Mercurial > hg > truffle
annotate src/share/vm/opto/loopnode.cpp @ 2403:1927db75dd85
7024475: loop doesn't terminate when compiled
Reviewed-by: kvn
| author | never |
|---|---|
| date | Sun, 27 Mar 2011 00:00:14 -0700 |
| parents | 9dc311b8473e |
| children | 08eb13460b3a |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 * Copyright (c) 1998, 2011, 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 "ci/ciMethodData.hpp" | |
| 27 #include "compiler/compileLog.hpp" | |
| 28 #include "libadt/vectset.hpp" | |
| 29 #include "memory/allocation.inline.hpp" | |
| 30 #include "opto/addnode.hpp" | |
| 31 #include "opto/callnode.hpp" | |
| 32 #include "opto/connode.hpp" | |
| 33 #include "opto/divnode.hpp" | |
| 34 #include "opto/idealGraphPrinter.hpp" | |
| 35 #include "opto/loopnode.hpp" | |
| 36 #include "opto/mulnode.hpp" | |
| 37 #include "opto/rootnode.hpp" | |
| 38 #include "opto/superword.hpp" | |
| 0 | 39 |
| 40 //============================================================================= | |
| 41 //------------------------------is_loop_iv------------------------------------- | |
| 42 // Determine if a node is Counted loop induction variable. | |
| 43 // The method is declared in node.hpp. | |
| 44 const Node* Node::is_loop_iv() const { | |
| 45 if (this->is_Phi() && !this->as_Phi()->is_copy() && | |
| 46 this->as_Phi()->region()->is_CountedLoop() && | |
| 47 this->as_Phi()->region()->as_CountedLoop()->phi() == this) { | |
| 48 return this; | |
| 49 } else { | |
| 50 return NULL; | |
| 51 } | |
| 52 } | |
| 53 | |
| 54 //============================================================================= | |
| 55 //------------------------------dump_spec-------------------------------------- | |
| 56 // Dump special per-node info | |
| 57 #ifndef PRODUCT | |
| 58 void LoopNode::dump_spec(outputStream *st) const { | |
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59 if (is_inner_loop()) st->print( "inner " ); |
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60 if (is_partial_peel_loop()) st->print( "partial_peel " ); |
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61 if (partial_peel_has_failed()) st->print( "partial_peel_failed " ); |
| 0 | 62 } |
| 63 #endif | |
| 64 | |
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65 //------------------------------is_valid_counted_loop------------------------- |
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66 bool LoopNode::is_valid_counted_loop() const { |
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67 if (is_CountedLoop()) { |
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68 CountedLoopNode* l = as_CountedLoop(); |
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69 CountedLoopEndNode* le = l->loopexit(); |
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70 if (le != NULL && |
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71 le->proj_out(1 /* true */) == l->in(LoopNode::LoopBackControl)) { |
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72 Node* phi = l->phi(); |
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73 Node* exit = le->proj_out(0 /* false */); |
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74 if (exit != NULL && exit->Opcode() == Op_IfFalse && |
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75 phi != NULL && phi->is_Phi() && |
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76 phi->in(LoopNode::LoopBackControl) == l->incr() && |
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77 le->loopnode() == l && le->stride_is_con()) { |
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78 return true; |
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79 } |
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80 } |
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81 } |
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82 return false; |
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83 } |
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84 |
| 0 | 85 //------------------------------get_early_ctrl--------------------------------- |
| 86 // Compute earliest legal control | |
| 87 Node *PhaseIdealLoop::get_early_ctrl( Node *n ) { | |
| 88 assert( !n->is_Phi() && !n->is_CFG(), "this code only handles data nodes" ); | |
| 89 uint i; | |
| 90 Node *early; | |
| 91 if( n->in(0) ) { | |
| 92 early = n->in(0); | |
| 93 if( !early->is_CFG() ) // Might be a non-CFG multi-def | |
| 94 early = get_ctrl(early); // So treat input as a straight data input | |
| 95 i = 1; | |
| 96 } else { | |
| 97 early = get_ctrl(n->in(1)); | |
| 98 i = 2; | |
| 99 } | |
| 100 uint e_d = dom_depth(early); | |
| 101 assert( early, "" ); | |
| 102 for( ; i < n->req(); i++ ) { | |
| 103 Node *cin = get_ctrl(n->in(i)); | |
| 104 assert( cin, "" ); | |
| 105 // Keep deepest dominator depth | |
| 106 uint c_d = dom_depth(cin); | |
| 107 if( c_d > e_d ) { // Deeper guy? | |
| 108 early = cin; // Keep deepest found so far | |
| 109 e_d = c_d; | |
| 110 } else if( c_d == e_d && // Same depth? | |
| 111 early != cin ) { // If not equal, must use slower algorithm | |
| 112 // If same depth but not equal, one _must_ dominate the other | |
| 113 // and we want the deeper (i.e., dominated) guy. | |
| 114 Node *n1 = early; | |
| 115 Node *n2 = cin; | |
| 116 while( 1 ) { | |
| 117 n1 = idom(n1); // Walk up until break cycle | |
| 118 n2 = idom(n2); | |
| 119 if( n1 == cin || // Walked early up to cin | |
| 120 dom_depth(n2) < c_d ) | |
| 121 break; // early is deeper; keep him | |
| 122 if( n2 == early || // Walked cin up to early | |
| 123 dom_depth(n1) < c_d ) { | |
| 124 early = cin; // cin is deeper; keep him | |
| 125 break; | |
| 126 } | |
| 127 } | |
| 128 e_d = dom_depth(early); // Reset depth register cache | |
| 129 } | |
| 130 } | |
| 131 | |
| 132 // Return earliest legal location | |
| 133 assert(early == find_non_split_ctrl(early), "unexpected early control"); | |
| 134 | |
| 135 return early; | |
| 136 } | |
| 137 | |
| 138 //------------------------------set_early_ctrl--------------------------------- | |
| 139 // Set earliest legal control | |
| 140 void PhaseIdealLoop::set_early_ctrl( Node *n ) { | |
| 141 Node *early = get_early_ctrl(n); | |
| 142 | |
| 143 // Record earliest legal location | |
| 144 set_ctrl(n, early); | |
| 145 } | |
| 146 | |
| 147 //------------------------------set_subtree_ctrl------------------------------- | |
| 148 // set missing _ctrl entries on new nodes | |
| 149 void PhaseIdealLoop::set_subtree_ctrl( Node *n ) { | |
| 150 // Already set? Get out. | |
| 151 if( _nodes[n->_idx] ) return; | |
| 152 // Recursively set _nodes array to indicate where the Node goes | |
| 153 uint i; | |
| 154 for( i = 0; i < n->req(); ++i ) { | |
| 155 Node *m = n->in(i); | |
| 156 if( m && m != C->root() ) | |
| 157 set_subtree_ctrl( m ); | |
| 158 } | |
| 159 | |
| 160 // Fixup self | |
| 161 set_early_ctrl( n ); | |
| 162 } | |
| 163 | |
| 164 //------------------------------is_counted_loop-------------------------------- | |
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165 bool PhaseIdealLoop::is_counted_loop( Node *x, IdealLoopTree *loop ) { |
| 0 | 166 PhaseGVN *gvn = &_igvn; |
| 167 | |
| 168 // Counted loop head must be a good RegionNode with only 3 not NULL | |
| 169 // control input edges: Self, Entry, LoopBack. | |
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170 if (x->in(LoopNode::Self) == NULL || x->req() != 3) |
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171 return false; |
| 0 | 172 |
| 173 Node *init_control = x->in(LoopNode::EntryControl); | |
| 174 Node *back_control = x->in(LoopNode::LoopBackControl); | |
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175 if (init_control == NULL || back_control == NULL) // Partially dead |
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176 return false; |
| 0 | 177 // Must also check for TOP when looking for a dead loop |
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178 if (init_control->is_top() || back_control->is_top()) |
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179 return false; |
| 0 | 180 |
| 181 // Allow funny placement of Safepoint | |
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182 if (back_control->Opcode() == Op_SafePoint) |
| 0 | 183 back_control = back_control->in(TypeFunc::Control); |
| 184 | |
| 185 // Controlling test for loop | |
| 186 Node *iftrue = back_control; | |
| 187 uint iftrue_op = iftrue->Opcode(); | |
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188 if (iftrue_op != Op_IfTrue && |
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189 iftrue_op != Op_IfFalse) |
| 0 | 190 // I have a weird back-control. Probably the loop-exit test is in |
| 191 // the middle of the loop and I am looking at some trailing control-flow | |
| 192 // merge point. To fix this I would have to partially peel the loop. | |
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193 return false; // Obscure back-control |
| 0 | 194 |
| 195 // Get boolean guarding loop-back test | |
| 196 Node *iff = iftrue->in(0); | |
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197 if (get_loop(iff) != loop || !iff->in(1)->is_Bool()) |
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198 return false; |
| 0 | 199 BoolNode *test = iff->in(1)->as_Bool(); |
| 200 BoolTest::mask bt = test->_test._test; | |
| 201 float cl_prob = iff->as_If()->_prob; | |
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202 if (iftrue_op == Op_IfFalse) { |
| 0 | 203 bt = BoolTest(bt).negate(); |
| 204 cl_prob = 1.0 - cl_prob; | |
| 205 } | |
| 206 // Get backedge compare | |
| 207 Node *cmp = test->in(1); | |
| 208 int cmp_op = cmp->Opcode(); | |
| 209 if( cmp_op != Op_CmpI ) | |
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210 return false; // Avoid pointer & float compares |
| 0 | 211 |
| 212 // Find the trip-counter increment & limit. Limit must be loop invariant. | |
| 213 Node *incr = cmp->in(1); | |
| 214 Node *limit = cmp->in(2); | |
| 215 | |
| 216 // --------- | |
| 217 // need 'loop()' test to tell if limit is loop invariant | |
| 218 // --------- | |
| 219 | |
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220 if (!is_member(loop, get_ctrl(incr))) { // Swapped trip counter and limit? |
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221 Node *tmp = incr; // Then reverse order into the CmpI |
| 0 | 222 incr = limit; |
| 223 limit = tmp; | |
| 224 bt = BoolTest(bt).commute(); // And commute the exit test | |
| 225 } | |
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226 if (is_member(loop, get_ctrl(limit))) // Limit must be loop-invariant |
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227 return false; |
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228 if (!is_member(loop, get_ctrl(incr))) // Trip counter must be loop-variant |
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229 return false; |
| 0 | 230 |
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231 Node* phi_incr = NULL; |
| 0 | 232 // Trip-counter increment must be commutative & associative. |
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233 if (incr->is_Phi()) { |
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234 if (incr->as_Phi()->region() != x || incr->req() != 3) |
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235 return false; // Not simple trip counter expression |
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236 phi_incr = incr; |
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237 incr = phi_incr->in(LoopNode::LoopBackControl); // Assume incr is on backedge of Phi |
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238 if (!is_member(loop, get_ctrl(incr))) // Trip counter must be loop-variant |
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239 return false; |
| 0 | 240 } |
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241 |
| 0 | 242 Node* trunc1 = NULL; |
| 243 Node* trunc2 = NULL; | |
| 244 const TypeInt* iv_trunc_t = NULL; | |
| 245 if (!(incr = CountedLoopNode::match_incr_with_optional_truncation(incr, &trunc1, &trunc2, &iv_trunc_t))) { | |
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246 return false; // Funny increment opcode |
| 0 | 247 } |
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248 assert(incr->Opcode() == Op_AddI, "wrong increment code"); |
| 0 | 249 |
| 250 // Get merge point | |
| 251 Node *xphi = incr->in(1); | |
| 252 Node *stride = incr->in(2); | |
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253 if (!stride->is_Con()) { // Oops, swap these |
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254 if (!xphi->is_Con()) // Is the other guy a constant? |
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255 return false; // Nope, unknown stride, bail out |
| 0 | 256 Node *tmp = xphi; // 'incr' is commutative, so ok to swap |
| 257 xphi = stride; | |
| 258 stride = tmp; | |
| 259 } | |
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260 // Stride must be constant |
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261 int stride_con = stride->get_int(); |
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262 assert(stride_con != 0, "missed some peephole opt"); |
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263 |
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264 if (!xphi->is_Phi()) |
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265 return false; // Too much math on the trip counter |
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266 if (phi_incr != NULL && phi_incr != xphi) |
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267 return false; |
| 0 | 268 PhiNode *phi = xphi->as_Phi(); |
| 269 | |
| 270 // Phi must be of loop header; backedge must wrap to increment | |
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271 if (phi->region() != x) |
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272 return false; |
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273 if (trunc1 == NULL && phi->in(LoopNode::LoopBackControl) != incr || |
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274 trunc1 != NULL && phi->in(LoopNode::LoopBackControl) != trunc1) { |
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275 return false; |
| 0 | 276 } |
| 277 Node *init_trip = phi->in(LoopNode::EntryControl); | |
| 278 | |
| 279 // If iv trunc type is smaller than int, check for possible wrap. | |
| 280 if (!TypeInt::INT->higher_equal(iv_trunc_t)) { | |
| 281 assert(trunc1 != NULL, "must have found some truncation"); | |
| 282 | |
| 283 // Get a better type for the phi (filtered thru if's) | |
| 284 const TypeInt* phi_ft = filtered_type(phi); | |
| 285 | |
| 286 // Can iv take on a value that will wrap? | |
| 287 // | |
| 288 // Ensure iv's limit is not within "stride" of the wrap value. | |
| 289 // | |
| 290 // Example for "short" type | |
| 291 // Truncation ensures value is in the range -32768..32767 (iv_trunc_t) | |
| 292 // If the stride is +10, then the last value of the induction | |
| 293 // variable before the increment (phi_ft->_hi) must be | |
| 294 // <= 32767 - 10 and (phi_ft->_lo) must be >= -32768 to | |
| 295 // ensure no truncation occurs after the increment. | |
| 296 | |
| 297 if (stride_con > 0) { | |
| 298 if (iv_trunc_t->_hi - phi_ft->_hi < stride_con || | |
| 299 iv_trunc_t->_lo > phi_ft->_lo) { | |
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300 return false; // truncation may occur |
| 0 | 301 } |
| 302 } else if (stride_con < 0) { | |
| 303 if (iv_trunc_t->_lo - phi_ft->_lo > stride_con || | |
| 304 iv_trunc_t->_hi < phi_ft->_hi) { | |
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305 return false; // truncation may occur |
| 0 | 306 } |
| 307 } | |
| 308 // No possibility of wrap so truncation can be discarded | |
| 309 // Promote iv type to Int | |
| 310 } else { | |
| 311 assert(trunc1 == NULL && trunc2 == NULL, "no truncation for int"); | |
| 312 } | |
| 313 | |
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314 // If the condition is inverted and we will be rolling |
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315 // through MININT to MAXINT, then bail out. |
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316 if (bt == BoolTest::eq || // Bail out, but this loop trips at most twice! |
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317 // Odd stride |
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318 bt == BoolTest::ne && stride_con != 1 && stride_con != -1 || |
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319 // Count down loop rolls through MAXINT |
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320 (bt == BoolTest::le || bt == BoolTest::lt) && stride_con < 0 || |
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321 // Count up loop rolls through MININT |
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322 (bt == BoolTest::ge || bt == BoolTest::gt) && stride_con > 0 ) { |
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323 return false; // Bail out |
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324 } |
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325 |
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326 const TypeInt* init_t = gvn->type(init_trip)->is_int(); |
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327 const TypeInt* limit_t = gvn->type(limit)->is_int(); |
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328 |
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329 if (stride_con > 0) { |
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330 long init_p = (long)init_t->_lo + stride_con; |
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331 if (init_p > (long)max_jint || init_p > (long)limit_t->_hi) |
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332 return false; // cyclic loop or this loop trips only once |
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333 } else { |
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334 long init_p = (long)init_t->_hi + stride_con; |
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335 if (init_p < (long)min_jint || init_p < (long)limit_t->_lo) |
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336 return false; // cyclic loop or this loop trips only once |
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337 } |
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338 |
| 0 | 339 // ================================================= |
| 340 // ---- SUCCESS! Found A Trip-Counted Loop! ----- | |
| 341 // | |
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342 assert(x->Opcode() == Op_Loop, "regular loops only"); |
| 0 | 343 C->print_method("Before CountedLoop", 3); |
| 344 | |
| 345 // If compare points to incr, we are ok. Otherwise the compare | |
| 346 // can directly point to the phi; in this case adjust the compare so that | |
| 605 | 347 // it points to the incr by adjusting the limit. |
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348 if (cmp->in(1) == phi || cmp->in(2) == phi) |
| 0 | 349 limit = gvn->transform(new (C, 3) AddINode(limit,stride)); |
| 350 | |
| 351 // trip-count for +-tive stride should be: (limit - init_trip + stride - 1)/stride. | |
| 352 // Final value for iterator should be: trip_count * stride + init_trip. | |
| 353 Node *one_p = gvn->intcon( 1); | |
| 354 Node *one_m = gvn->intcon(-1); | |
| 355 | |
| 356 Node *trip_count = NULL; | |
| 357 Node *hook = new (C, 6) Node(6); | |
| 358 switch( bt ) { | |
| 359 case BoolTest::eq: | |
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360 ShouldNotReachHere(); |
| 0 | 361 case BoolTest::ne: // Ahh, the case we desire |
