Fri, 12 Feb 2010 15:27:36 -0800
Merge
duke@435 | 1 | /* |
xdono@1279 | 2 | * Copyright 2000-2009 Sun Microsystems, Inc. All Rights Reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
duke@435 | 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
duke@435 | 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
duke@435 | 21 | * have any questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
duke@435 | 25 | #include "incls/_precompiled.incl" |
duke@435 | 26 | #include "incls/_loopTransform.cpp.incl" |
duke@435 | 27 | |
duke@435 | 28 | //------------------------------is_loop_exit----------------------------------- |
duke@435 | 29 | // Given an IfNode, return the loop-exiting projection or NULL if both |
duke@435 | 30 | // arms remain in the loop. |
duke@435 | 31 | Node *IdealLoopTree::is_loop_exit(Node *iff) const { |
duke@435 | 32 | if( iff->outcnt() != 2 ) return NULL; // Ignore partially dead tests |
duke@435 | 33 | PhaseIdealLoop *phase = _phase; |
duke@435 | 34 | // Test is an IfNode, has 2 projections. If BOTH are in the loop |
duke@435 | 35 | // we need loop unswitching instead of peeling. |
duke@435 | 36 | if( !is_member(phase->get_loop( iff->raw_out(0) )) ) |
duke@435 | 37 | return iff->raw_out(0); |
duke@435 | 38 | if( !is_member(phase->get_loop( iff->raw_out(1) )) ) |
duke@435 | 39 | return iff->raw_out(1); |
duke@435 | 40 | return NULL; |
duke@435 | 41 | } |
duke@435 | 42 | |
duke@435 | 43 | |
duke@435 | 44 | //============================================================================= |
duke@435 | 45 | |
duke@435 | 46 | |
duke@435 | 47 | //------------------------------record_for_igvn---------------------------- |
duke@435 | 48 | // Put loop body on igvn work list |
duke@435 | 49 | void IdealLoopTree::record_for_igvn() { |
duke@435 | 50 | for( uint i = 0; i < _body.size(); i++ ) { |
duke@435 | 51 | Node *n = _body.at(i); |
duke@435 | 52 | _phase->_igvn._worklist.push(n); |
duke@435 | 53 | } |
duke@435 | 54 | } |
duke@435 | 55 | |
duke@435 | 56 | //------------------------------compute_profile_trip_cnt---------------------------- |
duke@435 | 57 | // Compute loop trip count from profile data as |
duke@435 | 58 | // (backedge_count + loop_exit_count) / loop_exit_count |
duke@435 | 59 | void IdealLoopTree::compute_profile_trip_cnt( PhaseIdealLoop *phase ) { |
duke@435 | 60 | if (!_head->is_CountedLoop()) { |
duke@435 | 61 | return; |
duke@435 | 62 | } |
duke@435 | 63 | CountedLoopNode* head = _head->as_CountedLoop(); |
duke@435 | 64 | if (head->profile_trip_cnt() != COUNT_UNKNOWN) { |
duke@435 | 65 | return; // Already computed |
duke@435 | 66 | } |
duke@435 | 67 | float trip_cnt = (float)max_jint; // default is big |
duke@435 | 68 | |
duke@435 | 69 | Node* back = head->in(LoopNode::LoopBackControl); |
duke@435 | 70 | while (back != head) { |
duke@435 | 71 | if ((back->Opcode() == Op_IfTrue || back->Opcode() == Op_IfFalse) && |
duke@435 | 72 | back->in(0) && |
duke@435 | 73 | back->in(0)->is_If() && |
duke@435 | 74 | back->in(0)->as_If()->_fcnt != COUNT_UNKNOWN && |
duke@435 | 75 | back->in(0)->as_If()->_prob != PROB_UNKNOWN) { |
duke@435 | 76 | break; |
duke@435 | 77 | } |
duke@435 | 78 | back = phase->idom(back); |
duke@435 | 79 | } |
duke@435 | 80 | if (back != head) { |
duke@435 | 81 | assert((back->Opcode() == Op_IfTrue || back->Opcode() == Op_IfFalse) && |
duke@435 | 82 | back->in(0), "if-projection exists"); |
duke@435 | 83 | IfNode* back_if = back->in(0)->as_If(); |
duke@435 | 84 | float loop_back_cnt = back_if->_fcnt * back_if->_prob; |
duke@435 | 85 | |
duke@435 | 86 | // Now compute a loop exit count |
duke@435 | 87 | float loop_exit_cnt = 0.0f; |
duke@435 | 88 | for( uint i = 0; i < _body.size(); i++ ) { |
duke@435 | 89 | Node *n = _body[i]; |
duke@435 | 90 | if( n->is_If() ) { |
duke@435 | 91 | IfNode *iff = n->as_If(); |
duke@435 | 92 | if( iff->_fcnt != COUNT_UNKNOWN && iff->_prob != PROB_UNKNOWN ) { |
duke@435 | 93 | Node *exit = is_loop_exit(iff); |
duke@435 | 94 | if( exit ) { |
duke@435 | 95 | float exit_prob = iff->_prob; |
duke@435 | 96 | if (exit->Opcode() == Op_IfFalse) exit_prob = 1.0 - exit_prob; |
duke@435 | 97 | if (exit_prob > PROB_MIN) { |
duke@435 | 98 | float exit_cnt = iff->_fcnt * exit_prob; |
duke@435 | 99 | loop_exit_cnt += exit_cnt; |
duke@435 | 100 | } |
duke@435 | 101 | } |
duke@435 | 102 | } |
duke@435 | 103 | } |
duke@435 | 104 | } |
duke@435 | 105 | if (loop_exit_cnt > 0.0f) { |
duke@435 | 106 | trip_cnt = (loop_back_cnt + loop_exit_cnt) / loop_exit_cnt; |
duke@435 | 107 | } else { |
duke@435 | 108 | // No exit count so use |
duke@435 | 109 | trip_cnt = loop_back_cnt; |
duke@435 | 110 | } |
duke@435 | 111 | } |
duke@435 | 112 | #ifndef PRODUCT |
duke@435 | 113 | if (TraceProfileTripCount) { |
duke@435 | 114 | tty->print_cr("compute_profile_trip_cnt lp: %d cnt: %f\n", head->_idx, trip_cnt); |
duke@435 | 115 | } |
duke@435 | 116 | #endif |
duke@435 | 117 | head->set_profile_trip_cnt(trip_cnt); |
duke@435 | 118 | } |
duke@435 | 119 | |
duke@435 | 120 | //---------------------is_invariant_addition----------------------------- |
duke@435 | 121 | // Return nonzero index of invariant operand for an Add or Sub |
twisti@1040 | 122 | // of (nonconstant) invariant and variant values. Helper for reassociate_invariants. |
duke@435 | 123 | int IdealLoopTree::is_invariant_addition(Node* n, PhaseIdealLoop *phase) { |
duke@435 | 124 | int op = n->Opcode(); |
duke@435 | 125 | if (op == Op_AddI || op == Op_SubI) { |
duke@435 | 126 | bool in1_invar = this->is_invariant(n->in(1)); |
duke@435 | 127 | bool in2_invar = this->is_invariant(n->in(2)); |
duke@435 | 128 | if (in1_invar && !in2_invar) return 1; |
duke@435 | 129 | if (!in1_invar && in2_invar) return 2; |
duke@435 | 130 | } |
duke@435 | 131 | return 0; |
duke@435 | 132 | } |
duke@435 | 133 | |
duke@435 | 134 | //---------------------reassociate_add_sub----------------------------- |
duke@435 | 135 | // Reassociate invariant add and subtract expressions: |
duke@435 | 136 | // |
duke@435 | 137 | // inv1 + (x + inv2) => ( inv1 + inv2) + x |
duke@435 | 138 | // (x + inv2) + inv1 => ( inv1 + inv2) + x |
duke@435 | 139 | // inv1 + (x - inv2) => ( inv1 - inv2) + x |
duke@435 | 140 | // inv1 - (inv2 - x) => ( inv1 - inv2) + x |
duke@435 | 141 | // (x + inv2) - inv1 => (-inv1 + inv2) + x |
duke@435 | 142 | // (x - inv2) + inv1 => ( inv1 - inv2) + x |
duke@435 | 143 | // (x - inv2) - inv1 => (-inv1 - inv2) + x |
duke@435 | 144 | // inv1 + (inv2 - x) => ( inv1 + inv2) - x |
duke@435 | 145 | // inv1 - (x - inv2) => ( inv1 + inv2) - x |
duke@435 | 146 | // (inv2 - x) + inv1 => ( inv1 + inv2) - x |
duke@435 | 147 | // (inv2 - x) - inv1 => (-inv1 + inv2) - x |
duke@435 | 148 | // inv1 - (x + inv2) => ( inv1 - inv2) - x |
duke@435 | 149 | // |
duke@435 | 150 | Node* IdealLoopTree::reassociate_add_sub(Node* n1, PhaseIdealLoop *phase) { |
duke@435 | 151 | if (!n1->is_Add() && !n1->is_Sub() || n1->outcnt() == 0) return NULL; |
duke@435 | 152 | if (is_invariant(n1)) return NULL; |
duke@435 | 153 | int inv1_idx = is_invariant_addition(n1, phase); |
duke@435 | 154 | if (!inv1_idx) return NULL; |
duke@435 | 155 | // Don't mess with add of constant (igvn moves them to expression tree root.) |
duke@435 | 156 | if (n1->is_Add() && n1->in(2)->is_Con()) return NULL; |
duke@435 | 157 | Node* inv1 = n1->in(inv1_idx); |
duke@435 | 158 | Node* n2 = n1->in(3 - inv1_idx); |
duke@435 | 159 | int inv2_idx = is_invariant_addition(n2, phase); |
duke@435 | 160 | if (!inv2_idx) return NULL; |
duke@435 | 161 | Node* x = n2->in(3 - inv2_idx); |
duke@435 | 162 | Node* inv2 = n2->in(inv2_idx); |
duke@435 | 163 | |
duke@435 | 164 | bool neg_x = n2->is_Sub() && inv2_idx == 1; |
duke@435 | 165 | bool neg_inv2 = n2->is_Sub() && inv2_idx == 2; |
duke@435 | 166 | bool neg_inv1 = n1->is_Sub() && inv1_idx == 2; |
duke@435 | 167 | if (n1->is_Sub() && inv1_idx == 1) { |
duke@435 | 168 | neg_x = !neg_x; |
duke@435 | 169 | neg_inv2 = !neg_inv2; |
duke@435 | 170 | } |
duke@435 | 171 | Node* inv1_c = phase->get_ctrl(inv1); |
duke@435 | 172 | Node* inv2_c = phase->get_ctrl(inv2); |
duke@435 | 173 | Node* n_inv1; |
duke@435 | 174 | if (neg_inv1) { |
duke@435 | 175 | Node *zero = phase->_igvn.intcon(0); |
duke@435 | 176 | phase->set_ctrl(zero, phase->C->root()); |
duke@435 | 177 | n_inv1 = new (phase->C, 3) SubINode(zero, inv1); |
duke@435 | 178 | phase->register_new_node(n_inv1, inv1_c); |
duke@435 | 179 | } else { |
duke@435 | 180 | n_inv1 = inv1; |
duke@435 | 181 | } |
duke@435 | 182 | Node* inv; |
duke@435 | 183 | if (neg_inv2) { |
duke@435 | 184 | inv = new (phase->C, 3) SubINode(n_inv1, inv2); |
duke@435 | 185 | } else { |
duke@435 | 186 | inv = new (phase->C, 3) AddINode(n_inv1, inv2); |
duke@435 | 187 | } |
duke@435 | 188 | phase->register_new_node(inv, phase->get_early_ctrl(inv)); |
duke@435 | 189 | |
duke@435 | 190 | Node* addx; |
duke@435 | 191 | if (neg_x) { |
duke@435 | 192 | addx = new (phase->C, 3) SubINode(inv, x); |
duke@435 | 193 | } else { |
duke@435 | 194 | addx = new (phase->C, 3) AddINode(x, inv); |
duke@435 | 195 | } |
duke@435 | 196 | phase->register_new_node(addx, phase->get_ctrl(x)); |
duke@435 | 197 | phase->_igvn.hash_delete(n1); |
duke@435 | 198 | phase->_igvn.subsume_node(n1, addx); |
duke@435 | 199 | return addx; |
duke@435 | 200 | } |
duke@435 | 201 | |
duke@435 | 202 | //---------------------reassociate_invariants----------------------------- |
duke@435 | 203 | // Reassociate invariant expressions: |
duke@435 | 204 | void IdealLoopTree::reassociate_invariants(PhaseIdealLoop *phase) { |
duke@435 | 205 | for (int i = _body.size() - 1; i >= 0; i--) { |
duke@435 | 206 | Node *n = _body.at(i); |
duke@435 | 207 | for (int j = 0; j < 5; j++) { |
duke@435 | 208 | Node* nn = reassociate_add_sub(n, phase); |
duke@435 | 209 | if (nn == NULL) break; |
duke@435 | 210 | n = nn; // again |
duke@435 | 211 | }; |
duke@435 | 212 | } |
duke@435 | 213 | } |
duke@435 | 214 | |
duke@435 | 215 | //------------------------------policy_peeling--------------------------------- |
duke@435 | 216 | // Return TRUE or FALSE if the loop should be peeled or not. Peel if we can |
duke@435 | 217 | // make some loop-invariant test (usually a null-check) happen before the loop. |
duke@435 | 218 | bool IdealLoopTree::policy_peeling( PhaseIdealLoop *phase ) const { |
duke@435 | 219 | Node *test = ((IdealLoopTree*)this)->tail(); |
duke@435 | 220 | int body_size = ((IdealLoopTree*)this)->_body.size(); |
duke@435 | 221 | int uniq = phase->C->unique(); |
duke@435 | 222 | // Peeling does loop cloning which can result in O(N^2) node construction |
duke@435 | 223 | if( body_size > 255 /* Prevent overflow for large body_size */ |
duke@435 | 224 | || (body_size * body_size + uniq > MaxNodeLimit) ) { |
duke@435 | 225 | return false; // too large to safely clone |
duke@435 | 226 | } |
duke@435 | 227 | while( test != _head ) { // Scan till run off top of loop |
duke@435 | 228 | if( test->is_If() ) { // Test? |
duke@435 | 229 | Node *ctrl = phase->get_ctrl(test->in(1)); |
duke@435 | 230 | if (ctrl->is_top()) |
duke@435 | 231 | return false; // Found dead test on live IF? No peeling! |
duke@435 | 232 | // Standard IF only has one input value to check for loop invariance |
