Mercurial > hg > graal-compiler
annotate src/share/vm/opto/loopopts.cpp @ 2182:9569fdf936ff
Made merge compile.
author | Thomas Wuerthinger <wuerthinger@ssw.jku.at> |
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date | Wed, 16 Feb 2011 14:21:52 +0100 |
parents | f95d63e2154a |
children | 9dc311b8473e |
rev | line source |
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0 | 1 /* |
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2 * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved. |
0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
6 * under the terms of the GNU General Public License version 2 only, as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
14 * | |
15 * You should have received a copy of the GNU General Public License version | |
16 * 2 along with this work; if not, write to the Free Software Foundation, | |
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
1972 | 25 #include "precompiled.hpp" |
26 #include "memory/allocation.inline.hpp" | |
27 #include "opto/addnode.hpp" | |
28 #include "opto/connode.hpp" | |
29 #include "opto/divnode.hpp" | |
30 #include "opto/loopnode.hpp" | |
31 #include "opto/mulnode.hpp" | |
32 #include "opto/rootnode.hpp" | |
33 #include "opto/subnode.hpp" | |
0 | 34 |
35 //============================================================================= | |
36 //------------------------------split_thru_phi--------------------------------- | |
37 // Split Node 'n' through merge point if there is enough win. | |
38 Node *PhaseIdealLoop::split_thru_phi( Node *n, Node *region, int policy ) { | |
69 | 39 if (n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::LONG) { |
40 // ConvI2L may have type information on it which is unsafe to push up | |
41 // so disable this for now | |
42 return NULL; | |
43 } | |
0 | 44 int wins = 0; |
45 assert( !n->is_CFG(), "" ); | |
46 assert( region->is_Region(), "" ); | |
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47 |
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48 const Type* type = n->bottom_type(); |
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49 const TypeOopPtr *t_oop = _igvn.type(n)->isa_oopptr(); |
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50 Node *phi; |
223 | 51 if( t_oop != NULL && t_oop->is_known_instance_field() ) { |
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52 int iid = t_oop->instance_id(); |
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53 int index = C->get_alias_index(t_oop); |
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54 int offset = t_oop->offset(); |
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55 phi = new (C,region->req()) PhiNode(region, type, NULL, iid, index, offset); |
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56 } else { |
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57 phi = PhiNode::make_blank(region, n); |
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58 } |
0 | 59 uint old_unique = C->unique(); |
60 for( uint i = 1; i < region->req(); i++ ) { | |
61 Node *x; | |
62 Node* the_clone = NULL; | |
63 if( region->in(i) == C->top() ) { | |
64 x = C->top(); // Dead path? Use a dead data op | |
65 } else { | |
66 x = n->clone(); // Else clone up the data op | |
67 the_clone = x; // Remember for possible deletion. | |
68 // Alter data node to use pre-phi inputs | |
69 if( n->in(0) == region ) | |
70 x->set_req( 0, region->in(i) ); | |
71 for( uint j = 1; j < n->req(); j++ ) { | |
72 Node *in = n->in(j); | |
73 if( in->is_Phi() && in->in(0) == region ) | |
74 x->set_req( j, in->in(i) ); // Use pre-Phi input for the clone | |
75 } | |
76 } | |
77 // Check for a 'win' on some paths | |
78 const Type *t = x->Value(&_igvn); | |
79 | |
80 bool singleton = t->singleton(); | |
81 | |
82 // A TOP singleton indicates that there are no possible values incoming | |
83 // along a particular edge. In most cases, this is OK, and the Phi will | |
84 // be eliminated later in an Ideal call. However, we can't allow this to | |
85 // happen if the singleton occurs on loop entry, as the elimination of | |
86 // the PhiNode may cause the resulting node to migrate back to a previous | |
87 // loop iteration. | |
88 if( singleton && t == Type::TOP ) { | |
89 // Is_Loop() == false does not confirm the absence of a loop (e.g., an | |
90 // irreducible loop may not be indicated by an affirmative is_Loop()); | |
91 // therefore, the only top we can split thru a phi is on a backedge of | |
92 // a loop. | |
93 singleton &= region->is_Loop() && (i != LoopNode::EntryControl); | |
94 } | |
95 | |
96 if( singleton ) { | |
97 wins++; | |
98 x = ((PhaseGVN&)_igvn).makecon(t); | |
99 } else { | |
100 // We now call Identity to try to simplify the cloned node. | |
101 // Note that some Identity methods call phase->type(this). | |
102 // Make sure that the type array is big enough for | |
103 // our new node, even though we may throw the node away. | |
104 // (Note: This tweaking with igvn only works because x is a new node.) | |
105 _igvn.set_type(x, t); | |
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106 // If x is a TypeNode, capture any more-precise type permanently into Node |
605 | 107 // otherwise it will be not updated during igvn->transform since |
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108 // igvn->type(x) is set to x->Value() already. |
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109 x->raise_bottom_type(t); |
0 | 110 Node *y = x->Identity(&_igvn); |
111 if( y != x ) { | |
112 wins++; | |
113 x = y; | |
114 } else { | |
115 y = _igvn.hash_find(x); | |
116 if( y ) { | |
117 wins++; | |
118 x = y; | |
119 } else { | |
120 // Else x is a new node we are keeping | |
121 // We do not need register_new_node_with_optimizer | |
122 // because set_type has already been called. | |
123 _igvn._worklist.push(x); | |
124 } | |
125 } | |
126 } | |
127 if (x != the_clone && the_clone != NULL) | |
128 _igvn.remove_dead_node(the_clone); | |
129 phi->set_req( i, x ); | |
130 } | |
131 // Too few wins? | |
132 if( wins <= policy ) { | |
133 _igvn.remove_dead_node(phi); | |
134 return NULL; | |
135 } | |
136 | |
137 // Record Phi | |
138 register_new_node( phi, region ); | |
139 | |
140 for( uint i2 = 1; i2 < phi->req(); i2++ ) { | |
141 Node *x = phi->in(i2); | |
142 // If we commoned up the cloned 'x' with another existing Node, | |
143 // the existing Node picks up a new use. We need to make the | |
144 // existing Node occur higher up so it dominates its uses. | |
145 Node *old_ctrl; | |
146 IdealLoopTree *old_loop; | |
147 | |
148 // The occasional new node | |
149 if( x->_idx >= old_unique ) { // Found a new, unplaced node? | |
150 old_ctrl = x->is_Con() ? C->root() : NULL; | |
151 old_loop = NULL; // Not in any prior loop | |
152 } else { | |
153 old_ctrl = x->is_Con() ? C->root() : get_ctrl(x); | |
154 old_loop = get_loop(old_ctrl); // Get prior loop | |
155 } | |
156 // New late point must dominate new use | |
157 Node *new_ctrl = dom_lca( old_ctrl, region->in(i2) ); | |
158 // Set new location | |
159 set_ctrl(x, new_ctrl); | |
160 IdealLoopTree *new_loop = get_loop( new_ctrl ); | |
161 // If changing loop bodies, see if we need to collect into new body | |
162 if( old_loop != new_loop ) { | |
163 if( old_loop && !old_loop->_child ) | |
164 old_loop->_body.yank(x); | |
165 if( !new_loop->_child ) | |
166 new_loop->_body.push(x); // Collect body info | |
167 } | |
168 } | |
169 | |
170 return phi; | |
171 } | |
172 | |
173 //------------------------------dominated_by------------------------------------ | |
174 // Replace the dominated test with an obvious true or false. Place it on the | |
175 // IGVN worklist for later cleanup. Move control-dependent data Nodes on the | |
176 // live path up to the dominating control. | |
177 void PhaseIdealLoop::dominated_by( Node *prevdom, Node *iff ) { | |
178 #ifndef PRODUCT | |
179 if( VerifyLoopOptimizations && PrintOpto ) tty->print_cr("dominating test"); | |
180 #endif | |
181 | |
182 | |
183 // prevdom is the dominating projection of the dominating test. | |
184 assert( iff->is_If(), "" ); | |
185 assert( iff->Opcode() == Op_If || iff->Opcode() == Op_CountedLoopEnd, "Check this code when new subtype is added"); | |
186 int pop = prevdom->Opcode(); | |
187 assert( pop == Op_IfFalse || pop == Op_IfTrue, "" ); | |
188 // 'con' is set to true or false to kill the dominated test. | |
189 Node *con = _igvn.makecon(pop == Op_IfTrue ? TypeInt::ONE : TypeInt::ZERO); | |
190 set_ctrl(con, C->root()); // Constant gets a new use | |
191 // Hack the dominated test | |
192 _igvn.hash_delete(iff); | |
193 iff->set_req(1, con); | |
194 _igvn._worklist.push(iff); | |
195 | |
196 // If I dont have a reachable TRUE and FALSE path following the IfNode then | |
197 // I can assume this path reaches an infinite loop. In this case it's not | |
198 // important to optimize the data Nodes - either the whole compilation will | |
199 // be tossed or this path (and all data Nodes) will go dead. | |
200 if( iff->outcnt() != 2 ) return; | |
201 | |
202 // Make control-dependent data Nodes on the live path (path that will remain | |
203 // once the dominated IF is removed) become control-dependent on the | |
204 // dominating projection. | |
205 Node* dp = ((IfNode*)iff)->proj_out(pop == Op_IfTrue); | |
206 IdealLoopTree *old_loop = get_loop(dp); | |
207 | |
208 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) { | |
209 Node* cd = dp->fast_out(i); // Control-dependent node | |
210 if( cd->depends_only_on_test() ) { | |
211 assert( cd->in(0) == dp, "" ); | |
212 _igvn.hash_delete( cd ); | |
213 cd->set_req(0, prevdom); | |
214 set_early_ctrl( cd ); | |
215 _igvn._worklist.push(cd); | |
216 IdealLoopTree *new_loop = get_loop(get_ctrl(cd)); | |
217 if( old_loop != new_loop ) { | |
218 if( !old_loop->_child ) old_loop->_body.yank(cd); | |
219 if( !new_loop->_child ) new_loop->_body.push(cd); | |
220 } | |
221 --i; | |
222 --imax; | |
223 } | |
224 } | |
225 } | |
226 | |
227 //------------------------------has_local_phi_input---------------------------- | |
228 // Return TRUE if 'n' has Phi inputs from its local block and no other | |
229 // block-local inputs (all non-local-phi inputs come from earlier blocks) | |
230 Node *PhaseIdealLoop::has_local_phi_input( Node *n ) { | |
231 Node *n_ctrl = get_ctrl(n); | |
232 // See if some inputs come from a Phi in this block, or from before | |
233 // this block. | |
234 uint i; | |
235 for( i = 1; i < n->req(); i++ ) { | |
236 Node *phi = n->in(i); | |
237 if( phi->is_Phi() && phi->in(0) == n_ctrl ) | |
238 break; | |
239 } | |
240 if( i >= n->req() ) | |
241 return NULL; // No Phi inputs; nowhere to clone thru | |
242 | |
243 // Check for inputs created between 'n' and the Phi input. These | |
244 // must split as well; they have already been given the chance | |
245 // (courtesy of a post-order visit) and since they did not we must | |
246 // recover the 'cost' of splitting them by being very profitable | |
247 // when splitting 'n'. Since this is unlikely we simply give up. | |
248 for( i = 1; i < n->req(); i++ ) { | |
249 Node *m = n->in(i); | |
250 if( get_ctrl(m) == n_ctrl && !m->is_Phi() ) { | |
251 // We allow the special case of AddP's with no local inputs. | |
252 // This allows us to split-up address expressions. | |
253 if (m->is_AddP() && | |
254 get_ctrl(m->in(2)) != n_ctrl && | |
255 get_ctrl(m->in(3)) != n_ctrl) { | |
256 // Move the AddP up to dominating point | |
257 set_ctrl_and_loop(m, find_non_split_ctrl(idom(n_ctrl))); | |
258 continue; | |
259 } | |
260 return NULL; | |
261 } | |
262 } | |
263 | |
264 return n_ctrl; | |
265 } | |
266 | |
267 //------------------------------remix_address_expressions---------------------- | |
268 // Rework addressing expressions to get the most loop-invariant stuff | |
269 // moved out. We'd like to do all associative operators, but it's especially | |
270 // important (common) to do address expressions. | |
271 Node *PhaseIdealLoop::remix_address_expressions( Node *n ) { | |
272 if (!has_ctrl(n)) return NULL; | |
273 Node *n_ctrl = get_ctrl(n); | |
274 IdealLoopTree *n_loop = get_loop(n_ctrl); | |
275 | |
276 // See if 'n' mixes loop-varying and loop-invariant inputs and | |
277 // itself is loop-varying. | |
278 | |
279 // Only interested in binary ops (and AddP) | |
280 if( n->req() < 3 || n->req() > 4 ) return NULL; | |
281 | |
282 Node *n1_ctrl = get_ctrl(n->in( 1)); | |
283 Node *n2_ctrl = get_ctrl(n->in( 2)); | |
284 Node *n3_ctrl = get_ctrl(n->in(n->req() == 3 ? 2 : 3)); | |
285 IdealLoopTree *n1_loop = get_loop( n1_ctrl ); | |
286 IdealLoopTree *n2_loop = get_loop( n2_ctrl ); | |
287 IdealLoopTree *n3_loop = get_loop( n3_ctrl ); | |
288 | |
289 // Does one of my inputs spin in a tighter loop than self? | |
290 if( (n_loop->is_member( n1_loop ) && n_loop != n1_loop) || | |
291 (n_loop->is_member( n2_loop ) && n_loop != n2_loop) || | |
292 (n_loop->is_member( n3_loop ) && n_loop != n3_loop) ) | |
293 return NULL; // Leave well enough alone | |
294 | |
295 // Is at least one of my inputs loop-invariant? | |
296 if( n1_loop == n_loop && | |
297 n2_loop == n_loop && | |
298 n3_loop == n_loop ) | |
299 return NULL; // No loop-invariant inputs | |
300 | |
301 | |
302 int n_op = n->Opcode(); | |
303 | |
304 // Replace expressions like ((V+I) << 2) with (V<<2 + I<<2). | |
305 if( n_op == Op_LShiftI ) { | |
306 // Scale is loop invariant | |
307 Node *scale = n->in(2); | |
308 Node *scale_ctrl = get_ctrl(scale); | |
309 IdealLoopTree *scale_loop = get_loop(scale_ctrl ); | |
310 if( n_loop == scale_loop || !scale_loop->is_member( n_loop ) ) | |
311 return NULL; | |