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362 if (stride_con == 1) |
| 0 | 363 trip_count = gvn->transform(new (C, 3) SubINode(limit,init_trip)); |
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364 else if (stride_con == -1) |
| 0 | 365 trip_count = gvn->transform(new (C, 3) SubINode(init_trip,limit)); |
| 366 else | |
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367 ShouldNotReachHere(); |
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368 set_subtree_ctrl(trip_count); |
| 0 | 369 //_loop.map(trip_count->_idx,loop(limit)); |
| 370 break; | |
| 371 case BoolTest::le: // Maybe convert to '<' case | |
| 372 limit = gvn->transform(new (C, 3) AddINode(limit,one_p)); | |
| 373 set_subtree_ctrl( limit ); | |
| 374 hook->init_req(4, limit); | |
| 375 | |
| 376 bt = BoolTest::lt; | |
| 377 // Make the new limit be in the same loop nest as the old limit | |
| 378 //_loop.map(limit->_idx,limit_loop); | |
| 379 // Fall into next case | |
| 380 case BoolTest::lt: { // Maybe convert to '!=' case | |
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381 if (stride_con < 0) // Count down loop rolls through MAXINT |
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382 ShouldNotReachHere(); |
| 0 | 383 Node *range = gvn->transform(new (C, 3) SubINode(limit,init_trip)); |
| 384 set_subtree_ctrl( range ); | |
| 385 hook->init_req(0, range); | |
| 386 | |
| 387 Node *bias = gvn->transform(new (C, 3) AddINode(range,stride)); | |
| 388 set_subtree_ctrl( bias ); | |
| 389 hook->init_req(1, bias); | |
| 390 | |
| 391 Node *bias1 = gvn->transform(new (C, 3) AddINode(bias,one_m)); | |
| 392 set_subtree_ctrl( bias1 ); | |
| 393 hook->init_req(2, bias1); | |
| 394 | |
| 395 trip_count = gvn->transform(new (C, 3) DivINode(0,bias1,stride)); | |
| 396 set_subtree_ctrl( trip_count ); | |
| 397 hook->init_req(3, trip_count); | |
| 398 break; | |
| 399 } | |
| 400 | |
| 401 case BoolTest::ge: // Maybe convert to '>' case | |
| 402 limit = gvn->transform(new (C, 3) AddINode(limit,one_m)); | |
| 403 set_subtree_ctrl( limit ); | |
| 404 hook->init_req(4 ,limit); | |
| 405 | |
| 406 bt = BoolTest::gt; | |
| 407 // Make the new limit be in the same loop nest as the old limit | |
| 408 //_loop.map(limit->_idx,limit_loop); | |
| 409 // Fall into next case | |
| 410 case BoolTest::gt: { // Maybe convert to '!=' case | |
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411 if (stride_con > 0) // count up loop rolls through MININT |
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412 ShouldNotReachHere(); |
| 0 | 413 Node *range = gvn->transform(new (C, 3) SubINode(limit,init_trip)); |
| 414 set_subtree_ctrl( range ); | |
| 415 hook->init_req(0, range); | |
| 416 | |
| 417 Node *bias = gvn->transform(new (C, 3) AddINode(range,stride)); | |
| 418 set_subtree_ctrl( bias ); | |
| 419 hook->init_req(1, bias); | |
| 420 | |
| 421 Node *bias1 = gvn->transform(new (C, 3) AddINode(bias,one_p)); | |
| 422 set_subtree_ctrl( bias1 ); | |
| 423 hook->init_req(2, bias1); | |
| 424 | |
| 425 trip_count = gvn->transform(new (C, 3) DivINode(0,bias1,stride)); | |
| 426 set_subtree_ctrl( trip_count ); | |
| 427 hook->init_req(3, trip_count); | |
| 428 break; | |
| 429 } | |
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430 } // switch( bt ) |
| 0 | 431 |
| 432 Node *span = gvn->transform(new (C, 3) MulINode(trip_count,stride)); | |
| 433 set_subtree_ctrl( span ); | |
| 434 hook->init_req(5, span); | |
| 435 | |
| 436 limit = gvn->transform(new (C, 3) AddINode(span,init_trip)); | |
| 437 set_subtree_ctrl( limit ); | |
| 438 | |
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439 // Check for SafePoint on backedge and remove |
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440 Node *sfpt = x->in(LoopNode::LoopBackControl); |
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441 if (sfpt->Opcode() == Op_SafePoint && is_deleteable_safept(sfpt)) { |
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442 lazy_replace( sfpt, iftrue ); |
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443 loop->_tail = iftrue; |
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444 } |
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445 |
| 0 | 446 // Build a canonical trip test. |
| 447 // Clone code, as old values may be in use. | |
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448 Node* nphi = PhiNode::make(x, init_trip, TypeInt::INT); |
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449 nphi = _igvn.register_new_node_with_optimizer(nphi); |
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450 set_ctrl(nphi, get_ctrl(phi)); |
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451 |
| 0 | 452 incr = incr->clone(); |
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453 incr->set_req(1,nphi); |
| 0 | 454 incr->set_req(2,stride); |
| 455 incr = _igvn.register_new_node_with_optimizer(incr); | |
| 456 set_early_ctrl( incr ); | |
| 457 | |
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458 nphi->set_req(LoopNode::LoopBackControl, incr); |
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459 _igvn.replace_node(phi, nphi); |
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460 phi = nphi->as_Phi(); |
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461 |
| 0 | 462 cmp = cmp->clone(); |
| 463 cmp->set_req(1,incr); | |
| 464 cmp->set_req(2,limit); | |
| 465 cmp = _igvn.register_new_node_with_optimizer(cmp); | |
| 466 set_ctrl(cmp, iff->in(0)); | |
| 467 | |
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468 test = test->clone()->as_Bool(); |
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469 (*(BoolTest*)&test->_test)._test = bt; |
| 0 | 470 test->set_req(1,cmp); |
| 471 _igvn.register_new_node_with_optimizer(test); | |
| 472 set_ctrl(test, iff->in(0)); | |
| 473 | |
| 474 // Replace the old IfNode with a new LoopEndNode | |
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475 Node *lex = _igvn.register_new_node_with_optimizer(new (C, 2) CountedLoopEndNode( iff->in(0), test, cl_prob, iff->as_If()->_fcnt )); |
| 0 | 476 IfNode *le = lex->as_If(); |
| 477 uint dd = dom_depth(iff); | |
| 478 set_idom(le, le->in(0), dd); // Update dominance for loop exit | |
| 479 set_loop(le, loop); | |
| 480 | |
| 481 // Get the loop-exit control | |
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482 Node *iffalse = iff->as_If()->proj_out(!(iftrue_op == Op_IfTrue)); |
| 0 | 483 |
| 484 // Need to swap loop-exit and loop-back control? | |
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485 if (iftrue_op == Op_IfFalse) { |
| 0 | 486 Node *ift2=_igvn.register_new_node_with_optimizer(new (C, 1) IfTrueNode (le)); |
| 487 Node *iff2=_igvn.register_new_node_with_optimizer(new (C, 1) IfFalseNode(le)); | |
| 488 | |
| 489 loop->_tail = back_control = ift2; | |
| 490 set_loop(ift2, loop); | |
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491 set_loop(iff2, get_loop(iffalse)); |
| 0 | 492 |
| 493 // Lazy update of 'get_ctrl' mechanism. | |
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494 lazy_replace_proj( iffalse, iff2 ); |
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495 lazy_replace_proj( iftrue, ift2 ); |
| 0 | 496 |
| 497 // Swap names | |
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498 iffalse = iff2; |
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499 iftrue = ift2; |
| 0 | 500 } else { |
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501 _igvn.hash_delete(iffalse); |
| 0 | 502 _igvn.hash_delete(iftrue); |
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503 iffalse->set_req_X( 0, le, &_igvn ); |
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504 iftrue ->set_req_X( 0, le, &_igvn ); |
| 0 | 505 } |
| 506 | |
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507 set_idom(iftrue, le, dd+1); |
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508 set_idom(iffalse, le, dd+1); |
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509 assert(iff->outcnt() == 0, "should be dead now"); |
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510 lazy_replace( iff, le ); // fix 'get_ctrl' |
| 0 | 511 |
| 512 // Now setup a new CountedLoopNode to replace the existing LoopNode | |
| 513 CountedLoopNode *l = new (C, 3) CountedLoopNode(init_control, back_control); | |
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514 l->set_unswitch_count(x->as_Loop()->unswitch_count()); // Preserve |
| 0 | 515 // The following assert is approximately true, and defines the intention |
| 516 // of can_be_counted_loop. It fails, however, because phase->type | |
| 517 // is not yet initialized for this loop and its parts. | |
| 518 //assert(l->can_be_counted_loop(this), "sanity"); | |
| 519 _igvn.register_new_node_with_optimizer(l); | |
| 520 set_loop(l, loop); | |
| 521 loop->_head = l; | |
| 522 // Fix all data nodes placed at the old loop head. | |
| 523 // Uses the lazy-update mechanism of 'get_ctrl'. | |
| 524 lazy_replace( x, l ); | |
| 525 set_idom(l, init_control, dom_depth(x)); | |
| 526 | |
| 605 | 527 // Check for immediately preceding SafePoint and remove |
| 0 | 528 Node *sfpt2 = le->in(0); |
| 529 if( sfpt2->Opcode() == Op_SafePoint && is_deleteable_safept(sfpt2)) | |
| 530 lazy_replace( sfpt2, sfpt2->in(TypeFunc::Control)); | |
| 531 | |
| 532 // Free up intermediate goo | |
| 533 _igvn.remove_dead_node(hook); | |
| 534 | |
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535 #ifdef ASSERT |
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536 assert(l->is_valid_counted_loop(), "counted loop shape is messed up"); |
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537 assert(l == loop->_head && l->phi() == phi && l->loopexit() == lex, "" ); |
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538 #endif |
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539 |
| 0 | 540 C->print_method("After CountedLoop", 3); |
| 541 | |
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542 return true; |
| 0 | 543 } |
| 544 | |
| 545 | |
| 546 //------------------------------Ideal------------------------------------------ | |
| 547 // Return a node which is more "ideal" than the current node. | |
| 548 // Attempt to convert into a counted-loop. | |
| 549 Node *LoopNode::Ideal(PhaseGVN *phase, bool can_reshape) { | |
| 550 if (!can_be_counted_loop(phase)) { | |
| 551 phase->C->set_major_progress(); | |
| 552 } | |
| 553 return RegionNode::Ideal(phase, can_reshape); | |
| 554 } | |
| 555 | |
| 556 | |
| 557 //============================================================================= | |
| 558 //------------------------------Ideal------------------------------------------ | |
| 559 // Return a node which is more "ideal" than the current node. | |
| 560 // Attempt to convert into a counted-loop. | |
| 561 Node *CountedLoopNode::Ideal(PhaseGVN *phase, bool can_reshape) { | |
| 562 return RegionNode::Ideal(phase, can_reshape); | |
| 563 } | |
| 564 | |
| 565 //------------------------------dump_spec-------------------------------------- | |
| 566 // Dump special per-node info | |
| 567 #ifndef PRODUCT | |
| 568 void CountedLoopNode::dump_spec(outputStream *st) const { | |
| 569 LoopNode::dump_spec(st); | |
| 570 if( stride_is_con() ) { | |
| 571 st->print("stride: %d ",stride_con()); | |
| 572 } else { | |
| 573 st->print("stride: not constant "); | |
| 574 } | |
| 575 if( is_pre_loop () ) st->print("pre of N%d" , _main_idx ); | |
| 576 if( is_main_loop() ) st->print("main of N%d", _idx ); | |
| 577 if( is_post_loop() ) st->print("post of N%d", _main_idx ); | |
| 578 } | |
| 579 #endif | |
| 580 | |
| 581 //============================================================================= | |
| 582 int CountedLoopEndNode::stride_con() const { | |
| 583 return stride()->bottom_type()->is_int()->get_con(); | |
| 584 } | |
| 585 | |
| 586 | |
| 587 //----------------------match_incr_with_optional_truncation-------------------- | |
| 588 // Match increment with optional truncation: | |
| 589 // CHAR: (i+1)&0x7fff, BYTE: ((i+1)<<8)>>8, or SHORT: ((i+1)<<16)>>16 | |
| 590 // Return NULL for failure. Success returns the increment node. | |
| 591 Node* CountedLoopNode::match_incr_with_optional_truncation( | |
| 592 Node* expr, Node** trunc1, Node** trunc2, const TypeInt** trunc_type) { | |
| 593 // Quick cutouts: | |
| 594 if (expr == NULL || expr->req() != 3) return false; | |
| 595 | |
| 596 Node *t1 = NULL; | |
| 597 Node *t2 = NULL; | |
| 598 const TypeInt* trunc_t = TypeInt::INT; | |
| 599 Node* n1 = expr; | |
| 600 int n1op = n1->Opcode(); | |
| 601 | |
| 602 // Try to strip (n1 & M) or (n1 << N >> N) from n1. | |
| 603 if (n1op == Op_AndI && | |
| 604 n1->in(2)->is_Con() && | |
| 605 n1->in(2)->bottom_type()->is_int()->get_con() == 0x7fff) { | |
| 606 // %%% This check should match any mask of 2**K-1. | |
| 607 t1 = n1; | |
| 608 n1 = t1->in(1); | |
| 609 n1op = n1->Opcode(); | |
| 610 trunc_t = TypeInt::CHAR; | |
| 611 } else if (n1op == Op_RShiftI && | |
| 612 n1->in(1) != NULL && | |
| 613 n1->in(1)->Opcode() == Op_LShiftI && | |
| 614 n1->in(2) == n1->in(1)->in(2) && | |
| 615 n1->in(2)->is_Con()) { | |
| 616 jint shift = n1->in(2)->bottom_type()->is_int()->get_con(); | |
| 617 // %%% This check should match any shift in [1..31]. | |
| 618 if (shift == 16 || shift == 8) { | |
| 619 t1 = n1; | |
| 620 t2 = t1->in(1); | |
| 621 n1 = t2->in(1); | |
| 622 n1op = n1->Opcode(); | |
| 623 if (shift == 16) { | |
| 624 trunc_t = TypeInt::SHORT; | |
| 625 } else if (shift == 8) { | |
| 626 trunc_t = TypeInt::BYTE; | |
| 627 } | |
| 628 } | |
| 629 } | |
| 630 | |
| 631 // If (maybe after stripping) it is an AddI, we won: | |
| 632 if (n1op == Op_AddI) { | |
| 633 *trunc1 = t1; | |
| 634 *trunc2 = t2; | |
| 635 *trunc_type = trunc_t; | |
| 636 return n1; | |
| 637 } | |
| 638 | |
| 639 // failed | |
| 640 return NULL; | |
| 641 } | |
| 642 | |
| 643 | |
| 644 //------------------------------filtered_type-------------------------------- | |
| 645 // Return a type based on condition control flow | |
| 646 // A successful return will be a type that is restricted due | |
| 647 // to a series of dominating if-tests, such as: | |
| 648 // if (i < 10) { | |
| 649 // if (i > 0) { | |
| 650 // here: "i" type is [1..10) | |
| 651 // } | |
| 652 // } | |
| 653 // or a control flow merge | |
| 654 // if (i < 10) { | |
| 655 // do { | |
| 656 // phi( , ) -- at top of loop type is [min_int..10) | |
| 657 // i = ? | |
| 658 // } while ( i < 10) | |
| 659 // | |
| 660 const TypeInt* PhaseIdealLoop::filtered_type( Node *n, Node* n_ctrl) { | |
| 661 assert(n && n->bottom_type()->is_int(), "must be int"); | |
| 662 const TypeInt* filtered_t = NULL; | |
| 663 if (!n->is_Phi()) { | |
| 664 assert(n_ctrl != NULL || n_ctrl == C->top(), "valid control"); | |
| 665 filtered_t = filtered_type_from_dominators(n, n_ctrl); | |
| 666 | |
| 667 } else { | |
| 668 Node* phi = n->as_Phi(); | |
| 669 Node* region = phi->in(0); | |
| 670 assert(n_ctrl == NULL || n_ctrl == region, "ctrl parameter must be region"); | |
| 671 if (region && region != C->top()) { | |
| 672 for (uint i = 1; i < phi->req(); i++) { | |
| 673 Node* val = phi->in(i); | |
| 674 Node* use_c = region->in(i); | |
| 675 const TypeInt* val_t = filtered_type_from_dominators(val, use_c); | |
| 676 if (val_t != NULL) { | |
| 677 if (filtered_t == NULL) { | |
| 678 filtered_t = val_t; | |
| 679 } else { | |
| 680 filtered_t = filtered_t->meet(val_t)->is_int(); | |
| 681 } | |
| 682 } | |
| 683 } | |
| 684 } | |
| 685 } | |
| 686 const TypeInt* n_t = _igvn.type(n)->is_int(); | |
| 687 if (filtered_t != NULL) { | |
| 688 n_t = n_t->join(filtered_t)->is_int(); | |
| 689 } | |
| 690 return n_t; | |
| 691 } | |
| 692 | |
| 693 | |
| 694 //------------------------------filtered_type_from_dominators-------------------------------- | |
| 695 // Return a possibly more restrictive type for val based on condition control flow of dominators | |
| 696 const TypeInt* PhaseIdealLoop::filtered_type_from_dominators( Node* val, Node *use_ctrl) { | |
| 697 if (val->is_Con()) { | |
| 698 return val->bottom_type()->is_int(); | |
| 699 } | |
| 700 uint if_limit = 10; // Max number of dominating if's visited | |
| 701 const TypeInt* rtn_t = NULL; | |
| 702 | |
| 703 if (use_ctrl && use_ctrl != C->top()) { | |
| 704 Node* val_ctrl = get_ctrl(val); | |
| 705 uint val_dom_depth = dom_depth(val_ctrl); | |
| 706 Node* pred = use_ctrl; | |
| 707 uint if_cnt = 0; | |
| 708 while (if_cnt < if_limit) { | |
| 709 if ((pred->Opcode() == Op_IfTrue || pred->Opcode() == Op_IfFalse)) { | |
| 710 if_cnt++; | |
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711 const TypeInt* if_t = IfNode::filtered_int_type(&_igvn, val, pred); |
| 0 | 712 if (if_t != NULL) { |
| 713 if (rtn_t == NULL) { | |
| 714 rtn_t = if_t; | |
| 715 } else { | |
| 716 rtn_t = rtn_t->join(if_t)->is_int(); | |
| 717 } | |
| 718 } | |
| 719 } | |
| 720 pred = idom(pred); | |
| 721 if (pred == NULL || pred == C->top()) { | |
| 722 break; | |
| 723 } | |
| 724 // Stop if going beyond definition block of val | |
| 725 if (dom_depth(pred) < val_dom_depth) { | |
| 726 break; | |
| 727 } | |
| 728 } | |
| 729 } | |
| 730 return rtn_t; | |
| 731 } | |
| 732 | |
| 733 | |
| 734 //------------------------------dump_spec-------------------------------------- | |
| 735 // Dump special per-node info | |
| 736 #ifndef PRODUCT | |
| 737 void CountedLoopEndNode::dump_spec(outputStream *st) const { | |
| 738 if( in(TestValue)->is_Bool() ) { | |
| 739 BoolTest bt( test_trip()); // Added this for g++. | |
| 740 | |
| 741 st->print("["); | |
| 742 bt.dump_on(st); | |
| 743 st->print("]"); | |
| 744 } | |
| 745 st->print(" "); | |
| 746 IfNode::dump_spec(st); | |
| 747 } | |
| 748 #endif | |
| 749 | |
| 750 //============================================================================= | |
| 751 //------------------------------is_member-------------------------------------- | |
| 752 // Is 'l' a member of 'this'? | |
| 753 int IdealLoopTree::is_member( const IdealLoopTree *l ) const { | |
| 754 while( l->_nest > _nest ) l = l->_parent; | |
| 755 return l == this; | |
| 756 } | |
| 757 | |
| 758 //------------------------------set_nest--------------------------------------- | |
| 759 // Set loop tree nesting depth. Accumulate _has_call bits. | |
| 760 int IdealLoopTree::set_nest( uint depth ) { | |
| 761 _nest = depth; | |
| 762 int bits = _has_call; | |
| 763 if( _child ) bits |= _child->set_nest(depth+1); | |
| 764 if( bits ) _has_call = 1; | |
| 765 if( _next ) bits |= _next ->set_nest(depth ); | |
| 766 return bits; | |
| 767 } | |
| 768 | |
| 769 //------------------------------split_fall_in---------------------------------- | |
| 770 // Split out multiple fall-in edges from the loop header. Move them to a | |
| 771 // private RegionNode before the loop. This becomes the loop landing pad. | |
| 772 void IdealLoopTree::split_fall_in( PhaseIdealLoop *phase, int fall_in_cnt ) { | |
| 773 PhaseIterGVN &igvn = phase->_igvn; | |
| 774 uint i; | |
| 775 | |
| 776 // Make a new RegionNode to be the landing pad. | |
| 777 Node *landing_pad = new (phase->C, fall_in_cnt+1) RegionNode( fall_in_cnt+1 ); | |
| 778 phase->set_loop(landing_pad,_parent); | |
| 779 // Gather all the fall-in control paths into the landing pad | |
| 780 uint icnt = fall_in_cnt; | |
| 781 uint oreq = _head->req(); | |
| 782 for( i = oreq-1; i>0; i-- ) | |
| 783 if( !phase->is_member( this, _head->in(i) ) ) | |
| 784 landing_pad->set_req(icnt--,_head->in(i)); | |
| 785 | |
| 786 // Peel off PhiNode edges as well | |