duke@435 | 233 | assert( test->Opcode() == Op_If || test->Opcode() == Op_CountedLoopEnd, "Check this code when new subtype is added"); |
duke@435 | 234 | // Condition is not a member of this loop? |
duke@435 | 235 | if( !is_member(phase->get_loop(ctrl)) && |
duke@435 | 236 | is_loop_exit(test) ) |
duke@435 | 237 | return true; // Found reason to peel! |
duke@435 | 238 | } |
duke@435 | 239 | // Walk up dominators to loop _head looking for test which is |
duke@435 | 240 | // executed on every path thru loop. |
duke@435 | 241 | test = phase->idom(test); |
duke@435 | 242 | } |
duke@435 | 243 | return false; |
duke@435 | 244 | } |
duke@435 | 245 | |
duke@435 | 246 | //------------------------------peeled_dom_test_elim--------------------------- |
duke@435 | 247 | // If we got the effect of peeling, either by actually peeling or by making |
duke@435 | 248 | // a pre-loop which must execute at least once, we can remove all |
duke@435 | 249 | // loop-invariant dominated tests in the main body. |
duke@435 | 250 | void PhaseIdealLoop::peeled_dom_test_elim( IdealLoopTree *loop, Node_List &old_new ) { |
duke@435 | 251 | bool progress = true; |
duke@435 | 252 | while( progress ) { |
duke@435 | 253 | progress = false; // Reset for next iteration |
duke@435 | 254 | Node *prev = loop->_head->in(LoopNode::LoopBackControl);//loop->tail(); |
duke@435 | 255 | Node *test = prev->in(0); |
duke@435 | 256 | while( test != loop->_head ) { // Scan till run off top of loop |
duke@435 | 257 | |
duke@435 | 258 | int p_op = prev->Opcode(); |
duke@435 | 259 | if( (p_op == Op_IfFalse || p_op == Op_IfTrue) && |
duke@435 | 260 | test->is_If() && // Test? |
duke@435 | 261 | !test->in(1)->is_Con() && // And not already obvious? |
duke@435 | 262 | // Condition is not a member of this loop? |
duke@435 | 263 | !loop->is_member(get_loop(get_ctrl(test->in(1))))){ |
duke@435 | 264 | // Walk loop body looking for instances of this test |
duke@435 | 265 | for( uint i = 0; i < loop->_body.size(); i++ ) { |
duke@435 | 266 | Node *n = loop->_body.at(i); |
duke@435 | 267 | if( n->is_If() && n->in(1) == test->in(1) /*&& n != loop->tail()->in(0)*/ ) { |
duke@435 | 268 | // IfNode was dominated by version in peeled loop body |
duke@435 | 269 | progress = true; |
duke@435 | 270 | dominated_by( old_new[prev->_idx], n ); |
duke@435 | 271 | } |
duke@435 | 272 | } |
duke@435 | 273 | } |
duke@435 | 274 | prev = test; |
duke@435 | 275 | test = idom(test); |
duke@435 | 276 | } // End of scan tests in loop |
duke@435 | 277 | |
duke@435 | 278 | } // End of while( progress ) |
duke@435 | 279 | } |
duke@435 | 280 | |
duke@435 | 281 | //------------------------------do_peeling------------------------------------- |
duke@435 | 282 | // Peel the first iteration of the given loop. |
duke@435 | 283 | // Step 1: Clone the loop body. The clone becomes the peeled iteration. |
duke@435 | 284 | // The pre-loop illegally has 2 control users (old & new loops). |
duke@435 | 285 | // Step 2: Make the old-loop fall-in edges point to the peeled iteration. |
duke@435 | 286 | // Do this by making the old-loop fall-in edges act as if they came |
duke@435 | 287 | // around the loopback from the prior iteration (follow the old-loop |
duke@435 | 288 | // backedges) and then map to the new peeled iteration. This leaves |
duke@435 | 289 | // the pre-loop with only 1 user (the new peeled iteration), but the |
duke@435 | 290 | // peeled-loop backedge has 2 users. |
duke@435 | 291 | // Step 3: Cut the backedge on the clone (so its not a loop) and remove the |
duke@435 | 292 | // extra backedge user. |
duke@435 | 293 | void PhaseIdealLoop::do_peeling( IdealLoopTree *loop, Node_List &old_new ) { |
duke@435 | 294 | |
duke@435 | 295 | C->set_major_progress(); |
duke@435 | 296 | // Peeling a 'main' loop in a pre/main/post situation obfuscates the |
duke@435 | 297 | // 'pre' loop from the main and the 'pre' can no longer have it's |
duke@435 | 298 | // iterations adjusted. Therefore, we need to declare this loop as |
duke@435 | 299 | // no longer a 'main' loop; it will need new pre and post loops before |
duke@435 | 300 | // we can do further RCE. |
duke@435 | 301 | Node *h = loop->_head; |
duke@435 | 302 | if( h->is_CountedLoop() ) { |
duke@435 | 303 | CountedLoopNode *cl = h->as_CountedLoop(); |
duke@435 | 304 | assert(cl->trip_count() > 0, "peeling a fully unrolled loop"); |
duke@435 | 305 | cl->set_trip_count(cl->trip_count() - 1); |
duke@435 | 306 | if( cl->is_main_loop() ) { |
duke@435 | 307 | cl->set_normal_loop(); |
duke@435 | 308 | #ifndef PRODUCT |
duke@435 | 309 | if( PrintOpto && VerifyLoopOptimizations ) { |
duke@435 | 310 | tty->print("Peeling a 'main' loop; resetting to 'normal' "); |
duke@435 | 311 | loop->dump_head(); |
duke@435 | 312 | } |
duke@435 | 313 | #endif |
duke@435 | 314 | } |
duke@435 | 315 | } |
duke@435 | 316 | |
duke@435 | 317 | // Step 1: Clone the loop body. The clone becomes the peeled iteration. |
duke@435 | 318 | // The pre-loop illegally has 2 control users (old & new loops). |
duke@435 | 319 | clone_loop( loop, old_new, dom_depth(loop->_head) ); |
duke@435 | 320 | |
duke@435 | 321 | |
duke@435 | 322 | // Step 2: Make the old-loop fall-in edges point to the peeled iteration. |
duke@435 | 323 | // Do this by making the old-loop fall-in edges act as if they came |
duke@435 | 324 | // around the loopback from the prior iteration (follow the old-loop |
duke@435 | 325 | // backedges) and then map to the new peeled iteration. This leaves |
duke@435 | 326 | // the pre-loop with only 1 user (the new peeled iteration), but the |
duke@435 | 327 | // peeled-loop backedge has 2 users. |
duke@435 | 328 | for (DUIterator_Fast jmax, j = loop->_head->fast_outs(jmax); j < jmax; j++) { |
duke@435 | 329 | Node* old = loop->_head->fast_out(j); |
duke@435 | 330 | if( old->in(0) == loop->_head && old->req() == 3 && |
duke@435 | 331 | (old->is_Loop() || old->is_Phi()) ) { |
duke@435 | 332 | Node *new_exit_value = old_new[old->in(LoopNode::LoopBackControl)->_idx]; |
duke@435 | 333 | if( !new_exit_value ) // Backedge value is ALSO loop invariant? |
duke@435 | 334 | // Then loop body backedge value remains the same. |
duke@435 | 335 | new_exit_value = old->in(LoopNode::LoopBackControl); |
duke@435 | 336 | _igvn.hash_delete(old); |
duke@435 | 337 | old->set_req(LoopNode::EntryControl, new_exit_value); |
duke@435 | 338 | } |
duke@435 | 339 | } |
duke@435 | 340 | |
duke@435 | 341 | |
duke@435 | 342 | // Step 3: Cut the backedge on the clone (so its not a loop) and remove the |
duke@435 | 343 | // extra backedge user. |
duke@435 | 344 | Node *nnn = old_new[loop->_head->_idx]; |
duke@435 | 345 | _igvn.hash_delete(nnn); |
duke@435 | 346 | nnn->set_req(LoopNode::LoopBackControl, C->top()); |
duke@435 | 347 | for (DUIterator_Fast j2max, j2 = nnn->fast_outs(j2max); j2 < j2max; j2++) { |
duke@435 | 348 | Node* use = nnn->fast_out(j2); |
duke@435 | 349 | if( use->in(0) == nnn && use->req() == 3 && use->is_Phi() ) { |
duke@435 | 350 | _igvn.hash_delete(use); |
duke@435 | 351 | use->set_req(LoopNode::LoopBackControl, C->top()); |
duke@435 | 352 | } |
duke@435 | 353 | } |
duke@435 | 354 | |
duke@435 | 355 | |
duke@435 | 356 | // Step 4: Correct dom-depth info. Set to loop-head depth. |
duke@435 | 357 | int dd = dom_depth(loop->_head); |
duke@435 | 358 | set_idom(loop->_head, loop->_head->in(1), dd); |
duke@435 | 359 | for (uint j3 = 0; j3 < loop->_body.size(); j3++) { |
duke@435 | 360 | Node *old = loop->_body.at(j3); |
duke@435 | 361 | Node *nnn = old_new[old->_idx]; |
duke@435 | 362 | if (!has_ctrl(nnn)) |
duke@435 | 363 | set_idom(nnn, idom(nnn), dd-1); |
duke@435 | 364 | // While we're at it, remove any SafePoints from the peeled code |
duke@435 | 365 | if( old->Opcode() == Op_SafePoint ) { |
duke@435 | 366 | Node *nnn = old_new[old->_idx]; |
duke@435 | 367 | lazy_replace(nnn,nnn->in(TypeFunc::Control)); |
duke@435 | 368 | } |
duke@435 | 369 | } |
duke@435 | 370 | |
duke@435 | 371 | // Now force out all loop-invariant dominating tests. The optimizer |
duke@435 | 372 | // finds some, but we _know_ they are all useless. |
duke@435 | 373 | peeled_dom_test_elim(loop,old_new); |
duke@435 | 374 | |
duke@435 | 375 | loop->record_for_igvn(); |
duke@435 | 376 | } |
duke@435 | 377 | |
duke@435 | 378 | //------------------------------policy_maximally_unroll------------------------ |
duke@435 | 379 | // Return exact loop trip count, or 0 if not maximally unrolling |
duke@435 | 380 | bool IdealLoopTree::policy_maximally_unroll( PhaseIdealLoop *phase ) const { |
duke@435 | 381 | CountedLoopNode *cl = _head->as_CountedLoop(); |
duke@435 | 382 | assert( cl->is_normal_loop(), "" ); |
duke@435 | 383 | |
duke@435 | 384 | Node *init_n = cl->init_trip(); |
duke@435 | 385 | Node *limit_n = cl->limit(); |
duke@435 | 386 | |
duke@435 | 387 | // Non-constant bounds |
duke@435 | 388 | if( init_n == NULL || !init_n->is_Con() || |
duke@435 | 389 | limit_n == NULL || !limit_n->is_Con() || |
duke@435 | 390 | // protect against stride not being a constant |
duke@435 | 391 | !cl->stride_is_con() ) { |
duke@435 | 392 | return false; |
duke@435 | 393 | } |
duke@435 | 394 | int init = init_n->get_int(); |
duke@435 | 395 | int limit = limit_n->get_int(); |
duke@435 | 396 | int span = limit - init; |
duke@435 | 397 | int stride = cl->stride_con(); |
duke@435 | 398 | |
duke@435 | 399 | if (init >= limit || stride > span) { |
duke@435 | 400 | // return a false (no maximally unroll) and the regular unroll/peel |
duke@435 | 401 | // route will make a small mess which CCP will fold away. |
duke@435 | 402 | return false; |
duke@435 | 403 | } |
duke@435 | 404 | uint trip_count = span/stride; // trip_count can be greater than 2 Gig. |
duke@435 | 405 | assert( (int)trip_count*stride == span, "must divide evenly" ); |
duke@435 | 406 | |
duke@435 | 407 | // Real policy: if we maximally unroll, does it get too big? |
duke@435 | 408 | // Allow the unrolled mess to get larger than standard loop |
duke@435 | 409 | // size. After all, it will no longer be a loop. |
duke@435 | 410 | uint body_size = _body.size(); |
duke@435 | 411 | uint unroll_limit = (uint)LoopUnrollLimit * 4; |
duke@435 | 412 | assert( (intx)unroll_limit == LoopUnrollLimit * 4, "LoopUnrollLimit must fit in 32bits"); |
duke@435 | 413 | cl->set_trip_count(trip_count); |
duke@435 | 414 | if( trip_count <= unroll_limit && body_size <= unroll_limit ) { |
duke@435 | 415 | uint new_body_size = body_size * trip_count; |
duke@435 | 416 | if (new_body_size <= unroll_limit && |
duke@435 | 417 | body_size == new_body_size / trip_count && |
duke@435 | 418 | // Unrolling can result in a large amount of node construction |
duke@435 | 419 | new_body_size < MaxNodeLimit - phase->C->unique()) { |
duke@435 | 420 | return true; // maximally unroll |
duke@435 | 421 | } |
duke@435 | 422 | } |
duke@435 | 423 | |
duke@435 | 424 | return false; // Do not maximally unroll |
duke@435 | 425 | } |
duke@435 | 426 | |
duke@435 | 427 | |
duke@435 | 428 | //------------------------------policy_unroll---------------------------------- |
duke@435 | 429 | // Return TRUE or FALSE if the loop should be unrolled or not. Unroll if |
duke@435 | 430 | // the loop is a CountedLoop and the body is small enough. |