312 const TypeInt *scale_t = scale->bottom_type()->isa_int(); | |
313 if( scale_t && scale_t->is_con() && scale_t->get_con() >= 16 ) | |
314 return NULL; // Dont bother with byte/short masking | |
315 // Add must vary with loop (else shift would be loop-invariant) | |
316 Node *add = n->in(1); | |
317 Node *add_ctrl = get_ctrl(add); | |
318 IdealLoopTree *add_loop = get_loop(add_ctrl); | |
319 //assert( n_loop == add_loop, "" ); | |
320 if( n_loop != add_loop ) return NULL; // happens w/ evil ZKM loops | |
321 | |
322 // Convert I-V into I+ (0-V); same for V-I | |
323 if( add->Opcode() == Op_SubI && | |
324 _igvn.type( add->in(1) ) != TypeInt::ZERO ) { | |
325 Node *zero = _igvn.intcon(0); | |
326 set_ctrl(zero, C->root()); | |
327 Node *neg = new (C, 3) SubINode( _igvn.intcon(0), add->in(2) ); | |
328 register_new_node( neg, get_ctrl(add->in(2) ) ); | |
329 add = new (C, 3) AddINode( add->in(1), neg ); | |
330 register_new_node( add, add_ctrl ); | |
331 } | |
332 if( add->Opcode() != Op_AddI ) return NULL; | |
333 // See if one add input is loop invariant | |
334 Node *add_var = add->in(1); | |
335 Node *add_var_ctrl = get_ctrl(add_var); | |
336 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl ); | |
337 Node *add_invar = add->in(2); | |
338 Node *add_invar_ctrl = get_ctrl(add_invar); | |
339 IdealLoopTree *add_invar_loop = get_loop(add_invar_ctrl ); | |
340 if( add_var_loop == n_loop ) { | |
341 } else if( add_invar_loop == n_loop ) { | |
342 // Swap to find the invariant part | |
343 add_invar = add_var; | |
344 add_invar_ctrl = add_var_ctrl; | |
345 add_invar_loop = add_var_loop; | |
346 add_var = add->in(2); | |
347 Node *add_var_ctrl = get_ctrl(add_var); | |
348 IdealLoopTree *add_var_loop = get_loop(add_var_ctrl ); | |
349 } else // Else neither input is loop invariant | |
350 return NULL; | |
351 if( n_loop == add_invar_loop || !add_invar_loop->is_member( n_loop ) ) | |
352 return NULL; // No invariant part of the add? | |
353 | |
354 // Yes! Reshape address expression! | |
355 Node *inv_scale = new (C, 3) LShiftINode( add_invar, scale ); | |
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356 Node *inv_scale_ctrl = |
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357 dom_depth(add_invar_ctrl) > dom_depth(scale_ctrl) ? |
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358 add_invar_ctrl : scale_ctrl; |
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359 register_new_node( inv_scale, inv_scale_ctrl ); |
0 | 360 Node *var_scale = new (C, 3) LShiftINode( add_var, scale ); |
361 register_new_node( var_scale, n_ctrl ); | |
362 Node *var_add = new (C, 3) AddINode( var_scale, inv_scale ); | |
363 register_new_node( var_add, n_ctrl ); | |
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364 _igvn.replace_node( n, var_add ); |
0 | 365 return var_add; |
366 } | |
367 | |
368 // Replace (I+V) with (V+I) | |
369 if( n_op == Op_AddI || | |
370 n_op == Op_AddL || | |
371 n_op == Op_AddF || | |
372 n_op == Op_AddD || | |
373 n_op == Op_MulI || | |
374 n_op == Op_MulL || | |
375 n_op == Op_MulF || | |
376 n_op == Op_MulD ) { | |
377 if( n2_loop == n_loop ) { | |
378 assert( n1_loop != n_loop, "" ); | |
379 n->swap_edges(1, 2); | |
380 } | |
381 } | |
382 | |
383 // Replace ((I1 +p V) +p I2) with ((I1 +p I2) +p V), | |
384 // but not if I2 is a constant. | |
385 if( n_op == Op_AddP ) { | |
386 if( n2_loop == n_loop && n3_loop != n_loop ) { | |
387 if( n->in(2)->Opcode() == Op_AddP && !n->in(3)->is_Con() ) { | |
388 Node *n22_ctrl = get_ctrl(n->in(2)->in(2)); | |
389 Node *n23_ctrl = get_ctrl(n->in(2)->in(3)); | |
390 IdealLoopTree *n22loop = get_loop( n22_ctrl ); | |
391 IdealLoopTree *n23_loop = get_loop( n23_ctrl ); | |
392 if( n22loop != n_loop && n22loop->is_member(n_loop) && | |
393 n23_loop == n_loop ) { | |
394 Node *add1 = new (C, 4) AddPNode( n->in(1), n->in(2)->in(2), n->in(3) ); | |
395 // Stuff new AddP in the loop preheader | |
396 register_new_node( add1, n_loop->_head->in(LoopNode::EntryControl) ); | |
397 Node *add2 = new (C, 4) AddPNode( n->in(1), add1, n->in(2)->in(3) ); | |
398 register_new_node( add2, n_ctrl ); | |
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399 _igvn.replace_node( n, add2 ); |
0 | 400 return add2; |
401 } | |
402 } | |
403 } | |
404 | |
405 // Replace (I1 +p (I2 + V)) with ((I1 +p I2) +p V) | |
406 if( n2_loop != n_loop && n3_loop == n_loop ) { | |
407 if( n->in(3)->Opcode() == Op_AddI ) { | |
408 Node *V = n->in(3)->in(1); | |
409 Node *I = n->in(3)->in(2); | |
410 if( is_member(n_loop,get_ctrl(V)) ) { | |
411 } else { | |
412 Node *tmp = V; V = I; I = tmp; | |
413 } | |
414 if( !is_member(n_loop,get_ctrl(I)) ) { | |
415 Node *add1 = new (C, 4) AddPNode( n->in(1), n->in(2), I ); | |
416 // Stuff new AddP in the loop preheader | |
417 register_new_node( add1, n_loop->_head->in(LoopNode::EntryControl) ); | |
418 Node *add2 = new (C, 4) AddPNode( n->in(1), add1, V ); | |
419 register_new_node( add2, n_ctrl ); | |
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420 _igvn.replace_node( n, add2 ); |
0 | 421 return add2; |
422 } | |
423 } | |
424 } | |
425 } | |
426 | |
427 return NULL; | |
428 } | |
429 | |
430 //------------------------------conditional_move------------------------------- | |
431 // Attempt to replace a Phi with a conditional move. We have some pretty | |
432 // strict profitability requirements. All Phis at the merge point must | |
433 // be converted, so we can remove the control flow. We need to limit the | |
434 // number of c-moves to a small handful. All code that was in the side-arms | |
435 // of the CFG diamond is now speculatively executed. This code has to be | |
436 // "cheap enough". We are pretty much limited to CFG diamonds that merge | |
437 // 1 or 2 items with a total of 1 or 2 ops executed speculatively. | |
438 Node *PhaseIdealLoop::conditional_move( Node *region ) { | |
439 | |
440 assert( region->is_Region(), "sanity check" ); | |
441 if( region->req() != 3 ) return NULL; | |
442 | |
443 // Check for CFG diamond | |
444 Node *lp = region->in(1); | |
445 Node *rp = region->in(2); | |
446 if( !lp || !rp ) return NULL; | |
447 Node *lp_c = lp->in(0); | |
448 if( lp_c == NULL || lp_c != rp->in(0) || !lp_c->is_If() ) return NULL; | |
449 IfNode *iff = lp_c->as_If(); | |
450 | |
451 // Check for highly predictable branch. No point in CMOV'ing if | |
452 // we are going to predict accurately all the time. | |
453 // %%% This hides patterns produced by utility methods like Math.min. | |
454 if( iff->_prob < PROB_UNLIKELY_MAG(3) || | |
455 iff->_prob > PROB_LIKELY_MAG(3) ) | |
456 return NULL; | |
457 | |
458 // Check for ops pinned in an arm of the diamond. | |
459 // Can't remove the control flow in this case | |
460 if( lp->outcnt() > 1 ) return NULL; | |
461 if( rp->outcnt() > 1 ) return NULL; | |
462 | |
463 // Check profitability | |
464 int cost = 0; | |
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465 int phis = 0; |
0 | 466 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { |
467 Node *out = region->fast_out(i); | |
468 if( !out->is_Phi() ) continue; // Ignore other control edges, etc | |
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469 phis++; |
0 | 470 PhiNode* phi = out->as_Phi(); |
471 switch (phi->type()->basic_type()) { | |
472 case T_LONG: | |
473 cost++; // Probably encodes as 2 CMOV's | |
474 case T_INT: // These all CMOV fine | |
475 case T_FLOAT: | |
476 case T_DOUBLE: | |
477 case T_ADDRESS: // (RawPtr) | |
478 cost++; | |
479 break; | |
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480 case T_NARROWOOP: // Fall through |
0 | 481 case T_OBJECT: { // Base oops are OK, but not derived oops |
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482 const TypeOopPtr *tp = phi->type()->make_ptr()->isa_oopptr(); |
0 | 483 // Derived pointers are Bad (tm): what's the Base (for GC purposes) of a |
484 // CMOVE'd derived pointer? It's a CMOVE'd derived base. Thus | |
485 // CMOVE'ing a derived pointer requires we also CMOVE the base. If we | |
486 // have a Phi for the base here that we convert to a CMOVE all is well | |
487 // and good. But if the base is dead, we'll not make a CMOVE. Later | |
488 // the allocator will have to produce a base by creating a CMOVE of the | |
489 // relevant bases. This puts the allocator in the business of | |
490 // manufacturing expensive instructions, generally a bad plan. | |
491 // Just Say No to Conditionally-Moved Derived Pointers. | |
492 if( tp && tp->offset() != 0 ) | |
493 return NULL; | |
494 cost++; | |
495 break; | |
496 } | |
497 default: | |
498 return NULL; // In particular, can't do memory or I/O | |
499 } | |
500 // Add in cost any speculative ops | |
501 for( uint j = 1; j < region->req(); j++ ) { | |
502 Node *proj = region->in(j); | |
503 Node *inp = phi->in(j); | |
504 if (get_ctrl(inp) == proj) { // Found local op | |
505 cost++; | |
506 // Check for a chain of dependent ops; these will all become | |
507 // speculative in a CMOV. | |
508 for( uint k = 1; k < inp->req(); k++ ) | |
509 if (get_ctrl(inp->in(k)) == proj) | |
510 return NULL; // Too much speculative goo | |
511 } | |
512 } | |
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513 // See if the Phi is used by a Cmp or Narrow oop Decode/Encode. |
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514 // This will likely Split-If, a higher-payoff operation. |
0 | 515 for (DUIterator_Fast kmax, k = phi->fast_outs(kmax); k < kmax; k++) { |
516 Node* use = phi->fast_out(k); | |
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517 if( use->is_Cmp() || use->is_DecodeN() || use->is_EncodeP() ) |
0 | 518 return NULL; |
519 } | |
520 } | |
521 if( cost >= ConditionalMoveLimit ) return NULL; // Too much goo | |
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522 Node* bol = iff->in(1); |
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523 assert( bol->Opcode() == Op_Bool, "" ); |
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524 int cmp_op = bol->in(1)->Opcode(); |
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525 // It is expensive to generate flags from a float compare. |
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526 // Avoid duplicated float compare. |
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527 if( phis > 1 && (cmp_op == Op_CmpF || cmp_op == Op_CmpD)) return NULL; |
0 | 528 |
529 // -------------- | |
530 // Now replace all Phis with CMOV's | |
531 Node *cmov_ctrl = iff->in(0); | |
532 uint flip = (lp->Opcode() == Op_IfTrue); | |
533 while( 1 ) { | |
534 PhiNode* phi = NULL; | |
535 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { | |
536 Node *out = region->fast_out(i); | |
537 if (out->is_Phi()) { | |
538 phi = out->as_Phi(); | |
539 break; | |
540 } | |
541 } | |
542 if (phi == NULL) break; | |
543 #ifndef PRODUCT | |
544 if( PrintOpto && VerifyLoopOptimizations ) tty->print_cr("CMOV"); | |
545 #endif | |
546 // Move speculative ops | |
547 for( uint j = 1; j < region->req(); j++ ) { | |
548 Node *proj = region->in(j); | |
549 Node *inp = phi->in(j); | |
550 if (get_ctrl(inp) == proj) { // Found local op | |
551 #ifndef PRODUCT | |
552 if( PrintOpto && VerifyLoopOptimizations ) { | |
553 tty->print(" speculate: "); | |
554 inp->dump(); | |
555 } | |
556 #endif | |
557 set_ctrl(inp, cmov_ctrl); | |
558 } | |
559 } | |
560 Node *cmov = CMoveNode::make( C, cmov_ctrl, iff->in(1), phi->in(1+flip), phi->in(2-flip), _igvn.type(phi) ); | |
561 register_new_node( cmov, cmov_ctrl ); | |
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562 _igvn.replace_node( phi, cmov ); |
0 | 563 #ifndef PRODUCT |
564 if( VerifyLoopOptimizations ) verify(); | |
565 #endif | |
566 } | |
567 | |
568 // The useless CFG diamond will fold up later; see the optimization in | |
569 // RegionNode::Ideal. | |
570 _igvn._worklist.push(region); | |
571 | |
572 return iff->in(1); | |
573 } | |
574 | |
575 //------------------------------split_if_with_blocks_pre----------------------- | |
576 // Do the real work in a non-recursive function. Data nodes want to be | |
577 // cloned in the pre-order so they can feed each other nicely. | |
578 Node *PhaseIdealLoop::split_if_with_blocks_pre( Node *n ) { | |
579 // Cloning these guys is unlikely to win | |
580 int n_op = n->Opcode(); | |
581 if( n_op == Op_MergeMem ) return n; | |
582 if( n->is_Proj() ) return n; | |
583 // Do not clone-up CmpFXXX variations, as these are always | |
584 // followed by a CmpI | |
585 if( n->is_Cmp() ) return n; | |
586 // Attempt to use a conditional move instead of a phi/branch | |
587 if( ConditionalMoveLimit > 0 && n_op == Op_Region ) { | |
588 Node *cmov = conditional_move( n ); | |
589 if( cmov ) return cmov; | |
590 } | |
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591 if( n->is_CFG() || n->is_LoadStore() ) |
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592 return n; |
0 | 593 if( n_op == Op_Opaque1 || // Opaque nodes cannot be mod'd |
594 n_op == Op_Opaque2 ) { | |
595 if( !C->major_progress() ) // If chance of no more loop opts... | |
596 _igvn._worklist.push(n); // maybe we'll remove them | |
597 return n; | |
598 } | |
599 | |
600 if( n->is_Con() ) return n; // No cloning for Con nodes | |
601 | |
602 Node *n_ctrl = get_ctrl(n); | |
603 if( !n_ctrl ) return n; // Dead node | |
604 | |
605 // Attempt to remix address expressions for loop invariants | |
606 Node *m = remix_address_expressions( n ); | |
607 if( m ) return m; | |
608 | |
609 // Determine if the Node has inputs from some local Phi. | |
610 // Returns the block to clone thru. | |
611 Node *n_blk = has_local_phi_input( n ); | |
612 if( !n_blk ) return n; | |