| 787 for (DUIterator_Fast jmax, j = _head->fast_outs(jmax); j < jmax; j++) { | |
| 788 Node *oj = _head->fast_out(j); | |
| 789 if( oj->is_Phi() ) { | |
| 790 PhiNode* old_phi = oj->as_Phi(); | |
| 791 assert( old_phi->region() == _head, "" ); | |
| 792 igvn.hash_delete(old_phi); // Yank from hash before hacking edges | |
| 793 Node *p = PhiNode::make_blank(landing_pad, old_phi); | |
| 794 uint icnt = fall_in_cnt; | |
| 795 for( i = oreq-1; i>0; i-- ) { | |
| 796 if( !phase->is_member( this, _head->in(i) ) ) { | |
| 797 p->init_req(icnt--, old_phi->in(i)); | |
| 798 // Go ahead and clean out old edges from old phi | |
| 799 old_phi->del_req(i); | |
| 800 } | |
| 801 } | |
| 802 // Search for CSE's here, because ZKM.jar does a lot of | |
| 803 // loop hackery and we need to be a little incremental | |
| 804 // with the CSE to avoid O(N^2) node blow-up. | |
| 805 Node *p2 = igvn.hash_find_insert(p); // Look for a CSE | |
| 806 if( p2 ) { // Found CSE | |
| 807 p->destruct(); // Recover useless new node | |
| 808 p = p2; // Use old node | |
| 809 } else { | |
| 810 igvn.register_new_node_with_optimizer(p, old_phi); | |
| 811 } | |
| 812 // Make old Phi refer to new Phi. | |
| 813 old_phi->add_req(p); | |
| 814 // Check for the special case of making the old phi useless and | |
| 815 // disappear it. In JavaGrande I have a case where this useless | |
| 816 // Phi is the loop limit and prevents recognizing a CountedLoop | |
| 817 // which in turn prevents removing an empty loop. | |
| 818 Node *id_old_phi = old_phi->Identity( &igvn ); | |
| 819 if( id_old_phi != old_phi ) { // Found a simple identity? | |
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820 // Note that I cannot call 'replace_node' here, because |
| 0 | 821 // that will yank the edge from old_phi to the Region and |
| 822 // I'm mid-iteration over the Region's uses. | |
| 823 for (DUIterator_Last imin, i = old_phi->last_outs(imin); i >= imin; ) { | |
| 824 Node* use = old_phi->last_out(i); | |
| 825 igvn.hash_delete(use); | |
| 826 igvn._worklist.push(use); | |
| 827 uint uses_found = 0; | |
| 828 for (uint j = 0; j < use->len(); j++) { | |
| 829 if (use->in(j) == old_phi) { | |
| 830 if (j < use->req()) use->set_req (j, id_old_phi); | |
| 831 else use->set_prec(j, id_old_phi); | |
| 832 uses_found++; | |
| 833 } | |
| 834 } | |
| 835 i -= uses_found; // we deleted 1 or more copies of this edge | |
| 836 } | |
| 837 } | |
| 838 igvn._worklist.push(old_phi); | |
| 839 } | |
| 840 } | |
| 841 // Finally clean out the fall-in edges from the RegionNode | |
| 842 for( i = oreq-1; i>0; i-- ) { | |
| 843 if( !phase->is_member( this, _head->in(i) ) ) { | |
| 844 _head->del_req(i); | |
| 845 } | |
| 846 } | |
| 847 // Transform landing pad | |
| 848 igvn.register_new_node_with_optimizer(landing_pad, _head); | |
| 849 // Insert landing pad into the header | |
| 850 _head->add_req(landing_pad); | |
| 851 } | |
| 852 | |
| 853 //------------------------------split_outer_loop------------------------------- | |
| 854 // Split out the outermost loop from this shared header. | |
| 855 void IdealLoopTree::split_outer_loop( PhaseIdealLoop *phase ) { | |
| 856 PhaseIterGVN &igvn = phase->_igvn; | |
| 857 | |
| 858 // Find index of outermost loop; it should also be my tail. | |
| 859 uint outer_idx = 1; | |
| 860 while( _head->in(outer_idx) != _tail ) outer_idx++; | |
| 861 | |
| 862 // Make a LoopNode for the outermost loop. | |
| 863 Node *ctl = _head->in(LoopNode::EntryControl); | |
| 864 Node *outer = new (phase->C, 3) LoopNode( ctl, _head->in(outer_idx) ); | |
| 865 outer = igvn.register_new_node_with_optimizer(outer, _head); | |
| 866 phase->set_created_loop_node(); | |
| 867 // Outermost loop falls into '_head' loop | |
| 868 _head->set_req(LoopNode::EntryControl, outer); | |
| 869 _head->del_req(outer_idx); | |
| 870 // Split all the Phis up between '_head' loop and 'outer' loop. | |
| 871 for (DUIterator_Fast jmax, j = _head->fast_outs(jmax); j < jmax; j++) { | |
| 872 Node *out = _head->fast_out(j); | |
| 873 if( out->is_Phi() ) { | |
| 874 PhiNode *old_phi = out->as_Phi(); | |
| 875 assert( old_phi->region() == _head, "" ); | |
| 876 Node *phi = PhiNode::make_blank(outer, old_phi); | |
| 877 phi->init_req(LoopNode::EntryControl, old_phi->in(LoopNode::EntryControl)); | |
| 878 phi->init_req(LoopNode::LoopBackControl, old_phi->in(outer_idx)); | |
| 879 phi = igvn.register_new_node_with_optimizer(phi, old_phi); | |
| 880 // Make old Phi point to new Phi on the fall-in path | |
| 881 igvn.hash_delete(old_phi); | |
| 882 old_phi->set_req(LoopNode::EntryControl, phi); | |
| 883 old_phi->del_req(outer_idx); | |
| 884 igvn._worklist.push(old_phi); | |
| 885 } | |
| 886 } | |
| 887 | |
| 888 // Use the new loop head instead of the old shared one | |
| 889 _head = outer; | |
| 890 phase->set_loop(_head, this); | |
| 891 } | |
| 892 | |
| 893 //------------------------------fix_parent------------------------------------- | |
| 894 static void fix_parent( IdealLoopTree *loop, IdealLoopTree *parent ) { | |
| 895 loop->_parent = parent; | |
| 896 if( loop->_child ) fix_parent( loop->_child, loop ); | |
| 897 if( loop->_next ) fix_parent( loop->_next , parent ); | |
| 898 } | |
| 899 | |
| 900 //------------------------------estimate_path_freq----------------------------- | |
| 901 static float estimate_path_freq( Node *n ) { | |
| 902 // Try to extract some path frequency info | |
| 903 IfNode *iff; | |
| 904 for( int i = 0; i < 50; i++ ) { // Skip through a bunch of uncommon tests | |
| 905 uint nop = n->Opcode(); | |
| 906 if( nop == Op_SafePoint ) { // Skip any safepoint | |
| 907 n = n->in(0); | |
| 908 continue; | |
| 909 } | |
| 910 if( nop == Op_CatchProj ) { // Get count from a prior call | |
| 911 // Assume call does not always throw exceptions: means the call-site | |
| 912 // count is also the frequency of the fall-through path. | |
| 913 assert( n->is_CatchProj(), "" ); | |
| 914 if( ((CatchProjNode*)n)->_con != CatchProjNode::fall_through_index ) | |
| 915 return 0.0f; // Assume call exception path is rare | |
| 916 Node *call = n->in(0)->in(0)->in(0); | |
| 917 assert( call->is_Call(), "expect a call here" ); | |
| 918 const JVMState *jvms = ((CallNode*)call)->jvms(); | |
| 919 ciMethodData* methodData = jvms->method()->method_data(); | |
| 920 if (!methodData->is_mature()) return 0.0f; // No call-site data | |
| 921 ciProfileData* data = methodData->bci_to_data(jvms->bci()); | |
| 922 if ((data == NULL) || !data->is_CounterData()) { | |
| 923 // no call profile available, try call's control input | |
| 924 n = n->in(0); | |
| 925 continue; | |
| 926 } | |
| 927 return data->as_CounterData()->count()/FreqCountInvocations; | |
| 928 } | |
| 929 // See if there's a gating IF test | |
| 930 Node *n_c = n->in(0); | |
| 931 if( !n_c->is_If() ) break; // No estimate available | |
| 932 iff = n_c->as_If(); | |
| 933 if( iff->_fcnt != COUNT_UNKNOWN ) // Have a valid count? | |
| 934 // Compute how much count comes on this path | |
| 935 return ((nop == Op_IfTrue) ? iff->_prob : 1.0f - iff->_prob) * iff->_fcnt; | |
| 936 // Have no count info. Skip dull uncommon-trap like branches. | |
| 937 if( (nop == Op_IfTrue && iff->_prob < PROB_LIKELY_MAG(5)) || | |
| 938 (nop == Op_IfFalse && iff->_prob > PROB_UNLIKELY_MAG(5)) ) | |
| 939 break; | |
| 940 // Skip through never-taken branch; look for a real loop exit. | |
| 941 n = iff->in(0); | |
| 942 } | |
| 943 return 0.0f; // No estimate available | |
| 944 } | |
| 945 | |
| 946 //------------------------------merge_many_backedges--------------------------- | |
| 947 // Merge all the backedges from the shared header into a private Region. | |
| 948 // Feed that region as the one backedge to this loop. | |
| 949 void IdealLoopTree::merge_many_backedges( PhaseIdealLoop *phase ) { | |
| 950 uint i; | |
| 951 | |
| 952 // Scan for the top 2 hottest backedges | |
| 953 float hotcnt = 0.0f; | |
| 954 float warmcnt = 0.0f; | |
| 955 uint hot_idx = 0; | |
| 956 // Loop starts at 2 because slot 1 is the fall-in path | |
| 957 for( i = 2; i < _head->req(); i++ ) { | |
| 958 float cnt = estimate_path_freq(_head->in(i)); | |
| 959 if( cnt > hotcnt ) { // Grab hottest path | |
| 960 warmcnt = hotcnt; | |
| 961 hotcnt = cnt; | |
| 962 hot_idx = i; | |
| 963 } else if( cnt > warmcnt ) { // And 2nd hottest path | |
| 964 warmcnt = cnt; | |
| 965 } | |
| 966 } | |
| 967 | |
| 968 // See if the hottest backedge is worthy of being an inner loop | |
| 969 // by being much hotter than the next hottest backedge. | |
| 970 if( hotcnt <= 0.0001 || | |
| 971 hotcnt < 2.0*warmcnt ) hot_idx = 0;// No hot backedge | |
| 972 | |
| 973 // Peel out the backedges into a private merge point; peel | |
| 974 // them all except optionally hot_idx. | |
| 975 PhaseIterGVN &igvn = phase->_igvn; | |
| 976 | |
| 977 Node *hot_tail = NULL; | |
| 978 // Make a Region for the merge point | |
| 979 Node *r = new (phase->C, 1) RegionNode(1); | |
| 980 for( i = 2; i < _head->req(); i++ ) { | |
| 981 if( i != hot_idx ) | |
| 982 r->add_req( _head->in(i) ); | |
| 983 else hot_tail = _head->in(i); | |
| 984 } | |
| 985 igvn.register_new_node_with_optimizer(r, _head); | |
| 986 // Plug region into end of loop _head, followed by hot_tail | |
| 987 while( _head->req() > 3 ) _head->del_req( _head->req()-1 ); | |
| 988 _head->set_req(2, r); | |
| 989 if( hot_idx ) _head->add_req(hot_tail); | |
| 990 | |
| 991 // Split all the Phis up between '_head' loop and the Region 'r' | |
| 992 for (DUIterator_Fast jmax, j = _head->fast_outs(jmax); j < jmax; j++) { | |
| 993 Node *out = _head->fast_out(j); | |
| 994 if( out->is_Phi() ) { | |
| 995 PhiNode* n = out->as_Phi(); | |
| 996 igvn.hash_delete(n); // Delete from hash before hacking edges | |
| 997 Node *hot_phi = NULL; | |
| 998 Node *phi = new (phase->C, r->req()) PhiNode(r, n->type(), n->adr_type()); | |
| 999 // Check all inputs for the ones to peel out | |
| 1000 uint j = 1; | |
| 1001 for( uint i = 2; i < n->req(); i++ ) { | |
| 1002 if( i != hot_idx ) | |
| 1003 phi->set_req( j++, n->in(i) ); | |
| 1004 else hot_phi = n->in(i); | |
| 1005 } | |
| 1006 // Register the phi but do not transform until whole place transforms | |
| 1007 igvn.register_new_node_with_optimizer(phi, n); | |
| 1008 // Add the merge phi to the old Phi | |
| 1009 while( n->req() > 3 ) n->del_req( n->req()-1 ); | |
| 1010 n->set_req(2, phi); | |
| 1011 if( hot_idx ) n->add_req(hot_phi); | |
| 1012 } | |
| 1013 } | |
| 1014 | |
| 1015 | |
| 1016 // Insert a new IdealLoopTree inserted below me. Turn it into a clone | |
| 1017 // of self loop tree. Turn self into a loop headed by _head and with | |
| 1018 // tail being the new merge point. | |
| 1019 IdealLoopTree *ilt = new IdealLoopTree( phase, _head, _tail ); | |
| 1020 phase->set_loop(_tail,ilt); // Adjust tail | |
| 1021 _tail = r; // Self's tail is new merge point | |
| 1022 phase->set_loop(r,this); | |
| 1023 ilt->_child = _child; // New guy has my children | |
| 1024 _child = ilt; // Self has new guy as only child | |
| 1025 ilt->_parent = this; // new guy has self for parent | |
| 1026 ilt->_nest = _nest; // Same nesting depth (for now) | |
| 1027 | |
| 1028 // Starting with 'ilt', look for child loop trees using the same shared | |
| 1029 // header. Flatten these out; they will no longer be loops in the end. | |
| 1030 IdealLoopTree **pilt = &_child; | |
| 1031 while( ilt ) { | |
| 1032 if( ilt->_head == _head ) { | |
| 1033 uint i; | |
| 1034 for( i = 2; i < _head->req(); i++ ) | |
| 1035 if( _head->in(i) == ilt->_tail ) | |
| 1036 break; // Still a loop | |
| 1037 if( i == _head->req() ) { // No longer a loop | |
| 1038 // Flatten ilt. Hang ilt's "_next" list from the end of | |
| 1039 // ilt's '_child' list. Move the ilt's _child up to replace ilt. | |
| 1040 IdealLoopTree **cp = &ilt->_child; | |
| 1041 while( *cp ) cp = &(*cp)->_next; // Find end of child list | |
| 1042 *cp = ilt->_next; // Hang next list at end of child list | |
| 1043 *pilt = ilt->_child; // Move child up to replace ilt | |
| 1044 ilt->_head = NULL; // Flag as a loop UNIONED into parent | |
| 1045 ilt = ilt->_child; // Repeat using new ilt | |
| 1046 continue; // do not advance over ilt->_child | |
| 1047 } | |
| 1048 assert( ilt->_tail == hot_tail, "expected to only find the hot inner loop here" ); | |
| 1049 phase->set_loop(_head,ilt); | |
| 1050 } | |
| 1051 pilt = &ilt->_child; // Advance to next | |
| 1052 ilt = *pilt; | |
| 1053 } | |
| 1054 | |
| 1055 if( _child ) fix_parent( _child, this ); | |
| 1056 } | |
| 1057 | |
| 1058 //------------------------------beautify_loops--------------------------------- | |
| 1059 // Split shared headers and insert loop landing pads. | |
| 1060 // Insert a LoopNode to replace the RegionNode. | |
| 1061 // Return TRUE if loop tree is structurally changed. | |
| 1062 bool IdealLoopTree::beautify_loops( PhaseIdealLoop *phase ) { | |
| 1063 bool result = false; | |
| 1064 // Cache parts in locals for easy | |
| 1065 PhaseIterGVN &igvn = phase->_igvn; | |
| 1066 | |
| 1067 igvn.hash_delete(_head); // Yank from hash before hacking edges | |
| 1068 | |
| 1069 // Check for multiple fall-in paths. Peel off a landing pad if need be. | |
| 1070 int fall_in_cnt = 0; | |
| 1071 for( uint i = 1; i < _head->req(); i++ ) | |
| 1072 if( !phase->is_member( this, _head->in(i) ) ) | |
| 1073 fall_in_cnt++; | |
| 1074 assert( fall_in_cnt, "at least 1 fall-in path" ); | |
| 1075 if( fall_in_cnt > 1 ) // Need a loop landing pad to merge fall-ins | |
| 1076 split_fall_in( phase, fall_in_cnt ); | |
| 1077 | |
| 1078 // Swap inputs to the _head and all Phis to move the fall-in edge to | |
| 1079 // the left. | |
| 1080 fall_in_cnt = 1; | |
| 1081 while( phase->is_member( this, _head->in(fall_in_cnt) ) ) | |
| 1082 fall_in_cnt++; | |
| 1083 if( fall_in_cnt > 1 ) { | |
| 1084 // Since I am just swapping inputs I do not need to update def-use info | |
| 1085 Node *tmp = _head->in(1); | |
| 1086 _head->set_req( 1, _head->in(fall_in_cnt) ); | |
| 1087 _head->set_req( fall_in_cnt, tmp ); | |
| 1088 // Swap also all Phis | |
| 1089 for (DUIterator_Fast imax, i = _head->fast_outs(imax); i < imax; i++) { | |
| 1090 Node* phi = _head->fast_out(i); | |
| 1091 if( phi->is_Phi() ) { | |
| 1092 igvn.hash_delete(phi); // Yank from hash before hacking edges | |
| 1093 tmp = phi->in(1); | |
| 1094 phi->set_req( 1, phi->in(fall_in_cnt) ); | |
| 1095 phi->set_req( fall_in_cnt, tmp ); | |
| 1096 } | |
| 1097 } | |
| 1098 } | |
| 1099 assert( !phase->is_member( this, _head->in(1) ), "left edge is fall-in" ); | |
| 1100 assert( phase->is_member( this, _head->in(2) ), "right edge is loop" ); | |
| 1101 | |
| 1102 // If I am a shared header (multiple backedges), peel off the many | |
| 1103 // backedges into a private merge point and use the merge point as | |
| 1104 // the one true backedge. | |
| 1105 if( _head->req() > 3 ) { | |
| 1106 // Merge the many backedges into a single backedge. | |
| 1107 merge_many_backedges( phase ); | |
| 1108 result = true; | |
| 1109 } | |
| 1110 | |
| 1111 // If I am a shared header (multiple backedges), peel off myself loop. | |
| 1112 // I better be the outermost loop. | |
| 1113 if( _head->req() > 3 ) { | |
| 1114 split_outer_loop( phase ); | |
| 1115 result = true; | |
| 1116 | |
| 1117 } else if( !_head->is_Loop() && !_irreducible ) { | |
| 1118 // Make a new LoopNode to replace the old loop head | |
| 1119 Node *l = new (phase->C, 3) LoopNode( _head->in(1), _head->in(2) ); | |
| 1120 l = igvn.register_new_node_with_optimizer(l, _head); | |
| 1121 phase->set_created_loop_node(); | |
| 1122 // Go ahead and replace _head | |
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1123 phase->_igvn.replace_node( _head, l ); |
| 0 | 1124 _head = l; |
| 1125 phase->set_loop(_head, this); | |
| 1126 } | |
| 1127 | |
| 1128 // Now recursively beautify nested loops | |
| 1129 if( _child ) result |= _child->beautify_loops( phase ); | |
| 1130 if( _next ) result |= _next ->beautify_loops( phase ); | |
| 1131 return result; | |
| 1132 } | |
| 1133 | |
| 1134 //------------------------------allpaths_check_safepts---------------------------- | |
| 1135 // Allpaths backwards scan from loop tail, terminating each path at first safepoint | |
| 1136 // encountered. Helper for check_safepts. | |
| 1137 void IdealLoopTree::allpaths_check_safepts(VectorSet &visited, Node_List &stack) { | |
| 1138 assert(stack.size() == 0, "empty stack"); | |
| 1139 stack.push(_tail); | |
| 1140 visited.Clear(); | |
| 1141 visited.set(_tail->_idx); | |
| 1142 while (stack.size() > 0) { | |
| 1143 Node* n = stack.pop(); | |
| 1144 if (n->is_Call() && n->as_Call()->guaranteed_safepoint()) { | |
| 1145 // Terminate this path | |
| 1146 } else if (n->Opcode() == Op_SafePoint) { | |
| 1147 if (_phase->get_loop(n) != this) { | |
| 1148 if (_required_safept == NULL) _required_safept = new Node_List(); | |
| 1149 _required_safept->push(n); // save the one closest to the tail | |
| 1150 } | |
| 1151 // Terminate this path | |
| 1152 } else { | |
| 1153 uint start = n->is_Region() ? 1 : 0; | |
| 1154 uint end = n->is_Region() && !n->is_Loop() ? n->req() : start + 1; | |
| 1155 for (uint i = start; i < end; i++) { | |
| 1156 Node* in = n->in(i); | |
| 1157 assert(in->is_CFG(), "must be"); | |
| 1158 if (!visited.test_set(in->_idx) && is_member(_phase->get_loop(in))) { | |
| 1159 stack.push(in); | |
| 1160 } | |
| 1161 } | |
| 1162 } | |
| 1163 } | |
| 1164 } | |
| 1165 | |
| 1166 //------------------------------check_safepts---------------------------- | |
| 1167 // Given dominators, try to find loops with calls that must always be | |
| 1168 // executed (call dominates loop tail). These loops do not need non-call | |
| 1169 // safepoints (ncsfpt). | |
| 1170 // | |
| 1171 // A complication is that a safepoint in a inner loop may be needed | |
| 1172 // by an outer loop. In the following, the inner loop sees it has a | |
| 1173 // call (block 3) on every path from the head (block 2) to the | |
| 1174 // backedge (arc 3->2). So it deletes the ncsfpt (non-call safepoint) | |
| 1175 // in block 2, _but_ this leaves the outer loop without a safepoint. | |
| 1176 // | |
| 1177 // entry 0 | |
| 1178 // | | |
| 1179 // v | |
| 1180 // outer 1,2 +->1 | |
| 1181 // | | | |
| 1182 // | v | |
| 1183 // | 2<---+ ncsfpt in 2 | |
| 1184 // |_/|\ | | |
| 1185 // | v | | |
| 1186 // inner 2,3 / 3 | call in 3 | |
| 1187 // / | | | |
| 1188 // v +--+ | |
| 1189 // exit 4 | |
| 1190 // | |
| 1191 // | |
| 1192 // This method creates a list (_required_safept) of ncsfpt nodes that must | |
| 1193 // be protected is created for each loop. When a ncsfpt maybe deleted, it | |
| 1194 // is first looked for in the lists for the outer loops of the current loop. | |
| 1195 // | |
| 1196 // The insights into the problem: | |
| 1197 // A) counted loops are okay | |
| 1198 // B) innermost loops are okay (only an inner loop can delete | |
| 1199 // a ncsfpt needed by an outer loop) | |
| 1200 // C) a loop is immune from an inner loop deleting a safepoint | |
| 1201 // if the loop has a call on the idom-path | |
| 1202 // D) a loop is also immune if it has a ncsfpt (non-call safepoint) on the | |
| 1203 // idom-path that is not in a nested loop | |
| 1204 // E) otherwise, an ncsfpt on the idom-path that is nested in an inner | |
| 1205 // loop needs to be prevented from deletion by an inner loop | |
| 1206 // | |
| 1207 // There are two analyses: | |
| 1208 // 1) The first, and cheaper one, scans the loop body from | |
| 1209 // tail to head following the idom (immediate dominator) | |