duke@435 | 431 | bool IdealLoopTree::policy_unroll( PhaseIdealLoop *phase ) const { |
duke@435 | 432 | |
duke@435 | 433 | CountedLoopNode *cl = _head->as_CountedLoop(); |
duke@435 | 434 | assert( cl->is_normal_loop() || cl->is_main_loop(), "" ); |
duke@435 | 435 | |
duke@435 | 436 | // protect against stride not being a constant |
duke@435 | 437 | if( !cl->stride_is_con() ) return false; |
duke@435 | 438 | |
duke@435 | 439 | // protect against over-unrolling |
duke@435 | 440 | if( cl->trip_count() <= 1 ) return false; |
duke@435 | 441 | |
duke@435 | 442 | int future_unroll_ct = cl->unrolled_count() * 2; |
duke@435 | 443 | |
duke@435 | 444 | // Don't unroll if the next round of unrolling would push us |
duke@435 | 445 | // over the expected trip count of the loop. One is subtracted |
duke@435 | 446 | // from the expected trip count because the pre-loop normally |
duke@435 | 447 | // executes 1 iteration. |
duke@435 | 448 | if (UnrollLimitForProfileCheck > 0 && |
duke@435 | 449 | cl->profile_trip_cnt() != COUNT_UNKNOWN && |
duke@435 | 450 | future_unroll_ct > UnrollLimitForProfileCheck && |
duke@435 | 451 | (float)future_unroll_ct > cl->profile_trip_cnt() - 1.0) { |
duke@435 | 452 | return false; |
duke@435 | 453 | } |
duke@435 | 454 | |
duke@435 | 455 | // When unroll count is greater than LoopUnrollMin, don't unroll if: |
duke@435 | 456 | // the residual iterations are more than 10% of the trip count |
duke@435 | 457 | // and rounds of "unroll,optimize" are not making significant progress |
duke@435 | 458 | // Progress defined as current size less than 20% larger than previous size. |
duke@435 | 459 | if (UseSuperWord && cl->node_count_before_unroll() > 0 && |
duke@435 | 460 | future_unroll_ct > LoopUnrollMin && |
duke@435 | 461 | (future_unroll_ct - 1) * 10.0 > cl->profile_trip_cnt() && |
duke@435 | 462 | 1.2 * cl->node_count_before_unroll() < (double)_body.size()) { |
duke@435 | 463 | return false; |
duke@435 | 464 | } |
duke@435 | 465 | |
duke@435 | 466 | Node *init_n = cl->init_trip(); |
duke@435 | 467 | Node *limit_n = cl->limit(); |
duke@435 | 468 | // Non-constant bounds. |
duke@435 | 469 | // Protect against over-unrolling when init or/and limit are not constant |
duke@435 | 470 | // (so that trip_count's init value is maxint) but iv range is known. |
duke@435 | 471 | if( init_n == NULL || !init_n->is_Con() || |
duke@435 | 472 | limit_n == NULL || !limit_n->is_Con() ) { |
duke@435 | 473 | Node* phi = cl->phi(); |
duke@435 | 474 | if( phi != NULL ) { |
duke@435 | 475 | assert(phi->is_Phi() && phi->in(0) == _head, "Counted loop should have iv phi."); |
duke@435 | 476 | const TypeInt* iv_type = phase->_igvn.type(phi)->is_int(); |
duke@435 | 477 | int next_stride = cl->stride_con() * 2; // stride after this unroll |
duke@435 | 478 | if( next_stride > 0 ) { |
duke@435 | 479 | if( iv_type->_lo + next_stride <= iv_type->_lo || // overflow |
duke@435 | 480 | iv_type->_lo + next_stride > iv_type->_hi ) { |
duke@435 | 481 | return false; // over-unrolling |
duke@435 | 482 | } |
duke@435 | 483 | } else if( next_stride < 0 ) { |
duke@435 | 484 | if( iv_type->_hi + next_stride >= iv_type->_hi || // overflow |
duke@435 | 485 | iv_type->_hi + next_stride < iv_type->_lo ) { |
duke@435 | 486 | return false; // over-unrolling |
duke@435 | 487 | } |
duke@435 | 488 | } |
duke@435 | 489 | } |
duke@435 | 490 | } |
duke@435 | 491 | |
duke@435 | 492 | // Adjust body_size to determine if we unroll or not |
duke@435 | 493 | uint body_size = _body.size(); |
duke@435 | 494 | // Key test to unroll CaffeineMark's Logic test |
duke@435 | 495 | int xors_in_loop = 0; |
duke@435 | 496 | // Also count ModL, DivL and MulL which expand mightly |
duke@435 | 497 | for( uint k = 0; k < _body.size(); k++ ) { |
duke@435 | 498 | switch( _body.at(k)->Opcode() ) { |
duke@435 | 499 | case Op_XorI: xors_in_loop++; break; // CaffeineMark's Logic test |
duke@435 | 500 | case Op_ModL: body_size += 30; break; |
duke@435 | 501 | case Op_DivL: body_size += 30; break; |
duke@435 | 502 | case Op_MulL: body_size += 10; break; |
duke@435 | 503 | } |
duke@435 | 504 | } |
duke@435 | 505 | |
duke@435 | 506 | // Check for being too big |
duke@435 | 507 | if( body_size > (uint)LoopUnrollLimit ) { |
duke@435 | 508 | if( xors_in_loop >= 4 && body_size < (uint)LoopUnrollLimit*4) return true; |
duke@435 | 509 | // Normal case: loop too big |
duke@435 | 510 | return false; |
duke@435 | 511 | } |
duke@435 | 512 | |
duke@435 | 513 | // Check for stride being a small enough constant |
duke@435 | 514 | if( abs(cl->stride_con()) > (1<<3) ) return false; |
duke@435 | 515 | |
duke@435 | 516 | // Unroll once! (Each trip will soon do double iterations) |
duke@435 | 517 | return true; |
duke@435 | 518 | } |
duke@435 | 519 | |
duke@435 | 520 | //------------------------------policy_align----------------------------------- |
duke@435 | 521 | // Return TRUE or FALSE if the loop should be cache-line aligned. Gather the |
duke@435 | 522 | // expression that does the alignment. Note that only one array base can be |
twisti@1040 | 523 | // aligned in a loop (unless the VM guarantees mutual alignment). Note that |
duke@435 | 524 | // if we vectorize short memory ops into longer memory ops, we may want to |
duke@435 | 525 | // increase alignment. |
duke@435 | 526 | bool IdealLoopTree::policy_align( PhaseIdealLoop *phase ) const { |
duke@435 | 527 | return false; |
duke@435 | 528 | } |
duke@435 | 529 | |
duke@435 | 530 | //------------------------------policy_range_check----------------------------- |
duke@435 | 531 | // Return TRUE or FALSE if the loop should be range-check-eliminated. |
duke@435 | 532 | // Actually we do iteration-splitting, a more powerful form of RCE. |
duke@435 | 533 | bool IdealLoopTree::policy_range_check( PhaseIdealLoop *phase ) const { |
duke@435 | 534 | if( !RangeCheckElimination ) return false; |
duke@435 | 535 | |
duke@435 | 536 | CountedLoopNode *cl = _head->as_CountedLoop(); |
duke@435 | 537 | // If we unrolled with no intention of doing RCE and we later |
duke@435 | 538 | // changed our minds, we got no pre-loop. Either we need to |
duke@435 | 539 | // make a new pre-loop, or we gotta disallow RCE. |
duke@435 | 540 | if( cl->is_main_no_pre_loop() ) return false; // Disallowed for now. |
duke@435 | 541 | Node *trip_counter = cl->phi(); |
duke@435 | 542 | |
duke@435 | 543 | // Check loop body for tests of trip-counter plus loop-invariant vs |
duke@435 | 544 | // loop-invariant. |
duke@435 | 545 | for( uint i = 0; i < _body.size(); i++ ) { |
duke@435 | 546 | Node *iff = _body[i]; |
duke@435 | 547 | if( iff->Opcode() == Op_If ) { // Test? |
duke@435 | 548 | |
duke@435 | 549 | // Comparing trip+off vs limit |
duke@435 | 550 | Node *bol = iff->in(1); |
duke@435 | 551 | if( bol->req() != 2 ) continue; // dead constant test |
cfang@1607 | 552 | if (!bol->is_Bool()) { |
cfang@1607 | 553 | assert(UseLoopPredicate && bol->Opcode() == Op_Conv2B, "predicate check only"); |
cfang@1607 | 554 | continue; |
cfang@1607 | 555 | } |
duke@435 | 556 | Node *cmp = bol->in(1); |
duke@435 | 557 | |
duke@435 | 558 | Node *rc_exp = cmp->in(1); |
duke@435 | 559 | Node *limit = cmp->in(2); |
duke@435 | 560 | |
duke@435 | 561 | Node *limit_c = phase->get_ctrl(limit); |
duke@435 | 562 | if( limit_c == phase->C->top() ) |
duke@435 | 563 | return false; // Found dead test on live IF? No RCE! |
duke@435 | 564 | if( is_member(phase->get_loop(limit_c) ) ) { |
duke@435 | 565 | // Compare might have operands swapped; commute them |
duke@435 | 566 | rc_exp = cmp->in(2); |
duke@435 | 567 | limit = cmp->in(1); |
duke@435 | 568 | limit_c = phase->get_ctrl(limit); |
duke@435 | 569 | if( is_member(phase->get_loop(limit_c) ) ) |
duke@435 | 570 | continue; // Both inputs are loop varying; cannot RCE |
duke@435 | 571 | } |
duke@435 | 572 | |
duke@435 | 573 | if (!phase->is_scaled_iv_plus_offset(rc_exp, trip_counter, NULL, NULL)) { |
duke@435 | 574 | continue; |
duke@435 | 575 | } |
duke@435 | 576 | // Yeah! Found a test like 'trip+off vs limit' |
duke@435 | 577 | // Test is an IfNode, has 2 projections. If BOTH are in the loop |
duke@435 | 578 | // we need loop unswitching instead of iteration splitting. |
duke@435 | 579 | if( is_loop_exit(iff) ) |
duke@435 | 580 | return true; // Found reason to split iterations |
duke@435 | 581 | } // End of is IF |
duke@435 | 582 | } |
duke@435 | 583 | |
duke@435 | 584 | return false; |
duke@435 | 585 | } |
duke@435 | 586 | |
duke@435 | 587 | //------------------------------policy_peel_only------------------------------- |
duke@435 | 588 | // Return TRUE or FALSE if the loop should NEVER be RCE'd or aligned. Useful |
duke@435 | 589 | // for unrolling loops with NO array accesses. |
duke@435 | 590 | bool IdealLoopTree::policy_peel_only( PhaseIdealLoop *phase ) const { |
duke@435 | 591 | |
duke@435 | 592 | for( uint i = 0; i < _body.size(); i++ ) |
duke@435 | 593 | if( _body[i]->is_Mem() ) |
duke@435 | 594 | return false; |
duke@435 | 595 | |
duke@435 | 596 | // No memory accesses at all! |
duke@435 | 597 | return true; |
duke@435 | 598 | } |
duke@435 | 599 | |
duke@435 | 600 | //------------------------------clone_up_backedge_goo-------------------------- |
duke@435 | 601 | // If Node n lives in the back_ctrl block and cannot float, we clone a private |
duke@435 | 602 | // version of n in preheader_ctrl block and return that, otherwise return n. |
duke@435 | 603 | Node *PhaseIdealLoop::clone_up_backedge_goo( Node *back_ctrl, Node *preheader_ctrl, Node *n ) { |
duke@435 | 604 | if( get_ctrl(n) != back_ctrl ) return n; |
duke@435 | 605 | |
duke@435 | 606 | Node *x = NULL; // If required, a clone of 'n' |
duke@435 | 607 | // Check for 'n' being pinned in the backedge. |
duke@435 | 608 | if( n->in(0) && n->in(0) == back_ctrl ) { |
duke@435 | 609 | x = n->clone(); // Clone a copy of 'n' to preheader |
duke@435 | 610 | x->set_req( 0, preheader_ctrl ); // Fix x's control input to preheader |
duke@435 | 611 | } |
duke@435 | 612 | |
duke@435 | 613 | // Recursive fixup any other input edges into x. |
duke@435 | 614 | // If there are no changes we can just return 'n', otherwise |
duke@435 | 615 | // we need to clone a private copy and change it. |
duke@435 | 616 | for( uint i = 1; i < n->req(); i++ ) { |
duke@435 | 617 | Node *g = clone_up_backedge_goo( back_ctrl, preheader_ctrl, n->in(i) ); |
duke@435 | 618 | if( g != n->in(i) ) { |
duke@435 | 619 | if( !x ) |
duke@435 | 620 | x = n->clone(); |
duke@435 | 621 | x->set_req(i, g); |
duke@435 | 622 | } |
duke@435 | 623 | } |
duke@435 | 624 | if( x ) { // x can legally float to pre-header location |
duke@435 | 625 | register_new_node( x, preheader_ctrl ); |
duke@435 | 626 | return x; |
duke@435 | 627 | } else { // raise n to cover LCA of uses |
duke@435 | 628 | set_ctrl( n, find_non_split_ctrl(back_ctrl->in(0)) ); |
duke@435 | 629 | } |
duke@435 | 630 | return n; |
duke@435 | 631 | } |
duke@435 | 632 | |
duke@435 | 633 | //------------------------------insert_pre_post_loops-------------------------- |
duke@435 | 634 | // Insert pre and post loops. If peel_only is set, the pre-loop can not have |
duke@435 | 635 | // more iterations added. It acts as a 'peel' only, no lower-bound RCE, no |