613 // Do not clone the trip counter through on a CountedLoop | |
614 // (messes up the canonical shape). | |
615 if( n_blk->is_CountedLoop() && n->Opcode() == Op_AddI ) return n; | |
616 | |
617 // Check for having no control input; not pinned. Allow | |
618 // dominating control. | |
619 if( n->in(0) ) { | |
620 Node *dom = idom(n_blk); | |
621 if( dom_lca( n->in(0), dom ) != n->in(0) ) | |
622 return n; | |
623 } | |
624 // Policy: when is it profitable. You must get more wins than | |
625 // policy before it is considered profitable. Policy is usually 0, | |
626 // so 1 win is considered profitable. Big merges will require big | |
627 // cloning, so get a larger policy. | |
628 int policy = n_blk->req() >> 2; | |
629 | |
630 // If the loop is a candidate for range check elimination, | |
631 // delay splitting through it's phi until a later loop optimization | |
632 if (n_blk->is_CountedLoop()) { | |
633 IdealLoopTree *lp = get_loop(n_blk); | |
634 if (lp && lp->_rce_candidate) { | |
635 return n; | |
636 } | |
637 } | |
638 | |
639 // Use same limit as split_if_with_blocks_post | |
640 if( C->unique() > 35000 ) return n; // Method too big | |
641 | |
642 // Split 'n' through the merge point if it is profitable | |
643 Node *phi = split_thru_phi( n, n_blk, policy ); | |
644 if( !phi ) return n; | |
645 | |
646 // Found a Phi to split thru! | |
647 // Replace 'n' with the new phi | |
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648 _igvn.replace_node( n, phi ); |
0 | 649 // Moved a load around the loop, 'en-registering' something. |
650 if( n_blk->Opcode() == Op_Loop && n->is_Load() && | |
651 !phi->in(LoopNode::LoopBackControl)->is_Load() ) | |
652 C->set_major_progress(); | |
653 | |
654 return phi; | |
655 } | |
656 | |
657 static bool merge_point_too_heavy(Compile* C, Node* region) { | |
658 // Bail out if the region and its phis have too many users. | |
659 int weight = 0; | |
660 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { | |
661 weight += region->fast_out(i)->outcnt(); | |
662 } | |
663 int nodes_left = MaxNodeLimit - C->unique(); | |
664 if (weight * 8 > nodes_left) { | |
665 #ifndef PRODUCT | |
666 if (PrintOpto) | |
667 tty->print_cr("*** Split-if bails out: %d nodes, region weight %d", C->unique(), weight); | |
668 #endif | |
669 return true; | |
670 } else { | |
671 return false; | |
672 } | |
673 } | |
674 | |
675 static bool merge_point_safe(Node* region) { | |
676 // 4799512: Stop split_if_with_blocks from splitting a block with a ConvI2LNode | |
677 // having a PhiNode input. This sidesteps the dangerous case where the split | |
678 // ConvI2LNode may become TOP if the input Value() does not | |
679 // overlap the ConvI2L range, leaving a node which may not dominate its | |
680 // uses. | |
681 // A better fix for this problem can be found in the BugTraq entry, but | |
682 // expediency for Mantis demands this hack. | |
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683 // 6855164: If the merge point has a FastLockNode with a PhiNode input, we stop |
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684 // split_if_with_blocks from splitting a block because we could not move around |
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685 // the FastLockNode. |
0 | 686 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) { |
687 Node* n = region->fast_out(i); | |
688 if (n->is_Phi()) { | |
689 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
690 Node* m = n->fast_out(j); | |
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691 if (m->is_FastLock()) |
0 | 692 return false; |
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693 #ifdef _LP64 |
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694 if (m->Opcode() == Op_ConvI2L) |
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695 return false; |
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696 #endif |
0 | 697 } |
698 } | |
699 } | |
700 return true; | |
701 } | |
702 | |
703 | |
704 //------------------------------place_near_use--------------------------------- | |
705 // Place some computation next to use but not inside inner loops. | |
706 // For inner loop uses move it to the preheader area. | |
707 Node *PhaseIdealLoop::place_near_use( Node *useblock ) const { | |
708 IdealLoopTree *u_loop = get_loop( useblock ); | |
709 return (u_loop->_irreducible || u_loop->_child) | |
710 ? useblock | |
711 : u_loop->_head->in(LoopNode::EntryControl); | |
712 } | |
713 | |
714 | |
715 //------------------------------split_if_with_blocks_post---------------------- | |
716 // Do the real work in a non-recursive function. CFG hackery wants to be | |
717 // in the post-order, so it can dirty the I-DOM info and not use the dirtied | |
718 // info. | |
719 void PhaseIdealLoop::split_if_with_blocks_post( Node *n ) { | |
720 | |
721 // Cloning Cmp through Phi's involves the split-if transform. | |
722 // FastLock is not used by an If | |
723 if( n->is_Cmp() && !n->is_FastLock() ) { | |
724 if( C->unique() > 35000 ) return; // Method too big | |
725 | |
726 // Do not do 'split-if' if irreducible loops are present. | |
727 if( _has_irreducible_loops ) | |
728 return; | |
729 | |
730 Node *n_ctrl = get_ctrl(n); | |
731 // Determine if the Node has inputs from some local Phi. | |
732 // Returns the block to clone thru. | |
733 Node *n_blk = has_local_phi_input( n ); | |
734 if( n_blk != n_ctrl ) return; | |
735 | |
736 if( merge_point_too_heavy(C, n_ctrl) ) | |
737 return; | |
738 | |
739 if( n->outcnt() != 1 ) return; // Multiple bool's from 1 compare? | |
740 Node *bol = n->unique_out(); | |
741 assert( bol->is_Bool(), "expect a bool here" ); | |
742 if( bol->outcnt() != 1 ) return;// Multiple branches from 1 compare? | |
743 Node *iff = bol->unique_out(); | |
744 | |
745 // Check some safety conditions | |
746 if( iff->is_If() ) { // Classic split-if? | |
747 if( iff->in(0) != n_ctrl ) return; // Compare must be in same blk as if | |
748 } else if (iff->is_CMove()) { // Trying to split-up a CMOVE | |
749 if( get_ctrl(iff->in(2)) == n_ctrl || | |
750 get_ctrl(iff->in(3)) == n_ctrl ) | |
751 return; // Inputs not yet split-up | |
752 if ( get_loop(n_ctrl) != get_loop(get_ctrl(iff)) ) { | |
753 return; // Loop-invar test gates loop-varying CMOVE | |
754 } | |
755 } else { | |
756 return; // some other kind of node, such as an Allocate | |
757 } | |
758 | |
759 // Do not do 'split-if' if some paths are dead. First do dead code | |
760 // elimination and then see if its still profitable. | |
761 for( uint i = 1; i < n_ctrl->req(); i++ ) | |
762 if( n_ctrl->in(i) == C->top() ) | |
763 return; | |
764 | |
765 // When is split-if profitable? Every 'win' on means some control flow | |
766 // goes dead, so it's almost always a win. | |
767 int policy = 0; | |
768 // If trying to do a 'Split-If' at the loop head, it is only | |
769 // profitable if the cmp folds up on BOTH paths. Otherwise we | |
770 // risk peeling a loop forever. | |
771 | |
772 // CNC - Disabled for now. Requires careful handling of loop | |
773 // body selection for the cloned code. Also, make sure we check | |
774 // for any input path not being in the same loop as n_ctrl. For | |
775 // irreducible loops we cannot check for 'n_ctrl->is_Loop()' | |
776 // because the alternative loop entry points won't be converted | |
777 // into LoopNodes. | |
778 IdealLoopTree *n_loop = get_loop(n_ctrl); | |
779 for( uint j = 1; j < n_ctrl->req(); j++ ) | |
780 if( get_loop(n_ctrl->in(j)) != n_loop ) | |
781 return; | |
782 | |
783 // Check for safety of the merge point. | |
784 if( !merge_point_safe(n_ctrl) ) { | |
785 return; | |
786 } | |
787 | |
788 // Split compare 'n' through the merge point if it is profitable | |
789 Node *phi = split_thru_phi( n, n_ctrl, policy ); | |
790 if( !phi ) return; | |
791 | |
792 // Found a Phi to split thru! | |
793 // Replace 'n' with the new phi | |
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794 _igvn.replace_node( n, phi ); |
0 | 795 |
796 // Now split the bool up thru the phi | |
797 Node *bolphi = split_thru_phi( bol, n_ctrl, -1 ); | |
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798 _igvn.replace_node( bol, bolphi ); |
0 | 799 assert( iff->in(1) == bolphi, "" ); |
800 if( bolphi->Value(&_igvn)->singleton() ) | |
801 return; | |
802 | |
803 // Conditional-move? Must split up now | |
804 if( !iff->is_If() ) { | |
805 Node *cmovphi = split_thru_phi( iff, n_ctrl, -1 ); | |
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806 _igvn.replace_node( iff, cmovphi ); |
0 | 807 return; |
808 } | |
809 | |
810 // Now split the IF | |
811 do_split_if( iff ); | |
812 return; | |
813 } | |
814 | |
815 // Check for an IF ready to split; one that has its | |
816 // condition codes input coming from a Phi at the block start. | |
817 int n_op = n->Opcode(); | |
818 | |
819 // Check for an IF being dominated by another IF same test | |
820 if( n_op == Op_If ) { | |
821 Node *bol = n->in(1); | |
822 uint max = bol->outcnt(); | |
823 // Check for same test used more than once? | |
824 if( n_op == Op_If && max > 1 && bol->is_Bool() ) { | |
825 // Search up IDOMs to see if this IF is dominated. | |
826 Node *cutoff = get_ctrl(bol); | |
827 | |
828 // Now search up IDOMs till cutoff, looking for a dominating test | |
829 Node *prevdom = n; | |
830 Node *dom = idom(prevdom); | |
831 while( dom != cutoff ) { | |
832 if( dom->req() > 1 && dom->in(1) == bol && prevdom->in(0) == dom ) { | |
833 // Replace the dominated test with an obvious true or false. | |
834 // Place it on the IGVN worklist for later cleanup. | |
835 C->set_major_progress(); | |
836 dominated_by( prevdom, n ); | |
837 #ifndef PRODUCT | |
838 if( VerifyLoopOptimizations ) verify(); | |
839 #endif | |
840 return; | |
841 } | |
842 prevdom = dom; | |
843 dom = idom(prevdom); | |
844 } | |
845 } | |
846 } | |
847 | |
848 // See if a shared loop-varying computation has no loop-varying uses. | |
849 // Happens if something is only used for JVM state in uncommon trap exits, | |
850 // like various versions of induction variable+offset. Clone the | |
851 // computation per usage to allow it to sink out of the loop. | |
852 if (has_ctrl(n) && !n->in(0)) {// n not dead and has no control edge (can float about) | |
853 Node *n_ctrl = get_ctrl(n); | |
854 IdealLoopTree *n_loop = get_loop(n_ctrl); | |
855 if( n_loop != _ltree_root ) { | |
856 DUIterator_Fast imax, i = n->fast_outs(imax); | |
857 for (; i < imax; i++) { | |
858 Node* u = n->fast_out(i); | |
859 if( !has_ctrl(u) ) break; // Found control user | |
860 IdealLoopTree *u_loop = get_loop(get_ctrl(u)); | |
861 if( u_loop == n_loop ) break; // Found loop-varying use | |
862 if( n_loop->is_member( u_loop ) ) break; // Found use in inner loop | |
863 if( u->Opcode() == Op_Opaque1 ) break; // Found loop limit, bugfix for 4677003 | |
864 } | |
865 bool did_break = (i < imax); // Did we break out of the previous loop? | |
866 if (!did_break && n->outcnt() > 1) { // All uses in outer loops! | |
867 Node *late_load_ctrl; | |
868 if (n->is_Load()) { | |
869 // If n is a load, get and save the result from get_late_ctrl(), | |
870 // to be later used in calculating the control for n's clones. | |
871 clear_dom_lca_tags(); | |
872 late_load_ctrl = get_late_ctrl(n, n_ctrl); | |
873 } | |
874 // If n is a load, and the late control is the same as the current | |
875 // control, then the cloning of n is a pointless exercise, because | |
876 // GVN will ensure that we end up where we started. | |
877 if (!n->is_Load() || late_load_ctrl != n_ctrl) { | |
878 for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin; ) { | |
879 Node *u = n->last_out(j); // Clone private computation per use | |
880 _igvn.hash_delete(u); | |
881 _igvn._worklist.push(u); | |
882 Node *x = n->clone(); // Clone computation | |
883 Node *x_ctrl = NULL; | |
884 if( u->is_Phi() ) { | |
885 // Replace all uses of normal nodes. Replace Phi uses | |
605 | 886 // individually, so the separate Nodes can sink down |
0 | 887 // different paths. |
888 uint k = 1; | |
889 while( u->in(k) != n ) k++; | |
890 u->set_req( k, x ); | |
891 // x goes next to Phi input path | |
892 x_ctrl = u->in(0)->in(k); | |
893 --j; | |
894 } else { // Normal use | |
895 // Replace all uses | |
896 for( uint k = 0; k < u->req(); k++ ) { | |
897 if( u->in(k) == n ) { | |
898 u->set_req( k, x ); | |
899 --j; | |
900 } | |
901 } | |
902 x_ctrl = get_ctrl(u); | |
903 } | |
904 | |
905 // Find control for 'x' next to use but not inside inner loops. | |
906 // For inner loop uses get the preheader area. | |
907 x_ctrl = place_near_use(x_ctrl); | |
908 | |
909 if (n->is_Load()) { | |
910 // For loads, add a control edge to a CFG node outside of the loop | |
911 // to force them to not combine and return back inside the loop | |
912 // during GVN optimization (4641526). | |
913 // | |
914 // Because we are setting the actual control input, factor in | |
915 // the result from get_late_ctrl() so we respect any | |
916 // anti-dependences. (6233005). | |
917 x_ctrl = dom_lca(late_load_ctrl, x_ctrl); | |
918 | |
919 // Don't allow the control input to be a CFG splitting node. | |
920 // Such nodes should only have ProjNodes as outs, e.g. IfNode | |
921 // should only have IfTrueNode and IfFalseNode (4985384). | |
922 x_ctrl = find_non_split_ctrl(x_ctrl); | |
923 assert(dom_depth(n_ctrl) <= dom_depth(x_ctrl), "n is later than its clone"); | |
924 | |
925 x->set_req(0, x_ctrl); | |
926 } | |
927 register_new_node(x, x_ctrl); | |
928 | |
929 // Some institutional knowledge is needed here: 'x' is | |
930 // yanked because if the optimizer runs GVN on it all the | |