| 1210 // chain, looking for the cases (C,D,E) above. | |
| 1211 // Since inner loops are scanned before outer loops, there is summary | |
| 1212 // information about inner loops. Inner loops can be skipped over | |
| 1213 // when the tail of an inner loop is encountered. | |
| 1214 // | |
| 1215 // 2) The second, invoked if the first fails to find a call or ncsfpt on | |
| 1216 // the idom path (which is rare), scans all predecessor control paths | |
| 1217 // from the tail to the head, terminating a path when a call or sfpt | |
| 1218 // is encountered, to find the ncsfpt's that are closest to the tail. | |
| 1219 // | |
| 1220 void IdealLoopTree::check_safepts(VectorSet &visited, Node_List &stack) { | |
| 1221 // Bottom up traversal | |
| 1222 IdealLoopTree* ch = _child; | |
| 1223 while (ch != NULL) { | |
| 1224 ch->check_safepts(visited, stack); | |
| 1225 ch = ch->_next; | |
| 1226 } | |
| 1227 | |
| 1228 if (!_head->is_CountedLoop() && !_has_sfpt && _parent != NULL && !_irreducible) { | |
| 1229 bool has_call = false; // call on dom-path | |
| 1230 bool has_local_ncsfpt = false; // ncsfpt on dom-path at this loop depth | |
| 1231 Node* nonlocal_ncsfpt = NULL; // ncsfpt on dom-path at a deeper depth | |
| 1232 // Scan the dom-path nodes from tail to head | |
| 1233 for (Node* n = tail(); n != _head; n = _phase->idom(n)) { | |
| 1234 if (n->is_Call() && n->as_Call()->guaranteed_safepoint()) { | |
| 1235 has_call = true; | |
| 1236 _has_sfpt = 1; // Then no need for a safept! | |
| 1237 break; | |
| 1238 } else if (n->Opcode() == Op_SafePoint) { | |
| 1239 if (_phase->get_loop(n) == this) { | |
| 1240 has_local_ncsfpt = true; | |
| 1241 break; | |
| 1242 } | |
| 1243 if (nonlocal_ncsfpt == NULL) { | |
| 1244 nonlocal_ncsfpt = n; // save the one closest to the tail | |
| 1245 } | |
| 1246 } else { | |
| 1247 IdealLoopTree* nlpt = _phase->get_loop(n); | |
| 1248 if (this != nlpt) { | |
| 1249 // If at an inner loop tail, see if the inner loop has already | |
| 1250 // recorded seeing a call on the dom-path (and stop.) If not, | |
| 1251 // jump to the head of the inner loop. | |
| 1252 assert(is_member(nlpt), "nested loop"); | |
| 1253 Node* tail = nlpt->_tail; | |
| 1254 if (tail->in(0)->is_If()) tail = tail->in(0); | |
| 1255 if (n == tail) { | |
| 1256 // If inner loop has call on dom-path, so does outer loop | |
| 1257 if (nlpt->_has_sfpt) { | |
| 1258 has_call = true; | |
| 1259 _has_sfpt = 1; | |
| 1260 break; | |
| 1261 } | |
| 1262 // Skip to head of inner loop | |
| 1263 assert(_phase->is_dominator(_head, nlpt->_head), "inner head dominated by outer head"); | |
| 1264 n = nlpt->_head; | |
| 1265 } | |
| 1266 } | |
| 1267 } | |
| 1268 } | |
| 1269 // Record safept's that this loop needs preserved when an | |
| 1270 // inner loop attempts to delete it's safepoints. | |
| 1271 if (_child != NULL && !has_call && !has_local_ncsfpt) { | |
| 1272 if (nonlocal_ncsfpt != NULL) { | |
| 1273 if (_required_safept == NULL) _required_safept = new Node_List(); | |
| 1274 _required_safept->push(nonlocal_ncsfpt); | |
| 1275 } else { | |
| 1276 // Failed to find a suitable safept on the dom-path. Now use | |
| 1277 // an all paths walk from tail to head, looking for safepoints to preserve. | |
| 1278 allpaths_check_safepts(visited, stack); | |
| 1279 } | |
| 1280 } | |
| 1281 } | |
| 1282 } | |
| 1283 | |
| 1284 //---------------------------is_deleteable_safept---------------------------- | |
| 1285 // Is safept not required by an outer loop? | |
| 1286 bool PhaseIdealLoop::is_deleteable_safept(Node* sfpt) { | |
| 1287 assert(sfpt->Opcode() == Op_SafePoint, ""); | |
| 1288 IdealLoopTree* lp = get_loop(sfpt)->_parent; | |
| 1289 while (lp != NULL) { | |
| 1290 Node_List* sfpts = lp->_required_safept; | |
| 1291 if (sfpts != NULL) { | |
| 1292 for (uint i = 0; i < sfpts->size(); i++) { | |
| 1293 if (sfpt == sfpts->at(i)) | |
| 1294 return false; | |
| 1295 } | |
| 1296 } | |
| 1297 lp = lp->_parent; | |
| 1298 } | |
| 1299 return true; | |
| 1300 } | |
| 1301 | |
|
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1302 //---------------------------replace_parallel_iv------------------------------- |
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1303 // Replace parallel induction variable (parallel to trip counter) |
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1304 void PhaseIdealLoop::replace_parallel_iv(IdealLoopTree *loop) { |
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1305 assert(loop->_head->is_CountedLoop(), ""); |
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1306 CountedLoopNode *cl = loop->_head->as_CountedLoop(); |
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1307 Node *incr = cl->incr(); |
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1308 if (incr == NULL) |
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1309 return; // Dead loop? |
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1310 Node *init = cl->init_trip(); |
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1311 Node *phi = cl->phi(); |
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1312 // protect against stride not being a constant |
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1313 if (!cl->stride_is_con()) |
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1314 return; |
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1315 int stride_con = cl->stride_con(); |
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1316 |
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1317 PhaseGVN *gvn = &_igvn; |
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1318 |
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1319 // Visit all children, looking for Phis |
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1320 for (DUIterator i = cl->outs(); cl->has_out(i); i++) { |
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1321 Node *out = cl->out(i); |
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1322 // Look for other phis (secondary IVs). Skip dead ones |
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1323 if (!out->is_Phi() || out == phi || !has_node(out)) |
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1324 continue; |
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1325 PhiNode* phi2 = out->as_Phi(); |
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1326 Node *incr2 = phi2->in( LoopNode::LoopBackControl ); |
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1327 // Look for induction variables of the form: X += constant |
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1328 if (phi2->region() != loop->_head || |
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1329 incr2->req() != 3 || |
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1330 incr2->in(1) != phi2 || |
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1331 incr2 == incr || |
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1332 incr2->Opcode() != Op_AddI || |
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1333 !incr2->in(2)->is_Con()) |
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1334 continue; |
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1335 |
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1336 // Check for parallel induction variable (parallel to trip counter) |
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1337 // via an affine function. In particular, count-down loops with |
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1338 // count-up array indices are common. We only RCE references off |
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1339 // the trip-counter, so we need to convert all these to trip-counter |
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1340 // expressions. |
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1341 Node *init2 = phi2->in( LoopNode::EntryControl ); |
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1342 int stride_con2 = incr2->in(2)->get_int(); |
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1343 |
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1344 // The general case here gets a little tricky. We want to find the |
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1345 // GCD of all possible parallel IV's and make a new IV using this |
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1346 // GCD for the loop. Then all possible IVs are simple multiples of |
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1347 // the GCD. In practice, this will cover very few extra loops. |
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1348 // Instead we require 'stride_con2' to be a multiple of 'stride_con', |
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1349 // where +/-1 is the common case, but other integer multiples are |
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1350 // also easy to handle. |
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1351 int ratio_con = stride_con2/stride_con; |
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1352 |
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1353 if ((ratio_con * stride_con) == stride_con2) { // Check for exact |
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1354 // Convert to using the trip counter. The parallel induction |
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1355 // variable differs from the trip counter by a loop-invariant |
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1356 // amount, the difference between their respective initial values. |
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1357 // It is scaled by the 'ratio_con'. |
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1358 // Perform local Ideal transformation since in most cases ratio == 1. |
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1359 Node* ratio = _igvn.intcon(ratio_con); |
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1360 set_ctrl(ratio, C->root()); |
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1361 Node* hook = new (C, 3) Node(3); |
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1362 Node* ratio_init = gvn->transform(new (C, 3) MulINode(init, ratio)); |
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1363 hook->init_req(0, ratio_init); |
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1364 Node* diff = gvn->transform(new (C, 3) SubINode(init2, ratio_init)); |
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1365 hook->init_req(1, diff); |
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1366 Node* ratio_idx = gvn->transform(new (C, 3) MulINode(phi, ratio)); |
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1367 hook->init_req(2, ratio_idx); |
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1368 Node* add = gvn->transform(new (C, 3) AddINode(ratio_idx, diff)); |
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1369 set_subtree_ctrl(add); |
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1370 _igvn.replace_node( phi2, add ); |
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1371 // Free up intermediate goo |
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1372 _igvn.remove_dead_node(hook); |
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1373 // Sometimes an induction variable is unused |
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1374 if (add->outcnt() == 0) { |
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1375 _igvn.remove_dead_node(add); |
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1376 } |
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1377 --i; // deleted this phi; rescan starting with next position |
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1378 continue; |
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1379 } |
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1380 } |
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1381 } |
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1382 |
| 0 | 1383 //------------------------------counted_loop----------------------------------- |
| 1384 // Convert to counted loops where possible | |
| 1385 void IdealLoopTree::counted_loop( PhaseIdealLoop *phase ) { | |
| 1386 | |
| 1387 // For grins, set the inner-loop flag here | |
|
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1388 if (!_child) { |
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1389 if (_head->is_Loop()) _head->as_Loop()->set_inner_loop(); |
| 0 | 1390 } |
| 1391 | |
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1392 if (_head->is_CountedLoop() || |
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1393 phase->is_counted_loop(_head, this)) { |
| 0 | 1394 _has_sfpt = 1; // Indicate we do not need a safepoint here |
| 1395 | |
| 1396 // Look for a safepoint to remove | |
| 1397 for (Node* n = tail(); n != _head; n = phase->idom(n)) | |
| 1398 if (n->Opcode() == Op_SafePoint && phase->get_loop(n) == this && | |
| 1399 phase->is_deleteable_safept(n)) | |
| 1400 phase->lazy_replace(n,n->in(TypeFunc::Control)); | |
| 1401 | |
| 1402 // Look for induction variables | |
|
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1403 phase->replace_parallel_iv(this); |
| 0 | 1404 |
| 1405 } else if (_parent != NULL && !_irreducible) { | |
| 1406 // Not a counted loop. | |
| 1407 // Look for a safepoint on the idom-path to remove, preserving the first one | |
| 1408 bool found = false; | |
| 1409 Node* n = tail(); | |
| 1410 for (; n != _head && !found; n = phase->idom(n)) { | |
| 1411 if (n->Opcode() == Op_SafePoint && phase->get_loop(n) == this) | |
| 1412 found = true; // Found one | |
| 1413 } | |
| 1414 // Skip past it and delete the others | |
| 1415 for (; n != _head; n = phase->idom(n)) { | |
| 1416 if (n->Opcode() == Op_SafePoint && phase->get_loop(n) == this && | |
| 1417 phase->is_deleteable_safept(n)) | |
| 1418 phase->lazy_replace(n,n->in(TypeFunc::Control)); | |
| 1419 } | |
| 1420 } | |
| 1421 | |
| 1422 // Recursively | |
|
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1423 if (_child) _child->counted_loop( phase ); |
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1424 if (_next) _next ->counted_loop( phase ); |
| 0 | 1425 } |
| 1426 | |
| 1427 #ifndef PRODUCT | |
| 1428 //------------------------------dump_head-------------------------------------- | |
| 1429 // Dump 1 liner for loop header info | |
| 1430 void IdealLoopTree::dump_head( ) const { | |
|
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1431 for (uint i=0; i<_nest; i++) |
| 0 | 1432 tty->print(" "); |
| 1433 tty->print("Loop: N%d/N%d ",_head->_idx,_tail->_idx); | |
|
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1434 if (_irreducible) tty->print(" IRREDUCIBLE"); |
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1435 if (UseLoopPredicate) { |
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1436 Node* entry = _head->in(LoopNode::EntryControl); |
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1437 if (entry != NULL && entry->is_Proj() && |
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1438 PhaseIdealLoop::is_uncommon_trap_if_pattern(entry->as_Proj(), Deoptimization::Reason_predicate)) { |
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1439 tty->print(" predicated"); |
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1440 } |
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1441 } |
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1442 if (_head->is_CountedLoop()) { |
| 0 | 1443 CountedLoopNode *cl = _head->as_CountedLoop(); |
| 1444 tty->print(" counted"); | |
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1445 if (cl->is_pre_loop ()) tty->print(" pre" ); |
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1446 if (cl->is_main_loop()) tty->print(" main"); |
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1447 if (cl->is_post_loop()) tty->print(" post"); |
| 0 | 1448 } |
| 1449 tty->cr(); | |
| 1450 } | |
| 1451 | |
| 1452 //------------------------------dump------------------------------------------- | |
| 1453 // Dump loops by loop tree | |
| 1454 void IdealLoopTree::dump( ) const { | |
| 1455 dump_head(); | |
|
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1456 if (_child) _child->dump(); |
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1457 if (_next) _next ->dump(); |
| 0 | 1458 } |
| 1459 | |
| 1460 #endif | |
| 1461 | |
|
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1462 static void log_loop_tree(IdealLoopTree* root, IdealLoopTree* loop, CompileLog* log) { |
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1463 if (loop == root) { |
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1464 if (loop->_child != NULL) { |
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1465 log->begin_head("loop_tree"); |
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1466 log->end_head(); |
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1467 if( loop->_child ) log_loop_tree(root, loop->_child, log); |
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1468 log->tail("loop_tree"); |
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1469 assert(loop->_next == NULL, "what?"); |
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1470 } |
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1471 } else { |
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1472 Node* head = loop->_head; |
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1473 log->begin_head("loop"); |
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1474 log->print(" idx='%d' ", head->_idx); |
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1475 if (loop->_irreducible) log->print("irreducible='1' "); |
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1476 if (head->is_Loop()) { |
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1477 if (head->as_Loop()->is_inner_loop()) log->print("inner_loop='1' "); |
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1478 if (head->as_Loop()->is_partial_peel_loop()) log->print("partial_peel_loop='1' "); |
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1479 } |
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1480 if (head->is_CountedLoop()) { |
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1481 CountedLoopNode* cl = head->as_CountedLoop(); |
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1482 if (cl->is_pre_loop()) log->print("pre_loop='%d' ", cl->main_idx()); |
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1483 if (cl->is_main_loop()) log->print("main_loop='%d' ", cl->_idx); |
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1484 if (cl->is_post_loop()) log->print("post_loop='%d' ", cl->main_idx()); |
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1485 } |
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1486 log->end_head(); |
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1487 if( loop->_child ) log_loop_tree(root, loop->_child, log); |
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1488 log->tail("loop"); |
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1489 if( loop->_next ) log_loop_tree(root, loop->_next, log); |
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1490 } |
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1491 } |
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1492 |
| 1172 | 1493 //---------------------collect_potentially_useful_predicates----------------------- |
| 1494 // Helper function to collect potentially useful predicates to prevent them from | |
| 1495 // being eliminated by PhaseIdealLoop::eliminate_useless_predicates | |
| 1496 void PhaseIdealLoop::collect_potentially_useful_predicates( | |