duke@435 | 636 | // alignment. Useful to unroll loops that do no array accesses. |
duke@435 | 637 | void PhaseIdealLoop::insert_pre_post_loops( IdealLoopTree *loop, Node_List &old_new, bool peel_only ) { |
duke@435 | 638 | |
duke@435 | 639 | C->set_major_progress(); |
duke@435 | 640 | |
duke@435 | 641 | // Find common pieces of the loop being guarded with pre & post loops |
duke@435 | 642 | CountedLoopNode *main_head = loop->_head->as_CountedLoop(); |
duke@435 | 643 | assert( main_head->is_normal_loop(), "" ); |
duke@435 | 644 | CountedLoopEndNode *main_end = main_head->loopexit(); |
duke@435 | 645 | assert( main_end->outcnt() == 2, "1 true, 1 false path only" ); |
duke@435 | 646 | uint dd_main_head = dom_depth(main_head); |
duke@435 | 647 | uint max = main_head->outcnt(); |
duke@435 | 648 | |
duke@435 | 649 | Node *pre_header= main_head->in(LoopNode::EntryControl); |
duke@435 | 650 | Node *init = main_head->init_trip(); |
duke@435 | 651 | Node *incr = main_end ->incr(); |
duke@435 | 652 | Node *limit = main_end ->limit(); |
duke@435 | 653 | Node *stride = main_end ->stride(); |
duke@435 | 654 | Node *cmp = main_end ->cmp_node(); |
duke@435 | 655 | BoolTest::mask b_test = main_end->test_trip(); |
duke@435 | 656 | |
duke@435 | 657 | // Need only 1 user of 'bol' because I will be hacking the loop bounds. |
duke@435 | 658 | Node *bol = main_end->in(CountedLoopEndNode::TestValue); |
duke@435 | 659 | if( bol->outcnt() != 1 ) { |
duke@435 | 660 | bol = bol->clone(); |
duke@435 | 661 | register_new_node(bol,main_end->in(CountedLoopEndNode::TestControl)); |
duke@435 | 662 | _igvn.hash_delete(main_end); |
duke@435 | 663 | main_end->set_req(CountedLoopEndNode::TestValue, bol); |
duke@435 | 664 | } |
duke@435 | 665 | // Need only 1 user of 'cmp' because I will be hacking the loop bounds. |
duke@435 | 666 | if( cmp->outcnt() != 1 ) { |
duke@435 | 667 | cmp = cmp->clone(); |
duke@435 | 668 | register_new_node(cmp,main_end->in(CountedLoopEndNode::TestControl)); |
duke@435 | 669 | _igvn.hash_delete(bol); |
duke@435 | 670 | bol->set_req(1, cmp); |
duke@435 | 671 | } |
duke@435 | 672 | |
duke@435 | 673 | //------------------------------ |
duke@435 | 674 | // Step A: Create Post-Loop. |
duke@435 | 675 | Node* main_exit = main_end->proj_out(false); |
duke@435 | 676 | assert( main_exit->Opcode() == Op_IfFalse, "" ); |
duke@435 | 677 | int dd_main_exit = dom_depth(main_exit); |
duke@435 | 678 | |
duke@435 | 679 | // Step A1: Clone the loop body. The clone becomes the post-loop. The main |
duke@435 | 680 | // loop pre-header illegally has 2 control users (old & new loops). |
duke@435 | 681 | clone_loop( loop, old_new, dd_main_exit ); |
duke@435 | 682 | assert( old_new[main_end ->_idx]->Opcode() == Op_CountedLoopEnd, "" ); |
duke@435 | 683 | CountedLoopNode *post_head = old_new[main_head->_idx]->as_CountedLoop(); |
duke@435 | 684 | post_head->set_post_loop(main_head); |
duke@435 | 685 | |
kvn@835 | 686 | // Reduce the post-loop trip count. |
kvn@835 | 687 | CountedLoopEndNode* post_end = old_new[main_end ->_idx]->as_CountedLoopEnd(); |
kvn@835 | 688 | post_end->_prob = PROB_FAIR; |
kvn@835 | 689 | |
duke@435 | 690 | // Build the main-loop normal exit. |
duke@435 | 691 | IfFalseNode *new_main_exit = new (C, 1) IfFalseNode(main_end); |
duke@435 | 692 | _igvn.register_new_node_with_optimizer( new_main_exit ); |
duke@435 | 693 | set_idom(new_main_exit, main_end, dd_main_exit ); |
duke@435 | 694 | set_loop(new_main_exit, loop->_parent); |
duke@435 | 695 | |
duke@435 | 696 | // Step A2: Build a zero-trip guard for the post-loop. After leaving the |
duke@435 | 697 | // main-loop, the post-loop may not execute at all. We 'opaque' the incr |
duke@435 | 698 | // (the main-loop trip-counter exit value) because we will be changing |
duke@435 | 699 | // the exit value (via unrolling) so we cannot constant-fold away the zero |
duke@435 | 700 | // trip guard until all unrolling is done. |
kvn@651 | 701 | Node *zer_opaq = new (C, 2) Opaque1Node(C, incr); |
duke@435 | 702 | Node *zer_cmp = new (C, 3) CmpINode( zer_opaq, limit ); |
duke@435 | 703 | Node *zer_bol = new (C, 2) BoolNode( zer_cmp, b_test ); |
duke@435 | 704 | register_new_node( zer_opaq, new_main_exit ); |
duke@435 | 705 | register_new_node( zer_cmp , new_main_exit ); |
duke@435 | 706 | register_new_node( zer_bol , new_main_exit ); |
duke@435 | 707 | |
duke@435 | 708 | // Build the IfNode |
duke@435 | 709 | IfNode *zer_iff = new (C, 2) IfNode( new_main_exit, zer_bol, PROB_FAIR, COUNT_UNKNOWN ); |
duke@435 | 710 | _igvn.register_new_node_with_optimizer( zer_iff ); |
duke@435 | 711 | set_idom(zer_iff, new_main_exit, dd_main_exit); |
duke@435 | 712 | set_loop(zer_iff, loop->_parent); |
duke@435 | 713 | |
duke@435 | 714 | // Plug in the false-path, taken if we need to skip post-loop |
duke@435 | 715 | _igvn.hash_delete( main_exit ); |
duke@435 | 716 | main_exit->set_req(0, zer_iff); |
duke@435 | 717 | _igvn._worklist.push(main_exit); |
duke@435 | 718 | set_idom(main_exit, zer_iff, dd_main_exit); |
duke@435 | 719 | set_idom(main_exit->unique_out(), zer_iff, dd_main_exit); |
duke@435 | 720 | // Make the true-path, must enter the post loop |
duke@435 | 721 | Node *zer_taken = new (C, 1) IfTrueNode( zer_iff ); |
duke@435 | 722 | _igvn.register_new_node_with_optimizer( zer_taken ); |
duke@435 | 723 | set_idom(zer_taken, zer_iff, dd_main_exit); |
duke@435 | 724 | set_loop(zer_taken, loop->_parent); |
duke@435 | 725 | // Plug in the true path |
duke@435 | 726 | _igvn.hash_delete( post_head ); |
duke@435 | 727 | post_head->set_req(LoopNode::EntryControl, zer_taken); |
duke@435 | 728 | set_idom(post_head, zer_taken, dd_main_exit); |
duke@435 | 729 | |
duke@435 | 730 | // Step A3: Make the fall-in values to the post-loop come from the |
duke@435 | 731 | // fall-out values of the main-loop. |
duke@435 | 732 | for (DUIterator_Fast imax, i = main_head->fast_outs(imax); i < imax; i++) { |
duke@435 | 733 | Node* main_phi = main_head->fast_out(i); |
duke@435 | 734 | if( main_phi->is_Phi() && main_phi->in(0) == main_head && main_phi->outcnt() >0 ) { |
duke@435 | 735 | Node *post_phi = old_new[main_phi->_idx]; |
duke@435 | 736 | Node *fallmain = clone_up_backedge_goo(main_head->back_control(), |
duke@435 | 737 | post_head->init_control(), |
duke@435 | 738 | main_phi->in(LoopNode::LoopBackControl)); |
duke@435 | 739 | _igvn.hash_delete(post_phi); |
duke@435 | 740 | post_phi->set_req( LoopNode::EntryControl, fallmain ); |
duke@435 | 741 | } |
duke@435 | 742 | } |
duke@435 | 743 | |
duke@435 | 744 | // Update local caches for next stanza |
duke@435 | 745 | main_exit = new_main_exit; |
duke@435 | 746 | |
duke@435 | 747 | |
duke@435 | 748 | //------------------------------ |
duke@435 | 749 | // Step B: Create Pre-Loop. |
duke@435 | 750 | |
duke@435 | 751 | // Step B1: Clone the loop body. The clone becomes the pre-loop. The main |
duke@435 | 752 | // loop pre-header illegally has 2 control users (old & new loops). |
duke@435 | 753 | clone_loop( loop, old_new, dd_main_head ); |
duke@435 | 754 | CountedLoopNode* pre_head = old_new[main_head->_idx]->as_CountedLoop(); |
duke@435 | 755 | CountedLoopEndNode* pre_end = old_new[main_end ->_idx]->as_CountedLoopEnd(); |
duke@435 | 756 | pre_head->set_pre_loop(main_head); |
duke@435 | 757 | Node *pre_incr = old_new[incr->_idx]; |
duke@435 | 758 | |
kvn@835 | 759 | // Reduce the pre-loop trip count. |
kvn@835 | 760 | pre_end->_prob = PROB_FAIR; |
kvn@835 | 761 | |
duke@435 | 762 | // Find the pre-loop normal exit. |
duke@435 | 763 | Node* pre_exit = pre_end->proj_out(false); |
duke@435 | 764 | assert( pre_exit->Opcode() == Op_IfFalse, "" ); |
duke@435 | 765 | IfFalseNode *new_pre_exit = new (C, 1) IfFalseNode(pre_end); |
duke@435 | 766 | _igvn.register_new_node_with_optimizer( new_pre_exit ); |
duke@435 | 767 | set_idom(new_pre_exit, pre_end, dd_main_head); |
duke@435 | 768 | set_loop(new_pre_exit, loop->_parent); |
duke@435 | 769 | |
duke@435 | 770 | // Step B2: Build a zero-trip guard for the main-loop. After leaving the |
duke@435 | 771 | // pre-loop, the main-loop may not execute at all. Later in life this |
duke@435 | 772 | // zero-trip guard will become the minimum-trip guard when we unroll |
duke@435 | 773 | // the main-loop. |
kvn@651 | 774 | Node *min_opaq = new (C, 2) Opaque1Node(C, limit); |
duke@435 | 775 | Node *min_cmp = new (C, 3) CmpINode( pre_incr, min_opaq ); |
duke@435 | 776 | Node *min_bol = new (C, 2) BoolNode( min_cmp, b_test ); |
duke@435 | 777 | register_new_node( min_opaq, new_pre_exit ); |
duke@435 | 778 | register_new_node( min_cmp , new_pre_exit ); |
duke@435 | 779 | register_new_node( min_bol , new_pre_exit ); |
duke@435 | 780 | |
kvn@835 | 781 | // Build the IfNode (assume the main-loop is executed always). |
kvn@835 | 782 | IfNode *min_iff = new (C, 2) IfNode( new_pre_exit, min_bol, PROB_ALWAYS, COUNT_UNKNOWN ); |
duke@435 | 783 | _igvn.register_new_node_with_optimizer( min_iff ); |
duke@435 | 784 | set_idom(min_iff, new_pre_exit, dd_main_head); |
duke@435 | 785 | set_loop(min_iff, loop->_parent); |
duke@435 | 786 | |
duke@435 | 787 | // Plug in the false-path, taken if we need to skip main-loop |
duke@435 | 788 | _igvn.hash_delete( pre_exit ); |
duke@435 | 789 | pre_exit->set_req(0, min_iff); |
duke@435 | 790 | set_idom(pre_exit, min_iff, dd_main_head); |
duke@435 | 791 | set_idom(pre_exit->unique_out(), min_iff, dd_main_head); |
duke@435 | 792 | // Make the true-path, must enter the main loop |
duke@435 | 793 | Node *min_taken = new (C, 1) IfTrueNode( min_iff ); |
duke@435 | 794 | _igvn.register_new_node_with_optimizer( min_taken ); |
duke@435 | 795 | set_idom(min_taken, min_iff, dd_main_head); |
duke@435 | 796 | set_loop(min_taken, loop->_parent); |
duke@435 | 797 | // Plug in the true path |
duke@435 | 798 | _igvn.hash_delete( main_head ); |
duke@435 | 799 | main_head->set_req(LoopNode::EntryControl, min_taken); |
duke@435 | 800 | set_idom(main_head, min_taken, dd_main_head); |
duke@435 | 801 | |
duke@435 | 802 | // Step B3: Make the fall-in values to the main-loop come from the |
duke@435 | 803 | // fall-out values of the pre-loop. |
duke@435 | 804 | for (DUIterator_Fast i2max, i2 = main_head->fast_outs(i2max); i2 < i2max; i2++) { |
duke@435 | 805 | Node* main_phi = main_head->fast_out(i2); |
duke@435 | 806 | if( main_phi->is_Phi() && main_phi->in(0) == main_head && main_phi->outcnt() > 0 ) { |
duke@435 | 807 | Node *pre_phi = old_new[main_phi->_idx]; |
duke@435 | 808 | Node *fallpre = clone_up_backedge_goo(pre_head->back_control(), |
duke@435 | 809 | main_head->init_control(), |
duke@435 | 810 | pre_phi->in(LoopNode::LoopBackControl)); |
duke@435 | 811 | _igvn.hash_delete(main_phi); |
duke@435 | 812 | main_phi->set_req( LoopNode::EntryControl, fallpre ); |
duke@435 | 813 | } |
duke@435 | 814 | } |
duke@435 | 815 | |
duke@435 | 816 | // Step B4: Shorten the pre-loop to run only 1 iteration (for now). |
duke@435 | 817 | // RCE and alignment may change this later. |
duke@435 | 818 | Node *cmp_end = pre_end->cmp_node(); |
duke@435 | 819 | assert( cmp_end->in(2) == limit, "" ); |
duke@435 | 820 | Node *pre_limit = new (C, 3) AddINode( init, stride ); |
duke@435 | 821 | |