931 // cloned x's will common up and undo this optimization and | |
932 // be forced back in the loop. This is annoying because it | |
933 // makes +VerifyOpto report false-positives on progress. I | |
934 // tried setting control edges on the x's to force them to | |
935 // not combine, but the matching gets worried when it tries | |
936 // to fold a StoreP and an AddP together (as part of an | |
937 // address expression) and the AddP and StoreP have | |
938 // different controls. | |
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939 if( !x->is_Load() && !x->is_DecodeN() ) _igvn._worklist.yank(x); |
0 | 940 } |
941 _igvn.remove_dead_node(n); | |
942 } | |
943 } | |
944 } | |
945 } | |
946 | |
947 // Check for Opaque2's who's loop has disappeared - who's input is in the | |
948 // same loop nest as their output. Remove 'em, they are no longer useful. | |
949 if( n_op == Op_Opaque2 && | |
950 n->in(1) != NULL && | |
951 get_loop(get_ctrl(n)) == get_loop(get_ctrl(n->in(1))) ) { | |
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952 _igvn.replace_node( n, n->in(1) ); |
0 | 953 } |
954 } | |
955 | |
956 //------------------------------split_if_with_blocks--------------------------- | |
957 // Check for aggressive application of 'split-if' optimization, | |
958 // using basic block level info. | |
959 void PhaseIdealLoop::split_if_with_blocks( VectorSet &visited, Node_Stack &nstack ) { | |
960 Node *n = C->root(); | |
961 visited.set(n->_idx); // first, mark node as visited | |
962 // Do pre-visit work for root | |
963 n = split_if_with_blocks_pre( n ); | |
964 uint cnt = n->outcnt(); | |
965 uint i = 0; | |
966 while (true) { | |
967 // Visit all children | |
968 if (i < cnt) { | |
969 Node* use = n->raw_out(i); | |
970 ++i; | |
971 if (use->outcnt() != 0 && !visited.test_set(use->_idx)) { | |
972 // Now do pre-visit work for this use | |
973 use = split_if_with_blocks_pre( use ); | |
974 nstack.push(n, i); // Save parent and next use's index. | |
975 n = use; // Process all children of current use. | |
976 cnt = use->outcnt(); | |
977 i = 0; | |
978 } | |
979 } | |
980 else { | |
981 // All of n's children have been processed, complete post-processing. | |
982 if (cnt != 0 && !n->is_Con()) { | |
983 assert(has_node(n), "no dead nodes"); | |
984 split_if_with_blocks_post( n ); | |
985 } | |
986 if (nstack.is_empty()) { | |
987 // Finished all nodes on stack. | |
988 break; | |
989 } | |
990 // Get saved parent node and next use's index. Visit the rest of uses. | |
991 n = nstack.node(); | |
992 cnt = n->outcnt(); | |
993 i = nstack.index(); | |
994 nstack.pop(); | |
995 } | |
996 } | |
997 } | |
998 | |
999 | |
1000 //============================================================================= | |
1001 // | |
1002 // C L O N E A L O O P B O D Y | |
1003 // | |
1004 | |
1005 //------------------------------clone_iff-------------------------------------- | |
1006 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. | |
1007 // "Nearly" because all Nodes have been cloned from the original in the loop, | |
1008 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs | |
1009 // through the Phi recursively, and return a Bool. | |
1010 BoolNode *PhaseIdealLoop::clone_iff( PhiNode *phi, IdealLoopTree *loop ) { | |
1011 | |
1012 // Convert this Phi into a Phi merging Bools | |
1013 uint i; | |
1014 for( i = 1; i < phi->req(); i++ ) { | |
1015 Node *b = phi->in(i); | |
1016 if( b->is_Phi() ) { | |
1017 _igvn.hash_delete(phi); | |
1018 _igvn._worklist.push(phi); | |
1019 phi->set_req(i, clone_iff( b->as_Phi(), loop )); | |
1020 } else { | |
1021 assert( b->is_Bool(), "" ); | |
1022 } | |
1023 } | |
1024 | |
1025 Node *sample_bool = phi->in(1); | |
1026 Node *sample_cmp = sample_bool->in(1); | |
1027 | |
1028 // Make Phis to merge the Cmp's inputs. | |
1029 int size = phi->in(0)->req(); | |
1030 PhiNode *phi1 = new (C, size) PhiNode( phi->in(0), Type::TOP ); | |
1031 PhiNode *phi2 = new (C, size) PhiNode( phi->in(0), Type::TOP ); | |
1032 for( i = 1; i < phi->req(); i++ ) { | |
1033 Node *n1 = phi->in(i)->in(1)->in(1); | |
1034 Node *n2 = phi->in(i)->in(1)->in(2); | |
1035 phi1->set_req( i, n1 ); | |
1036 phi2->set_req( i, n2 ); | |
1037 phi1->set_type( phi1->type()->meet(n1->bottom_type()) ); | |
1038 phi2->set_type( phi2->type()->meet(n2->bottom_type()) ); | |
1039 } | |
1040 // See if these Phis have been made before. | |
1041 // Register with optimizer | |
1042 Node *hit1 = _igvn.hash_find_insert(phi1); | |
1043 if( hit1 ) { // Hit, toss just made Phi | |
1044 _igvn.remove_dead_node(phi1); // Remove new phi | |
1045 assert( hit1->is_Phi(), "" ); | |
1046 phi1 = (PhiNode*)hit1; // Use existing phi | |
1047 } else { // Miss | |
1048 _igvn.register_new_node_with_optimizer(phi1); | |
1049 } | |
1050 Node *hit2 = _igvn.hash_find_insert(phi2); | |
1051 if( hit2 ) { // Hit, toss just made Phi | |
1052 _igvn.remove_dead_node(phi2); // Remove new phi | |
1053 assert( hit2->is_Phi(), "" ); | |
1054 phi2 = (PhiNode*)hit2; // Use existing phi | |
1055 } else { // Miss | |
1056 _igvn.register_new_node_with_optimizer(phi2); | |
1057 } | |
1058 // Register Phis with loop/block info | |
1059 set_ctrl(phi1, phi->in(0)); | |
1060 set_ctrl(phi2, phi->in(0)); | |
1061 // Make a new Cmp | |
1062 Node *cmp = sample_cmp->clone(); | |
1063 cmp->set_req( 1, phi1 ); | |
1064 cmp->set_req( 2, phi2 ); | |
1065 _igvn.register_new_node_with_optimizer(cmp); | |
1066 set_ctrl(cmp, phi->in(0)); | |
1067 | |
1068 // Make a new Bool | |
1069 Node *b = sample_bool->clone(); | |
1070 b->set_req(1,cmp); | |
1071 _igvn.register_new_node_with_optimizer(b); | |
1072 set_ctrl(b, phi->in(0)); | |
1073 | |
1074 assert( b->is_Bool(), "" ); | |
1075 return (BoolNode*)b; | |
1076 } | |
1077 | |
1078 //------------------------------clone_bool------------------------------------- | |
1079 // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. | |
1080 // "Nearly" because all Nodes have been cloned from the original in the loop, | |
1081 // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs | |
1082 // through the Phi recursively, and return a Bool. | |
1083 CmpNode *PhaseIdealLoop::clone_bool( PhiNode *phi, IdealLoopTree *loop ) { | |
1084 uint i; | |
1085 // Convert this Phi into a Phi merging Bools | |
1086 for( i = 1; i < phi->req(); i++ ) { | |
1087 Node *b = phi->in(i); | |
1088 if( b->is_Phi() ) { | |
1089 _igvn.hash_delete(phi); | |
1090 _igvn._worklist.push(phi); | |
1091 phi->set_req(i, clone_bool( b->as_Phi(), loop )); | |
1092 } else { | |
1093 assert( b->is_Cmp() || b->is_top(), "inputs are all Cmp or TOP" ); | |
1094 } | |
1095 } | |
1096 | |
1097 Node *sample_cmp = phi->in(1); | |
1098 | |
1099 // Make Phis to merge the Cmp's inputs. | |
1100 int size = phi->in(0)->req(); | |
1101 PhiNode *phi1 = new (C, size) PhiNode( phi->in(0), Type::TOP ); | |
1102 PhiNode *phi2 = new (C, size) PhiNode( phi->in(0), Type::TOP ); | |
1103 for( uint j = 1; j < phi->req(); j++ ) { | |
1104 Node *cmp_top = phi->in(j); // Inputs are all Cmp or TOP | |
1105 Node *n1, *n2; | |
1106 if( cmp_top->is_Cmp() ) { | |
1107 n1 = cmp_top->in(1); | |
1108 n2 = cmp_top->in(2); | |
1109 } else { | |
1110 n1 = n2 = cmp_top; | |
1111 } | |
1112 phi1->set_req( j, n1 ); | |
1113 phi2->set_req( j, n2 ); | |
1114 phi1->set_type( phi1->type()->meet(n1->bottom_type()) ); | |
1115 phi2->set_type( phi2->type()->meet(n2->bottom_type()) ); | |
1116 } | |
1117 | |
1118 // See if these Phis have been made before. | |
1119 // Register with optimizer | |
1120 Node *hit1 = _igvn.hash_find_insert(phi1); | |
1121 if( hit1 ) { // Hit, toss just made Phi | |
1122 _igvn.remove_dead_node(phi1); // Remove new phi | |
1123 assert( hit1->is_Phi(), "" ); | |
1124 phi1 = (PhiNode*)hit1; // Use existing phi | |
1125 } else { // Miss | |
1126 _igvn.register_new_node_with_optimizer(phi1); | |
1127 } | |
1128 Node *hit2 = _igvn.hash_find_insert(phi2); | |
1129 if( hit2 ) { // Hit, toss just made Phi | |
1130 _igvn.remove_dead_node(phi2); // Remove new phi | |
1131 assert( hit2->is_Phi(), "" ); | |
1132 phi2 = (PhiNode*)hit2; // Use existing phi | |
1133 } else { // Miss | |
1134 _igvn.register_new_node_with_optimizer(phi2); | |
1135 } | |
1136 // Register Phis with loop/block info | |
1137 set_ctrl(phi1, phi->in(0)); | |
1138 set_ctrl(phi2, phi->in(0)); | |
1139 // Make a new Cmp | |
1140 Node *cmp = sample_cmp->clone(); | |
1141 cmp->set_req( 1, phi1 ); | |
1142 cmp->set_req( 2, phi2 ); | |
1143 _igvn.register_new_node_with_optimizer(cmp); | |
1144 set_ctrl(cmp, phi->in(0)); | |
1145 | |
1146 assert( cmp->is_Cmp(), "" ); | |
1147 return (CmpNode*)cmp; | |
1148 } | |
1149 | |
1150 //------------------------------sink_use--------------------------------------- | |
1151 // If 'use' was in the loop-exit block, it now needs to be sunk | |
1152 // below the post-loop merge point. | |
1153 void PhaseIdealLoop::sink_use( Node *use, Node *post_loop ) { | |
1154 if (!use->is_CFG() && get_ctrl(use) == post_loop->in(2)) { | |
1155 set_ctrl(use, post_loop); | |
1156 for (DUIterator j = use->outs(); use->has_out(j); j++) | |
1157 sink_use(use->out(j), post_loop); | |
1158 } | |
1159 } | |
1160 | |
1161 //------------------------------clone_loop------------------------------------- | |
1162 // | |
1163 // C L O N E A L O O P B O D Y | |
1164 // | |
1165 // This is the basic building block of the loop optimizations. It clones an | |
1166 // entire loop body. It makes an old_new loop body mapping; with this mapping | |
1167 // you can find the new-loop equivalent to an old-loop node. All new-loop | |
1168 // nodes are exactly equal to their old-loop counterparts, all edges are the | |
1169 // same. All exits from the old-loop now have a RegionNode that merges the | |
1170 // equivalent new-loop path. This is true even for the normal "loop-exit" | |
1171 // condition. All uses of loop-invariant old-loop values now come from (one | |
1172 // or more) Phis that merge their new-loop equivalents. | |
1173 // | |
1174 // This operation leaves the graph in an illegal state: there are two valid | |
1175 // control edges coming from the loop pre-header to both loop bodies. I'll | |
1176 // definitely have to hack the graph after running this transform. | |
1177 // | |
1178 // From this building block I will further edit edges to perform loop peeling | |
1179 // or loop unrolling or iteration splitting (Range-Check-Elimination), etc. | |
1180 // | |
1181 // Parameter side_by_size_idom: | |
1182 // When side_by_size_idom is NULL, the dominator tree is constructed for | |
1183 // the clone loop to dominate the original. Used in construction of | |
1184 // pre-main-post loop sequence. | |
1185 // When nonnull, the clone and original are side-by-side, both are | |
1186 // dominated by the side_by_side_idom node. Used in construction of | |
1187 // unswitched loops. | |
1188 void PhaseIdealLoop::clone_loop( IdealLoopTree *loop, Node_List &old_new, int dd, | |
1189 Node* side_by_side_idom) { | |
1190 | |
1191 // Step 1: Clone the loop body. Make the old->new mapping. | |
1192 uint i; | |
1193 for( i = 0; i < loop->_body.size(); i++ ) { | |
1194 Node *old = loop->_body.at(i); | |
1195 Node *nnn = old->clone(); | |
1196 old_new.map( old->_idx, nnn ); | |
1197 _igvn.register_new_node_with_optimizer(nnn); | |
1198 } | |
1199 | |
1200 | |
1201 // Step 2: Fix the edges in the new body. If the old input is outside the | |
1202 // loop use it. If the old input is INside the loop, use the corresponding | |
1203 // new node instead. | |
1204 for( i = 0; i < loop->_body.size(); i++ ) { | |
1205 Node *old = loop->_body.at(i); | |
1206 Node *nnn = old_new[old->_idx]; | |
1207 // Fix CFG/Loop controlling the new node | |
1208 if (has_ctrl(old)) { | |
1209 set_ctrl(nnn, old_new[get_ctrl(old)->_idx]); | |
1210 } else { | |
1211 set_loop(nnn, loop->_parent); | |
1212 if (old->outcnt() > 0) { | |
1213 set_idom( nnn, old_new[idom(old)->_idx], dd ); | |
1214 } | |
1215 } | |
1216 // Correct edges to the new node | |
1217 for( uint j = 0; j < nnn->req(); j++ ) { | |
1218 Node *n = nnn->in(j); | |
1219 if( n ) { | |
1220 IdealLoopTree *old_in_loop = get_loop( has_ctrl(n) ? get_ctrl(n) : n ); | |
1221 if( loop->is_member( old_in_loop ) ) | |
1222 nnn->set_req(j, old_new[n->_idx]); | |
1223 } | |
1224 } | |
1225 _igvn.hash_find_insert(nnn); | |
1226 } | |
1227 Node *newhead = old_new[loop->_head->_idx]; | |
1228 set_idom(newhead, newhead->in(LoopNode::EntryControl), dd); | |
1229 | |
1230 | |
1231 // Step 3: Now fix control uses. Loop varying control uses have already | |
1232 // been fixed up (as part of all input edges in Step 2). Loop invariant | |
1233 // control uses must be either an IfFalse or an IfTrue. Make a merge | |
1234 // point to merge the old and new IfFalse/IfTrue nodes; make the use | |
1235 // refer to this. | |
1236 ResourceArea *area = Thread::current()->resource_area(); | |
1237 Node_List worklist(area); | |
1238 uint new_counter = C->unique(); | |
1239 for( i = 0; i < loop->_body.size(); i++ ) { | |
1240 Node* old = loop->_body.at(i); | |
1241 if( !old->is_CFG() ) continue; | |
1242 Node* nnn = old_new[old->_idx]; | |
1243 | |
1244 // Copy uses to a worklist, so I can munge the def-use info | |
1245 // with impunity. | |
1246 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) | |
1247 worklist.push(old->fast_out(j)); | |
1248 | |
1249 while( worklist.size() ) { // Visit all uses | |
1250 Node *use = worklist.pop(); | |
1251 if (!has_node(use)) continue; // Ignore dead nodes | |
1252 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use ); | |
1253 if( !loop->is_member( use_loop ) && use->is_CFG() ) { | |