| 1497 IdealLoopTree * loop, Unique_Node_List &useful_predicates) { | |
| 1498 if (loop->_child) { // child | |
| 1499 collect_potentially_useful_predicates(loop->_child, useful_predicates); | |
| 1500 } | |
| 1501 | |
| 1502 // self (only loops that we can apply loop predication may use their predicates) | |
|
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1503 if (loop->_head->is_Loop() && |
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1504 !loop->_irreducible && |
| 1172 | 1505 !loop->tail()->is_top()) { |
|
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1506 LoopNode* lpn = loop->_head->as_Loop(); |
| 1172 | 1507 Node* entry = lpn->in(LoopNode::EntryControl); |
|
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1508 Node* predicate_proj = find_predicate(entry); |
| 1172 | 1509 if (predicate_proj != NULL ) { // right pattern that can be used by loop predication |
|
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1510 assert(entry->in(0)->in(1)->in(1)->Opcode() == Op_Opaque1, "must be"); |
| 1172 | 1511 useful_predicates.push(entry->in(0)->in(1)->in(1)); // good one |
| 1512 } | |
| 1513 } | |
| 1514 | |
|
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1515 if (loop->_next) { // sibling |
| 1172 | 1516 collect_potentially_useful_predicates(loop->_next, useful_predicates); |
| 1517 } | |
| 1518 } | |
| 1519 | |
| 1520 //------------------------eliminate_useless_predicates----------------------------- | |
| 1521 // Eliminate all inserted predicates if they could not be used by loop predication. | |
| 1522 void PhaseIdealLoop::eliminate_useless_predicates() { | |
|
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1523 if (C->predicate_count() == 0) |
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1524 return; // no predicate left |
| 1172 | 1525 |
| 1526 Unique_Node_List useful_predicates; // to store useful predicates | |
| 1527 if (C->has_loops()) { | |
| 1528 collect_potentially_useful_predicates(_ltree_root->_child, useful_predicates); | |
| 1529 } | |
| 1530 | |
| 1531 for (int i = C->predicate_count(); i > 0; i--) { | |
| 1532 Node * n = C->predicate_opaque1_node(i-1); | |
| 1533 assert(n->Opcode() == Op_Opaque1, "must be"); | |
| 1534 if (!useful_predicates.member(n)) { // not in the useful list | |
| 1535 _igvn.replace_node(n, n->in(1)); | |
| 1536 } | |
| 1537 } | |
| 1538 } | |
| 1539 | |
| 0 | 1540 //============================================================================= |
|
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1541 //----------------------------build_and_optimize------------------------------- |
| 0 | 1542 // Create a PhaseLoop. Build the ideal Loop tree. Map each Ideal Node to |
| 1543 // its corresponding LoopNode. If 'optimize' is true, do some loop cleanups. | |
| 1172 | 1544 void PhaseIdealLoop::build_and_optimize(bool do_split_ifs, bool do_loop_pred) { |
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1545 ResourceMark rm; |
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1546 |
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1547 int old_progress = C->major_progress(); |
| 2403 | 1548 uint orig_worklist_size = _igvn._worklist.size(); |
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1549 |
| 0 | 1550 // Reset major-progress flag for the driver's heuristics |
| 1551 C->clear_major_progress(); | |
| 1552 | |
| 1553 #ifndef PRODUCT | |
| 1554 // Capture for later assert | |
| 1555 uint unique = C->unique(); | |
| 1556 _loop_invokes++; | |
| 1557 _loop_work += unique; | |
| 1558 #endif | |
| 1559 | |
| 1560 // True if the method has at least 1 irreducible loop | |
| 1561 _has_irreducible_loops = false; | |
| 1562 | |
| 1563 _created_loop_node = false; | |
| 1564 | |
| 1565 Arena *a = Thread::current()->resource_area(); | |
| 1566 VectorSet visited(a); | |
| 1567 // Pre-grow the mapping from Nodes to IdealLoopTrees. | |
| 1568 _nodes.map(C->unique(), NULL); | |
| 1569 memset(_nodes.adr(), 0, wordSize * C->unique()); | |
| 1570 | |
| 1571 // Pre-build the top-level outermost loop tree entry | |
| 1572 _ltree_root = new IdealLoopTree( this, C->root(), C->root() ); | |
| 1573 // Do not need a safepoint at the top level | |
| 1574 _ltree_root->_has_sfpt = 1; | |
| 1575 | |
| 1576 // Empty pre-order array | |
| 1577 allocate_preorders(); | |
| 1578 | |
| 1579 // Build a loop tree on the fly. Build a mapping from CFG nodes to | |
| 1580 // IdealLoopTree entries. Data nodes are NOT walked. | |
| 1581 build_loop_tree(); | |
| 1582 // Check for bailout, and return | |
| 1583 if (C->failing()) { | |
| 1584 return; | |
| 1585 } | |
| 1586 | |
| 1587 // No loops after all | |
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1588 if( !_ltree_root->_child && !_verify_only ) C->set_has_loops(false); |
| 0 | 1589 |
| 1590 // There should always be an outer loop containing the Root and Return nodes. | |
| 1591 // If not, we have a degenerate empty program. Bail out in this case. | |
| 1592 if (!has_node(C->root())) { | |
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1593 if (!_verify_only) { |
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1594 C->clear_major_progress(); |
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1595 C->record_method_not_compilable("empty program detected during loop optimization"); |
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1596 } |
| 0 | 1597 return; |
| 1598 } | |
| 1599 | |
| 1600 // Nothing to do, so get out | |
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1601 if( !C->has_loops() && !do_split_ifs && !_verify_me && !_verify_only ) { |
| 0 | 1602 _igvn.optimize(); // Cleanup NeverBranches |
| 1603 return; | |
| 1604 } | |
| 1605 | |
| 1606 // Set loop nesting depth | |
| 1607 _ltree_root->set_nest( 0 ); | |
| 1608 | |
| 1609 // Split shared headers and insert loop landing pads. | |
| 1610 // Do not bother doing this on the Root loop of course. | |
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1611 if( !_verify_me && !_verify_only && _ltree_root->_child ) { |
| 2403 | 1612 C->print_method("Before beautify loops", 3); |
| 0 | 1613 if( _ltree_root->_child->beautify_loops( this ) ) { |
| 1614 // Re-build loop tree! | |
| 1615 _ltree_root->_child = NULL; | |
| 1616 _nodes.clear(); | |
| 1617 reallocate_preorders(); | |
| 1618 build_loop_tree(); | |
| 1619 // Check for bailout, and return | |
| 1620 if (C->failing()) { | |
| 1621 return; | |
| 1622 } | |
| 1623 // Reset loop nesting depth | |
| 1624 _ltree_root->set_nest( 0 ); | |
| 222 | 1625 |
| 1626 C->print_method("After beautify loops", 3); | |
| 0 | 1627 } |
| 1628 } | |
| 1629 | |
| 1630 // Build Dominators for elision of NULL checks & loop finding. | |
| 1631 // Since nodes do not have a slot for immediate dominator, make | |
| 605 | 1632 // a persistent side array for that info indexed on node->_idx. |
| 0 | 1633 _idom_size = C->unique(); |
| 1634 _idom = NEW_RESOURCE_ARRAY( Node*, _idom_size ); | |
| 1635 _dom_depth = NEW_RESOURCE_ARRAY( uint, _idom_size ); | |
| 1636 _dom_stk = NULL; // Allocated on demand in recompute_dom_depth | |
| 1637 memset( _dom_depth, 0, _idom_size * sizeof(uint) ); | |
| 1638 | |
| 1639 Dominators(); | |
| 1640 | |
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1641 if (!_verify_only) { |
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1642 // As a side effect, Dominators removed any unreachable CFG paths |
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1643 // into RegionNodes. It doesn't do this test against Root, so |
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1644 // we do it here. |
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1645 for( uint i = 1; i < C->root()->req(); i++ ) { |
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1646 if( !_nodes[C->root()->in(i)->_idx] ) { // Dead path into Root? |
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1647 _igvn.hash_delete(C->root()); |
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1648 C->root()->del_req(i); |
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1649 _igvn._worklist.push(C->root()); |
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1650 i--; // Rerun same iteration on compressed edges |
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1651 } |
| 0 | 1652 } |
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1653 |
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1654 // Given dominators, try to find inner loops with calls that must |
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1655 // always be executed (call dominates loop tail). These loops do |
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1656 // not need a separate safepoint. |
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1657 Node_List cisstack(a); |
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1658 _ltree_root->check_safepts(visited, cisstack); |
| 0 | 1659 } |
| 1660 | |
| 1661 // Walk the DATA nodes and place into loops. Find earliest control | |
| 1662 // node. For CFG nodes, the _nodes array starts out and remains | |
| 1663 // holding the associated IdealLoopTree pointer. For DATA nodes, the | |
| 1664 // _nodes array holds the earliest legal controlling CFG node. | |
| 1665 | |
| 1666 // Allocate stack with enough space to avoid frequent realloc | |
| 1667 int stack_size = (C->unique() >> 1) + 16; // (unique>>1)+16 from Java2D stats | |
| 1668 Node_Stack nstack( a, stack_size ); | |
| 1669 | |
| 1670 visited.Clear(); | |
| 1671 Node_List worklist(a); | |
| 1672 // Don't need C->root() on worklist since | |
| 1673 // it will be processed among C->top() inputs | |
| 1674 worklist.push( C->top() ); | |
| 1675 visited.set( C->top()->_idx ); // Set C->top() as visited now | |
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1676 build_loop_early( visited, worklist, nstack ); |
| 0 | 1677 |
| 1678 // Given early legal placement, try finding counted loops. This placement | |
| 1679 // is good enough to discover most loop invariants. | |
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1680 if( !_verify_me && !_verify_only ) |
| 0 | 1681 _ltree_root->counted_loop( this ); |
| 1682 | |
| 1683 // Find latest loop placement. Find ideal loop placement. | |
| 1684 visited.Clear(); | |
| 1685 init_dom_lca_tags(); | |
| 1686 // Need C->root() on worklist when processing outs | |
| 1687 worklist.push( C->root() ); | |
| 1688 NOT_PRODUCT( C->verify_graph_edges(); ) | |
| 1689 worklist.push( C->top() ); | |
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1690 build_loop_late( visited, worklist, nstack ); |
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1691 |
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1692 if (_verify_only) { |
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1693 // restore major progress flag |
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1694 for (int i = 0; i < old_progress; i++) |
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1695 C->set_major_progress(); |
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1696 assert(C->unique() == unique, "verification mode made Nodes? ? ?"); |
| 2403 | 1697 assert(_igvn._worklist.size() == orig_worklist_size, "shouldn't push anything"); |
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1698 return; |
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1699 } |
| 0 | 1700 |
| 1172 | 1701 // some parser-inserted loop predicates could never be used by loop |
| 1702 // predication. Eliminate them before loop optimization | |
| 1703 if (UseLoopPredicate) { | |
| 1704 eliminate_useless_predicates(); | |
| 1705 } | |
| 1706 | |
| 0 | 1707 // clear out the dead code |
| 1708 while(_deadlist.size()) { | |
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1709 _igvn.remove_globally_dead_node(_deadlist.pop()); |
| 0 | 1710 } |
| 1711 | |
| 1712 #ifndef PRODUCT | |
| 1713 C->verify_graph_edges(); | |
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1714 if (_verify_me) { // Nested verify pass? |
| 0 | 1715 // Check to see if the verify mode is broken |
| 1716 assert(C->unique() == unique, "non-optimize mode made Nodes? ? ?"); | |
| 1717 return; | |
| 1718 } | |
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1719 if(VerifyLoopOptimizations) verify(); |
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1720 if(TraceLoopOpts && C->has_loops()) { |
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1721 _ltree_root->dump(); |
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1722 } |
| 0 | 1723 #endif |
| 1724 | |
| 1725 if (ReassociateInvariants) { | |
| 1726 // Reassociate invariants and prep for split_thru_phi | |
| 1727 for (LoopTreeIterator iter(_ltree_root); !iter.done(); iter.next()) { | |
| 1728 IdealLoopTree* lpt = iter.current(); | |
| 1729 if (!lpt->is_counted() || !lpt->is_inner()) continue; | |
| 1730 | |
| 1731 lpt->reassociate_invariants(this); | |
| 1732 | |
| 1733 // Because RCE opportunities can be masked by split_thru_phi, | |
| 1734 // look for RCE candidates and inhibit split_thru_phi | |
| 1735 // on just their loop-phi's for this pass of loop opts | |
| 1172 | 1736 if (SplitIfBlocks && do_split_ifs) { |
| 0 | 1737 if (lpt->policy_range_check(this)) { |
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1738 lpt->_rce_candidate = 1; // = true |
| 0 | 1739 } |
| 1740 } | |
| 1741 } | |
| 1742 } | |
| 1743 | |
| 1744 // Check for aggressive application of split-if and other transforms | |
| 1745 // that require basic-block info (like cloning through Phi's) | |
| 1746 if( SplitIfBlocks && do_split_ifs ) { | |
| 1747 visited.Clear(); | |
| 1748 split_if_with_blocks( visited, nstack ); | |
| 1749 NOT_PRODUCT( if( VerifyLoopOptimizations ) verify(); ); | |
| 1750 } | |
| 1751 | |
| 1172 | 1752 // Perform loop predication before iteration splitting |
| 1753 if (do_loop_pred && C->has_loops() && !C->major_progress()) { | |
| 1754 _ltree_root->_child->loop_predication(this); | |
| 1755 } | |
| 1756 | |
| 1763 | 1757 if (OptimizeFill && UseLoopPredicate && C->has_loops() && !C->major_progress()) { |
| 1758 if (do_intrinsify_fill()) { | |
| 1759 C->set_major_progress(); | |
| 1760 } | |
| 1761 } | |
| 1762 | |
| 0 | 1763 // Perform iteration-splitting on inner loops. Split iterations to avoid |
| 1764 // range checks or one-shot null checks. | |
| 1765 | |
| 1766 // If split-if's didn't hack the graph too bad (no CFG changes) | |
| 1767 // then do loop opts. | |
| 1172 | 1768 if (C->has_loops() && !C->major_progress()) { |
| 0 | 1769 memset( worklist.adr(), 0, worklist.Size()*sizeof(Node*) ); |
| 1770 _ltree_root->_child->iteration_split( this, worklist ); | |
| 1771 // No verify after peeling! GCM has hoisted code out of the loop. | |
| 1772 // After peeling, the hoisted code could sink inside the peeled area. | |
| 1773 // The peeling code does not try to recompute the best location for | |
| 1774 // all the code before the peeled area, so the verify pass will always | |
| 1775 // complain about it. | |
| 1776 } | |
| 1777 // Do verify graph edges in any case | |
| 1778 NOT_PRODUCT( C->verify_graph_edges(); ); | |
| 1779 | |
| 1172 | 1780 if (!do_split_ifs) { |
| 0 | 1781 // We saw major progress in Split-If to get here. We forced a |
| 1782 // pass with unrolling and not split-if, however more split-if's | |
| 1783 // might make progress. If the unrolling didn't make progress | |
| 1784 // then the major-progress flag got cleared and we won't try | |
| 1785 // another round of Split-If. In particular the ever-common | |
| 1786 // instance-of/check-cast pattern requires at least 2 rounds of | |
| 1787 // Split-If to clear out. | |
| 1788 C->set_major_progress(); | |
| 1789 } | |
| 1790 | |
| 1791 // Repeat loop optimizations if new loops were seen | |
| 1792 if (created_loop_node()) { | |
| 1793 C->set_major_progress(); | |
| 1794 } | |
| 1795 | |
| 1796 // Convert scalar to superword operations | |
| 1797 | |
| 1798 if (UseSuperWord && C->has_loops() && !C->major_progress()) { | |
| 1799 // SuperWord transform | |
| 1800 SuperWord sw(this); | |
| 1801 for (LoopTreeIterator iter(_ltree_root); !iter.done(); iter.next()) { | |
| 1802 IdealLoopTree* lpt = iter.current(); | |
| 1803 if (lpt->is_counted()) { | |
| 1804 sw.transform_loop(lpt); | |
| 1805 } | |
| 1806 } | |
| 1807 } | |
| 1808 | |
| 1809 // Cleanup any modified bits | |
| 1810 _igvn.optimize(); | |
| 1811 | |
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1812 // disable assert until issue with split_flow_path is resolved (6742111) |
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1813 // assert(!_has_irreducible_loops || C->parsed_irreducible_loop() || C->is_osr_compilation(), |
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1814 // "shouldn't introduce irreducible loops"); |
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1815 |
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1816 if (C->log() != NULL) { |
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1817 log_loop_tree(_ltree_root, _ltree_root, C->log()); |
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1818 } |
| 0 | 1819 } |
| 1820 | |
| 1821 #ifndef PRODUCT | |
| 1822 //------------------------------print_statistics------------------------------- | |
| 1823 int PhaseIdealLoop::_loop_invokes=0;// Count of PhaseIdealLoop invokes | |
| 1824 int PhaseIdealLoop::_loop_work=0; // Sum of PhaseIdealLoop x unique | |
| 1825 void PhaseIdealLoop::print_statistics() { | |
| 1826 tty->print_cr("PhaseIdealLoop=%d, sum _unique=%d", _loop_invokes, _loop_work); | |
| 1827 } | |
| 1828 | |
| 1829 //------------------------------verify----------------------------------------- | |
| 1830 // Build a verify-only PhaseIdealLoop, and see that it agrees with me. | |
| 1831 static int fail; // debug only, so its multi-thread dont care | |
| 1832 void PhaseIdealLoop::verify() const { | |
| 1833 int old_progress = C->major_progress(); | |
| 1834 ResourceMark rm; | |
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1835 PhaseIdealLoop loop_verify( _igvn, this ); |
| 0 | 1836 VectorSet visited(Thread::current()->resource_area()); |
| 1837 | |
| 1838 fail = 0; | |
| 1839 verify_compare( C->root(), &loop_verify, visited ); | |
| 1840 assert( fail == 0, "verify loops failed" ); | |
| 1841 // Verify loop structure is the same | |
| 1842 _ltree_root->verify_tree(loop_verify._ltree_root, NULL); | |
| 1843 // Reset major-progress. It was cleared by creating a verify version of | |
| 1844 // PhaseIdealLoop. | |
| 1845 for( int i=0; i<old_progress; i++ ) | |
| 1846 C->set_major_progress(); | |
| 1847 } | |
| 1848 | |
| 1849 //------------------------------verify_compare--------------------------------- | |
| 1850 // Make sure me and the given PhaseIdealLoop agree on key data structures | |
| 1851 void PhaseIdealLoop::verify_compare( Node *n, const PhaseIdealLoop *loop_verify, VectorSet &visited ) const { | |
| 1852 if( !n ) return; | |
| 1853 if( visited.test_set( n->_idx ) ) return; | |
| 1854 if( !_nodes[n->_idx] ) { // Unreachable | |
| 1855 assert( !loop_verify->_nodes[n->_idx], "both should be unreachable" ); | |
| 1856 return; | |
| 1857 } | |
| 1858 | |
| 1859 uint i; | |
| 1860 for( i = 0; i < n->req(); i++ ) | |
| 1861 verify_compare( n->in(i), loop_verify, visited ); | |
| 1862 | |
| 1863 // Check the '_nodes' block/loop structure | |
| 1864 i = n->_idx; | |
| 1865 if( has_ctrl(n) ) { // We have control; verify has loop or ctrl | |
| 1866 if( _nodes[i] != loop_verify->_nodes[i] && | |
| 1867 get_ctrl_no_update(n) != loop_verify->get_ctrl_no_update(n) ) { | |
| 1868 tty->print("Mismatched control setting for: "); | |