duke@435 | 822 | // Save the original loop limit in this Opaque1 node for |
duke@435 | 823 | // use by range check elimination. |
kvn@651 | 824 | Node *pre_opaq = new (C, 3) Opaque1Node(C, pre_limit, limit); |
duke@435 | 825 | |
duke@435 | 826 | register_new_node( pre_limit, pre_head->in(0) ); |
duke@435 | 827 | register_new_node( pre_opaq , pre_head->in(0) ); |
duke@435 | 828 | |
duke@435 | 829 | // Since no other users of pre-loop compare, I can hack limit directly |
duke@435 | 830 | assert( cmp_end->outcnt() == 1, "no other users" ); |
duke@435 | 831 | _igvn.hash_delete(cmp_end); |
duke@435 | 832 | cmp_end->set_req(2, peel_only ? pre_limit : pre_opaq); |
duke@435 | 833 | |
duke@435 | 834 | // Special case for not-equal loop bounds: |
duke@435 | 835 | // Change pre loop test, main loop test, and the |
duke@435 | 836 | // main loop guard test to use lt or gt depending on stride |
duke@435 | 837 | // direction: |
duke@435 | 838 | // positive stride use < |
duke@435 | 839 | // negative stride use > |
duke@435 | 840 | |
duke@435 | 841 | if (pre_end->in(CountedLoopEndNode::TestValue)->as_Bool()->_test._test == BoolTest::ne) { |
duke@435 | 842 | |
duke@435 | 843 | BoolTest::mask new_test = (main_end->stride_con() > 0) ? BoolTest::lt : BoolTest::gt; |
duke@435 | 844 | // Modify pre loop end condition |
duke@435 | 845 | Node* pre_bol = pre_end->in(CountedLoopEndNode::TestValue)->as_Bool(); |
duke@435 | 846 | BoolNode* new_bol0 = new (C, 2) BoolNode(pre_bol->in(1), new_test); |
duke@435 | 847 | register_new_node( new_bol0, pre_head->in(0) ); |
duke@435 | 848 | _igvn.hash_delete(pre_end); |
duke@435 | 849 | pre_end->set_req(CountedLoopEndNode::TestValue, new_bol0); |
duke@435 | 850 | // Modify main loop guard condition |
duke@435 | 851 | assert(min_iff->in(CountedLoopEndNode::TestValue) == min_bol, "guard okay"); |
duke@435 | 852 | BoolNode* new_bol1 = new (C, 2) BoolNode(min_bol->in(1), new_test); |
duke@435 | 853 | register_new_node( new_bol1, new_pre_exit ); |
duke@435 | 854 | _igvn.hash_delete(min_iff); |
duke@435 | 855 | min_iff->set_req(CountedLoopEndNode::TestValue, new_bol1); |
duke@435 | 856 | // Modify main loop end condition |
duke@435 | 857 | BoolNode* main_bol = main_end->in(CountedLoopEndNode::TestValue)->as_Bool(); |
duke@435 | 858 | BoolNode* new_bol2 = new (C, 2) BoolNode(main_bol->in(1), new_test); |
duke@435 | 859 | register_new_node( new_bol2, main_end->in(CountedLoopEndNode::TestControl) ); |
duke@435 | 860 | _igvn.hash_delete(main_end); |
duke@435 | 861 | main_end->set_req(CountedLoopEndNode::TestValue, new_bol2); |
duke@435 | 862 | } |
duke@435 | 863 | |
duke@435 | 864 | // Flag main loop |
duke@435 | 865 | main_head->set_main_loop(); |
duke@435 | 866 | if( peel_only ) main_head->set_main_no_pre_loop(); |
duke@435 | 867 | |
duke@435 | 868 | // It's difficult to be precise about the trip-counts |
duke@435 | 869 | // for the pre/post loops. They are usually very short, |
duke@435 | 870 | // so guess that 4 trips is a reasonable value. |
duke@435 | 871 | post_head->set_profile_trip_cnt(4.0); |
duke@435 | 872 | pre_head->set_profile_trip_cnt(4.0); |
duke@435 | 873 | |
duke@435 | 874 | // Now force out all loop-invariant dominating tests. The optimizer |
duke@435 | 875 | // finds some, but we _know_ they are all useless. |
duke@435 | 876 | peeled_dom_test_elim(loop,old_new); |
duke@435 | 877 | } |
duke@435 | 878 | |
duke@435 | 879 | //------------------------------is_invariant----------------------------- |
duke@435 | 880 | // Return true if n is invariant |
duke@435 | 881 | bool IdealLoopTree::is_invariant(Node* n) const { |
cfang@1607 | 882 | Node *n_c = _phase->has_ctrl(n) ? _phase->get_ctrl(n) : n; |
duke@435 | 883 | if (n_c->is_top()) return false; |
duke@435 | 884 | return !is_member(_phase->get_loop(n_c)); |
duke@435 | 885 | } |
duke@435 | 886 | |
duke@435 | 887 | |
duke@435 | 888 | //------------------------------do_unroll-------------------------------------- |
duke@435 | 889 | // Unroll the loop body one step - make each trip do 2 iterations. |
duke@435 | 890 | void PhaseIdealLoop::do_unroll( IdealLoopTree *loop, Node_List &old_new, bool adjust_min_trip ) { |
duke@435 | 891 | assert( LoopUnrollLimit, "" ); |
duke@435 | 892 | #ifndef PRODUCT |
duke@435 | 893 | if( PrintOpto && VerifyLoopOptimizations ) { |
duke@435 | 894 | tty->print("Unrolling "); |
duke@435 | 895 | loop->dump_head(); |
duke@435 | 896 | } |
duke@435 | 897 | #endif |
duke@435 | 898 | CountedLoopNode *loop_head = loop->_head->as_CountedLoop(); |
duke@435 | 899 | CountedLoopEndNode *loop_end = loop_head->loopexit(); |
duke@435 | 900 | assert( loop_end, "" ); |
duke@435 | 901 | |
duke@435 | 902 | // Remember loop node count before unrolling to detect |
duke@435 | 903 | // if rounds of unroll,optimize are making progress |
duke@435 | 904 | loop_head->set_node_count_before_unroll(loop->_body.size()); |
duke@435 | 905 | |
duke@435 | 906 | Node *ctrl = loop_head->in(LoopNode::EntryControl); |
duke@435 | 907 | Node *limit = loop_head->limit(); |
duke@435 | 908 | Node *init = loop_head->init_trip(); |
duke@435 | 909 | Node *strid = loop_head->stride(); |
duke@435 | 910 | |
duke@435 | 911 | Node *opaq = NULL; |
duke@435 | 912 | if( adjust_min_trip ) { // If not maximally unrolling, need adjustment |
duke@435 | 913 | assert( loop_head->is_main_loop(), "" ); |
duke@435 | 914 | assert( ctrl->Opcode() == Op_IfTrue || ctrl->Opcode() == Op_IfFalse, "" ); |
duke@435 | 915 | Node *iff = ctrl->in(0); |
duke@435 | 916 | assert( iff->Opcode() == Op_If, "" ); |
duke@435 | 917 | Node *bol = iff->in(1); |
duke@435 | 918 | assert( bol->Opcode() == Op_Bool, "" ); |
duke@435 | 919 | Node *cmp = bol->in(1); |
duke@435 | 920 | assert( cmp->Opcode() == Op_CmpI, "" ); |
duke@435 | 921 | opaq = cmp->in(2); |
duke@435 | 922 | // Occasionally it's possible for a pre-loop Opaque1 node to be |
duke@435 | 923 | // optimized away and then another round of loop opts attempted. |
duke@435 | 924 | // We can not optimize this particular loop in that case. |
duke@435 | 925 | if( opaq->Opcode() != Op_Opaque1 ) |
duke@435 | 926 | return; // Cannot find pre-loop! Bail out! |
duke@435 | 927 | } |
duke@435 | 928 | |
duke@435 | 929 | C->set_major_progress(); |
duke@435 | 930 | |
duke@435 | 931 | // Adjust max trip count. The trip count is intentionally rounded |
duke@435 | 932 | // down here (e.g. 15-> 7-> 3-> 1) because if we unwittingly over-unroll, |
duke@435 | 933 | // the main, unrolled, part of the loop will never execute as it is protected |
duke@435 | 934 | // by the min-trip test. See bug 4834191 for a case where we over-unrolled |
duke@435 | 935 | // and later determined that part of the unrolled loop was dead. |
duke@435 | 936 | loop_head->set_trip_count(loop_head->trip_count() / 2); |
duke@435 | 937 | |
duke@435 | 938 | // Double the count of original iterations in the unrolled loop body. |
duke@435 | 939 | loop_head->double_unrolled_count(); |
duke@435 | 940 | |
duke@435 | 941 | // ----------- |
duke@435 | 942 | // Step 2: Cut back the trip counter for an unroll amount of 2. |
duke@435 | 943 | // Loop will normally trip (limit - init)/stride_con. Since it's a |
duke@435 | 944 | // CountedLoop this is exact (stride divides limit-init exactly). |
duke@435 | 945 | // We are going to double the loop body, so we want to knock off any |
duke@435 | 946 | // odd iteration: (trip_cnt & ~1). Then back compute a new limit. |
duke@435 | 947 | Node *span = new (C, 3) SubINode( limit, init ); |
duke@435 | 948 | register_new_node( span, ctrl ); |
duke@435 | 949 | Node *trip = new (C, 3) DivINode( 0, span, strid ); |
duke@435 | 950 | register_new_node( trip, ctrl ); |
duke@435 | 951 | Node *mtwo = _igvn.intcon(-2); |
duke@435 | 952 | set_ctrl(mtwo, C->root()); |
duke@435 | 953 | Node *rond = new (C, 3) AndINode( trip, mtwo ); |
duke@435 | 954 | register_new_node( rond, ctrl ); |
duke@435 | 955 | Node *spn2 = new (C, 3) MulINode( rond, strid ); |
duke@435 | 956 | register_new_node( spn2, ctrl ); |
duke@435 | 957 | Node *lim2 = new (C, 3) AddINode( spn2, init ); |
duke@435 | 958 | register_new_node( lim2, ctrl ); |
duke@435 | 959 | |
duke@435 | 960 | // Hammer in the new limit |
duke@435 | 961 | Node *ctrl2 = loop_end->in(0); |
duke@435 | 962 | Node *cmp2 = new (C, 3) CmpINode( loop_head->incr(), lim2 ); |
duke@435 | 963 | register_new_node( cmp2, ctrl2 ); |
duke@435 | 964 | Node *bol2 = new (C, 2) BoolNode( cmp2, loop_end->test_trip() ); |
duke@435 | 965 | register_new_node( bol2, ctrl2 ); |
duke@435 | 966 | _igvn.hash_delete(loop_end); |
duke@435 | 967 | loop_end->set_req(CountedLoopEndNode::TestValue, bol2); |
duke@435 | 968 | |
duke@435 | 969 | // Step 3: Find the min-trip test guaranteed before a 'main' loop. |
duke@435 | 970 | // Make it a 1-trip test (means at least 2 trips). |
duke@435 | 971 | if( adjust_min_trip ) { |
duke@435 | 972 | // Guard test uses an 'opaque' node which is not shared. Hence I |
duke@435 | 973 | // can edit it's inputs directly. Hammer in the new limit for the |
duke@435 | 974 | // minimum-trip guard. |
duke@435 | 975 | assert( opaq->outcnt() == 1, "" ); |
duke@435 | 976 | _igvn.hash_delete(opaq); |
duke@435 | 977 | opaq->set_req(1, lim2); |
duke@435 | 978 | } |
duke@435 | 979 | |
duke@435 | 980 | // --------- |
duke@435 | 981 | // Step 4: Clone the loop body. Move it inside the loop. This loop body |
duke@435 | 982 | // represents the odd iterations; since the loop trips an even number of |
duke@435 | 983 | // times its backedge is never taken. Kill the backedge. |
duke@435 | 984 | uint dd = dom_depth(loop_head); |
duke@435 | 985 | clone_loop( loop, old_new, dd ); |
duke@435 | 986 | |
duke@435 | 987 | // Make backedges of the clone equal to backedges of the original. |
duke@435 | 988 | // Make the fall-in from the original come from the fall-out of the clone. |
duke@435 | 989 | for (DUIterator_Fast jmax, j = loop_head->fast_outs(jmax); j < jmax; j++) { |
duke@435 | 990 | Node* phi = loop_head->fast_out(j); |
duke@435 | 991 | if( phi->is_Phi() && phi->in(0) == loop_head && phi->outcnt() > 0 ) { |
duke@435 | 992 | Node *newphi = old_new[phi->_idx]; |
duke@435 | 993 | _igvn.hash_delete( phi ); |
duke@435 | 994 | _igvn.hash_delete( newphi ); |
duke@435 | 995 | |
duke@435 | 996 | phi ->set_req(LoopNode:: EntryControl, newphi->in(LoopNode::LoopBackControl)); |
duke@435 | 997 | newphi->set_req(LoopNode::LoopBackControl, phi ->in(LoopNode::LoopBackControl)); |
duke@435 | 998 | phi ->set_req(LoopNode::LoopBackControl, C->top()); |
duke@435 | 999 | } |
duke@435 | 1000 | } |
duke@435 | 1001 | Node *clone_head = old_new[loop_head->_idx]; |
duke@435 | 1002 | _igvn.hash_delete( clone_head ); |
duke@435 | 1003 | loop_head ->set_req(LoopNode:: EntryControl, clone_head->in(LoopNode::LoopBackControl)); |
duke@435 | 1004 | clone_head->set_req(LoopNode::LoopBackControl, loop_head ->in(LoopNode::LoopBackControl)); |
duke@435 | 1005 | loop_head ->set_req(LoopNode::LoopBackControl, C->top()); |
duke@435 | 1006 | loop->_head = clone_head; // New loop header |
duke@435 | 1007 | |
duke@435 | 1008 | set_idom(loop_head, loop_head ->in(LoopNode::EntryControl), dd); |
duke@435 | 1009 | set_idom(clone_head, clone_head->in(LoopNode::EntryControl), dd); |