1254 // Both OLD and USE are CFG nodes here. | |
1255 assert( use->is_Proj(), "" ); | |
1256 | |
1257 // Clone the loop exit control projection | |
1258 Node *newuse = use->clone(); | |
1259 newuse->set_req(0,nnn); | |
1260 _igvn.register_new_node_with_optimizer(newuse); | |
1261 set_loop(newuse, use_loop); | |
1262 set_idom(newuse, nnn, dom_depth(nnn) + 1 ); | |
1263 | |
1264 // We need a Region to merge the exit from the peeled body and the | |
1265 // exit from the old loop body. | |
1266 RegionNode *r = new (C, 3) RegionNode(3); | |
1267 // Map the old use to the new merge point | |
1268 old_new.map( use->_idx, r ); | |
1269 uint dd_r = MIN2(dom_depth(newuse),dom_depth(use)); | |
1270 assert( dd_r >= dom_depth(dom_lca(newuse,use)), "" ); | |
1271 | |
1272 // The original user of 'use' uses 'r' instead. | |
1273 for (DUIterator_Last lmin, l = use->last_outs(lmin); l >= lmin;) { | |
1274 Node* useuse = use->last_out(l); | |
1275 _igvn.hash_delete(useuse); | |
1276 _igvn._worklist.push(useuse); | |
1277 uint uses_found = 0; | |
1278 if( useuse->in(0) == use ) { | |
1279 useuse->set_req(0, r); | |
1280 uses_found++; | |
1281 if( useuse->is_CFG() ) { | |
1282 assert( dom_depth(useuse) > dd_r, "" ); | |
1283 set_idom(useuse, r, dom_depth(useuse)); | |
1284 } | |
1285 } | |
1286 for( uint k = 1; k < useuse->req(); k++ ) { | |
1287 if( useuse->in(k) == use ) { | |
1288 useuse->set_req(k, r); | |
1289 uses_found++; | |
1290 } | |
1291 } | |
1292 l -= uses_found; // we deleted 1 or more copies of this edge | |
1293 } | |
1294 | |
1295 // Now finish up 'r' | |
1296 r->set_req( 1, newuse ); | |
1297 r->set_req( 2, use ); | |
1298 _igvn.register_new_node_with_optimizer(r); | |
1299 set_loop(r, use_loop); | |
1300 set_idom(r, !side_by_side_idom ? newuse->in(0) : side_by_side_idom, dd_r); | |
1301 } // End of if a loop-exit test | |
1302 } | |
1303 } | |
1304 | |
1305 // Step 4: If loop-invariant use is not control, it must be dominated by a | |
1306 // loop exit IfFalse/IfTrue. Find "proper" loop exit. Make a Region | |
1307 // there if needed. Make a Phi there merging old and new used values. | |
1308 Node_List *split_if_set = NULL; | |
1309 Node_List *split_bool_set = NULL; | |
1310 Node_List *split_cex_set = NULL; | |
1311 for( i = 0; i < loop->_body.size(); i++ ) { | |
1312 Node* old = loop->_body.at(i); | |
1313 Node* nnn = old_new[old->_idx]; | |
1314 // Copy uses to a worklist, so I can munge the def-use info | |
1315 // with impunity. | |
1316 for (DUIterator_Fast jmax, j = old->fast_outs(jmax); j < jmax; j++) | |
1317 worklist.push(old->fast_out(j)); | |
1318 | |
1319 while( worklist.size() ) { | |
1320 Node *use = worklist.pop(); | |
1321 if (!has_node(use)) continue; // Ignore dead nodes | |
1322 if (use->in(0) == C->top()) continue; | |
1323 IdealLoopTree *use_loop = get_loop( has_ctrl(use) ? get_ctrl(use) : use ); | |
1324 // Check for data-use outside of loop - at least one of OLD or USE | |
1325 // must not be a CFG node. | |
1326 if( !loop->is_member( use_loop ) && (!old->is_CFG() || !use->is_CFG())) { | |
1327 | |
1328 // If the Data use is an IF, that means we have an IF outside of the | |
1329 // loop that is switching on a condition that is set inside of the | |
1330 // loop. Happens if people set a loop-exit flag; then test the flag | |
1331 // in the loop to break the loop, then test is again outside of the | |
1332 // loop to determine which way the loop exited. | |
1333 if( use->is_If() || use->is_CMove() ) { | |
1334 // Since this code is highly unlikely, we lazily build the worklist | |
1335 // of such Nodes to go split. | |
1336 if( !split_if_set ) | |
1337 split_if_set = new Node_List(area); | |
1338 split_if_set->push(use); | |
1339 } | |
1340 if( use->is_Bool() ) { | |
1341 if( !split_bool_set ) | |
1342 split_bool_set = new Node_List(area); | |
1343 split_bool_set->push(use); | |
1344 } | |
1345 if( use->Opcode() == Op_CreateEx ) { | |
1346 if( !split_cex_set ) | |
1347 split_cex_set = new Node_List(area); | |
1348 split_cex_set->push(use); | |
1349 } | |
1350 | |
1351 | |
1352 // Get "block" use is in | |
1353 uint idx = 0; | |
1354 while( use->in(idx) != old ) idx++; | |
1355 Node *prev = use->is_CFG() ? use : get_ctrl(use); | |
1356 assert( !loop->is_member( get_loop( prev ) ), "" ); | |
1357 Node *cfg = prev->_idx >= new_counter | |
1358 ? prev->in(2) | |
1359 : idom(prev); | |
1360 if( use->is_Phi() ) // Phi use is in prior block | |
1361 cfg = prev->in(idx); // NOT in block of Phi itself | |
1362 if (cfg->is_top()) { // Use is dead? | |
1363 _igvn.hash_delete(use); | |
1364 _igvn._worklist.push(use); | |
1365 use->set_req(idx, C->top()); | |
1366 continue; | |
1367 } | |
1368 | |
1369 while( !loop->is_member( get_loop( cfg ) ) ) { | |
1370 prev = cfg; | |
1371 cfg = cfg->_idx >= new_counter ? cfg->in(2) : idom(cfg); | |
1372 } | |
1373 // If the use occurs after merging several exits from the loop, then | |
1374 // old value must have dominated all those exits. Since the same old | |
1375 // value was used on all those exits we did not need a Phi at this | |
1376 // merge point. NOW we do need a Phi here. Each loop exit value | |
1377 // is now merged with the peeled body exit; each exit gets its own | |
1378 // private Phi and those Phis need to be merged here. | |
1379 Node *phi; | |
1380 if( prev->is_Region() ) { | |
1381 if( idx == 0 ) { // Updating control edge? | |
1382 phi = prev; // Just use existing control | |
1383 } else { // Else need a new Phi | |
1384 phi = PhiNode::make( prev, old ); | |
1385 // Now recursively fix up the new uses of old! | |
1386 for( uint i = 1; i < prev->req(); i++ ) { | |
1387 worklist.push(phi); // Onto worklist once for each 'old' input | |
1388 } | |
1389 } | |
1390 } else { | |
1391 // Get new RegionNode merging old and new loop exits | |
1392 prev = old_new[prev->_idx]; | |
1393 assert( prev, "just made this in step 7" ); | |
1394 if( idx == 0 ) { // Updating control edge? | |
1395 phi = prev; // Just use existing control | |
1396 } else { // Else need a new Phi | |
1397 // Make a new Phi merging data values properly | |
1398 phi = PhiNode::make( prev, old ); | |
1399 phi->set_req( 1, nnn ); | |
1400 } | |
1401 } | |
1402 // If inserting a new Phi, check for prior hits | |
1403 if( idx != 0 ) { | |
1404 Node *hit = _igvn.hash_find_insert(phi); | |
1405 if( hit == NULL ) { | |
1406 _igvn.register_new_node_with_optimizer(phi); // Register new phi | |
1407 } else { // or | |
1408 // Remove the new phi from the graph and use the hit | |
1409 _igvn.remove_dead_node(phi); | |
1410 phi = hit; // Use existing phi | |
1411 } | |
1412 set_ctrl(phi, prev); | |
1413 } | |
1414 // Make 'use' use the Phi instead of the old loop body exit value | |
1415 _igvn.hash_delete(use); | |
1416 _igvn._worklist.push(use); | |
1417 use->set_req(idx, phi); | |
1418 if( use->_idx >= new_counter ) { // If updating new phis | |
1419 // Not needed for correctness, but prevents a weak assert | |
1420 // in AddPNode from tripping (when we end up with different | |
1421 // base & derived Phis that will become the same after | |
1422 // IGVN does CSE). | |
1423 Node *hit = _igvn.hash_find_insert(use); | |
1424 if( hit ) // Go ahead and re-hash for hits. | |
1621
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1425 _igvn.replace_node( use, hit ); |
0 | 1426 } |
1427 | |
1428 // If 'use' was in the loop-exit block, it now needs to be sunk | |
1429 // below the post-loop merge point. | |
1430 sink_use( use, prev ); | |
1431 } | |
1432 } | |
1433 } | |
1434 | |
1435 // Check for IFs that need splitting/cloning. Happens if an IF outside of | |
1436 // the loop uses a condition set in the loop. The original IF probably | |
1437 // takes control from one or more OLD Regions (which in turn get from NEW | |
1438 // Regions). In any case, there will be a set of Phis for each merge point | |
1439 // from the IF up to where the original BOOL def exists the loop. | |
1440 if( split_if_set ) { | |
1441 while( split_if_set->size() ) { | |
1442 Node *iff = split_if_set->pop(); | |
1443 if( iff->in(1)->is_Phi() ) { | |
1444 BoolNode *b = clone_iff( iff->in(1)->as_Phi(), loop ); | |
1445 _igvn.hash_delete(iff); | |
1446 _igvn._worklist.push(iff); | |
1447 iff->set_req(1, b); | |
1448 } | |
1449 } | |
1450 } | |
1451 if( split_bool_set ) { | |
1452 while( split_bool_set->size() ) { | |
1453 Node *b = split_bool_set->pop(); | |
1454 Node *phi = b->in(1); | |
1455 assert( phi->is_Phi(), "" ); | |
1456 CmpNode *cmp = clone_bool( (PhiNode*)phi, loop ); | |
1457 _igvn.hash_delete(b); | |
1458 _igvn._worklist.push(b); | |
1459 b->set_req(1, cmp); | |
1460 } | |
1461 } | |
1462 if( split_cex_set ) { | |
1463 while( split_cex_set->size() ) { | |
1464 Node *b = split_cex_set->pop(); | |
1465 assert( b->in(0)->is_Region(), "" ); | |
1466 assert( b->in(1)->is_Phi(), "" ); | |
1467 assert( b->in(0)->in(0) == b->in(1)->in(0), "" ); | |
1468 split_up( b, b->in(0), NULL ); | |
1469 } | |
1470 } | |
1471 | |
1472 } | |
1473 | |
1474 | |
1475 //---------------------- stride_of_possible_iv ------------------------------------- | |
1476 // Looks for an iff/bool/comp with one operand of the compare | |
1477 // being a cycle involving an add and a phi, | |
1478 // with an optional truncation (left-shift followed by a right-shift) | |
1479 // of the add. Returns zero if not an iv. | |
1480 int PhaseIdealLoop::stride_of_possible_iv(Node* iff) { | |
1481 Node* trunc1 = NULL; | |
1482 Node* trunc2 = NULL; | |
1483 const TypeInt* ttype = NULL; | |
1484 if (!iff->is_If() || iff->in(1) == NULL || !iff->in(1)->is_Bool()) { | |
1485 return 0; | |
1486 } | |
1487 BoolNode* bl = iff->in(1)->as_Bool(); | |
1488 Node* cmp = bl->in(1); | |
1489 if (!cmp || cmp->Opcode() != Op_CmpI && cmp->Opcode() != Op_CmpU) { | |
1490 return 0; | |
1491 } | |
1492 // Must have an invariant operand | |
1493 if (is_member(get_loop(iff), get_ctrl(cmp->in(2)))) { | |
1494 return 0; | |
1495 } | |
1496 Node* add2 = NULL; | |
1497 Node* cmp1 = cmp->in(1); | |
1498 if (cmp1->is_Phi()) { | |
1499 // (If (Bool (CmpX phi:(Phi ...(Optional-trunc(AddI phi add2))) ))) | |
1500 Node* phi = cmp1; | |
1501 for (uint i = 1; i < phi->req(); i++) { | |
1502 Node* in = phi->in(i); | |
1503 Node* add = CountedLoopNode::match_incr_with_optional_truncation(in, | |
1504 &trunc1, &trunc2, &ttype); | |
1505 if (add && add->in(1) == phi) { | |
1506 add2 = add->in(2); | |
1507 break; | |
1508 } | |
1509 } | |
1510 } else { | |
1511 // (If (Bool (CmpX addtrunc:(Optional-trunc((AddI (Phi ...addtrunc...) add2)) ))) | |
1512 Node* addtrunc = cmp1; | |
1513 Node* add = CountedLoopNode::match_incr_with_optional_truncation(addtrunc, | |
1514 &trunc1, &trunc2, &ttype); | |
1515 if (add && add->in(1)->is_Phi()) { | |
1516 Node* phi = add->in(1); | |
1517 for (uint i = 1; i < phi->req(); i++) { | |
1518 if (phi->in(i) == addtrunc) { | |
1519 add2 = add->in(2); | |
1520 break; | |
1521 } | |
1522 } | |
1523 } | |
1524 } | |
1525 if (add2 != NULL) { | |
1526 const TypeInt* add2t = _igvn.type(add2)->is_int(); | |
1527 if (add2t->is_con()) { | |
1528 return add2t->get_con(); | |
1529 } | |
1530 } | |
1531 return 0; | |
1532 } | |
1533 | |
1534 | |
1535 //---------------------- stay_in_loop ------------------------------------- | |
1536 // Return the (unique) control output node that's in the loop (if it exists.) | |
1537 Node* PhaseIdealLoop::stay_in_loop( Node* n, IdealLoopTree *loop) { | |
1538 Node* unique = NULL; | |
1539 if (!n) return NULL; | |
1540 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { | |
1541 Node* use = n->fast_out(i); | |
1542 if (!has_ctrl(use) && loop->is_member(get_loop(use))) { | |
1543 if (unique != NULL) { | |
1544 return NULL; | |
1545 } | |
1546 unique = use; | |
1547 } | |
1548 } | |
1549 return unique; | |
1550 } | |
1551 | |
1552 //------------------------------ register_node ------------------------------------- | |
1553 // Utility to register node "n" with PhaseIdealLoop | |
1554 void PhaseIdealLoop::register_node(Node* n, IdealLoopTree *loop, Node* pred, int ddepth) { | |
1555 _igvn.register_new_node_with_optimizer(n); | |
1556 loop->_body.push(n); | |
1557 if (n->is_CFG()) { | |
1558 set_loop(n, loop); | |
1559 set_idom(n, pred, ddepth); | |
1560 } else { | |
1561 set_ctrl(n, pred); | |
1562 } | |
1563 } | |
1564 | |
1565 //------------------------------ proj_clone ------------------------------------- | |
1566 // Utility to create an if-projection | |
1567 ProjNode* PhaseIdealLoop::proj_clone(ProjNode* p, IfNode* iff) { | |
1568 ProjNode* c = p->clone()->as_Proj(); | |
1569 c->set_req(0, iff); | |
1570 return c; | |
1571 } | |
1572 | |
1573 //------------------------------ short_circuit_if ------------------------------------- | |
1574 // Force the iff control output to be the live_proj | |
1575 Node* PhaseIdealLoop::short_circuit_if(IfNode* iff, ProjNode* live_proj) { | |
1576 int proj_con = live_proj->_con; | |
1577 assert(proj_con == 0 || proj_con == 1, "false or true projection"); | |
1578 Node *con = _igvn.intcon(proj_con); | |
1579 set_ctrl(con, C->root()); | |
1580 if (iff) { | |
1581 iff->set_req(1, con); | |
1582 } | |
1583 return con; | |
1584 } | |
1585 | |
1586 //------------------------------ insert_if_before_proj ------------------------------------- | |
1587 // Insert a new if before an if projection (* - new node) | |
1588 // | |
1589 // before | |
1590 // if(test) | |
1591 // / \ | |
1592 // v v | |
1593 // other-proj proj (arg) | |
1594 // | |
1595 // after | |
1596 // if(test) | |
1597 // / \ | |
1598 // / v | |
1599 // | * proj-clone | |
1600 // v | | |
1601 // other-proj v | |
1602 // * new_if(relop(cmp[IU](left,right))) | |