| 1869 n->dump(); | |
| 1870 if( fail++ > 10 ) return; | |
| 1871 Node *c = get_ctrl_no_update(n); | |
| 1872 tty->print("We have it as: "); | |
| 1873 if( c->in(0) ) c->dump(); | |
| 1874 else tty->print_cr("N%d",c->_idx); | |
| 1875 tty->print("Verify thinks: "); | |
| 1876 if( loop_verify->has_ctrl(n) ) | |
| 1877 loop_verify->get_ctrl_no_update(n)->dump(); | |
| 1878 else | |
| 1879 loop_verify->get_loop_idx(n)->dump(); | |
| 1880 tty->cr(); | |
| 1881 } | |
| 1882 } else { // We have a loop | |
| 1883 IdealLoopTree *us = get_loop_idx(n); | |
| 1884 if( loop_verify->has_ctrl(n) ) { | |
| 1885 tty->print("Mismatched loop setting for: "); | |
| 1886 n->dump(); | |
| 1887 if( fail++ > 10 ) return; | |
| 1888 tty->print("We have it as: "); | |
| 1889 us->dump(); | |
| 1890 tty->print("Verify thinks: "); | |
| 1891 loop_verify->get_ctrl_no_update(n)->dump(); | |
| 1892 tty->cr(); | |
| 1893 } else if (!C->major_progress()) { | |
| 1894 // Loop selection can be messed up if we did a major progress | |
| 1895 // operation, like split-if. Do not verify in that case. | |
| 1896 IdealLoopTree *them = loop_verify->get_loop_idx(n); | |
| 1897 if( us->_head != them->_head || us->_tail != them->_tail ) { | |
| 1898 tty->print("Unequals loops for: "); | |
| 1899 n->dump(); | |
| 1900 if( fail++ > 10 ) return; | |
| 1901 tty->print("We have it as: "); | |
| 1902 us->dump(); | |
| 1903 tty->print("Verify thinks: "); | |
| 1904 them->dump(); | |
| 1905 tty->cr(); | |
| 1906 } | |
| 1907 } | |
| 1908 } | |
| 1909 | |
| 1910 // Check for immediate dominators being equal | |
| 1911 if( i >= _idom_size ) { | |
| 1912 if( !n->is_CFG() ) return; | |
| 1913 tty->print("CFG Node with no idom: "); | |
| 1914 n->dump(); | |
| 1915 return; | |
| 1916 } | |
| 1917 if( !n->is_CFG() ) return; | |
| 1918 if( n == C->root() ) return; // No IDOM here | |
| 1919 | |
| 1920 assert(n->_idx == i, "sanity"); | |
| 1921 Node *id = idom_no_update(n); | |
| 1922 if( id != loop_verify->idom_no_update(n) ) { | |
| 1923 tty->print("Unequals idoms for: "); | |
| 1924 n->dump(); | |
| 1925 if( fail++ > 10 ) return; | |
| 1926 tty->print("We have it as: "); | |
| 1927 id->dump(); | |
| 1928 tty->print("Verify thinks: "); | |
| 1929 loop_verify->idom_no_update(n)->dump(); | |
| 1930 tty->cr(); | |
| 1931 } | |
| 1932 | |
| 1933 } | |
| 1934 | |
| 1935 //------------------------------verify_tree------------------------------------ | |
| 1936 // Verify that tree structures match. Because the CFG can change, siblings | |
| 1937 // within the loop tree can be reordered. We attempt to deal with that by | |
| 1938 // reordering the verify's loop tree if possible. | |
| 1939 void IdealLoopTree::verify_tree(IdealLoopTree *loop, const IdealLoopTree *parent) const { | |
| 1940 assert( _parent == parent, "Badly formed loop tree" ); | |
| 1941 | |
| 1942 // Siblings not in same order? Attempt to re-order. | |
| 1943 if( _head != loop->_head ) { | |
| 1944 // Find _next pointer to update | |
| 1945 IdealLoopTree **pp = &loop->_parent->_child; | |
| 1946 while( *pp != loop ) | |
| 1947 pp = &((*pp)->_next); | |
| 1948 // Find proper sibling to be next | |
| 1949 IdealLoopTree **nn = &loop->_next; | |
| 1950 while( (*nn) && (*nn)->_head != _head ) | |
| 1951 nn = &((*nn)->_next); | |
| 1952 | |
| 1953 // Check for no match. | |
| 1954 if( !(*nn) ) { | |
| 1955 // Annoyingly, irreducible loops can pick different headers | |
| 1956 // after a major_progress operation, so the rest of the loop | |
| 1957 // tree cannot be matched. | |
| 1958 if (_irreducible && Compile::current()->major_progress()) return; | |
| 1959 assert( 0, "failed to match loop tree" ); | |
| 1960 } | |
| 1961 | |
| 1962 // Move (*nn) to (*pp) | |
| 1963 IdealLoopTree *hit = *nn; | |
| 1964 *nn = hit->_next; | |
| 1965 hit->_next = loop; | |
| 1966 *pp = loop; | |
| 1967 loop = hit; | |
| 1968 // Now try again to verify | |
| 1969 } | |
| 1970 | |
| 1971 assert( _head == loop->_head , "mismatched loop head" ); | |
| 1972 Node *tail = _tail; // Inline a non-updating version of | |
| 1973 while( !tail->in(0) ) // the 'tail()' call. | |
| 1974 tail = tail->in(1); | |
| 1975 assert( tail == loop->_tail, "mismatched loop tail" ); | |
| 1976 | |
| 1977 // Counted loops that are guarded should be able to find their guards | |
| 1978 if( _head->is_CountedLoop() && _head->as_CountedLoop()->is_main_loop() ) { | |
| 1979 CountedLoopNode *cl = _head->as_CountedLoop(); | |
| 1980 Node *init = cl->init_trip(); | |
| 1981 Node *ctrl = cl->in(LoopNode::EntryControl); | |
| 1982 assert( ctrl->Opcode() == Op_IfTrue || ctrl->Opcode() == Op_IfFalse, "" ); | |
| 1983 Node *iff = ctrl->in(0); | |
| 1984 assert( iff->Opcode() == Op_If, "" ); | |
| 1985 Node *bol = iff->in(1); | |
| 1986 assert( bol->Opcode() == Op_Bool, "" ); | |
| 1987 Node *cmp = bol->in(1); | |
| 1988 assert( cmp->Opcode() == Op_CmpI, "" ); | |
| 1989 Node *add = cmp->in(1); | |
| 1990 Node *opaq; | |
| 1991 if( add->Opcode() == Op_Opaque1 ) { | |
| 1992 opaq = add; | |
| 1993 } else { | |
| 1994 assert( add->Opcode() == Op_AddI || add->Opcode() == Op_ConI , "" ); | |
| 1995 assert( add == init, "" ); | |
| 1996 opaq = cmp->in(2); | |
| 1997 } | |
| 1998 assert( opaq->Opcode() == Op_Opaque1, "" ); | |
| 1999 | |
| 2000 } | |
| 2001 | |
| 2002 if (_child != NULL) _child->verify_tree(loop->_child, this); | |
| 2003 if (_next != NULL) _next ->verify_tree(loop->_next, parent); | |
| 2004 // Innermost loops need to verify loop bodies, | |
| 2005 // but only if no 'major_progress' | |
| 2006 int fail = 0; | |
| 2007 if (!Compile::current()->major_progress() && _child == NULL) { | |
| 2008 for( uint i = 0; i < _body.size(); i++ ) { | |
| 2009 Node *n = _body.at(i); | |
| 2010 if (n->outcnt() == 0) continue; // Ignore dead | |
| 2011 uint j; | |
| 2012 for( j = 0; j < loop->_body.size(); j++ ) | |
| 2013 if( loop->_body.at(j) == n ) | |
| 2014 break; | |
| 2015 if( j == loop->_body.size() ) { // Not found in loop body | |
| 2016 // Last ditch effort to avoid assertion: Its possible that we | |
| 2017 // have some users (so outcnt not zero) but are still dead. | |
| 2018 // Try to find from root. | |
| 2019 if (Compile::current()->root()->find(n->_idx)) { | |
| 2020 fail++; | |
| 2021 tty->print("We have that verify does not: "); | |
| 2022 n->dump(); | |
| 2023 } | |
| 2024 } | |
| 2025 } | |
| 2026 for( uint i2 = 0; i2 < loop->_body.size(); i2++ ) { | |
| 2027 Node *n = loop->_body.at(i2); | |
| 2028 if (n->outcnt() == 0) continue; // Ignore dead | |
| 2029 uint j; | |
| 2030 for( j = 0; j < _body.size(); j++ ) | |
| 2031 if( _body.at(j) == n ) | |
| 2032 break; | |
| 2033 if( j == _body.size() ) { // Not found in loop body | |
| 2034 // Last ditch effort to avoid assertion: Its possible that we | |
| 2035 // have some users (so outcnt not zero) but are still dead. | |
| 2036 // Try to find from root. | |
| 2037 if (Compile::current()->root()->find(n->_idx)) { | |
| 2038 fail++; | |
| 2039 tty->print("Verify has that we do not: "); | |
| 2040 n->dump(); | |
| 2041 } | |
| 2042 } | |
| 2043 } | |
| 2044 assert( !fail, "loop body mismatch" ); | |
| 2045 } | |
| 2046 } | |
| 2047 | |
| 2048 #endif | |
| 2049 | |
| 2050 //------------------------------set_idom--------------------------------------- | |
| 2051 void PhaseIdealLoop::set_idom(Node* d, Node* n, uint dom_depth) { | |
| 2052 uint idx = d->_idx; | |
| 2053 if (idx >= _idom_size) { | |
| 2054 uint newsize = _idom_size<<1; | |
| 2055 while( idx >= newsize ) { | |
| 2056 newsize <<= 1; | |
| 2057 } | |
| 2058 _idom = REALLOC_RESOURCE_ARRAY( Node*, _idom,_idom_size,newsize); | |
| 2059 _dom_depth = REALLOC_RESOURCE_ARRAY( uint, _dom_depth,_idom_size,newsize); | |
| 2060 memset( _dom_depth + _idom_size, 0, (newsize - _idom_size) * sizeof(uint) ); | |
| 2061 _idom_size = newsize; | |
| 2062 } | |
| 2063 _idom[idx] = n; | |
| 2064 _dom_depth[idx] = dom_depth; | |
| 2065 } | |
| 2066 | |
| 2067 //------------------------------recompute_dom_depth--------------------------------------- | |
| 2068 // The dominator tree is constructed with only parent pointers. | |
| 2069 // This recomputes the depth in the tree by first tagging all | |
| 2070 // nodes as "no depth yet" marker. The next pass then runs up | |
| 2071 // the dom tree from each node marked "no depth yet", and computes | |
| 2072 // the depth on the way back down. | |
| 2073 void PhaseIdealLoop::recompute_dom_depth() { | |
| 2074 uint no_depth_marker = C->unique(); | |
| 2075 uint i; | |
| 2076 // Initialize depth to "no depth yet" | |
| 2077 for (i = 0; i < _idom_size; i++) { | |
| 2078 if (_dom_depth[i] > 0 && _idom[i] != NULL) { | |
| 2079 _dom_depth[i] = no_depth_marker; | |
| 2080 } | |
| 2081 } | |
| 2082 if (_dom_stk == NULL) { | |
| 2083 uint init_size = C->unique() / 100; // Guess that 1/100 is a reasonable initial size. | |
| 2084 if (init_size < 10) init_size = 10; | |
|
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2085 _dom_stk = new GrowableArray<uint>(init_size); |
| 0 | 2086 } |
| 2087 // Compute new depth for each node. | |
| 2088 for (i = 0; i < _idom_size; i++) { | |
| 2089 uint j = i; | |
| 2090 // Run up the dom tree to find a node with a depth | |
| 2091 while (_dom_depth[j] == no_depth_marker) { | |
| 2092 _dom_stk->push(j); | |
| 2093 j = _idom[j]->_idx; | |
| 2094 } | |
| 2095 // Compute the depth on the way back down this tree branch | |
| 2096 uint dd = _dom_depth[j] + 1; | |
| 2097 while (_dom_stk->length() > 0) { | |
| 2098 uint j = _dom_stk->pop(); | |
| 2099 _dom_depth[j] = dd; | |
| 2100 dd++; | |
| 2101 } | |
| 2102 } | |
| 2103 } | |
| 2104 | |
| 2105 //------------------------------sort------------------------------------------- | |
| 2106 // Insert 'loop' into the existing loop tree. 'innermost' is a leaf of the | |
| 2107 // loop tree, not the root. | |
| 2108 IdealLoopTree *PhaseIdealLoop::sort( IdealLoopTree *loop, IdealLoopTree *innermost ) { | |
| 2109 if( !innermost ) return loop; // New innermost loop | |
| 2110 | |
| 2111 int loop_preorder = get_preorder(loop->_head); // Cache pre-order number | |
| 2112 assert( loop_preorder, "not yet post-walked loop" ); | |
| 2113 IdealLoopTree **pp = &innermost; // Pointer to previous next-pointer | |
| 2114 IdealLoopTree *l = *pp; // Do I go before or after 'l'? | |
| 2115 | |
| 2116 // Insert at start of list | |
| 2117 while( l ) { // Insertion sort based on pre-order | |
| 2118 if( l == loop ) return innermost; // Already on list! | |
| 2119 int l_preorder = get_preorder(l->_head); // Cache pre-order number | |
| 2120 assert( l_preorder, "not yet post-walked l" ); | |
| 2121 // Check header pre-order number to figure proper nesting | |
| 2122 if( loop_preorder > l_preorder ) | |
| 2123 break; // End of insertion | |
| 2124 // If headers tie (e.g., shared headers) check tail pre-order numbers. | |
| 2125 // Since I split shared headers, you'd think this could not happen. | |
| 2126 // BUT: I must first do the preorder numbering before I can discover I | |
| 2127 // have shared headers, so the split headers all get the same preorder | |
| 2128 // number as the RegionNode they split from. | |
| 2129 if( loop_preorder == l_preorder && | |
| 2130 get_preorder(loop->_tail) < get_preorder(l->_tail) ) | |
| 2131 break; // Also check for shared headers (same pre#) | |
| 2132 pp = &l->_parent; // Chain up list | |
| 2133 l = *pp; | |
| 2134 } | |
| 2135 // Link into list | |
| 2136 // Point predecessor to me | |
| 2137 *pp = loop; | |
| 2138 // Point me to successor | |
| 2139 IdealLoopTree *p = loop->_parent; | |
| 2140 loop->_parent = l; // Point me to successor | |
| 2141 if( p ) sort( p, innermost ); // Insert my parents into list as well | |
| 2142 return innermost; | |
| 2143 } | |
| 2144 | |
| 2145 //------------------------------build_loop_tree-------------------------------- | |
| 2146 // I use a modified Vick/Tarjan algorithm. I need pre- and a post- visit | |
| 2147 // bits. The _nodes[] array is mapped by Node index and holds a NULL for | |
| 2148 // not-yet-pre-walked, pre-order # for pre-but-not-post-walked and holds the | |
| 2149 // tightest enclosing IdealLoopTree for post-walked. | |
| 2150 // | |
| 2151 // During my forward walk I do a short 1-layer lookahead to see if I can find | |
| 2152 // a loop backedge with that doesn't have any work on the backedge. This | |
| 2153 // helps me construct nested loops with shared headers better. | |
| 2154 // | |
| 2155 // Once I've done the forward recursion, I do the post-work. For each child | |
| 2156 // I check to see if there is a backedge. Backedges define a loop! I | |
| 2157 // insert an IdealLoopTree at the target of the backedge. | |
| 2158 // | |
| 2159 // During the post-work I also check to see if I have several children | |
| 2160 // belonging to different loops. If so, then this Node is a decision point | |
| 2161 // where control flow can choose to change loop nests. It is at this | |
| 2162 // decision point where I can figure out how loops are nested. At this | |
| 2163 // time I can properly order the different loop nests from my children. | |
| 2164 // Note that there may not be any backedges at the decision point! | |
| 2165 // | |
| 2166 // Since the decision point can be far removed from the backedges, I can't | |
| 2167 // order my loops at the time I discover them. Thus at the decision point | |
| 2168 // I need to inspect loop header pre-order numbers to properly nest my | |
| 2169 // loops. This means I need to sort my childrens' loops by pre-order. | |
| 2170 // The sort is of size number-of-control-children, which generally limits | |
| 2171 // it to size 2 (i.e., I just choose between my 2 target loops). | |
| 2172 void PhaseIdealLoop::build_loop_tree() { | |
| 2173 // Allocate stack of size C->unique()/2 to avoid frequent realloc | |
| 2174 GrowableArray <Node *> bltstack(C->unique() >> 1); | |
| 2175 Node *n = C->root(); | |
| 2176 bltstack.push(n); | |
| 2177 int pre_order = 1; | |
| 2178 int stack_size; | |
| 2179 | |
| 2180 while ( ( stack_size = bltstack.length() ) != 0 ) { | |
| 2181 n = bltstack.top(); // Leave node on stack | |
| 2182 if ( !is_visited(n) ) { | |
| 2183 // ---- Pre-pass Work ---- | |
| 2184 // Pre-walked but not post-walked nodes need a pre_order number. | |
| 2185 | |
| 2186 set_preorder_visited( n, pre_order ); // set as visited | |
| 2187 | |
| 2188 // ---- Scan over children ---- | |
| 2189 // Scan first over control projections that lead to loop headers. | |
| 2190 // This helps us find inner-to-outer loops with shared headers better. | |
| 2191 | |
| 2192 // Scan children's children for loop headers. | |
| 2193 for ( int i = n->outcnt() - 1; i >= 0; --i ) { | |
| 2194 Node* m = n->raw_out(i); // Child | |
| 2195 if( m->is_CFG() && !is_visited(m) ) { // Only for CFG children | |
| 2196 // Scan over children's children to find loop | |
| 2197 for (DUIterator_Fast jmax, j = m->fast_outs(jmax); j < jmax; j++) { | |
| 2198 Node* l = m->fast_out(j); | |
| 2199 if( is_visited(l) && // Been visited? | |
| 2200 !is_postvisited(l) && // But not post-visited | |
| 2201 get_preorder(l) < pre_order ) { // And smaller pre-order | |
| 2202 // Found! Scan the DFS down this path before doing other paths | |
| 2203 bltstack.push(m); | |
| 2204 break; | |
| 2205 } | |
| 2206 } | |
| 2207 } | |
| 2208 } | |
| 2209 pre_order++; | |
| 2210 } | |
| 2211 else if ( !is_postvisited(n) ) { | |
| 2212 // Note: build_loop_tree_impl() adds out edges on rare occasions, | |
| 2213 // such as com.sun.rsasign.am::a. | |
| 2214 // For non-recursive version, first, process current children. | |
| 2215 // On next iteration, check if additional children were added. | |
| 2216 for ( int k = n->outcnt() - 1; k >= 0; --k ) { | |
| 2217 Node* u = n->raw_out(k); | |
| 2218 if ( u->is_CFG() && !is_visited(u) ) { | |
| 2219 bltstack.push(u); | |
| 2220 } | |
| 2221 } | |
| 2222 if ( bltstack.length() == stack_size ) { | |
| 2223 // There were no additional children, post visit node now | |
| 2224 (void)bltstack.pop(); // Remove node from stack | |
| 2225 pre_order = build_loop_tree_impl( n, pre_order ); | |
| 2226 // Check for bailout | |
| 2227 if (C->failing()) { | |
| 2228 return; | |
| 2229 } | |
| 2230 // Check to grow _preorders[] array for the case when | |
| 2231 // build_loop_tree_impl() adds new nodes. | |
| 2232 check_grow_preorders(); | |
| 2233 } | |
| 2234 } | |
| 2235 else { | |
| 2236 (void)bltstack.pop(); // Remove post-visited node from stack | |
| 2237 } | |
| 2238 } | |
| 2239 } | |
| 2240 | |
| 2241 //------------------------------build_loop_tree_impl--------------------------- | |
| 2242 int PhaseIdealLoop::build_loop_tree_impl( Node *n, int pre_order ) { | |
| 2243 // ---- Post-pass Work ---- | |
| 2244 // Pre-walked but not post-walked nodes need a pre_order number. | |
| 2245 | |
| 2246 // Tightest enclosing loop for this Node | |
| 2247 IdealLoopTree *innermost = NULL; | |
| 2248 | |
| 2249 // For all children, see if any edge is a backedge. If so, make a loop | |
| 2250 // for it. Then find the tightest enclosing loop for the self Node. | |
| 2251 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { | |
| 2252 Node* m = n->fast_out(i); // Child | |
| 2253 if( n == m ) continue; // Ignore control self-cycles | |
| 2254 if( !m->is_CFG() ) continue;// Ignore non-CFG edges | |
| 2255 | |
| 2256 IdealLoopTree *l; // Child's loop | |
| 2257 if( !is_postvisited(m) ) { // Child visited but not post-visited? | |
| 2258 // Found a backedge | |
| 2259 assert( get_preorder(m) < pre_order, "should be backedge" ); | |
| 2260 // Check for the RootNode, which is already a LoopNode and is allowed | |
| 2261 // to have multiple "backedges". | |
| 2262 if( m == C->root()) { // Found the root? | |
| 2263 l = _ltree_root; // Root is the outermost LoopNode | |
| 2264 } else { // Else found a nested loop | |
| 2265 // Insert a LoopNode to mark this loop. | |
| 2266 l = new IdealLoopTree(this, m, n); | |
| 2267 } // End of Else found a nested loop | |
| 2268 if( !has_loop(m) ) // If 'm' does not already have a loop set | |
| 2269 set_loop(m, l); // Set loop header to loop now | |
| 2270 | |
| 2271 } else { // Else not a nested loop | |
| 2272 if( !_nodes[m->_idx] ) continue; // Dead code has no loop | |
| 2273 l = get_loop(m); // Get previously determined loop | |
| 2274 // If successor is header of a loop (nest), move up-loop till it | |
| 2275 // is a member of some outer enclosing loop. Since there are no | |
| 2276 // shared headers (I've split them already) I only need to go up | |
| 2277 // at most 1 level. | |
| 2278 while( l && l->_head == m ) // Successor heads loop? | |
| 2279 l = l->_parent; // Move up 1 for me | |
| 2280 // If this loop is not properly parented, then this loop | |
| 2281 // has no exit path out, i.e. its an infinite loop. | |
| 2282 if( !l ) { | |
| 2283 // Make loop "reachable" from root so the CFG is reachable. Basically | |
| 2284 // insert a bogus loop exit that is never taken. 'm', the loop head, | |
| 2285 // points to 'n', one (of possibly many) fall-in paths. There may be | |
| 2286 // many backedges as well. | |
| 2287 | |
| 2288 // Here I set the loop to be the root loop. I could have, after | |
| 2289 // inserting a bogus loop exit, restarted the recursion and found my | |
| 2290 // new loop exit. This would make the infinite loop a first-class | |
| 2291 // loop and it would then get properly optimized. What's the use of | |
| 2292 // optimizing an infinite loop? | |
| 2293 l = _ltree_root; // Oops, found infinite loop | |
| 2294 | |
|