duke@435 | 1010 | |
duke@435 | 1011 | // Kill the clone's backedge |
duke@435 | 1012 | Node *newcle = old_new[loop_end->_idx]; |
duke@435 | 1013 | _igvn.hash_delete( newcle ); |
duke@435 | 1014 | Node *one = _igvn.intcon(1); |
duke@435 | 1015 | set_ctrl(one, C->root()); |
duke@435 | 1016 | newcle->set_req(1, one); |
duke@435 | 1017 | // Force clone into same loop body |
duke@435 | 1018 | uint max = loop->_body.size(); |
duke@435 | 1019 | for( uint k = 0; k < max; k++ ) { |
duke@435 | 1020 | Node *old = loop->_body.at(k); |
duke@435 | 1021 | Node *nnn = old_new[old->_idx]; |
duke@435 | 1022 | loop->_body.push(nnn); |
duke@435 | 1023 | if (!has_ctrl(old)) |
duke@435 | 1024 | set_loop(nnn, loop); |
duke@435 | 1025 | } |
never@802 | 1026 | |
never@802 | 1027 | loop->record_for_igvn(); |
duke@435 | 1028 | } |
duke@435 | 1029 | |
duke@435 | 1030 | //------------------------------do_maximally_unroll---------------------------- |
duke@435 | 1031 | |
duke@435 | 1032 | void PhaseIdealLoop::do_maximally_unroll( IdealLoopTree *loop, Node_List &old_new ) { |
duke@435 | 1033 | CountedLoopNode *cl = loop->_head->as_CountedLoop(); |
duke@435 | 1034 | assert( cl->trip_count() > 0, ""); |
duke@435 | 1035 | |
duke@435 | 1036 | // If loop is tripping an odd number of times, peel odd iteration |
duke@435 | 1037 | if( (cl->trip_count() & 1) == 1 ) { |
duke@435 | 1038 | do_peeling( loop, old_new ); |
duke@435 | 1039 | } |
duke@435 | 1040 | |
duke@435 | 1041 | // Now its tripping an even number of times remaining. Double loop body. |
duke@435 | 1042 | // Do not adjust pre-guards; they are not needed and do not exist. |
duke@435 | 1043 | if( cl->trip_count() > 0 ) { |
duke@435 | 1044 | do_unroll( loop, old_new, false ); |
duke@435 | 1045 | } |
duke@435 | 1046 | } |
duke@435 | 1047 | |
duke@435 | 1048 | //------------------------------dominates_backedge--------------------------------- |
duke@435 | 1049 | // Returns true if ctrl is executed on every complete iteration |
duke@435 | 1050 | bool IdealLoopTree::dominates_backedge(Node* ctrl) { |
duke@435 | 1051 | assert(ctrl->is_CFG(), "must be control"); |
duke@435 | 1052 | Node* backedge = _head->as_Loop()->in(LoopNode::LoopBackControl); |
duke@435 | 1053 | return _phase->dom_lca_internal(ctrl, backedge) == ctrl; |
duke@435 | 1054 | } |
duke@435 | 1055 | |
duke@435 | 1056 | //------------------------------add_constraint--------------------------------- |
duke@435 | 1057 | // Constrain the main loop iterations so the condition: |
duke@435 | 1058 | // scale_con * I + offset < limit |
duke@435 | 1059 | // always holds true. That is, either increase the number of iterations in |
duke@435 | 1060 | // the pre-loop or the post-loop until the condition holds true in the main |
duke@435 | 1061 | // loop. Stride, scale, offset and limit are all loop invariant. Further, |
duke@435 | 1062 | // stride and scale are constants (offset and limit often are). |
duke@435 | 1063 | void PhaseIdealLoop::add_constraint( int stride_con, int scale_con, Node *offset, Node *limit, Node *pre_ctrl, Node **pre_limit, Node **main_limit ) { |
duke@435 | 1064 | |
duke@435 | 1065 | // Compute "I :: (limit-offset)/scale_con" |
duke@435 | 1066 | Node *con = new (C, 3) SubINode( limit, offset ); |
duke@435 | 1067 | register_new_node( con, pre_ctrl ); |
duke@435 | 1068 | Node *scale = _igvn.intcon(scale_con); |
duke@435 | 1069 | set_ctrl(scale, C->root()); |
duke@435 | 1070 | Node *X = new (C, 3) DivINode( 0, con, scale ); |
duke@435 | 1071 | register_new_node( X, pre_ctrl ); |
duke@435 | 1072 | |
duke@435 | 1073 | // For positive stride, the pre-loop limit always uses a MAX function |
duke@435 | 1074 | // and the main loop a MIN function. For negative stride these are |
duke@435 | 1075 | // reversed. |
duke@435 | 1076 | |
duke@435 | 1077 | // Also for positive stride*scale the affine function is increasing, so the |
duke@435 | 1078 | // pre-loop must check for underflow and the post-loop for overflow. |
duke@435 | 1079 | // Negative stride*scale reverses this; pre-loop checks for overflow and |
duke@435 | 1080 | // post-loop for underflow. |
duke@435 | 1081 | if( stride_con*scale_con > 0 ) { |
duke@435 | 1082 | // Compute I < (limit-offset)/scale_con |
duke@435 | 1083 | // Adjust main-loop last iteration to be MIN/MAX(main_loop,X) |
duke@435 | 1084 | *main_limit = (stride_con > 0) |
duke@435 | 1085 | ? (Node*)(new (C, 3) MinINode( *main_limit, X )) |
duke@435 | 1086 | : (Node*)(new (C, 3) MaxINode( *main_limit, X )); |
duke@435 | 1087 | register_new_node( *main_limit, pre_ctrl ); |
duke@435 | 1088 | |
duke@435 | 1089 | } else { |
duke@435 | 1090 | // Compute (limit-offset)/scale_con + SGN(-scale_con) <= I |
duke@435 | 1091 | // Add the negation of the main-loop constraint to the pre-loop. |
duke@435 | 1092 | // See footnote [++] below for a derivation of the limit expression. |
duke@435 | 1093 | Node *incr = _igvn.intcon(scale_con > 0 ? -1 : 1); |
duke@435 | 1094 | set_ctrl(incr, C->root()); |
duke@435 | 1095 | Node *adj = new (C, 3) AddINode( X, incr ); |
duke@435 | 1096 | register_new_node( adj, pre_ctrl ); |
duke@435 | 1097 | *pre_limit = (scale_con > 0) |
duke@435 | 1098 | ? (Node*)new (C, 3) MinINode( *pre_limit, adj ) |
duke@435 | 1099 | : (Node*)new (C, 3) MaxINode( *pre_limit, adj ); |
duke@435 | 1100 | register_new_node( *pre_limit, pre_ctrl ); |
duke@435 | 1101 | |
duke@435 | 1102 | // [++] Here's the algebra that justifies the pre-loop limit expression: |
duke@435 | 1103 | // |
duke@435 | 1104 | // NOT( scale_con * I + offset < limit ) |
duke@435 | 1105 | // == |
duke@435 | 1106 | // scale_con * I + offset >= limit |
duke@435 | 1107 | // == |
duke@435 | 1108 | // SGN(scale_con) * I >= (limit-offset)/|scale_con| |
duke@435 | 1109 | // == |
duke@435 | 1110 | // (limit-offset)/|scale_con| <= I * SGN(scale_con) |
duke@435 | 1111 | // == |
duke@435 | 1112 | // (limit-offset)/|scale_con|-1 < I * SGN(scale_con) |
duke@435 | 1113 | // == |
duke@435 | 1114 | // ( if (scale_con > 0) /*common case*/ |
duke@435 | 1115 | // (limit-offset)/scale_con - 1 < I |
duke@435 | 1116 | // else |
duke@435 | 1117 | // (limit-offset)/scale_con + 1 > I |
duke@435 | 1118 | // ) |
duke@435 | 1119 | // ( if (scale_con > 0) /*common case*/ |
duke@435 | 1120 | // (limit-offset)/scale_con + SGN(-scale_con) < I |
duke@435 | 1121 | // else |
duke@435 | 1122 | // (limit-offset)/scale_con + SGN(-scale_con) > I |
duke@435 | 1123 | } |
duke@435 | 1124 | } |
duke@435 | 1125 | |
duke@435 | 1126 | |
duke@435 | 1127 | //------------------------------is_scaled_iv--------------------------------- |
duke@435 | 1128 | // Return true if exp is a constant times an induction var |
duke@435 | 1129 | bool PhaseIdealLoop::is_scaled_iv(Node* exp, Node* iv, int* p_scale) { |
duke@435 | 1130 | if (exp == iv) { |
duke@435 | 1131 | if (p_scale != NULL) { |
duke@435 | 1132 | *p_scale = 1; |
duke@435 | 1133 | } |
duke@435 | 1134 | return true; |
duke@435 | 1135 | } |
duke@435 | 1136 | int opc = exp->Opcode(); |
duke@435 | 1137 | if (opc == Op_MulI) { |
duke@435 | 1138 | if (exp->in(1) == iv && exp->in(2)->is_Con()) { |
duke@435 | 1139 | if (p_scale != NULL) { |
duke@435 | 1140 | *p_scale = exp->in(2)->get_int(); |
duke@435 | 1141 | } |
duke@435 | 1142 | return true; |
duke@435 | 1143 | } |
duke@435 | 1144 | if (exp->in(2) == iv && exp->in(1)->is_Con()) { |
duke@435 | 1145 | if (p_scale != NULL) { |
duke@435 | 1146 | *p_scale = exp->in(1)->get_int(); |
duke@435 | 1147 | } |
duke@435 | 1148 | return true; |
duke@435 | 1149 | } |
duke@435 | 1150 | } else if (opc == Op_LShiftI) { |
duke@435 | 1151 | if (exp->in(1) == iv && exp->in(2)->is_Con()) { |
duke@435 | 1152 | if (p_scale != NULL) { |
duke@435 | 1153 | *p_scale = 1 << exp->in(2)->get_int(); |
duke@435 | 1154 | } |
duke@435 | 1155 | return true; |
duke@435 | 1156 | } |
duke@435 | 1157 | } |
duke@435 | 1158 | return false; |
duke@435 | 1159 | } |
duke@435 | 1160 | |
duke@435 | 1161 | //-----------------------------is_scaled_iv_plus_offset------------------------------ |
duke@435 | 1162 | // Return true if exp is a simple induction variable expression: k1*iv + (invar + k2) |
duke@435 | 1163 | bool PhaseIdealLoop::is_scaled_iv_plus_offset(Node* exp, Node* iv, int* p_scale, Node** p_offset, int depth) { |
duke@435 | 1164 | if (is_scaled_iv(exp, iv, p_scale)) { |
duke@435 | 1165 | if (p_offset != NULL) { |
duke@435 | 1166 | Node *zero = _igvn.intcon(0); |
duke@435 | 1167 | set_ctrl(zero, C->root()); |
duke@435 | 1168 | *p_offset = zero; |
duke@435 | 1169 | } |
duke@435 | 1170 | return true; |
duke@435 | 1171 | } |
duke@435 | 1172 | int opc = exp->Opcode(); |
duke@435 | 1173 | if (opc == Op_AddI) { |
duke@435 | 1174 | if (is_scaled_iv(exp->in(1), iv, p_scale)) { |
duke@435 | 1175 | if (p_offset != NULL) { |
duke@435 | 1176 | *p_offset = exp->in(2); |
duke@435 | 1177 | } |
duke@435 | 1178 | return true; |
duke@435 | 1179 | } |
duke@435 | 1180 | if (exp->in(2)->is_Con()) { |
duke@435 | 1181 | Node* offset2 = NULL; |
duke@435 | 1182 | if (depth < 2 && |
duke@435 | 1183 | is_scaled_iv_plus_offset(exp->in(1), iv, p_scale, |
duke@435 | 1184 | p_offset != NULL ? &offset2 : NULL, depth+1)) { |
duke@435 | 1185 | if (p_offset != NULL) { |
duke@435 | 1186 | Node *ctrl_off2 = get_ctrl(offset2); |
duke@435 | 1187 | Node* offset = new (C, 3) AddINode(offset2, exp->in(2)); |
duke@435 | 1188 | register_new_node(offset, ctrl_off2); |
duke@435 | 1189 | *p_offset = offset; |
duke@435 | 1190 | } |
duke@435 | 1191 | return true; |
duke@435 | 1192 | } |
duke@435 | 1193 | } |
duke@435 | 1194 | } else if (opc == Op_SubI) { |
duke@435 | 1195 | if (is_scaled_iv(exp->in(1), iv, p_scale)) { |
duke@435 | 1196 | if (p_offset != NULL) { |
duke@435 | 1197 | Node *zero = _igvn.intcon(0); |
duke@435 | 1198 | set_ctrl(zero, C->root()); |
duke@435 | 1199 | Node *ctrl_off = get_ctrl(exp->in(2)); |
duke@435 | 1200 | Node* offset = new (C, 3) SubINode(zero, exp->in(2)); |
duke@435 | 1201 | register_new_node(offset, ctrl_off); |
duke@435 | 1202 | *p_offset = offset; |
duke@435 | 1203 | } |
duke@435 | 1204 | return true; |
duke@435 | 1205 | } |
duke@435 | 1206 | if (is_scaled_iv(exp->in(2), iv, p_scale)) { |
duke@435 | 1207 | if (p_offset != NULL) { |
duke@435 | 1208 | *p_scale *= -1; |
duke@435 | 1209 | *p_offset = exp->in(1); |
duke@435 | 1210 | } |
duke@435 | 1211 | return true; |
duke@435 | 1212 | } |
duke@435 | 1213 | } |
duke@435 | 1214 | return false; |
duke@435 | 1215 | } |
duke@435 | 1216 | |
duke@435 | 1217 | //------------------------------do_range_check--------------------------------- |
duke@435 | 1218 | // Eliminate range-checks and other trip-counter vs loop-invariant tests. |
duke@435 | 1219 | void PhaseIdealLoop::do_range_check( IdealLoopTree *loop, Node_List &old_new ) { |
duke@435 | 1220 | #ifndef PRODUCT |
duke@435 | 1221 | if( PrintOpto && VerifyLoopOptimizations ) { |
duke@435 | 1222 | tty->print("Range Check Elimination "); |
duke@435 | 1223 | loop->dump_head(); |
duke@435 | 1224 | } |
duke@435 | 1225 | #endif |
duke@435 | 1226 | assert( RangeCheckElimination, "" ); |
duke@435 | 1227 | CountedLoopNode *cl = loop->_head->as_CountedLoop(); |
duke@435 | 1228 | assert( cl->is_main_loop(), "" ); |
duke@435 | 1229 | |