1603 // / \ | |
1604 // v v | |
1605 // * new-proj proj | |
1606 // (returned) | |
1607 // | |
1608 ProjNode* PhaseIdealLoop::insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj) { | |
1609 IfNode* iff = proj->in(0)->as_If(); | |
1610 IdealLoopTree *loop = get_loop(proj); | |
1611 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); | |
1612 int ddepth = dom_depth(proj); | |
1613 | |
1614 _igvn.hash_delete(iff); | |
1615 _igvn._worklist.push(iff); | |
1616 _igvn.hash_delete(proj); | |
1617 _igvn._worklist.push(proj); | |
1618 | |
1619 proj->set_req(0, NULL); // temporary disconnect | |
1620 ProjNode* proj2 = proj_clone(proj, iff); | |
1621 register_node(proj2, loop, iff, ddepth); | |
1622 | |
1623 Node* cmp = Signed ? (Node*) new (C,3)CmpINode(left, right) : (Node*) new (C,3)CmpUNode(left, right); | |
1624 register_node(cmp, loop, proj2, ddepth); | |
1625 | |
1626 BoolNode* bol = new (C,2)BoolNode(cmp, relop); | |
1627 register_node(bol, loop, proj2, ddepth); | |
1628 | |
1629 IfNode* new_if = new (C,2)IfNode(proj2, bol, iff->_prob, iff->_fcnt); | |
1630 register_node(new_if, loop, proj2, ddepth); | |
1631 | |
1632 proj->set_req(0, new_if); // reattach | |
1633 set_idom(proj, new_if, ddepth); | |
1634 | |
1635 ProjNode* new_exit = proj_clone(other_proj, new_if)->as_Proj(); | |
1636 register_node(new_exit, get_loop(other_proj), new_if, ddepth); | |
1637 | |
1638 return new_exit; | |
1639 } | |
1640 | |
1641 //------------------------------ insert_region_before_proj ------------------------------------- | |
1642 // Insert a region before an if projection (* - new node) | |
1643 // | |
1644 // before | |
1645 // if(test) | |
1646 // / | | |
1647 // v | | |
1648 // proj v | |
1649 // other-proj | |
1650 // | |
1651 // after | |
1652 // if(test) | |
1653 // / | | |
1654 // v | | |
1655 // * proj-clone v | |
1656 // | other-proj | |
1657 // v | |
1658 // * new-region | |
1659 // | | |
1660 // v | |
1661 // * dum_if | |
1662 // / \ | |
1663 // v \ | |
1664 // * dum-proj v | |
1665 // proj | |
1666 // | |
1667 RegionNode* PhaseIdealLoop::insert_region_before_proj(ProjNode* proj) { | |
1668 IfNode* iff = proj->in(0)->as_If(); | |
1669 IdealLoopTree *loop = get_loop(proj); | |
1670 ProjNode *other_proj = iff->proj_out(!proj->is_IfTrue())->as_Proj(); | |
1671 int ddepth = dom_depth(proj); | |
1672 | |
1673 _igvn.hash_delete(iff); | |
1674 _igvn._worklist.push(iff); | |
1675 _igvn.hash_delete(proj); | |
1676 _igvn._worklist.push(proj); | |
1677 | |
1678 proj->set_req(0, NULL); // temporary disconnect | |
1679 ProjNode* proj2 = proj_clone(proj, iff); | |
1680 register_node(proj2, loop, iff, ddepth); | |
1681 | |
1682 RegionNode* reg = new (C,2)RegionNode(2); | |
1683 reg->set_req(1, proj2); | |
1684 register_node(reg, loop, iff, ddepth); | |
1685 | |
1686 IfNode* dum_if = new (C,2)IfNode(reg, short_circuit_if(NULL, proj), iff->_prob, iff->_fcnt); | |
1687 register_node(dum_if, loop, reg, ddepth); | |
1688 | |
1689 proj->set_req(0, dum_if); // reattach | |
1690 set_idom(proj, dum_if, ddepth); | |
1691 | |
1692 ProjNode* dum_proj = proj_clone(other_proj, dum_if); | |
1693 register_node(dum_proj, loop, dum_if, ddepth); | |
1694 | |
1695 return reg; | |
1696 } | |
1697 | |
1698 //------------------------------ insert_cmpi_loop_exit ------------------------------------- | |
1699 // Clone a signed compare loop exit from an unsigned compare and | |
1700 // insert it before the unsigned cmp on the stay-in-loop path. | |
1701 // All new nodes inserted in the dominator tree between the original | |
1702 // if and it's projections. The original if test is replaced with | |
1703 // a constant to force the stay-in-loop path. | |
1704 // | |
1705 // This is done to make sure that the original if and it's projections | |
1706 // still dominate the same set of control nodes, that the ctrl() relation | |
1707 // from data nodes to them is preserved, and that their loop nesting is | |
1708 // preserved. | |
1709 // | |
1710 // before | |
1711 // if(i <u limit) unsigned compare loop exit | |
1712 // / | | |
1713 // v v | |
1714 // exit-proj stay-in-loop-proj | |
1715 // | |
1716 // after | |
1717 // if(stay-in-loop-const) original if | |
1718 // / | | |
1719 // / v | |
1720 // / if(i < limit) new signed test | |
1721 // / / | | |
1722 // / / v | |
1723 // / / if(i <u limit) new cloned unsigned test | |
1724 // / / / | | |
1725 // v v v | | |
1726 // region | | |
1727 // | | | |
1728 // dum-if | | |
1729 // / | | | |
1730 // ether | | | |
1731 // v v | |
1732 // exit-proj stay-in-loop-proj | |
1733 // | |
1734 IfNode* PhaseIdealLoop::insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *loop) { | |
1735 const bool Signed = true; | |
1736 const bool Unsigned = false; | |
1737 | |
1738 BoolNode* bol = if_cmpu->in(1)->as_Bool(); | |
1739 if (bol->_test._test != BoolTest::lt) return NULL; | |
1740 CmpNode* cmpu = bol->in(1)->as_Cmp(); | |
1741 if (cmpu->Opcode() != Op_CmpU) return NULL; | |
1742 int stride = stride_of_possible_iv(if_cmpu); | |
1743 if (stride == 0) return NULL; | |
1744 | |
1745 ProjNode* lp_continue = stay_in_loop(if_cmpu, loop)->as_Proj(); | |
1746 ProjNode* lp_exit = if_cmpu->proj_out(!lp_continue->is_IfTrue())->as_Proj(); | |
1747 | |
1748 Node* limit = NULL; | |
1749 if (stride > 0) { | |
1750 limit = cmpu->in(2); | |
1751 } else { | |
1752 limit = _igvn.makecon(TypeInt::ZERO); | |
1753 set_ctrl(limit, C->root()); | |
1754 } | |
1755 // Create a new region on the exit path | |
1756 RegionNode* reg = insert_region_before_proj(lp_exit); | |
1757 | |
1758 // Clone the if-cmpu-true-false using a signed compare | |
1759 BoolTest::mask rel_i = stride > 0 ? bol->_test._test : BoolTest::ge; | |
1760 ProjNode* cmpi_exit = insert_if_before_proj(cmpu->in(1), Signed, rel_i, limit, lp_continue); | |
1761 reg->add_req(cmpi_exit); | |
1762 | |
1763 // Clone the if-cmpu-true-false | |
1764 BoolTest::mask rel_u = bol->_test._test; | |
1765 ProjNode* cmpu_exit = insert_if_before_proj(cmpu->in(1), Unsigned, rel_u, cmpu->in(2), lp_continue); | |
1766 reg->add_req(cmpu_exit); | |
1767 | |
1768 // Force original if to stay in loop. | |
1769 short_circuit_if(if_cmpu, lp_continue); | |
1770 | |
1771 return cmpi_exit->in(0)->as_If(); | |
1772 } | |
1773 | |
1774 //------------------------------ remove_cmpi_loop_exit ------------------------------------- | |
1775 // Remove a previously inserted signed compare loop exit. | |
1776 void PhaseIdealLoop::remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop) { | |
1777 Node* lp_proj = stay_in_loop(if_cmp, loop); | |
1778 assert(if_cmp->in(1)->in(1)->Opcode() == Op_CmpI && | |
1779 stay_in_loop(lp_proj, loop)->is_If() && | |
1780 stay_in_loop(lp_proj, loop)->in(1)->in(1)->Opcode() == Op_CmpU, "inserted cmpi before cmpu"); | |
1781 Node *con = _igvn.makecon(lp_proj->is_IfTrue() ? TypeInt::ONE : TypeInt::ZERO); | |
1782 set_ctrl(con, C->root()); | |
1783 if_cmp->set_req(1, con); | |
1784 } | |
1785 | |
1786 //------------------------------ scheduled_nodelist ------------------------------------- | |
1787 // Create a post order schedule of nodes that are in the | |
1788 // "member" set. The list is returned in "sched". | |
1789 // The first node in "sched" is the loop head, followed by | |
1790 // nodes which have no inputs in the "member" set, and then | |
1791 // followed by the nodes that have an immediate input dependence | |
1792 // on a node in "sched". | |
1793 void PhaseIdealLoop::scheduled_nodelist( IdealLoopTree *loop, VectorSet& member, Node_List &sched ) { | |
1794 | |
1795 assert(member.test(loop->_head->_idx), "loop head must be in member set"); | |
1796 Arena *a = Thread::current()->resource_area(); | |
1797 VectorSet visited(a); | |
1798 Node_Stack nstack(a, loop->_body.size()); | |
1799 | |
1800 Node* n = loop->_head; // top of stack is cached in "n" | |
1801 uint idx = 0; | |
1802 visited.set(n->_idx); | |
1803 | |
1804 // Initially push all with no inputs from within member set | |
1805 for(uint i = 0; i < loop->_body.size(); i++ ) { | |
1806 Node *elt = loop->_body.at(i); | |
1807 if (member.test(elt->_idx)) { | |
1808 bool found = false; | |
1809 for (uint j = 0; j < elt->req(); j++) { | |
1810 Node* def = elt->in(j); | |
1811 if (def && member.test(def->_idx) && def != elt) { | |
1812 found = true; | |
1813 break; | |
1814 } | |
1815 } | |
1816 if (!found && elt != loop->_head) { | |
1817 nstack.push(n, idx); | |
1818 n = elt; | |
1819 assert(!visited.test(n->_idx), "not seen yet"); | |
1820 visited.set(n->_idx); | |
1821 } | |
1822 } | |
1823 } | |
1824 | |
1825 // traverse out's that are in the member set | |
1826 while (true) { | |
1827 if (idx < n->outcnt()) { | |
1828 Node* use = n->raw_out(idx); | |
1829 idx++; | |
1830 if (!visited.test_set(use->_idx)) { | |
1831 if (member.test(use->_idx)) { | |
1832 nstack.push(n, idx); | |
1833 n = use; | |
1834 idx = 0; | |
1835 } | |
1836 } | |
1837 } else { | |
1838 // All outputs processed | |
1839 sched.push(n); | |
1840 if (nstack.is_empty()) break; | |
1841 n = nstack.node(); | |
1842 idx = nstack.index(); | |
1843 nstack.pop(); | |
1844 } | |
1845 } | |
1846 } | |
1847 | |
1848 | |
1849 //------------------------------ has_use_in_set ------------------------------------- | |
1850 // Has a use in the vector set | |
1851 bool PhaseIdealLoop::has_use_in_set( Node* n, VectorSet& vset ) { | |
1852 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
1853 Node* use = n->fast_out(j); | |
1854 if (vset.test(use->_idx)) { | |
1855 return true; | |
1856 } | |
1857 } | |
1858 return false; | |
1859 } | |
1860 | |
1861 | |
1862 //------------------------------ has_use_internal_to_set ------------------------------------- | |
1863 // Has use internal to the vector set (ie. not in a phi at the loop head) | |
1864 bool PhaseIdealLoop::has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ) { | |
1865 Node* head = loop->_head; | |
1866 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
1867 Node* use = n->fast_out(j); | |
1868 if (vset.test(use->_idx) && !(use->is_Phi() && use->in(0) == head)) { | |
1869 return true; | |
1870 } | |
1871 } | |
1872 return false; | |
1873 } | |
1874 | |
1875 | |
1876 //------------------------------ clone_for_use_outside_loop ------------------------------------- | |
1877 // clone "n" for uses that are outside of loop | |
1878 void PhaseIdealLoop::clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ) { | |
1879 | |
1880 assert(worklist.size() == 0, "should be empty"); | |
1881 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
1882 Node* use = n->fast_out(j); | |
1883 if( !loop->is_member(get_loop(has_ctrl(use) ? get_ctrl(use) : use)) ) { | |
1884 worklist.push(use); | |
1885 } | |
1886 } | |
1887 while( worklist.size() ) { | |
1888 Node *use = worklist.pop(); | |
1889 if (!has_node(use) || use->in(0) == C->top()) continue; | |
1890 uint j; | |
1891 for (j = 0; j < use->req(); j++) { | |
1892 if (use->in(j) == n) break; | |
1893 } | |
1894 assert(j < use->req(), "must be there"); | |
1895 | |
1896 // clone "n" and insert it between the inputs of "n" and the use outside the loop | |
1897 Node* n_clone = n->clone(); | |
1898 _igvn.hash_delete(use); | |
1899 use->set_req(j, n_clone); | |
1900 _igvn._worklist.push(use); | |
251 | 1901 Node* use_c; |
0 | 1902 if (!use->is_Phi()) { |
251 | 1903 use_c = has_ctrl(use) ? get_ctrl(use) : use->in(0); |
0 | 1904 } else { |
1905 // Use in a phi is considered a use in the associated predecessor block | |
251 | 1906 use_c = use->in(0)->in(j); |
0 | 1907 } |
251 | 1908 set_ctrl(n_clone, use_c); |
1909 assert(!loop->is_member(get_loop(use_c)), "should be outside loop"); | |
1910 get_loop(use_c)->_body.push(n_clone); | |
0 | 1911 _igvn.register_new_node_with_optimizer(n_clone); |
1912 #if !defined(PRODUCT) | |
1913 if (TracePartialPeeling) { | |
1914 tty->print_cr("loop exit cloning old: %d new: %d newbb: %d", n->_idx, n_clone->_idx, get_ctrl(n_clone)->_idx); | |
1915 } | |
1916 #endif | |
1917 } | |
1918 } | |
1919 | |
1920 | |
1921 //------------------------------ clone_for_special_use_inside_loop ------------------------------------- | |
1922 // clone "n" for special uses that are in the not_peeled region. | |
1923 // If these def-uses occur in separate blocks, the code generator | |
1924 // marks the method as not compilable. For example, if a "BoolNode" | |
1925 // is in a different basic block than the "IfNode" that uses it, then | |
1926 // the compilation is aborted in the code generator. | |
1927 void PhaseIdealLoop::clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n, | |
1928 VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ) { | |
1929 if (n->is_Phi() || n->is_Load()) { | |
1930 return; | |
1931 } | |
1932 assert(worklist.size() == 0, "should be empty"); | |
1933 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
1934 Node* use = n->fast_out(j); | |
1935 if ( not_peel.test(use->_idx) && | |
1936 (use->is_If() || use->is_CMove() || use->is_Bool()) && | |
1937 use->in(1) == n) { | |
1938 worklist.push(use); | |
1939 } | |
1940 } | |
1941 if (worklist.size() > 0) { | |
1942 // clone "n" and insert it between inputs of "n" and the use | |
1943 Node* n_clone = n->clone(); | |
1944 loop->_body.push(n_clone); | |
1945 _igvn.register_new_node_with_optimizer(n_clone); | |
1946 set_ctrl(n_clone, get_ctrl(n)); | |
1947 sink_list.push(n_clone); | |
1948 not_peel <<= n_clone->_idx; // add n_clone to not_peel set. | |
1949 #if !defined(PRODUCT) | |
1950 if (TracePartialPeeling) { | |
1951 tty->print_cr("special not_peeled cloning old: %d new: %d", n->_idx, n_clone->_idx); | |
1952 } | |
1953 #endif | |
1954 while( worklist.size() ) { | |