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2295 if (!_verify_only) { |
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2296 // Insert the NeverBranch between 'm' and it's control user. |
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2297 NeverBranchNode *iff = new (C, 1) NeverBranchNode( m ); |
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2298 _igvn.register_new_node_with_optimizer(iff); |
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2299 set_loop(iff, l); |
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2300 Node *if_t = new (C, 1) CProjNode( iff, 0 ); |
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2301 _igvn.register_new_node_with_optimizer(if_t); |
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2302 set_loop(if_t, l); |
| 0 | 2303 |
|
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2304 Node* cfg = NULL; // Find the One True Control User of m |
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2305 for (DUIterator_Fast jmax, j = m->fast_outs(jmax); j < jmax; j++) { |
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2306 Node* x = m->fast_out(j); |
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2307 if (x->is_CFG() && x != m && x != iff) |
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2308 { cfg = x; break; } |
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2309 } |
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2310 assert(cfg != NULL, "must find the control user of m"); |
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2311 uint k = 0; // Probably cfg->in(0) |
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2312 while( cfg->in(k) != m ) k++; // But check incase cfg is a Region |
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2313 cfg->set_req( k, if_t ); // Now point to NeverBranch |
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2314 |
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2315 // Now create the never-taken loop exit |
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2316 Node *if_f = new (C, 1) CProjNode( iff, 1 ); |
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2317 _igvn.register_new_node_with_optimizer(if_f); |
|
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2318 set_loop(if_f, l); |
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2319 // Find frame ptr for Halt. Relies on the optimizer |
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2320 // V-N'ing. Easier and quicker than searching through |
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2321 // the program structure. |
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2322 Node *frame = new (C, 1) ParmNode( C->start(), TypeFunc::FramePtr ); |
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2323 _igvn.register_new_node_with_optimizer(frame); |
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2324 // Halt & Catch Fire |
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2325 Node *halt = new (C, TypeFunc::Parms) HaltNode( if_f, frame ); |
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2326 _igvn.register_new_node_with_optimizer(halt); |
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2327 set_loop(halt, l); |
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2328 C->root()->add_req(halt); |
| 0 | 2329 } |
| 2330 set_loop(C->root(), _ltree_root); | |
| 2331 } | |
| 2332 } | |
| 2333 // Weeny check for irreducible. This child was already visited (this | |
| 2334 // IS the post-work phase). Is this child's loop header post-visited | |
| 2335 // as well? If so, then I found another entry into the loop. | |
|
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2336 if (!_verify_only) { |
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2337 while( is_postvisited(l->_head) ) { |
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2338 // found irreducible |
|
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2339 l->_irreducible = 1; // = true |
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2340 l = l->_parent; |
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2341 _has_irreducible_loops = true; |
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2342 // Check for bad CFG here to prevent crash, and bailout of compile |
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2343 if (l == NULL) { |
|
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2344 C->record_method_not_compilable("unhandled CFG detected during loop optimization"); |
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2345 return pre_order; |
|
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|
2346 } |
| 0 | 2347 } |
| 2348 } | |
| 2349 | |
| 2350 // This Node might be a decision point for loops. It is only if | |
| 2351 // it's children belong to several different loops. The sort call | |
| 2352 // does a trivial amount of work if there is only 1 child or all | |
| 2353 // children belong to the same loop. If however, the children | |
| 2354 // belong to different loops, the sort call will properly set the | |
| 2355 // _parent pointers to show how the loops nest. | |
| 2356 // | |
| 2357 // In any case, it returns the tightest enclosing loop. | |
| 2358 innermost = sort( l, innermost ); | |
| 2359 } | |
| 2360 | |
| 2361 // Def-use info will have some dead stuff; dead stuff will have no | |
| 2362 // loop decided on. | |
| 2363 | |
| 2364 // Am I a loop header? If so fix up my parent's child and next ptrs. | |
| 2365 if( innermost && innermost->_head == n ) { | |
| 2366 assert( get_loop(n) == innermost, "" ); | |
| 2367 IdealLoopTree *p = innermost->_parent; | |
| 2368 IdealLoopTree *l = innermost; | |
| 2369 while( p && l->_head == n ) { | |
| 2370 l->_next = p->_child; // Put self on parents 'next child' | |
| 2371 p->_child = l; // Make self as first child of parent | |
| 2372 l = p; // Now walk up the parent chain | |
| 2373 p = l->_parent; | |
| 2374 } | |
| 2375 } else { | |
| 2376 // Note that it is possible for a LoopNode to reach here, if the | |
| 2377 // backedge has been made unreachable (hence the LoopNode no longer | |
| 2378 // denotes a Loop, and will eventually be removed). | |
| 2379 | |
| 2380 // Record tightest enclosing loop for self. Mark as post-visited. | |
| 2381 set_loop(n, innermost); | |
| 2382 // Also record has_call flag early on | |
| 2383 if( innermost ) { | |
| 2384 if( n->is_Call() && !n->is_CallLeaf() && !n->is_macro() ) { | |
| 2385 // Do not count uncommon calls | |
| 2386 if( !n->is_CallStaticJava() || !n->as_CallStaticJava()->_name ) { | |
| 2387 Node *iff = n->in(0)->in(0); | |
| 2388 if( !iff->is_If() || | |
| 2389 (n->in(0)->Opcode() == Op_IfFalse && | |
| 2390 (1.0 - iff->as_If()->_prob) >= 0.01) || | |
| 2391 (iff->as_If()->_prob >= 0.01) ) | |
| 2392 innermost->_has_call = 1; | |
| 2393 } | |
|
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2394 } else if( n->is_Allocate() && n->as_Allocate()->_is_scalar_replaceable ) { |
|
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2395 // Disable loop optimizations if the loop has a scalar replaceable |
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2396 // allocation. This disabling may cause a potential performance lost |
|
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2397 // if the allocation is not eliminated for some reason. |
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2398 innermost->_allow_optimizations = false; |
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2399 innermost->_has_call = 1; // = true |
| 0 | 2400 } |
| 2401 } | |
| 2402 } | |
| 2403 | |
| 2404 // Flag as post-visited now | |
| 2405 set_postvisited(n); | |
| 2406 return pre_order; | |
| 2407 } | |
| 2408 | |
| 2409 | |
| 2410 //------------------------------build_loop_early------------------------------- | |
| 2411 // Put Data nodes into some loop nest, by setting the _nodes[]->loop mapping. | |
| 2412 // First pass computes the earliest controlling node possible. This is the | |
| 2413 // controlling input with the deepest dominating depth. | |
|
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2414 void PhaseIdealLoop::build_loop_early( VectorSet &visited, Node_List &worklist, Node_Stack &nstack ) { |
| 0 | 2415 while (worklist.size() != 0) { |
| 2416 // Use local variables nstack_top_n & nstack_top_i to cache values | |
| 2417 // on nstack's top. | |
| 2418 Node *nstack_top_n = worklist.pop(); | |
| 2419 uint nstack_top_i = 0; | |
| 2420 //while_nstack_nonempty: | |
| 2421 while (true) { | |
| 2422 // Get parent node and next input's index from stack's top. | |
| 2423 Node *n = nstack_top_n; | |
| 2424 uint i = nstack_top_i; | |
| 2425 uint cnt = n->req(); // Count of inputs | |
| 2426 if (i == 0) { // Pre-process the node. | |
| 2427 if( has_node(n) && // Have either loop or control already? | |
| 2428 !has_ctrl(n) ) { // Have loop picked out already? | |
| 2429 // During "merge_many_backedges" we fold up several nested loops | |
| 2430 // into a single loop. This makes the members of the original | |
| 2431 // loop bodies pointing to dead loops; they need to move up | |
| 2432 // to the new UNION'd larger loop. I set the _head field of these | |
| 2433 // dead loops to NULL and the _parent field points to the owning | |
| 2434 // loop. Shades of UNION-FIND algorithm. | |
| 2435 IdealLoopTree *ilt; | |
| 2436 while( !(ilt = get_loop(n))->_head ) { | |
| 2437 // Normally I would use a set_loop here. But in this one special | |
| 2438 // case, it is legal (and expected) to change what loop a Node | |
| 2439 // belongs to. | |
| 2440 _nodes.map(n->_idx, (Node*)(ilt->_parent) ); | |
| 2441 } | |
| 2442 // Remove safepoints ONLY if I've already seen I don't need one. | |
| 2443 // (the old code here would yank a 2nd safepoint after seeing a | |
| 2444 // first one, even though the 1st did not dominate in the loop body | |
| 2445 // and thus could be avoided indefinitely) | |
|
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2446 if( !_verify_only && !_verify_me && ilt->_has_sfpt && n->Opcode() == Op_SafePoint && |
| 0 | 2447 is_deleteable_safept(n)) { |
| 2448 Node *in = n->in(TypeFunc::Control); | |
| 2449 lazy_replace(n,in); // Pull safepoint now | |
| 2450 // Carry on with the recursion "as if" we are walking | |
| 2451 // only the control input | |
| 2452 if( !visited.test_set( in->_idx ) ) { | |
| 2453 worklist.push(in); // Visit this guy later, using worklist | |
| 2454 } | |
| 2455 // Get next node from nstack: | |
| 2456 // - skip n's inputs processing by setting i > cnt; | |
| 2457 // - we also will not call set_early_ctrl(n) since | |
| 2458 // has_node(n) == true (see the condition above). | |
| 2459 i = cnt + 1; | |
| 2460 } | |
| 2461 } | |
| 2462 } // if (i == 0) | |
| 2463 | |
| 2464 // Visit all inputs | |
| 2465 bool done = true; // Assume all n's inputs will be processed | |
| 2466 while (i < cnt) { | |
| 2467 Node *in = n->in(i); | |
| 2468 ++i; | |
| 2469 if (in == NULL) continue; | |
| 2470 if (in->pinned() && !in->is_CFG()) | |
| 2471 set_ctrl(in, in->in(0)); | |
| 2472 int is_visited = visited.test_set( in->_idx ); | |
| 2473 if (!has_node(in)) { // No controlling input yet? | |
| 2474 assert( !in->is_CFG(), "CFG Node with no controlling input?" ); | |
| 2475 assert( !is_visited, "visit only once" ); | |
| 2476 nstack.push(n, i); // Save parent node and next input's index. | |
| 2477 nstack_top_n = in; // Process current input now. | |
| 2478 nstack_top_i = 0; | |
| 2479 done = false; // Not all n's inputs processed. | |
| 2480 break; // continue while_nstack_nonempty; | |
| 2481 } else if (!is_visited) { | |
| 2482 // This guy has a location picked out for him, but has not yet | |
| 2483 // been visited. Happens to all CFG nodes, for instance. | |
| 2484 // Visit him using the worklist instead of recursion, to break | |
| 2485 // cycles. Since he has a location already we do not need to | |
| 2486 // find his location before proceeding with the current Node. | |
| 2487 worklist.push(in); // Visit this guy later, using worklist | |
| 2488 } | |
| 2489 } | |
| 2490 if (done) { | |
| 2491 // All of n's inputs have been processed, complete post-processing. | |
| 2492 | |
| 605 | 2493 // Compute earliest point this Node can go. |
| 0 | 2494 // CFG, Phi, pinned nodes already know their controlling input. |
| 2495 if (!has_node(n)) { | |
| 2496 // Record earliest legal location | |
| 2497 set_early_ctrl( n ); | |
| 2498 } | |
| 2499 if (nstack.is_empty()) { | |
| 2500 // Finished all nodes on stack. | |
| 2501 // Process next node on the worklist. | |
| 2502 break; | |
| 2503 } | |
| 2504 // Get saved parent node and next input's index. | |
| 2505 nstack_top_n = nstack.node(); | |
| 2506 nstack_top_i = nstack.index(); | |
| 2507 nstack.pop(); | |
| 2508 } | |
| 2509 } // while (true) | |
| 2510 } | |
| 2511 } | |
| 2512 | |
| 2513 //------------------------------dom_lca_internal-------------------------------- | |
| 2514 // Pair-wise LCA | |
| 2515 Node *PhaseIdealLoop::dom_lca_internal( Node *n1, Node *n2 ) const { | |
| 2516 if( !n1 ) return n2; // Handle NULL original LCA | |
| 2517 assert( n1->is_CFG(), "" ); | |
| 2518 assert( n2->is_CFG(), "" ); | |
| 2519 // find LCA of all uses | |
| 2520 uint d1 = dom_depth(n1); | |
| 2521 uint d2 = dom_depth(n2); | |
| 2522 while (n1 != n2) { | |
| 2523 if (d1 > d2) { | |
| 2524 n1 = idom(n1); | |
| 2525 d1 = dom_depth(n1); | |
| 2526 } else if (d1 < d2) { | |
| 2527 n2 = idom(n2); | |
| 2528 d2 = dom_depth(n2); | |
| 2529 } else { | |
| 2530 // Here d1 == d2. Due to edits of the dominator-tree, sections | |
| 2531 // of the tree might have the same depth. These sections have | |
| 2532 // to be searched more carefully. | |
| 2533 | |
| 2534 // Scan up all the n1's with equal depth, looking for n2. | |
| 2535 Node *t1 = idom(n1); | |
| 2536 while (dom_depth(t1) == d1) { | |
| 2537 if (t1 == n2) return n2; | |
| 2538 t1 = idom(t1); | |
| 2539 } | |
| 2540 // Scan up all the n2's with equal depth, looking for n1. | |
| 2541 Node *t2 = idom(n2); | |
| 2542 while (dom_depth(t2) == d2) { | |
| 2543 if (t2 == n1) return n1; | |
| 2544 t2 = idom(t2); | |
| 2545 } | |
| 2546 // Move up to a new dominator-depth value as well as up the dom-tree. | |
| 2547 n1 = t1; | |
| 2548 n2 = t2; | |
| 2549 d1 = dom_depth(n1); | |
| 2550 d2 = dom_depth(n2); | |
| 2551 } | |
| 2552 } | |
| 2553 return n1; | |
| 2554 } | |
| 2555 | |
| 2556 //------------------------------compute_idom----------------------------------- | |
| 2557 // Locally compute IDOM using dom_lca call. Correct only if the incoming | |
| 2558 // IDOMs are correct. | |
| 2559 Node *PhaseIdealLoop::compute_idom( Node *region ) const { | |
| 2560 assert( region->is_Region(), "" ); | |
| 2561 Node *LCA = NULL; | |
| 2562 for( uint i = 1; i < region->req(); i++ ) { | |
| 2563 if( region->in(i) != C->top() ) | |
| 2564 LCA = dom_lca( LCA, region->in(i) ); | |
| 2565 } | |
| 2566 return LCA; | |
| 2567 } | |
| 2568 | |
|
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|
2569 bool PhaseIdealLoop::verify_dominance(Node* n, Node* use, Node* LCA, Node* early) { |
|
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|
2570 bool had_error = false; |
|
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|
2571 #ifdef ASSERT |
|
046932b72aa2
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|
2572 if (early != C->root()) { |
|
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|
2573 // Make sure that there's a dominance path from use to LCA |
|
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|
2574 Node* d = use; |
|
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|
2575 while (d != LCA) { |
|
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diff
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|
2576 d = idom(d); |
|
046932b72aa2
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|
2577 if (d == C->root()) { |
|
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|
2578 tty->print_cr("*** Use %d isn't dominated by def %s", use->_idx, n->_idx); |
|
046932b72aa2
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|
2579 n->dump(); |
|
046932b72aa2
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|
2580 use->dump(); |
|
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|
2581 had_error = true; |
|
046932b72aa2
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|
2582 break; |
|
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|
2583 } |
|
046932b72aa2
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|
2584 } |
|
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|
2585 } |
|
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|
2586 #endif |
|
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|
2587 return had_error; |
|
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|
2588 } |
| 0 | 2589 |
|
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2590 |
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2591 Node* PhaseIdealLoop::compute_lca_of_uses(Node* n, Node* early, bool verify) { |
| 0 | 2592 // Compute LCA over list of uses |
|
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2593 bool had_error = false; |
| 0 | 2594 Node *LCA = NULL; |
| 2595 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax && LCA != early; i++) { | |
| 2596 Node* c = n->fast_out(i); | |
| 2597 if (_nodes[c->_idx] == NULL) | |
| 2598 continue; // Skip the occasional dead node | |
| 2599 if( c->is_Phi() ) { // For Phis, we must land above on the path | |
| 2600 for( uint j=1; j<c->req(); j++ ) {// For all inputs | |
| 2601 if( c->in(j) == n ) { // Found matching input? | |
| 2602 Node *use = c->in(0)->in(j); | |
|
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2603 if (_verify_only && use->is_top()) continue; |
| 0 | 2604 LCA = dom_lca_for_get_late_ctrl( LCA, use, n ); |
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2605 if (verify) had_error = verify_dominance(n, use, LCA, early) || had_error; |
| 0 | 2606 } |
| 2607 } | |
| 2608 } else { | |
| 2609 // For CFG data-users, use is in the block just prior | |
| 2610 Node *use = has_ctrl(c) ? get_ctrl(c) : c->in(0); | |
| 2611 LCA = dom_lca_for_get_late_ctrl( LCA, use, n ); | |
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2612 if (verify) had_error = verify_dominance(n, use, LCA, early) || had_error; |
| 0 | 2613 } |
| 2614 } | |
|
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2615 assert(!had_error, "bad dominance"); |
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2616 return LCA; |
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2617 } |
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2618 |
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2619 //------------------------------get_late_ctrl---------------------------------- |
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2620 // Compute latest legal control. |
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2621 Node *PhaseIdealLoop::get_late_ctrl( Node *n, Node *early ) { |
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2622 assert(early != NULL, "early control should not be NULL"); |
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2623 |
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2624 Node* LCA = compute_lca_of_uses(n, early); |
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2625 #ifdef ASSERT |
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2626 if (LCA == C->root() && LCA != early) { |
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2627 // def doesn't dominate uses so print some useful debugging output |
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2628 compute_lca_of_uses(n, early, true); |