duke@435 | 1230 | // Find the trip counter; we are iteration splitting based on it |
duke@435 | 1231 | Node *trip_counter = cl->phi(); |
duke@435 | 1232 | // Find the main loop limit; we will trim it's iterations |
duke@435 | 1233 | // to not ever trip end tests |
duke@435 | 1234 | Node *main_limit = cl->limit(); |
duke@435 | 1235 | // Find the pre-loop limit; we will expand it's iterations to |
duke@435 | 1236 | // not ever trip low tests. |
duke@435 | 1237 | Node *ctrl = cl->in(LoopNode::EntryControl); |
duke@435 | 1238 | assert( ctrl->Opcode() == Op_IfTrue || ctrl->Opcode() == Op_IfFalse, "" ); |
duke@435 | 1239 | Node *iffm = ctrl->in(0); |
duke@435 | 1240 | assert( iffm->Opcode() == Op_If, "" ); |
duke@435 | 1241 | Node *p_f = iffm->in(0); |
duke@435 | 1242 | assert( p_f->Opcode() == Op_IfFalse, "" ); |
duke@435 | 1243 | CountedLoopEndNode *pre_end = p_f->in(0)->as_CountedLoopEnd(); |
duke@435 | 1244 | assert( pre_end->loopnode()->is_pre_loop(), "" ); |
duke@435 | 1245 | Node *pre_opaq1 = pre_end->limit(); |
duke@435 | 1246 | // Occasionally it's possible for a pre-loop Opaque1 node to be |
duke@435 | 1247 | // optimized away and then another round of loop opts attempted. |
duke@435 | 1248 | // We can not optimize this particular loop in that case. |
duke@435 | 1249 | if( pre_opaq1->Opcode() != Op_Opaque1 ) |
duke@435 | 1250 | return; |
duke@435 | 1251 | Opaque1Node *pre_opaq = (Opaque1Node*)pre_opaq1; |
duke@435 | 1252 | Node *pre_limit = pre_opaq->in(1); |
duke@435 | 1253 | |
duke@435 | 1254 | // Where do we put new limit calculations |
duke@435 | 1255 | Node *pre_ctrl = pre_end->loopnode()->in(LoopNode::EntryControl); |
duke@435 | 1256 | |
duke@435 | 1257 | // Ensure the original loop limit is available from the |
duke@435 | 1258 | // pre-loop Opaque1 node. |
duke@435 | 1259 | Node *orig_limit = pre_opaq->original_loop_limit(); |
duke@435 | 1260 | if( orig_limit == NULL || _igvn.type(orig_limit) == Type::TOP ) |
duke@435 | 1261 | return; |
duke@435 | 1262 | |
duke@435 | 1263 | // Need to find the main-loop zero-trip guard |
duke@435 | 1264 | Node *bolzm = iffm->in(1); |
duke@435 | 1265 | assert( bolzm->Opcode() == Op_Bool, "" ); |
duke@435 | 1266 | Node *cmpzm = bolzm->in(1); |
duke@435 | 1267 | assert( cmpzm->is_Cmp(), "" ); |
duke@435 | 1268 | Node *opqzm = cmpzm->in(2); |
duke@435 | 1269 | if( opqzm->Opcode() != Op_Opaque1 ) |
duke@435 | 1270 | return; |
duke@435 | 1271 | assert( opqzm->in(1) == main_limit, "do not understand situation" ); |
duke@435 | 1272 | |
duke@435 | 1273 | // Must know if its a count-up or count-down loop |
duke@435 | 1274 | |
duke@435 | 1275 | // protect against stride not being a constant |
duke@435 | 1276 | if ( !cl->stride_is_con() ) { |
duke@435 | 1277 | return; |
duke@435 | 1278 | } |
duke@435 | 1279 | int stride_con = cl->stride_con(); |
duke@435 | 1280 | Node *zero = _igvn.intcon(0); |
duke@435 | 1281 | Node *one = _igvn.intcon(1); |
duke@435 | 1282 | set_ctrl(zero, C->root()); |
duke@435 | 1283 | set_ctrl(one, C->root()); |
duke@435 | 1284 | |
duke@435 | 1285 | // Range checks that do not dominate the loop backedge (ie. |
duke@435 | 1286 | // conditionally executed) can lengthen the pre loop limit beyond |
duke@435 | 1287 | // the original loop limit. To prevent this, the pre limit is |
duke@435 | 1288 | // (for stride > 0) MINed with the original loop limit (MAXed |
duke@435 | 1289 | // stride < 0) when some range_check (rc) is conditionally |
duke@435 | 1290 | // executed. |
duke@435 | 1291 | bool conditional_rc = false; |
duke@435 | 1292 | |
duke@435 | 1293 | // Check loop body for tests of trip-counter plus loop-invariant vs |
duke@435 | 1294 | // loop-invariant. |
duke@435 | 1295 | for( uint i = 0; i < loop->_body.size(); i++ ) { |
duke@435 | 1296 | Node *iff = loop->_body[i]; |
duke@435 | 1297 | if( iff->Opcode() == Op_If ) { // Test? |
duke@435 | 1298 | |
duke@435 | 1299 | // Test is an IfNode, has 2 projections. If BOTH are in the loop |
duke@435 | 1300 | // we need loop unswitching instead of iteration splitting. |
duke@435 | 1301 | Node *exit = loop->is_loop_exit(iff); |
duke@435 | 1302 | if( !exit ) continue; |
duke@435 | 1303 | int flip = (exit->Opcode() == Op_IfTrue) ? 1 : 0; |
duke@435 | 1304 | |
duke@435 | 1305 | // Get boolean condition to test |
duke@435 | 1306 | Node *i1 = iff->in(1); |
duke@435 | 1307 | if( !i1->is_Bool() ) continue; |
duke@435 | 1308 | BoolNode *bol = i1->as_Bool(); |
duke@435 | 1309 | BoolTest b_test = bol->_test; |
duke@435 | 1310 | // Flip sense of test if exit condition is flipped |
duke@435 | 1311 | if( flip ) |
duke@435 | 1312 | b_test = b_test.negate(); |
duke@435 | 1313 | |
duke@435 | 1314 | // Get compare |
duke@435 | 1315 | Node *cmp = bol->in(1); |
duke@435 | 1316 | |
duke@435 | 1317 | // Look for trip_counter + offset vs limit |
duke@435 | 1318 | Node *rc_exp = cmp->in(1); |
duke@435 | 1319 | Node *limit = cmp->in(2); |
duke@435 | 1320 | jint scale_con= 1; // Assume trip counter not scaled |
duke@435 | 1321 | |
duke@435 | 1322 | Node *limit_c = get_ctrl(limit); |
duke@435 | 1323 | if( loop->is_member(get_loop(limit_c) ) ) { |
duke@435 | 1324 | // Compare might have operands swapped; commute them |
duke@435 | 1325 | b_test = b_test.commute(); |
duke@435 | 1326 | rc_exp = cmp->in(2); |
duke@435 | 1327 | limit = cmp->in(1); |
duke@435 | 1328 | limit_c = get_ctrl(limit); |
duke@435 | 1329 | if( loop->is_member(get_loop(limit_c) ) ) |
duke@435 | 1330 | continue; // Both inputs are loop varying; cannot RCE |
duke@435 | 1331 | } |
duke@435 | 1332 | // Here we know 'limit' is loop invariant |
duke@435 | 1333 | |
duke@435 | 1334 | // 'limit' maybe pinned below the zero trip test (probably from a |
duke@435 | 1335 | // previous round of rce), in which case, it can't be used in the |
duke@435 | 1336 | // zero trip test expression which must occur before the zero test's if. |
duke@435 | 1337 | if( limit_c == ctrl ) { |
duke@435 | 1338 | continue; // Don't rce this check but continue looking for other candidates. |
duke@435 | 1339 | } |
duke@435 | 1340 | |
duke@435 | 1341 | // Check for scaled induction variable plus an offset |
duke@435 | 1342 | Node *offset = NULL; |
duke@435 | 1343 | |
duke@435 | 1344 | if (!is_scaled_iv_plus_offset(rc_exp, trip_counter, &scale_con, &offset)) { |
duke@435 | 1345 | continue; |
duke@435 | 1346 | } |
duke@435 | 1347 | |
duke@435 | 1348 | Node *offset_c = get_ctrl(offset); |
duke@435 | 1349 | if( loop->is_member( get_loop(offset_c) ) ) |
duke@435 | 1350 | continue; // Offset is not really loop invariant |
duke@435 | 1351 | // Here we know 'offset' is loop invariant. |
duke@435 | 1352 | |
duke@435 | 1353 | // As above for the 'limit', the 'offset' maybe pinned below the |
duke@435 | 1354 | // zero trip test. |
duke@435 | 1355 | if( offset_c == ctrl ) { |
duke@435 | 1356 | continue; // Don't rce this check but continue looking for other candidates. |
duke@435 | 1357 | } |
duke@435 | 1358 | |
duke@435 | 1359 | // At this point we have the expression as: |
duke@435 | 1360 | // scale_con * trip_counter + offset :: limit |
duke@435 | 1361 | // where scale_con, offset and limit are loop invariant. Trip_counter |
duke@435 | 1362 | // monotonically increases by stride_con, a constant. Both (or either) |
duke@435 | 1363 | // stride_con and scale_con can be negative which will flip about the |
duke@435 | 1364 | // sense of the test. |
duke@435 | 1365 | |
duke@435 | 1366 | // Adjust pre and main loop limits to guard the correct iteration set |
duke@435 | 1367 | if( cmp->Opcode() == Op_CmpU ) {// Unsigned compare is really 2 tests |
duke@435 | 1368 | if( b_test._test == BoolTest::lt ) { // Range checks always use lt |
duke@435 | 1369 | // The overflow limit: scale*I+offset < limit |
duke@435 | 1370 | add_constraint( stride_con, scale_con, offset, limit, pre_ctrl, &pre_limit, &main_limit ); |
duke@435 | 1371 | // The underflow limit: 0 <= scale*I+offset. |
duke@435 | 1372 | // Some math yields: -scale*I-(offset+1) < 0 |
duke@435 | 1373 | Node *plus_one = new (C, 3) AddINode( offset, one ); |
duke@435 | 1374 | register_new_node( plus_one, pre_ctrl ); |
duke@435 | 1375 | Node *neg_offset = new (C, 3) SubINode( zero, plus_one ); |
duke@435 | 1376 | register_new_node( neg_offset, pre_ctrl ); |
duke@435 | 1377 | add_constraint( stride_con, -scale_con, neg_offset, zero, pre_ctrl, &pre_limit, &main_limit ); |
duke@435 | 1378 | if (!conditional_rc) { |
duke@435 | 1379 | conditional_rc = !loop->dominates_backedge(iff); |
duke@435 | 1380 | } |
duke@435 | 1381 | } else { |
duke@435 | 1382 | #ifndef PRODUCT |
duke@435 | 1383 | if( PrintOpto ) |
duke@435 | 1384 | tty->print_cr("missed RCE opportunity"); |
duke@435 | 1385 | #endif |
duke@435 | 1386 | continue; // In release mode, ignore it |
duke@435 | 1387 | } |
duke@435 | 1388 | } else { // Otherwise work on normal compares |
duke@435 | 1389 | switch( b_test._test ) { |
duke@435 | 1390 | case BoolTest::ge: // Convert X >= Y to -X <= -Y |
duke@435 | 1391 | scale_con = -scale_con; |
duke@435 | 1392 | offset = new (C, 3) SubINode( zero, offset ); |
duke@435 | 1393 | register_new_node( offset, pre_ctrl ); |
duke@435 | 1394 | limit = new (C, 3) SubINode( zero, limit ); |
duke@435 | 1395 | register_new_node( limit, pre_ctrl ); |
duke@435 | 1396 | // Fall into LE case |
duke@435 | 1397 | case BoolTest::le: // Convert X <= Y to X < Y+1 |
duke@435 | 1398 | limit = new (C, 3) AddINode( limit, one ); |
duke@435 | 1399 | register_new_node( limit, pre_ctrl ); |
duke@435 | 1400 | // Fall into LT case |
duke@435 | 1401 | case BoolTest::lt: |
duke@435 | 1402 | add_constraint( stride_con, scale_con, offset, limit, pre_ctrl, &pre_limit, &main_limit ); |
duke@435 | 1403 | if (!conditional_rc) { |
duke@435 | 1404 | conditional_rc = !loop->dominates_backedge(iff); |
duke@435 | 1405 | } |
duke@435 | 1406 | break; |
duke@435 | 1407 | default: |
duke@435 | 1408 | #ifndef PRODUCT |
duke@435 | 1409 | if( PrintOpto ) |
duke@435 | 1410 | tty->print_cr("missed RCE opportunity"); |
duke@435 | 1411 | #endif |
duke@435 | 1412 | continue; // Unhandled case |
duke@435 | 1413 | } |
duke@435 | 1414 | } |
duke@435 | 1415 | |
duke@435 | 1416 | // Kill the eliminated test |
duke@435 | 1417 | C->set_major_progress(); |
duke@435 | 1418 | Node *kill_con = _igvn.intcon( 1-flip ); |
duke@435 | 1419 | set_ctrl(kill_con, C->root()); |
duke@435 | 1420 | _igvn.hash_delete(iff); |
duke@435 | 1421 | iff->set_req(1, kill_con); |
duke@435 | 1422 | _igvn._worklist.push(iff); |
duke@435 | 1423 | // Find surviving projection |
duke@435 | 1424 | assert(iff->is_If(), ""); |
duke@435 | 1425 | ProjNode* dp = ((IfNode*)iff)->proj_out(1-flip); |
duke@435 | 1426 | // Find loads off the surviving projection; remove their control edge |
duke@435 | 1427 | for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) { |
duke@435 | 1428 | Node* cd = dp->fast_out(i); // Control-dependent node |
duke@435 | 1429 | if( cd->is_Load() ) { // Loads can now float around in the loop |
duke@435 | 1430 | _igvn.hash_delete(cd); |
duke@435 | 1431 | // Allow the load to float around in the loop, or before it |
duke@435 | 1432 | // but NOT before the pre-loop. |
duke@435 | 1433 | cd->set_req(0, ctrl); // ctrl, not NULL |
