl(use) ? get_ctrl(use) : use; | |
2508 | |
2509 if ( loop->is_member(get_loop( use_c )) ) { | |
2510 // use is in loop | |
2511 if (old_new[use->_idx] != NULL) { // null for dead code | |
2512 Node* use_clone = old_new[use->_idx]; | |
2513 _igvn.hash_delete(use); | |
2514 use->set_req(j, C->top()); | |
2515 _igvn._worklist.push(use); | |
2516 insert_phi_for_loop( use_clone, j, old_new[def->_idx], def, new_head_clone ); | |
2517 } | |
2518 } else { | |
2519 assert(is_valid_clone_loop_exit_use(loop, use, orig_exit_idx), "clone loop format"); | |
2520 // use is not in the loop, check if the live range includes the cut | |
2521 Node* lp_if = use_c->in(orig_exit_idx)->in(0); | |
2522 if (not_peel.test(lp_if->_idx)) { | |
2523 assert(j == orig_exit_idx, "use from original loop"); | |
2524 insert_phi_for_loop( use, clone_exit_idx, old_new[def->_idx], def, new_head_clone ); | |
2525 } | |
2526 } | |
2527 } | |
2528 } | |
2529 } | |
2530 } | |
2531 } | |
2532 | |
2533 // Step 3b: retarget control | |
2534 | |
2535 // Redirect control to the new loop head if a cloned node in | |
2536 // the not_peeled region has control that points into the peeled region. | |
2537 // This necessary because the cloned peeled region will be outside | |
2538 // the loop. | |
2539 // from to | |
2540 // cloned-peeled <---+ | |
2541 // new_head_clone: | <--+ | |
2542 // cloned-not_peeled in(0) in(0) | |
2543 // orig-peeled | |
2544 | |
2545 for(i = 0; i < loop->_body.size(); i++ ) { | |
2546 Node *n = loop->_body.at(i); | |
2547 if (!n->is_CFG() && n->in(0) != NULL && | |
2548 not_peel.test(n->_idx) && peel.test(n->in(0)->_idx)) { | |
2549 Node* n_clone = old_new[n->_idx]; | |
2550 _igvn.hash_delete(n_clone); | |
2551 n_clone->set_req(0, new_head_clone); | |
2552 _igvn._worklist.push(n_clone); | |
2553 } | |
2554 } | |
2555 | |
2556 // Backedge of the surviving new_head (the clone) is original last_peel | |
2557 _igvn.hash_delete(new_head_clone); | |
2558 new_head_clone->set_req(LoopNode::LoopBackControl, last_peel); | |
2559 _igvn._worklist.push(new_head_clone); | |
2560 | |
2561 // Cut first node in original not_peel set | |
2562 _igvn.hash_delete(new_head); | |
2563 new_head->set_req(LoopNode::EntryControl, C->top()); | |
2564 new_head->set_req(LoopNode::LoopBackControl, C->top()); | |
2565 _igvn._worklist.push(new_head); | |
2566 | |
2567 // Copy head_clone back-branch info to original head | |
2568 // and remove original head's loop entry and | |
2569 // clone head's back-branch | |
2570 _igvn.hash_delete(head); | |
2571 _igvn.hash_delete(head_clone); | |
2572 head->set_req(LoopNode::EntryControl, head_clone->in(LoopNode::LoopBackControl)); | |
2573 head->set_req(LoopNode::LoopBackControl, C->top()); | |
2574 head_clone->set_req(LoopNode::LoopBackControl, C->top()); | |
2575 _igvn._worklist.push(head); | |
2576 _igvn._worklist.push(head_clone); | |
2577 | |
2578 // Similarly modify the phis | |
2579 for (DUIterator_Fast kmax, k = head->fast_outs(kmax); k < kmax; k++) { | |
2580 Node* use = head->fast_out(k); | |
2581 if (use->is_Phi() && use->outcnt() > 0) { | |
2582 Node* use_clone = old_new[use->_idx]; | |
2583 _igvn.hash_delete(use); | |
2584 _igvn.hash_delete(use_clone); | |
2585 use->set_req(LoopNode::EntryControl, use_clone->in(LoopNode::LoopBackControl)); | |
2586 use->set_req(LoopNode::LoopBackControl, C->top()); | |
2587 use_clone->set_req(LoopNode::LoopBackControl, C->top()); | |
2588 _igvn._worklist.push(use); | |
2589 _igvn._worklist.push(use_clone); | |
2590 } | |
2591 } | |
2592 | |
2593 // Step 4: update dominator tree and dominator depth | |
2594 | |
2595 set_idom(head, orig_tail_clone, dd); | |
2596 recompute_dom_depth(); | |