1955 Node *use = worklist.pop(); | |
1956 _igvn.hash_delete(use); | |
1957 _igvn._worklist.push(use); | |
1958 for (uint j = 1; j < use->req(); j++) { | |
1959 if (use->in(j) == n) { | |
1960 use->set_req(j, n_clone); | |
1961 } | |
1962 } | |
1963 } | |
1964 } | |
1965 } | |
1966 | |
1967 | |
1968 //------------------------------ insert_phi_for_loop ------------------------------------- | |
1969 // Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist | |
1970 void PhaseIdealLoop::insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ) { | |
1971 Node *phi = PhiNode::make(lp, back_edge_val); | |
1972 phi->set_req(LoopNode::EntryControl, lp_entry_val); | |
1973 // Use existing phi if it already exists | |
1974 Node *hit = _igvn.hash_find_insert(phi); | |
1975 if( hit == NULL ) { | |
1976 _igvn.register_new_node_with_optimizer(phi); | |
1977 set_ctrl(phi, lp); | |
1978 } else { | |
1979 // Remove the new phi from the graph and use the hit | |
1980 _igvn.remove_dead_node(phi); | |
1981 phi = hit; | |
1982 } | |
1983 _igvn.hash_delete(use); | |
1984 _igvn._worklist.push(use); | |
1985 use->set_req(idx, phi); | |
1986 } | |
1987 | |
1988 #ifdef ASSERT | |
1989 //------------------------------ is_valid_loop_partition ------------------------------------- | |
1990 // Validate the loop partition sets: peel and not_peel | |
1991 bool PhaseIdealLoop::is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list, | |
1992 VectorSet& not_peel ) { | |
1993 uint i; | |
1994 // Check that peel_list entries are in the peel set | |
1995 for (i = 0; i < peel_list.size(); i++) { | |
1996 if (!peel.test(peel_list.at(i)->_idx)) { | |
1997 return false; | |
1998 } | |
1999 } | |
2000 // Check at loop members are in one of peel set or not_peel set | |
2001 for (i = 0; i < loop->_body.size(); i++ ) { | |
2002 Node *def = loop->_body.at(i); | |
2003 uint di = def->_idx; | |
2004 // Check that peel set elements are in peel_list | |
2005 if (peel.test(di)) { | |
2006 if (not_peel.test(di)) { | |
2007 return false; | |
2008 } | |
2009 // Must be in peel_list also | |
2010 bool found = false; | |
2011 for (uint j = 0; j < peel_list.size(); j++) { | |
2012 if (peel_list.at(j)->_idx == di) { | |
2013 found = true; | |
2014 break; | |
2015 } | |
2016 } | |
2017 if (!found) { | |
2018 return false; | |
2019 } | |
2020 } else if (not_peel.test(di)) { | |
2021 if (peel.test(di)) { | |
2022 return false; | |
2023 } | |
2024 } else { | |
2025 return false; | |
2026 } | |
2027 } | |
2028 return true; | |
2029 } | |
2030 | |
2031 //------------------------------ is_valid_clone_loop_exit_use ------------------------------------- | |
2032 // Ensure a use outside of loop is of the right form | |
2033 bool PhaseIdealLoop::is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx) { | |
2034 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; | |
2035 return (use->is_Phi() && | |
2036 use_c->is_Region() && use_c->req() == 3 && | |
2037 (use_c->in(exit_idx)->Opcode() == Op_IfTrue || | |
2038 use_c->in(exit_idx)->Opcode() == Op_IfFalse || | |
2039 use_c->in(exit_idx)->Opcode() == Op_JumpProj) && | |
2040 loop->is_member( get_loop( use_c->in(exit_idx)->in(0) ) ) ); | |
2041 } | |
2042 | |
2043 //------------------------------ is_valid_clone_loop_form ------------------------------------- | |
2044 // Ensure that all uses outside of loop are of the right form | |
2045 bool PhaseIdealLoop::is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list, | |
2046 uint orig_exit_idx, uint clone_exit_idx) { | |
2047 uint len = peel_list.size(); | |
2048 for (uint i = 0; i < len; i++) { | |
2049 Node *def = peel_list.at(i); | |
2050 | |
2051 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { | |
2052 Node *use = def->fast_out(j); | |
2053 Node *use_c = has_ctrl(use) ? get_ctrl(use) : use; | |
2054 if (!loop->is_member(get_loop(use_c))) { | |
2055 // use is not in the loop, check for correct structure | |
2056 if (use->in(0) == def) { | |
2057 // Okay | |
2058 } else if (!is_valid_clone_loop_exit_use(loop, use, orig_exit_idx)) { | |
2059 return false; | |
2060 } | |
2061 } | |
2062 } | |
2063 } | |
2064 return true; | |
2065 } | |
2066 #endif | |
2067 | |
2068 //------------------------------ partial_peel ------------------------------------- | |
2069 // Partially peel (aka loop rotation) the top portion of a loop (called | |
2070 // the peel section below) by cloning it and placing one copy just before | |
2071 // the new loop head and the other copy at the bottom of the new loop. | |
2072 // | |
2073 // before after where it came from | |
2074 // | |
2075 // stmt1 stmt1 | |
2076 // loop: stmt2 clone | |
2077 // stmt2 if condA goto exitA clone | |
2078 // if condA goto exitA new_loop: new | |
2079 // stmt3 stmt3 clone | |
2080 // if !condB goto loop if condB goto exitB clone | |
2081 // exitB: stmt2 orig | |
2082 // stmt4 if !condA goto new_loop orig | |
2083 // exitA: goto exitA | |
2084 // exitB: | |
2085 // stmt4 | |
2086 // exitA: | |
2087 // | |
2088 // Step 1: find the cut point: an exit test on probable | |
2089 // induction variable. | |
2090 // Step 2: schedule (with cloning) operations in the peel | |
2091 // section that can be executed after the cut into | |
2092 // the section that is not peeled. This may need | |
2093 // to clone operations into exit blocks. For | |
2094 // instance, a reference to A[i] in the not-peel | |
2095 // section and a reference to B[i] in an exit block | |
2096 // may cause a left-shift of i by 2 to be placed | |
2097 // in the peel block. This step will clone the left | |
2098 // shift into the exit block and sink the left shift | |
2099 // from the peel to the not-peel section. | |
2100 // Step 3: clone the loop, retarget the control, and insert | |
2101 // phis for values that are live across the new loop | |
2102 // head. This is very dependent on the graph structure | |
2103 // from clone_loop. It creates region nodes for | |
2104 // exit control and associated phi nodes for values | |
2105 // flow out of the loop through that exit. The region | |
2106 // node is dominated by the clone's control projection. | |
2107 // So the clone's peel section is placed before the | |
2108 // new loop head, and the clone's not-peel section is | |
2109 // forms the top part of the new loop. The original | |
2110 // peel section forms the tail of the new loop. | |
2111 // Step 4: update the dominator tree and recompute the | |
2112 // dominator depth. | |
2113 // | |
2114 // orig | |
2115 // | |
2116 // stmt1 | |
2117 // | | |
2118 // v | |
2119 // loop<----+ | |
2120 // | | | |
2121 // stmt2 | | |
2122 // | | | |
2123 // v | | |
2124 // ifA | | |
2125 // / | | | |
2126 // v v | | |
2127 // false true ^ <-- last_peel | |
2128 // / | | | |
2129 // / ===|==cut | | |
2130 // / stmt3 | <-- first_not_peel | |
2131 // / | | | |
2132 // | v | | |
2133 // v ifB | | |
2134 // exitA: / \ | | |
2135 // / \ | | |
2136 // v v | | |
2137 // false true | | |
2138 // / \ | | |
2139 // / ----+ | |
2140 // | | |
2141 // v | |
2142 // exitB: | |
2143 // stmt4 | |
2144 // | |
2145 // | |
2146 // after clone loop | |
2147 // | |
2148 // stmt1 | |
2149 // / \ | |
2150 // clone / \ orig | |
2151 // / \ | |
2152 // / \ | |
2153 // v v | |
2154 // +---->loop loop<----+ | |
2155 // | | | | | |
2156 // | stmt2 stmt2 | | |
2157 // | | | | | |
2158 // | v v | | |
2159 // | ifA ifA | | |
2160 // | | \ / | | | |
2161 // | v v v v | | |
2162 // ^ true false false true ^ <-- last_peel | |
2163 // | | ^ \ / | | | |
2164 // | cut==|== \ \ / ===|==cut | | |
2165 // | stmt3 \ \ / stmt3 | <-- first_not_peel | |
2166 // | | dom | | | | | |
2167 // | v \ 1v v2 v | | |
2168 // | ifB regionA ifB | | |
2169 // | / \ | / \ | | |
2170 // | / \ v / \ | | |
2171 // | v v exitA: v v | | |
2172 // | true false false true | | |
2173 // | / ^ \ / \ | | |
2174 // +---- \ \ / ----+ | |
2175 // dom \ / | |
2176 // \ 1v v2 | |
2177 // regionB | |
2178 // | | |
2179 // v | |
2180 // exitB: | |
2181 // stmt4 | |
2182 // | |
2183 // | |
2184 // after partial peel | |
2185 // | |
2186 // stmt1 | |
2187 // / | |
2188 // clone / orig | |
2189 // / TOP | |
2190 // / \ | |
2191 // v v | |
2192 // TOP->region region----+ | |
2193 // | | | | |
2194 // stmt2 stmt2 | | |
2195 // | | | | |
2196 // v v | | |
2197 // ifA ifA | | |
2198 // | \ / | | | |
2199 // v v v v | | |
2200 // true false false true | <-- last_peel | |
2201 // | ^ \ / +------|---+ | |
2202 // +->newloop \ \ / === ==cut | | | |
2203 // | stmt3 \ \ / TOP | | | |
2204 // | | dom | | stmt3 | | <-- first_not_peel | |
2205 // | v \ 1v v2 v | | | |
2206 // | ifB regionA ifB ^ v | |
2207 // | / \ | / \ | | | |
2208 // | / \ v / \ | | | |
2209 // | v v exitA: v v | | | |
2210 // | true false false true | | | |
2211 // | / ^ \ / \ | | | |
2212 // | | \ \ / v | | | |
2213 // | | dom \ / TOP | | | |
2214 // | | \ 1v v2 | | | |
2215 // ^ v regionB | | | |
2216 // | | | | | | |
2217 // | | v ^ v | |
2218 // | | exitB: | | | |
2219 // | | stmt4 | | | |
2220 // | +------------>-----------------+ | | |
2221 // | | | |
2222 // +-----------------<---------------------+ | |
2223 // | |
2224 // | |
2225 // final graph | |
2226 // | |
2227 // stmt1 | |
2228 // | | |
2229 // v | |
2230 // ........> ifA clone | |
2231 // : / | | |
2232 // dom / | | |
2233 // : v v | |
2234 // : false true | |
2235 // : | | | |
2236 // : | stmt2 clone | |
2237 // : | | | |
2238 // : | v | |
2239 // : | newloop<-----+ | |
2240 // : | | | | |
2241 // : | stmt3 clone | | |
2242 // : | | | | |
2243 // : | v | | |
2244 // : | ifB | | |
2245 // : | / \ | | |
2246 // : | v v | | |
2247 // : | false true | | |
2248 // : | | | | | |
2249 // : | v stmt2 | | |
2250 // : | exitB: | | | |
2251 // : | stmt4 v | | |
2252 // : | ifA orig | | |
2253 // : | / \ | | |
2254 // : | / \ | | |
2255 // : | v v | | |
2256 // : | false true | | |
2257 // : | / \ | | |
2258 // : v v -----+ | |
2259 // RegionA | |
2260 // | | |
2261 // v | |
2262 // exitA | |
2263 // | |
2264 bool PhaseIdealLoop::partial_peel( IdealLoopTree *loop, Node_List &old_new ) { | |
2265 | |
108 | 2266 if (!loop->_head->is_Loop()) { |
2267 return false; } | |
2268 | |
0 | 2269 LoopNode *head = loop->_head->as_Loop(); |
2270 | |
2271 if (head->is_partial_peel_loop() || head->partial_peel_has_failed()) { | |
2272 return false; | |
2273 } | |
2274 | |
2275 // Check for complex exit control | |
2276 for(uint ii = 0; ii < loop->_body.size(); ii++ ) { | |
2277 Node *n = loop->_body.at(ii); | |
2278 int opc = n->Opcode(); | |
2279 if (n->is_Call() || | |
2280 opc == Op_Catch || | |
2281 opc == Op_CatchProj || | |
2282 opc == Op_Jump || | |
2283 opc == Op_JumpProj) { | |
2284 #if !defined(PRODUCT) | |
2285 if (TracePartialPeeling) { | |
2286 tty->print_cr("\nExit control too complex: lp: %d", head->_idx); | |
2287 } | |
2288 #endif | |
2289 return false; | |
2290 } | |
2291 } | |
2292 | |
2293 int dd = dom_depth(head); | |
2294 | |
2295 // Step 1: find cut point | |
2296 | |
2297 // Walk up dominators to loop head looking for first loop exit | |
2298 // which is executed on every path thru loop. | |
2299 IfNode *peel_if = NULL; | |
2300 IfNode *peel_if_cmpu = NULL; | |
2301 | |
2302 Node *iff = loop->tail(); | |
2303 while( iff != head ) { | |
2304 if( iff->is_If() ) { | |
2305 Node *ctrl = get_ctrl(iff->in(1)); | |
2306 if (ctrl->is_top()) return false; // Dead test on live IF. | |
2307 // If loop-varying exit-test, check for induction variable | |
2308 if( loop->is_member(get_loop(ctrl)) && | |
2309 loop->is_loop_exit(iff) && | |
2310 is_possible_iv_test(iff)) { | |
2311 Node* cmp = iff->in(1)->in(1); | |
2312 if (cmp->Opcode() == Op_CmpI) { | |
2313 peel_if = iff->as_If(); | |
2314 } else { | |
2315 assert(cmp->Opcode() == Op_CmpU, "must be CmpI or CmpU"); | |
2316 peel_if_cmpu = iff->as_If(); | |
2317 } | |
2318 } | |
2319 } | |
2320 iff = idom(iff); | |
2321 } | |
2322 // Prefer signed compare over unsigned compare. | |
2323 IfNode* new_peel_if = NULL; | |
2324 if (peel_if == NULL) { | |
2325 if (!PartialPeelAtUnsignedTests || peel_if_cmpu == NULL) { | |
2326 return false; // No peel point found | |
2327 } | |
2328 new_peel_if = insert_cmpi_loop_exit(peel_if_cmpu, loop); | |
2329 if (new_peel_if == NULL) { | |
2330 return false; // No peel point found | |
2331 } | |
2332 peel_if = new_peel_if; | |
2333 } | |
2334 Node* last_peel = stay_in_loop(peel_if, loop); | |
2335 Node* first_not_peeled = stay_in_loop(last_peel, loop); | |
2336 if (first_not_peeled == NULL || first_not_peeled == head) { | |
2337 return false; | |
2338 } | |
2339 | |
2340 #if !defined(PRODUCT) | |
2341 if (TracePartialPeeling) { | |
2342 tty->print_cr("before partial peel one iteration"); | |
2343 Node_List wl; | |
2344 Node* t = head->in(2); | |
2345 while (true) { | |
2346 wl.push(t); | |
2347 if (t == head) break; | |
2348 t = idom(t); | |
2349 } | |
2350 while (wl.size() > 0) { | |
2351 Node* tt = wl.pop(); | |
2352 tt->dump(); | |
2353 if (tt == last_peel) tty->print_cr("-- cut --"); | |
2354 } | |
2355 } | |
2356 #endif | |
2357 ResourceArea *area = Thread::current()->resource_area(); | |
2358 VectorSet peel(area); | |
2359 VectorSet not_peel(area); | |
2360 Node_List peel_list(area); | |
2361 Node_List worklist(area); | |
2362 Node_List sink_list(area); | |
2363 | |
2364 // Set of cfg nodes to peel are those that are executable from | |
2365 // the head through last_peel. | |
2366 assert(worklist.size() == 0, "should be empty"); | |
2367 worklist.push(head); | |
2368 peel.set(head->_idx); | |
2369 while (worklist.size() > 0) { | |
2370 Node *n = worklist.pop(); | |
2371 if (n != last_peel) { | |
2372 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) { | |