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2629 } |
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2630 #endif |
| 0 | 2631 |
| 2632 // if this is a load, check for anti-dependent stores | |
| 2633 // We use a conservative algorithm to identify potential interfering | |
| 2634 // instructions and for rescheduling the load. The users of the memory | |
| 2635 // input of this load are examined. Any use which is not a load and is | |
| 2636 // dominated by early is considered a potentially interfering store. | |
| 2637 // This can produce false positives. | |
| 2638 if (n->is_Load() && LCA != early) { | |
| 2639 Node_List worklist; | |
| 2640 | |
| 2641 Node *mem = n->in(MemNode::Memory); | |
| 2642 for (DUIterator_Fast imax, i = mem->fast_outs(imax); i < imax; i++) { | |
| 2643 Node* s = mem->fast_out(i); | |
| 2644 worklist.push(s); | |
| 2645 } | |
| 2646 while(worklist.size() != 0 && LCA != early) { | |
| 2647 Node* s = worklist.pop(); | |
| 2648 if (s->is_Load()) { | |
| 2649 continue; | |
| 2650 } else if (s->is_MergeMem()) { | |
| 2651 for (DUIterator_Fast imax, i = s->fast_outs(imax); i < imax; i++) { | |
| 2652 Node* s1 = s->fast_out(i); | |
| 2653 worklist.push(s1); | |
| 2654 } | |
| 2655 } else { | |
| 2656 Node *sctrl = has_ctrl(s) ? get_ctrl(s) : s->in(0); | |
| 2657 assert(sctrl != NULL || s->outcnt() == 0, "must have control"); | |
| 2658 if (sctrl != NULL && !sctrl->is_top() && is_dominator(early, sctrl)) { | |
| 2659 LCA = dom_lca_for_get_late_ctrl(LCA, sctrl, n); | |
| 2660 } | |
| 2661 } | |
| 2662 } | |
| 2663 } | |
| 2664 | |
| 2665 assert(LCA == find_non_split_ctrl(LCA), "unexpected late control"); | |
| 2666 return LCA; | |
| 2667 } | |
| 2668 | |
| 2669 // true if CFG node d dominates CFG node n | |
| 2670 bool PhaseIdealLoop::is_dominator(Node *d, Node *n) { | |
| 2671 if (d == n) | |
| 2672 return true; | |
| 2673 assert(d->is_CFG() && n->is_CFG(), "must have CFG nodes"); | |
| 2674 uint dd = dom_depth(d); | |
| 2675 while (dom_depth(n) >= dd) { | |
| 2676 if (n == d) | |
| 2677 return true; | |
| 2678 n = idom(n); | |
| 2679 } | |
| 2680 return false; | |
| 2681 } | |
| 2682 | |
| 2683 //------------------------------dom_lca_for_get_late_ctrl_internal------------- | |
| 2684 // Pair-wise LCA with tags. | |
| 2685 // Tag each index with the node 'tag' currently being processed | |
| 2686 // before advancing up the dominator chain using idom(). | |
| 2687 // Later calls that find a match to 'tag' know that this path has already | |
| 2688 // been considered in the current LCA (which is input 'n1' by convention). | |
| 2689 // Since get_late_ctrl() is only called once for each node, the tag array | |
| 2690 // does not need to be cleared between calls to get_late_ctrl(). | |
| 2691 // Algorithm trades a larger constant factor for better asymptotic behavior | |
| 2692 // | |
| 2693 Node *PhaseIdealLoop::dom_lca_for_get_late_ctrl_internal( Node *n1, Node *n2, Node *tag ) { | |
| 2694 uint d1 = dom_depth(n1); | |
| 2695 uint d2 = dom_depth(n2); | |
| 2696 | |
| 2697 do { | |
| 2698 if (d1 > d2) { | |
| 2699 // current lca is deeper than n2 | |
| 2700 _dom_lca_tags.map(n1->_idx, tag); | |
| 2701 n1 = idom(n1); | |
| 2702 d1 = dom_depth(n1); | |
| 2703 } else if (d1 < d2) { | |
| 2704 // n2 is deeper than current lca | |
| 2705 Node *memo = _dom_lca_tags[n2->_idx]; | |
| 2706 if( memo == tag ) { | |
| 2707 return n1; // Return the current LCA | |
| 2708 } | |
| 2709 _dom_lca_tags.map(n2->_idx, tag); | |
| 2710 n2 = idom(n2); | |
| 2711 d2 = dom_depth(n2); | |
| 2712 } else { | |
| 2713 // Here d1 == d2. Due to edits of the dominator-tree, sections | |
| 2714 // of the tree might have the same depth. These sections have | |
| 2715 // to be searched more carefully. | |
| 2716 | |
| 2717 // Scan up all the n1's with equal depth, looking for n2. | |
| 2718 _dom_lca_tags.map(n1->_idx, tag); | |
| 2719 Node *t1 = idom(n1); | |
| 2720 while (dom_depth(t1) == d1) { | |
| 2721 if (t1 == n2) return n2; | |
| 2722 _dom_lca_tags.map(t1->_idx, tag); | |
| 2723 t1 = idom(t1); | |
| 2724 } | |
| 2725 // Scan up all the n2's with equal depth, looking for n1. | |
| 2726 _dom_lca_tags.map(n2->_idx, tag); | |
| 2727 Node *t2 = idom(n2); | |
| 2728 while (dom_depth(t2) == d2) { | |
| 2729 if (t2 == n1) return n1; | |
| 2730 _dom_lca_tags.map(t2->_idx, tag); | |
| 2731 t2 = idom(t2); | |
| 2732 } | |
| 2733 // Move up to a new dominator-depth value as well as up the dom-tree. | |
| 2734 n1 = t1; | |
| 2735 n2 = t2; | |
| 2736 d1 = dom_depth(n1); | |
| 2737 d2 = dom_depth(n2); | |
| 2738 } | |
| 2739 } while (n1 != n2); | |
| 2740 return n1; | |
| 2741 } | |
| 2742 | |
| 2743 //------------------------------init_dom_lca_tags------------------------------ | |
| 2744 // Tag could be a node's integer index, 32bits instead of 64bits in some cases | |
| 2745 // Intended use does not involve any growth for the array, so it could | |
| 2746 // be of fixed size. | |
| 2747 void PhaseIdealLoop::init_dom_lca_tags() { | |
| 2748 uint limit = C->unique() + 1; | |
| 2749 _dom_lca_tags.map( limit, NULL ); | |
| 2750 #ifdef ASSERT | |
| 2751 for( uint i = 0; i < limit; ++i ) { | |
| 2752 assert(_dom_lca_tags[i] == NULL, "Must be distinct from each node pointer"); | |
| 2753 } | |
| 2754 #endif // ASSERT | |
| 2755 } | |
| 2756 | |
| 2757 //------------------------------clear_dom_lca_tags------------------------------ | |
| 2758 // Tag could be a node's integer index, 32bits instead of 64bits in some cases | |
| 2759 // Intended use does not involve any growth for the array, so it could | |
| 2760 // be of fixed size. | |
| 2761 void PhaseIdealLoop::clear_dom_lca_tags() { | |
| 2762 uint limit = C->unique() + 1; | |
| 2763 _dom_lca_tags.map( limit, NULL ); | |
| 2764 _dom_lca_tags.clear(); | |
| 2765 #ifdef ASSERT | |
| 2766 for( uint i = 0; i < limit; ++i ) { | |
| 2767 assert(_dom_lca_tags[i] == NULL, "Must be distinct from each node pointer"); | |
| 2768 } | |
| 2769 #endif // ASSERT | |
| 2770 } | |
| 2771 | |
| 2772 //------------------------------build_loop_late-------------------------------- | |
| 2773 // Put Data nodes into some loop nest, by setting the _nodes[]->loop mapping. | |
| 2774 // Second pass finds latest legal placement, and ideal loop placement. | |
|
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2775 void PhaseIdealLoop::build_loop_late( VectorSet &visited, Node_List &worklist, Node_Stack &nstack ) { |
| 0 | 2776 while (worklist.size() != 0) { |
| 2777 Node *n = worklist.pop(); | |
| 2778 // Only visit once | |
| 2779 if (visited.test_set(n->_idx)) continue; | |
| 2780 uint cnt = n->outcnt(); | |
| 2781 uint i = 0; | |
| 2782 while (true) { | |
| 2783 assert( _nodes[n->_idx], "no dead nodes" ); | |
| 2784 // Visit all children | |
| 2785 if (i < cnt) { | |
| 2786 Node* use = n->raw_out(i); | |
| 2787 ++i; | |
| 2788 // Check for dead uses. Aggressively prune such junk. It might be | |
| 2789 // dead in the global sense, but still have local uses so I cannot | |
| 2790 // easily call 'remove_dead_node'. | |
| 2791 if( _nodes[use->_idx] != NULL || use->is_top() ) { // Not dead? | |
| 2792 // Due to cycles, we might not hit the same fixed point in the verify | |
| 2793 // pass as we do in the regular pass. Instead, visit such phis as | |
| 2794 // simple uses of the loop head. | |
| 2795 if( use->in(0) && (use->is_CFG() || use->is_Phi()) ) { | |
| 2796 if( !visited.test(use->_idx) ) | |
| 2797 worklist.push(use); | |
| 2798 } else if( !visited.test_set(use->_idx) ) { | |
| 2799 nstack.push(n, i); // Save parent and next use's index. | |
| 2800 n = use; // Process all children of current use. | |
| 2801 cnt = use->outcnt(); | |
| 2802 i = 0; | |
| 2803 } | |
| 2804 } else { | |
| 2805 // Do not visit around the backedge of loops via data edges. | |
| 2806 // push dead code onto a worklist | |
| 2807 _deadlist.push(use); | |
| 2808 } | |
| 2809 } else { | |
| 2810 // All of n's children have been processed, complete post-processing. | |
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2811 build_loop_late_post(n); |
| 0 | 2812 if (nstack.is_empty()) { |
| 2813 // Finished all nodes on stack. | |
| 2814 // Process next node on the worklist. | |
| 2815 break; | |
| 2816 } | |
| 2817 // Get saved parent node and next use's index. Visit the rest of uses. | |
| 2818 n = nstack.node(); | |
| 2819 cnt = n->outcnt(); | |
| 2820 i = nstack.index(); | |
| 2821 nstack.pop(); | |
| 2822 } | |
| 2823 } | |
| 2824 } | |
| 2825 } | |
| 2826 | |
| 2827 //------------------------------build_loop_late_post--------------------------- | |
| 2828 // Put Data nodes into some loop nest, by setting the _nodes[]->loop mapping. | |
| 2829 // Second pass finds latest legal placement, and ideal loop placement. | |
|
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2830 void PhaseIdealLoop::build_loop_late_post( Node *n ) { |
| 0 | 2831 |
|
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2832 if (n->req() == 2 && n->Opcode() == Op_ConvI2L && !C->major_progress() && !_verify_only) { |
| 0 | 2833 _igvn._worklist.push(n); // Maybe we'll normalize it, if no more loops. |
| 2834 } | |
| 2835 | |
| 2836 // CFG and pinned nodes already handled | |
| 2837 if( n->in(0) ) { | |
| 2838 if( n->in(0)->is_top() ) return; // Dead? | |
| 2839 | |
| 2840 // We'd like +VerifyLoopOptimizations to not believe that Mod's/Loads | |
| 2841 // _must_ be pinned (they have to observe their control edge of course). | |
| 2842 // Unlike Stores (which modify an unallocable resource, the memory | |
| 2843 // state), Mods/Loads can float around. So free them up. | |
| 2844 bool pinned = true; | |
| 2845 switch( n->Opcode() ) { | |
| 2846 case Op_DivI: | |
| 2847 case Op_DivF: | |
| 2848 case Op_DivD: | |
| 2849 case Op_ModI: | |
| 2850 case Op_ModF: | |
| 2851 case Op_ModD: | |
| 2852 case Op_LoadB: // Same with Loads; they can sink | |
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2853 case Op_LoadUS: // during loop optimizations. |
| 0 | 2854 case Op_LoadD: |
| 2855 case Op_LoadF: | |
| 2856 case Op_LoadI: | |
| 2857 case Op_LoadKlass: | |
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2858 case Op_LoadNKlass: |
| 0 | 2859 case Op_LoadL: |
| 2860 case Op_LoadS: | |
| 2861 case Op_LoadP: | |
|
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2862 case Op_LoadN: |
| 0 | 2863 case Op_LoadRange: |
| 2864 case Op_LoadD_unaligned: | |
| 2865 case Op_LoadL_unaligned: | |
| 2866 case Op_StrComp: // Does a bunch of load-like effects | |
| 681 | 2867 case Op_StrEquals: |
| 2868 case Op_StrIndexOf: | |
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2869 case Op_AryEq: |
| 0 | 2870 pinned = false; |
| 2871 } | |
| 2872 if( pinned ) { | |
| 605 | 2873 IdealLoopTree *chosen_loop = get_loop(n->is_CFG() ? n : get_ctrl(n)); |
| 2874 if( !chosen_loop->_child ) // Inner loop? | |
| 2875 chosen_loop->_body.push(n); // Collect inner loops | |
| 0 | 2876 return; |
| 2877 } | |
| 2878 } else { // No slot zero | |
| 2879 if( n->is_CFG() ) { // CFG with no slot 0 is dead | |
| 2880 _nodes.map(n->_idx,0); // No block setting, it's globally dead | |
| 2881 return; | |
| 2882 } | |
| 2883 assert(!n->is_CFG() || n->outcnt() == 0, ""); | |
| 2884 } | |
| 2885 | |
| 2886 // Do I have a "safe range" I can select over? | |
| 2887 Node *early = get_ctrl(n);// Early location already computed | |
| 2888 | |
| 2889 // Compute latest point this Node can go | |
| 2890 Node *LCA = get_late_ctrl( n, early ); | |
| 2891 // LCA is NULL due to uses being dead | |
| 2892 if( LCA == NULL ) { | |
| 2893 #ifdef ASSERT | |
| 2894 for (DUIterator i1 = n->outs(); n->has_out(i1); i1++) { | |
| 2895 assert( _nodes[n->out(i1)->_idx] == NULL, "all uses must also be dead"); | |
| 2896 } | |
| 2897 #endif | |
| 2898 _nodes.map(n->_idx, 0); // This node is useless | |
| 2899 _deadlist.push(n); | |
| 2900 return; | |
| 2901 } | |
| 2902 assert(LCA != NULL && !LCA->is_top(), "no dead nodes"); | |
| 2903 | |
| 2904 Node *legal = LCA; // Walk 'legal' up the IDOM chain | |
| 2905 Node *least = legal; // Best legal position so far | |
| 2906 while( early != legal ) { // While not at earliest legal | |
| 1172 | 2907 #ifdef ASSERT |
| 2908 if (legal->is_Start() && !early->is_Root()) { | |
| 2909 // Bad graph. Print idom path and fail. | |
| 2910 tty->print_cr( "Bad graph detected in build_loop_late"); | |
| 2911 tty->print("n: ");n->dump(); tty->cr(); | |
| 2912 tty->print("early: ");early->dump(); tty->cr(); | |
| 2913 int ct = 0; | |
| 2914 Node *dbg_legal = LCA; | |
| 2915 while(!dbg_legal->is_Start() && ct < 100) { | |
| 2916 tty->print("idom[%d] ",ct); dbg_legal->dump(); tty->cr(); | |
| 2917 ct++; | |
| 2918 dbg_legal = idom(dbg_legal); | |
| 2919 } | |
| 2920 assert(false, "Bad graph detected in build_loop_late"); | |
| 2921 } | |
| 2922 #endif | |
| 0 | 2923 // Find least loop nesting depth |
| 2924 legal = idom(legal); // Bump up the IDOM tree | |
| 2925 // Check for lower nesting depth | |
| 2926 if( get_loop(legal)->_nest < get_loop(least)->_nest ) | |
| 2927 least = legal; | |
| 2928 } | |
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2929 assert(early == legal || legal != C->root(), "bad dominance of inputs"); |
| 0 | 2930 |
| 2931 // Try not to place code on a loop entry projection | |
| 2932 // which can inhibit range check elimination. | |
| 2933 if (least != early) { | |
| 2934 Node* ctrl_out = least->unique_ctrl_out(); | |
| 2935 if (ctrl_out && ctrl_out->is_CountedLoop() && | |
| 2936 least == ctrl_out->in(LoopNode::EntryControl)) { | |
| 2937 Node* least_dom = idom(least); | |
| 2938 if (get_loop(least_dom)->is_member(get_loop(least))) { | |
| 2939 least = least_dom; | |
| 2940 } | |
| 2941 } | |
| 2942 } | |
| 2943 | |
| 2944 #ifdef ASSERT | |
| 2945 // If verifying, verify that 'verify_me' has a legal location | |
| 2946 // and choose it as our location. | |
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2947 if( _verify_me ) { |
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2948 Node *v_ctrl = _verify_me->get_ctrl_no_update(n); |
| 0 | 2949 Node *legal = LCA; |
| 2950 while( early != legal ) { // While not at earliest legal | |
| 2951 if( legal == v_ctrl ) break; // Check for prior good location | |
| 2952 legal = idom(legal) ;// Bump up the IDOM tree | |
| 2953 } | |
| 2954 // Check for prior good location | |
| 2955 if( legal == v_ctrl ) least = legal; // Keep prior if found | |
| 2956 } | |
| 2957 #endif | |
| 2958 | |
| 2959 // Assign discovered "here or above" point | |
| 2960 least = find_non_split_ctrl(least); | |
| 2961 set_ctrl(n, least); | |
| 2962 | |
| 2963 // Collect inner loop bodies | |
| 605 | 2964 IdealLoopTree *chosen_loop = get_loop(least); |
| 2965 if( !chosen_loop->_child ) // Inner loop? | |
| 2966 chosen_loop->_body.push(n);// Collect inner loops | |
| 0 | 2967 } |
| 2968 | |
| 2969 #ifndef PRODUCT | |
| 2970 //------------------------------dump------------------------------------------- | |
| 2971 void PhaseIdealLoop::dump( ) const { | |
| 2972 ResourceMark rm; | |
| 2973 Arena* arena = Thread::current()->resource_area(); | |
| 2974 Node_Stack stack(arena, C->unique() >> 2); | |
| 2975 Node_List rpo_list; | |
| 2976 VectorSet visited(arena); | |
| 2977 visited.set(C->top()->_idx); | |
| 2978 rpo( C->root(), stack, visited, rpo_list ); | |
| 2979 // Dump root loop indexed by last element in PO order | |
| 2980 dump( _ltree_root, rpo_list.size(), rpo_list ); | |
| 2981 } | |
| 2982 | |
| 2983 void PhaseIdealLoop::dump( IdealLoopTree *loop, uint idx, Node_List &rpo_list ) const { | |
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2984 loop->dump_head(); |
| 0 | 2985 |
| 2986 // Now scan for CFG nodes in the same loop | |
| 2987 for( uint j=idx; j > 0; j-- ) { | |
| 2988 Node *n = rpo_list[j-1]; | |
| 2989 if( !_nodes[n->_idx] ) // Skip dead nodes | |
| 2990 continue; | |
| 2991 if( get_loop(n) != loop ) { // Wrong loop nest | |
| 2992 if( get_loop(n)->_head == n && // Found nested loop? | |
| 2993 get_loop(n)->_parent == loop ) | |
| 2994 dump(get_loop(n),rpo_list.size(),rpo_list); // Print it nested-ly | |
| 2995 continue; | |
| 2996 } | |
| 2997 | |
| 2998 // Dump controlling node | |
| 2999 for( uint x = 0; x < loop->_nest; x++ ) | |
| 3000 tty->print(" "); | |
| 3001 tty->print("C"); | |
| 3002 if( n == C->root() ) { | |
| 3003 n->dump(); | |
| 3004 } else { | |
| 3005 Node* cached_idom = idom_no_update(n); | |
| 3006 Node *computed_idom = n->in(0); | |
| 3007 if( n->is_Region() ) { | |
| 3008 computed_idom = compute_idom(n); | |
| 3009 // computed_idom() will return n->in(0) when idom(n) is an IfNode (or | |
| 3010 // any MultiBranch ctrl node), so apply a similar transform to | |
| 3011 // the cached idom returned from idom_no_update. | |
| 3012 cached_idom = find_non_split_ctrl(cached_idom); | |
| 3013 } | |
| 3014 tty->print(" ID:%d",computed_idom->_idx); | |
| 3015 n->dump(); | |
| 3016 if( cached_idom != computed_idom ) { | |
| 3017 tty->print_cr("*** BROKEN IDOM! Computed as: %d, cached as: %d", | |
| 3018 computed_idom->_idx, cached_idom->_idx); | |
| 3019 } | |
| 3020 } | |
| 3021 // Dump nodes it controls | |
| 3022 for( uint k = 0; k < _nodes.Size(); k++ ) { | |
| 3023 // (k < C->unique() && get_ctrl(find(k)) == n) | |
| 3024 if (k < C->unique() && _nodes[k] == (Node*)((intptr_t)n + 1)) { | |
| 3025 Node *m = C->root()->find(k); | |
| 3026 if( m && m->outcnt() > 0 ) { | |
| 3027 if (!(has_ctrl(m) && get_ctrl_no_update(m) == n)) { | |
| 3028 tty->print_cr("*** BROKEN CTRL ACCESSOR! _nodes[k] is %p, ctrl is %p", | |
| 3029 _nodes[k], has_ctrl(m) ? get_ctrl_no_update(m) : NULL); | |
| 3030 } | |
| 3031 for( uint j = 0; j < loop->_nest; j++ ) | |
| 3032 tty->print(" "); | |
| 3033 tty->print(" "); | |
| 3034 m->dump(); | |
| 3035 } | |
| 3036 } | |
| 3037 } | |
| 3038 } | |
| 3039 } | |
| 3040 | |
| 3041 // Collect a R-P-O for the whole CFG. | |
| 3042 // Result list is in post-order (scan backwards for RPO) | |
| 3043 void PhaseIdealLoop::rpo( Node *start, Node_Stack &stk, VectorSet &visited, Node_List &rpo_list ) const { | |
| 3044 stk.push(start, 0); | |
| 3045 visited.set(start->_idx); | |
| 3046 | |
| 3047 while (stk.is_nonempty()) { | |
| 3048 Node* m = stk.node(); | |
| 3049 uint idx = stk.index(); | |
| 3050 if (idx < m->outcnt()) { | |
| 3051 stk.set_index(idx + 1); | |
| 3052 Node* n = m->raw_out(idx); | |
| 3053 if (n->is_CFG() && !visited.test_set(n->_idx)) { | |
| 3054 stk.push(n, 0); | |
| 3055 } | |
| 3056 } else { | |
| 3057 rpo_list.push(m); | |
| 3058 stk.pop(); | |
| 3059 } | |
| 3060 } | |
| 3061 } | |
| 3062 #endif | |
| 3063 | |
| 3064 | |
| 3065 //============================================================================= | |
| 3066 //------------------------------LoopTreeIterator----------------------------------- | |
| 3067 | |
| 3068 // Advance to next loop tree using a preorder, left-to-right traversal. | |
| 3069 void LoopTreeIterator::next() { | |
| 3070 assert(!done(), "must not be done."); | |
| 3071 if (_curnt->_child != NULL) { | |
| 3072 _curnt = _curnt->_child; | |
| 3073 } else if (_curnt->_next != NULL) { | |
| 3074 _curnt = _curnt->_next; | |
| 3075 } else { | |
| 3076 while (_curnt != _root && _curnt->_next == NULL) { | |
| 3077 _curnt = _curnt->_parent; | |
| 3078 } | |
| 3079 if (_curnt == _root) { | |
| 3080 _curnt = NULL; | |
| 3081 assert(done(), "must be done."); | |
| 3082 } else { | |
| 3083 assert(_curnt->_next != NULL, "must be more to do"); | |
| 3084 _curnt = _curnt->_next; | |
| 3085 } | |
| 3086 } | |
| 3087 } |