2597 | |
2598 // Inhibit more partial peeling on this loop | |
2599 new_head_clone->set_partial_peel_loop(); | |
2600 C->set_major_progress(); | |
2601 | |
2602 #if !defined(PRODUCT) | |
2603 if (TracePartialPeeling) { | |
2604 tty->print_cr("\nafter partial peel one iteration"); | |
2605 Node_List wl(area); | |
2606 Node* t = last_peel; | |
2607 while (true) { | |
2608 wl.push(t); | |
2609 if (t == head_clone) break; | |
2610 t = idom(t); | |
2611 } | |
2612 while (wl.size() > 0) { | |
2613 Node* tt = wl.pop(); | |
2614 if (tt == head) tty->print_cr("orig head"); | |
2615 else if (tt == new_head_clone) tty->print_cr("new head"); | |
2616 else if (tt == head_clone) tty->print_cr("clone head"); | |
2617 tt->dump(); | |
2618 } | |
2619 } | |
2620 #endif | |
2621 return true; | |
2622 } | |
2623 | |
2624 //------------------------------reorg_offsets---------------------------------- | |
2625 // Reorganize offset computations to lower register pressure. Mostly | |
2626 // prevent loop-fallout uses of the pre-incremented trip counter (which are | |
2627 // then alive with the post-incremented trip counter forcing an extra | |
2628 // register move) | |
2629 void PhaseIdealLoop::reorg_offsets( IdealLoopTree *loop ) { | |
2630 | |
2631 CountedLoopNode *cl = loop->_head->as_CountedLoop(); | |
2632 CountedLoopEndNode *cle = cl->loopexit(); | |
2633 if( !cle ) return; // The occasional dead loop | |
2634 // Find loop exit control | |
2635 Node *exit = cle->proj_out(false); | |
2636 assert( exit->Opcode() == Op_IfFalse, "" ); | |
2637 | |
2638 // Check for the special case of folks using the pre-incremented | |
2639 // trip-counter on the fall-out path (forces the pre-incremented | |
2640 // and post-incremented trip counter to be live at the same time). | |
2641 // Fix this by adjusting to use the post-increment trip counter. | |
2642 Node *phi = cl->phi(); | |
2643 if( !phi ) return; // Dead infinite loop | |
2644 bool progress = true; | |
2645 while (progress) { | |
2646 progress = false; | |
2647 for (DUIterator_Fast imax, i = phi->fast_outs(imax); i < imax; i++) { | |
2648 Node* use = phi->fast_out(i); // User of trip-counter | |
2649 if (!has_ctrl(use)) continue; | |
2650 Node *u_ctrl = get_ctrl(use); | |
2651 if( use->is_Phi() ) { | |
2652 u_ctrl = NULL; | |
2653 for( uint j = 1; j < use->req(); j++ ) | |
2654 if( use->in(j) == phi ) | |
2655 u_ctrl = dom_lca( u_ctrl, use->in(0)->in(j) ); | |
2656 } | |
2657 IdealLoopTree *u_loop = get_loop(u_ctrl); | |
2658 // Look for loop-invariant use | |
2659 if( u_loop == loop ) continue; | |
2660 if( loop->is_member( u_loop ) ) continue; | |
2661 // Check that use is live out the bottom. Assuming the trip-counter | |
2662 // update is right at the bottom, uses of of the loop middle are ok. | |
2663 if( dom_lca( exit, u_ctrl ) != exit ) continue; | |
2664 // protect against stride not being a constant | |
2665 if( !cle->stride_is_con() ) continue; | |
2666 // Hit! Refactor use to use the post-incremented tripcounter. | |
2667 // Compute a post-increment tripcounter. | |
2668 Node *opaq = new (C, 2) Opaque2Node( cle->incr() ); | |
2669 register_new_node( opaq, u_ctrl ); | |
2670 Node *neg_stride = _igvn.intcon(-cle->stride_con()); | |
2671 set_ctrl(neg_stride, C->root()); | |
2672 Node *post = new (C, 3) AddINode( opaq, neg_stride); | |
2673 register_new_node( post, u_ctrl ); | |
2674 _igvn.hash_delete(use); | |
2675 _igvn._worklist.push(use); | |
2676 for( uint j = 1; j < use->req(); j++ ) | |
2677 if( use->in(j) == phi ) | |
2678 use->set_req(j, post); | |
2679 // Since DU info changed, rerun loop | |
2680 progress = true; | |
2681 break; | |
2682 } | |
2683 } | |
2684 | |
2685 } |