2373 Node* use = n->fast_out(j); | |
2374 if (use->is_CFG() && | |
2375 loop->is_member(get_loop(use)) && | |
2376 !peel.test_set(use->_idx)) { | |
2377 worklist.push(use); | |
2378 } | |
2379 } | |
2380 } | |
2381 } | |
2382 | |
2383 // Set of non-cfg nodes to peel are those that are control | |
2384 // dependent on the cfg nodes. | |
2385 uint i; | |
2386 for(i = 0; i < loop->_body.size(); i++ ) { | |
2387 Node *n = loop->_body.at(i); | |
2388 Node *n_c = has_ctrl(n) ? get_ctrl(n) : n; | |
2389 if (peel.test(n_c->_idx)) { | |
2390 peel.set(n->_idx); | |
2391 } else { | |
2392 not_peel.set(n->_idx); | |
2393 } | |
2394 } | |
2395 | |
2396 // Step 2: move operations from the peeled section down into the | |
2397 // not-peeled section | |
2398 | |
2399 // Get a post order schedule of nodes in the peel region | |
2400 // Result in right-most operand. | |
2401 scheduled_nodelist(loop, peel, peel_list ); | |
2402 | |
2403 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); | |
2404 | |
2405 // For future check for too many new phis | |
2406 uint old_phi_cnt = 0; | |
2407 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) { | |
2408 Node* use = head->fast_out(j); | |
2409 if (use->is_Phi()) old_phi_cnt++; | |
2410 } | |
2411 | |
2412 #if !defined(PRODUCT) | |
2413 if (TracePartialPeeling) { | |
2414 tty->print_cr("\npeeled list"); | |
2415 } | |
2416 #endif | |
2417 | |
2418 // Evacuate nodes in peel region into the not_peeled region if possible | |
2419 uint new_phi_cnt = 0; | |
2420 for (i = 0; i < peel_list.size();) { | |
2421 Node* n = peel_list.at(i); | |
2422 #if !defined(PRODUCT) | |
2423 if (TracePartialPeeling) n->dump(); | |
2424 #endif | |
2425 bool incr = true; | |
2426 if ( !n->is_CFG() ) { | |
2427 | |
2428 if ( has_use_in_set(n, not_peel) ) { | |
2429 | |
2430 // If not used internal to the peeled region, | |
2431 // move "n" from peeled to not_peeled region. | |
2432 | |
2433 if ( !has_use_internal_to_set(n, peel, loop) ) { | |
2434 | |
2435 // if not pinned and not a load (which maybe anti-dependent on a store) | |
2436 // and not a CMove (Matcher expects only bool->cmove). | |
2437 if ( n->in(0) == NULL && !n->is_Load() && !n->is_CMove() ) { | |
2438 clone_for_use_outside_loop( loop, n, worklist ); | |
2439 | |
2440 sink_list.push(n); | |
2441 peel >>= n->_idx; // delete n from peel set. | |
2442 not_peel <<= n->_idx; // add n to not_peel set. | |
2443 peel_list.remove(i); | |
2444 incr = false; | |
2445 #if !defined(PRODUCT) | |
2446 if (TracePartialPeeling) { | |
2447 tty->print_cr("sink to not_peeled region: %d newbb: %d", | |
2448 n->_idx, get_ctrl(n)->_idx); | |
2449 } | |
2450 #endif | |
2451 } | |
2452 } else { | |
2453 // Otherwise check for special def-use cases that span | |
2454 // the peel/not_peel boundary such as bool->if | |
2455 clone_for_special_use_inside_loop( loop, n, not_peel, sink_list, worklist ); | |
2456 new_phi_cnt++; | |
2457 } | |
2458 } | |
2459 } | |
2460 if (incr) i++; | |
2461 } | |
2462 | |
2463 if (new_phi_cnt > old_phi_cnt + PartialPeelNewPhiDelta) { | |
2464 #if !defined(PRODUCT) | |
2465 if (TracePartialPeeling) { | |
2466 tty->print_cr("\nToo many new phis: %d old %d new cmpi: %c", | |
2467 new_phi_cnt, old_phi_cnt, new_peel_if != NULL?'T':'F'); | |
2468 } | |
2469 #endif | |
2470 if (new_peel_if != NULL) { | |
2471 remove_cmpi_loop_exit(new_peel_if, loop); | |
2472 } | |
2473 // Inhibit more partial peeling on this loop | |
2474 assert(!head->is_partial_peel_loop(), "not partial peeled"); | |
2475 head->mark_partial_peel_failed(); | |
2476 return false; | |
2477 } | |
2478 | |
2479 // Step 3: clone loop, retarget control, and insert new phis | |
2480 | |
2481 // Create new loop head for new phis and to hang | |
2482 // the nodes being moved (sinked) from the peel region. | |
2483 LoopNode* new_head = new (C, 3) LoopNode(last_peel, last_peel); | |
2484 _igvn.register_new_node_with_optimizer(new_head); | |
2485 assert(first_not_peeled->in(0) == last_peel, "last_peel <- first_not_peeled"); | |
2486 first_not_peeled->set_req(0, new_head); | |
2487 set_loop(new_head, loop); | |
2488 loop->_body.push(new_head); | |
2489 not_peel.set(new_head->_idx); | |
2490 set_idom(new_head, last_peel, dom_depth(first_not_peeled)); | |
2491 set_idom(first_not_peeled, new_head, dom_depth(first_not_peeled)); | |
2492 | |
2493 while (sink_list.size() > 0) { | |
2494 Node* n = sink_list.pop(); | |
2495 set_ctrl(n, new_head); | |
2496 } | |
2497 | |
2498 assert(is_valid_loop_partition(loop, peel, peel_list, not_peel), "bad partition"); | |
2499 | |
2500 clone_loop( loop, old_new, dd ); | |
2501 | |
2502 const uint clone_exit_idx = 1; | |
2503 const uint orig_exit_idx = 2; | |
2504 assert(is_valid_clone_loop_form( loop, peel_list, orig_exit_idx, clone_exit_idx ), "bad clone loop"); | |
2505 | |
2506 Node* head_clone = old_new[head->_idx]; | |
2507 LoopNode* new_head_clone = old_new[new_head->_idx]->as_Loop(); | |
2508 Node* orig_tail_clone = head_clone->in(2); | |
2509 | |
2510 // Add phi if "def" node is in peel set and "use" is not | |
2511 | |
2512 for(i = 0; i < peel_list.size(); i++ ) { | |
2513 Node *def = peel_list.at(i); | |
2514 if (!def->is_CFG()) { | |
2515 for (DUIterator_Fast jmax, j = def->fast_outs(jmax); j < jmax; j++) { | |
2516 Node *use = def->fast_out(j); | |
2517 if (has_node(use) && use->in(0) != C->top() && | |
2518 (!peel.test(use->_idx) || | |
2519 (use->is_Phi() && use->in(0) == head)) ) { | |
2520 worklist.push(use); | |
2521 } | |
2522 } | |
2523 while( worklist.size() ) { | |
2524 Node *use = worklist.pop(); | |
2525 for (uint j = 1; j < use->req(); j++) { | |
2526 Node* n = use->in(j); | |
2527 if (n == def) { | |
2528 | |
2529 // "def" is in peel set, "use" is not in peel set | |
2530 // or "use" is in the entry boundary (a phi) of the peel set | |
2531 | |
2532 Node* use_c = has_ctrl(use) ? get_ctrl(use) : use; | |
2533 | |
2534 if ( loop->is_member(get_loop( use_c )) ) { | |
2535 // use is in loop | |
2536 if (old_new[use->_idx] != NULL) { // null for dead code | |
2537 Node* use_clone = old_new[use->_idx]; | |
2538 _igvn.hash_delete(use); | |
2539 use->set_req(j, C->top()); | |
2540 _igvn._worklist.push(use); | |
2541 insert_phi_for_loop( use_clone, j, old_new[def->_idx], def, new_head_clone ); | |
2542 } | |
2543 } else { | |
2544 assert(is_valid_clone_loop_exit_use(loop, use, orig_exit_idx), "clone loop format"); | |
2545 // use is not in the loop, check if the live range includes the cut | |
2546 Node* lp_if = use_c->in(orig_exit_idx)->in(0); | |
2547 if (not_peel.test(lp_if->_idx)) { | |
2548 assert(j == orig_exit_idx, "use from original loop"); | |
2549 insert_phi_for_loop( use, clone_exit_idx, old_new[def->_idx], def, new_head_clone ); | |
2550 } | |
2551 } | |
2552 } | |
2553 } | |
2554 } | |
2555 } | |
2556 } | |
2557 | |
2558 // Step 3b: retarget control | |
2559 | |
2560 // Redirect control to the new loop head if a cloned node in | |
2561 // the not_peeled region has control that points into the peeled region. | |
2562 // This necessary because the cloned peeled region will be outside | |
2563 // the loop. | |
2564 // from to | |
2565 // cloned-peeled <---+ | |
2566 // new_head_clone: | <--+ | |
2567 // cloned-not_peeled in(0) in(0) | |
2568 // orig-peeled | |
2569 | |
2570 for(i = 0; i < loop->_body.size(); i++ ) { | |
2571 Node *n = loop->_body.at(i); | |
2572 if (!n->is_CFG() && n->in(0) != NULL && | |
2573 not_peel.test(n->_idx) && peel.test(n->in(0)->_idx)) { | |
2574 Node* n_clone = old_new[n->_idx]; | |
2575 _igvn.hash_delete(n_clone); | |
2576 n_clone->set_req(0, new_head_clone); | |
2577 _igvn._worklist.push(n_clone); | |
2578 } | |
2579 } | |
2580 | |
2581 // Backedge of the surviving new_head (the clone) is original last_peel | |
2582 _igvn.hash_delete(new_head_clone); | |
2583 new_head_clone->set_req(LoopNode::LoopBackControl, last_peel); | |
2584 _igvn._worklist.push(new_head_clone); | |
2585 | |
2586 // Cut first node in original not_peel set | |
2587 _igvn.hash_delete(new_head); | |
2588 new_head->set_req(LoopNode::EntryControl, C->top()); | |
2589 new_head->set_req(LoopNode::LoopBackControl, C->top()); | |
2590 _igvn._worklist.push(new_head); | |
2591 | |
2592 // Copy head_clone back-branch info to original head | |
2593 // and remove original head's loop entry and | |
2594 // clone head's back-branch | |
2595 _igvn.hash_delete(head); | |
2596 _igvn.hash_delete(head_clone); | |
2597 head->set_req(LoopNode::EntryControl, head_clone->in(LoopNode::LoopBackControl)); | |
2598 head->set_req(LoopNode::LoopBackControl, C->top()); | |
2599 head_clone->set_req(LoopNode::LoopBackControl, C->top()); | |
2600 _igvn._worklist.push(head); | |
2601 _igvn._worklist.push(head_clone); | |
2602 | |
2603 // Similarly modify the phis | |
2604 for (DUIterator_Fast kmax, k = head->fast_outs(kmax); k < kmax; k++) { | |
2605 Node* use = head->fast_out(k); | |
2606 if (use->is_Phi() && use->outcnt() > 0) { | |
2607 Node* use_clone = old_new[use->_idx]; | |
2608 _igvn.hash_delete(use); | |
2609 _igvn.hash_delete(use_clone); | |
2610 use->set_req(LoopNode::EntryControl, use_clone->in(LoopNode::LoopBackControl)); | |
2611 use->set_req(LoopNode::LoopBackControl, C->top()); | |
2612 use_clone->set_req(LoopNode::LoopBackControl, C->top()); | |
2613 _igvn._worklist.push(use); | |
2614 _igvn._worklist.push(use_clone); | |
2615 } | |
2616 } | |
2617 | |
2618 // Step 4: update dominator tree and dominator depth | |
2619 | |
2620 set_idom(head, orig_tail_clone, dd); | |
2621 recompute_dom_depth(); | |
2622 | |
2623 // Inhibit more partial peeling on this loop | |
2624 new_head_clone->set_partial_peel_loop(); | |
2625 C->set_major_progress(); | |
2626 | |
2627 #if !defined(PRODUCT) | |
2628 if (TracePartialPeeling) { | |
2629 tty->print_cr("\nafter partial peel one iteration"); | |
2630 Node_List wl(area); | |
2631 Node* t = last_peel; | |
2632 while (true) { | |
2633 wl.push(t); | |
2634 if (t == head_clone) break; | |
2635 t = idom(t); | |
2636 } | |
2637 while (wl.size() > 0) { | |
2638 Node* tt = wl.pop(); | |
2639 if (tt == head) tty->print_cr("orig head"); | |
2640 else if (tt == new_head_clone) tty->print_cr("new head"); | |
2641 else if (tt == head_clone) tty->print_cr("clone head"); | |
2642 tt->dump(); | |
2643 } | |
2644 } | |
2645 #endif | |
2646 return true; | |
2647 } | |
2648 | |
2649 //------------------------------reorg_offsets---------------------------------- | |
2650 // Reorganize offset computations to lower register pressure. Mostly | |
2651 // prevent loop-fallout uses of the pre-incremented trip counter (which are | |
2652 // then alive with the post-incremented trip counter forcing an extra | |
2653 // register move) | |
2654 void PhaseIdealLoop::reorg_offsets( IdealLoopTree *loop ) { | |
2655 | |
2656 CountedLoopNode *cl = loop->_head->as_CountedLoop(); | |
2657 CountedLoopEndNode *cle = cl->loopexit(); | |
2658 if( !cle ) return; // The occasional dead loop | |
2659 // Find loop exit control | |
2660 Node *exit = cle->proj_out(false); | |
2661 assert( exit->Opcode() == Op_IfFalse, "" ); | |
2662 | |
2663 // Check for the special case of folks using the pre-incremented | |
2664 // trip-counter on the fall-out path (forces the pre-incremented | |
2665 // and post-incremented trip counter to be live at the same time). | |
2666 // Fix this by adjusting to use the post-increment trip counter. | |
2667 Node *phi = cl->phi(); | |
2668 if( !phi ) return; // Dead infinite loop | |
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2669 |
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2670 // Shape messed up, probably by iteration_split_impl |
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2671 if (phi->in(LoopNode::LoopBackControl) != cl->incr()) return; |
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2672 |
0 | 2673 bool progress = true; |
2674 while (progress) { | |
2675 progress = false; | |
2676 for (DUIterator_Fast imax, i = phi->fast_outs(imax); i < imax; i++) { | |
2677 Node* use = phi->fast_out(i); // User of trip-counter | |
2678 if (!has_ctrl(use)) continue; | |
2679 Node *u_ctrl = get_ctrl(use); | |
2680 if( use->is_Phi() ) { | |
2681 u_ctrl = NULL; | |
2682 for( uint j = 1; j < use->req(); j++ ) | |
2683 if( use->in(j) == phi ) | |
2684 u_ctrl = dom_lca( u_ctrl, use->in(0)->in(j) ); | |
2685 } | |
2686 IdealLoopTree *u_loop = get_loop(u_ctrl); | |
2687 // Look for loop-invariant use | |
2688 if( u_loop == loop ) continue; | |
2689 if( loop->is_member( u_loop ) ) continue; | |
2690 // Check that use is live out the bottom. Assuming the trip-counter | |
2691 // update is right at the bottom, uses of of the loop middle are ok. | |
2692 if( dom_lca( exit, u_ctrl ) != exit ) continue; | |
2693 // protect against stride not being a constant | |
2694 if( !cle->stride_is_con() ) continue; | |
2695 // Hit! Refactor use to use the post-incremented tripcounter. | |
2696 // Compute a post-increment tripcounter. | |
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2697 Node *opaq = new (C, 2) Opaque2Node( C, cle->incr() ); |
0 | 2698 register_new_node( opaq, u_ctrl ); |
2699 Node *neg_stride = _igvn.intcon(-cle->stride_con()); | |
2700 set_ctrl(neg_stride, C->root()); | |
2701 Node *post = new (C, 3) AddINode( opaq, neg_stride); | |
2702 register_new_node( post, u_ctrl ); | |
2703 _igvn.hash_delete(use); | |
2704 _igvn._worklist.push(use); | |
2705 for( uint j = 1; j < use->req(); j++ ) | |
2706 if( use->in(j) == phi ) | |
2707 use->set_req(j, post); | |
2708 // Since DU info changed, rerun loop | |
2709 progress = true; | |
2710 break; | |
2711 } | |
2712 } | |
2713 | |
2714 } |