duke@435 | 1434 | _igvn._worklist.push(cd); |
duke@435 | 1435 | --i; |
duke@435 | 1436 | --imax; |
duke@435 | 1437 | } |
duke@435 | 1438 | } |
duke@435 | 1439 | |
duke@435 | 1440 | } // End of is IF |
duke@435 | 1441 | |
duke@435 | 1442 | } |
duke@435 | 1443 | |
duke@435 | 1444 | // Update loop limits |
duke@435 | 1445 | if (conditional_rc) { |
duke@435 | 1446 | pre_limit = (stride_con > 0) ? (Node*)new (C,3) MinINode(pre_limit, orig_limit) |
duke@435 | 1447 | : (Node*)new (C,3) MaxINode(pre_limit, orig_limit); |
duke@435 | 1448 | register_new_node(pre_limit, pre_ctrl); |
duke@435 | 1449 | } |
duke@435 | 1450 | _igvn.hash_delete(pre_opaq); |
duke@435 | 1451 | pre_opaq->set_req(1, pre_limit); |
duke@435 | 1452 | |
duke@435 | 1453 | // Note:: we are making the main loop limit no longer precise; |
duke@435 | 1454 | // need to round up based on stride. |
duke@435 | 1455 | if( stride_con != 1 && stride_con != -1 ) { // Cutout for common case |
duke@435 | 1456 | // "Standard" round-up logic: ([main_limit-init+(y-1)]/y)*y+init |
duke@435 | 1457 | // Hopefully, compiler will optimize for powers of 2. |
duke@435 | 1458 | Node *ctrl = get_ctrl(main_limit); |
duke@435 | 1459 | Node *stride = cl->stride(); |
duke@435 | 1460 | Node *init = cl->init_trip(); |
duke@435 | 1461 | Node *span = new (C, 3) SubINode(main_limit,init); |
duke@435 | 1462 | register_new_node(span,ctrl); |
duke@435 | 1463 | Node *rndup = _igvn.intcon(stride_con + ((stride_con>0)?-1:1)); |
duke@435 | 1464 | Node *add = new (C, 3) AddINode(span,rndup); |
duke@435 | 1465 | register_new_node(add,ctrl); |
duke@435 | 1466 | Node *div = new (C, 3) DivINode(0,add,stride); |
duke@435 | 1467 | register_new_node(div,ctrl); |
duke@435 | 1468 | Node *mul = new (C, 3) MulINode(div,stride); |
duke@435 | 1469 | register_new_node(mul,ctrl); |
duke@435 | 1470 | Node *newlim = new (C, 3) AddINode(mul,init); |
duke@435 | 1471 | register_new_node(newlim,ctrl); |
duke@435 | 1472 | main_limit = newlim; |
duke@435 | 1473 | } |
duke@435 | 1474 | |
duke@435 | 1475 | Node *main_cle = cl->loopexit(); |
duke@435 | 1476 | Node *main_bol = main_cle->in(1); |
duke@435 | 1477 | // Hacking loop bounds; need private copies of exit test |
duke@435 | 1478 | if( main_bol->outcnt() > 1 ) {// BoolNode shared? |
duke@435 | 1479 | _igvn.hash_delete(main_cle); |
duke@435 | 1480 | main_bol = main_bol->clone();// Clone a private BoolNode |
duke@435 | 1481 | register_new_node( main_bol, main_cle->in(0) ); |
duke@435 | 1482 | main_cle->set_req(1,main_bol); |
duke@435 | 1483 | } |
duke@435 | 1484 | Node *main_cmp = main_bol->in(1); |
duke@435 | 1485 | if( main_cmp->outcnt() > 1 ) { // CmpNode shared? |
duke@435 | 1486 | _igvn.hash_delete(main_bol); |
duke@435 | 1487 | main_cmp = main_cmp->clone();// Clone a private CmpNode |
duke@435 | 1488 | register_new_node( main_cmp, main_cle->in(0) ); |
duke@435 | 1489 | main_bol->set_req(1,main_cmp); |
duke@435 | 1490 | } |
duke@435 | 1491 | // Hack the now-private loop bounds |
duke@435 | 1492 | _igvn.hash_delete(main_cmp); |
duke@435 | 1493 | main_cmp->set_req(2, main_limit); |
duke@435 | 1494 | _igvn._worklist.push(main_cmp); |
duke@435 | 1495 | // The OpaqueNode is unshared by design |
duke@435 | 1496 | _igvn.hash_delete(opqzm); |
duke@435 | 1497 | assert( opqzm->outcnt() == 1, "cannot hack shared node" ); |
duke@435 | 1498 | opqzm->set_req(1,main_limit); |
duke@435 | 1499 | _igvn._worklist.push(opqzm); |
duke@435 | 1500 | } |
duke@435 | 1501 | |
duke@435 | 1502 | //------------------------------DCE_loop_body---------------------------------- |
duke@435 | 1503 | // Remove simplistic dead code from loop body |
duke@435 | 1504 | void IdealLoopTree::DCE_loop_body() { |
duke@435 | 1505 | for( uint i = 0; i < _body.size(); i++ ) |
duke@435 | 1506 | if( _body.at(i)->outcnt() == 0 ) |
duke@435 | 1507 | _body.map( i--, _body.pop() ); |
duke@435 | 1508 | } |
duke@435 | 1509 | |
duke@435 | 1510 | |
duke@435 | 1511 | //------------------------------adjust_loop_exit_prob-------------------------- |
duke@435 | 1512 | // Look for loop-exit tests with the 50/50 (or worse) guesses from the parsing stage. |
duke@435 | 1513 | // Replace with a 1-in-10 exit guess. |
duke@435 | 1514 | void IdealLoopTree::adjust_loop_exit_prob( PhaseIdealLoop *phase ) { |
duke@435 | 1515 | Node *test = tail(); |
duke@435 | 1516 | while( test != _head ) { |
duke@435 | 1517 | uint top = test->Opcode(); |
duke@435 | 1518 | if( top == Op_IfTrue || top == Op_IfFalse ) { |
duke@435 | 1519 | int test_con = ((ProjNode*)test)->_con; |
duke@435 | 1520 | assert(top == (uint)(test_con? Op_IfTrue: Op_IfFalse), "sanity"); |
duke@435 | 1521 | IfNode *iff = test->in(0)->as_If(); |
duke@435 | 1522 | if( iff->outcnt() == 2 ) { // Ignore dead tests |
duke@435 | 1523 | Node *bol = iff->in(1); |
duke@435 | 1524 | if( bol && bol->req() > 1 && bol->in(1) && |
duke@435 | 1525 | ((bol->in(1)->Opcode() == Op_StorePConditional ) || |
kvn@855 | 1526 | (bol->in(1)->Opcode() == Op_StoreIConditional ) || |
duke@435 | 1527 | (bol->in(1)->Opcode() == Op_StoreLConditional ) || |
duke@435 | 1528 | (bol->in(1)->Opcode() == Op_CompareAndSwapI ) || |
duke@435 | 1529 | (bol->in(1)->Opcode() == Op_CompareAndSwapL ) || |
coleenp@548 | 1530 | (bol->in(1)->Opcode() == Op_CompareAndSwapP ) || |
coleenp@548 | 1531 | (bol->in(1)->Opcode() == Op_CompareAndSwapN ))) |
duke@435 | 1532 | return; // Allocation loops RARELY take backedge |
duke@435 | 1533 | // Find the OTHER exit path from the IF |
duke@435 | 1534 | Node* ex = iff->proj_out(1-test_con); |
duke@435 | 1535 | float p = iff->_prob; |
duke@435 | 1536 | if( !phase->is_member( this, ex ) && iff->_fcnt == COUNT_UNKNOWN ) { |
duke@435 | 1537 | if( top == Op_IfTrue ) { |
duke@435 | 1538 | if( p < (PROB_FAIR + PROB_UNLIKELY_MAG(3))) { |
duke@435 | 1539 | iff->_prob = PROB_STATIC_FREQUENT; |
duke@435 | 1540 | } |
duke@435 | 1541 | } else { |
duke@435 | 1542 | if( p > (PROB_FAIR - PROB_UNLIKELY_MAG(3))) { |
duke@435 | 1543 | iff->_prob = PROB_STATIC_INFREQUENT; |
duke@435 | 1544 | } |
duke@435 | 1545 | } |
duke@435 | 1546 | } |
duke@435 | 1547 | } |
duke@435 | 1548 | } |
duke@435 | 1549 | test = phase->idom(test); |
duke@435 | 1550 | } |
duke@435 | 1551 | } |
duke@435 | 1552 | |
duke@435 | 1553 | |
duke@435 | 1554 | //------------------------------policy_do_remove_empty_loop-------------------- |
duke@435 | 1555 | // Micro-benchmark spamming. Policy is to always remove empty loops. |
duke@435 | 1556 | // The 'DO' part is to replace the trip counter with the value it will |
duke@435 | 1557 | // have on the last iteration. This will break the loop. |
duke@435 | 1558 | bool IdealLoopTree::policy_do_remove_empty_loop( PhaseIdealLoop *phase ) { |
duke@435 | 1559 | // Minimum size must be empty loop |
duke@435 | 1560 | if( _body.size() > 7/*number of nodes in an empty loop*/ ) return false; |
duke@435 | 1561 | |
duke@435 | 1562 | if( !_head->is_CountedLoop() ) return false; // Dead loop |
duke@435 | 1563 | CountedLoopNode *cl = _head->as_CountedLoop(); |
duke@435 | 1564 | if( !cl->loopexit() ) return false; // Malformed loop |
duke@435 | 1565 | if( !phase->is_member(this,phase->get_ctrl(cl->loopexit()->in(CountedLoopEndNode::TestValue)) ) ) |
duke@435 | 1566 | return false; // Infinite loop |
duke@435 | 1567 | #ifndef PRODUCT |
duke@435 | 1568 | if( PrintOpto ) |
duke@435 | 1569 | tty->print_cr("Removing empty loop"); |
duke@435 | 1570 | #endif |
duke@435 | 1571 | #ifdef ASSERT |
duke@435 | 1572 | // Ensure only one phi which is the iv. |
duke@435 | 1573 | Node* iv = NULL; |
duke@435 | 1574 | for (DUIterator_Fast imax, i = cl->fast_outs(imax); i < imax; i++) { |
duke@435 | 1575 | Node* n = cl->fast_out(i); |
duke@435 | 1576 | if (n->Opcode() == Op_Phi) { |
duke@435 | 1577 | assert(iv == NULL, "Too many phis" ); |
duke@435 | 1578 | iv = n; |
duke@435 | 1579 | } |
duke@435 | 1580 | } |
duke@435 | 1581 | assert(iv == cl->phi(), "Wrong phi" ); |
duke@435 | 1582 | #endif |
duke@435 | 1583 | // Replace the phi at loop head with the final value of the last |
duke@435 | 1584 | // iteration. Then the CountedLoopEnd will collapse (backedge never |
duke@435 | 1585 | // taken) and all loop-invariant uses of the exit values will be correct. |
duke@435 | 1586 | Node *phi = cl->phi(); |
duke@435 | 1587 | Node *final = new (phase->C, 3) SubINode( cl->limit(), cl->stride() ); |
duke@435 | 1588 | phase->register_new_node(final,cl->in(LoopNode::EntryControl)); |
duke@435 | 1589 | phase->_igvn.hash_delete(phi); |
duke@435 | 1590 | phase->_igvn.subsume_node(phi,final); |
duke@435 | 1591 | phase->C->set_major_progress(); |
duke@435 | 1592 | return true; |
duke@435 | 1593 | } |
duke@435 | 1594 | |
duke@435 | 1595 | |
duke@435 | 1596 | //============================================================================= |
duke@435 | 1597 | //------------------------------iteration_split_impl--------------------------- |
never@836 | 1598 | bool IdealLoopTree::iteration_split_impl( PhaseIdealLoop *phase, Node_List &old_new ) { |
duke@435 | 1599 | // Check and remove empty loops (spam micro-benchmarks) |
duke@435 | 1600 | if( policy_do_remove_empty_loop(phase) ) |
cfang@1607 | 1601 | return true; // Here we removed an empty loop |
duke@435 | 1602 | |
duke@435 | 1603 | bool should_peel = policy_peeling(phase); // Should we peel? |
duke@435 | 1604 | |
duke@435 | 1605 | bool should_unswitch = policy_unswitching(phase); |
duke@435 | 1606 | |
duke@435 | 1607 | // Non-counted loops may be peeled; exactly 1 iteration is peeled. |
duke@435 | 1608 | // This removes loop-invariant tests (usually null checks). |
duke@435 | 1609 | if( !_head->is_CountedLoop() ) { // Non-counted loop |
duke@435 | 1610 | if (PartialPeelLoop && phase->partial_peel(this, old_new)) { |
never@836 | 1611 | // Partial peel succeeded so terminate this round of loop opts |
never@836 | 1612 | return false; |
duke@435 | 1613 | } |
duke@435 | 1614 | if( should_peel ) { // Should we peel? |
duke@435 | 1615 | #ifndef PRODUCT |
duke@435 | 1616 | if (PrintOpto) tty->print_cr("should_peel"); |
duke@435 | 1617 | #endif |
duke@435 | 1618 | phase->do_peeling(this,old_new); |
duke@435 | 1619 | } else if( should_unswitch ) { |
duke@435 | 1620 | phase->do_unswitching(this, old_new); |
duke@435 | 1621 | } |
never@836 | 1622 | return true; |
duke@435 | 1623 | } |
duke@435 | 1624 | CountedLoopNode *cl = _head->as_CountedLoop(); |
duke@435 | 1625 | |
never@836 | 1626 | if( !cl->loopexit() ) return true; // Ignore various kinds of broken loops |
duke@435 | 1627 | |
duke@435 | 1628 | // Do nothing special to pre- and post- loops |
never@836 | 1629 | if( cl->is_pre_loop() || cl->is_post_loop() ) return true; |
duke@435 | 1630 | |
duke@435 | 1631 | // Compute loop trip count from profile data |
duke@435 | 1632 | compute_profile_trip_cnt(phase); |
duke@435 | 1633 | |
duke@435 | 1634 | // Before attempting fancy unrolling, RCE or alignment, see if we want |
duke@435 | 1635 | // to completely unroll this loop or do loop unswitching. |
duke@435 | 1636 | if( cl->is_normal_loop() ) { |
cfang@1224 | 1637 | if (should_unswitch) { |
cfang@1224 | 1638 | phase->do_unswitching(this, old_new); |
cfang@1224 | 1639 | return true; |
cfang@1224 | 1640 | } |
duke@435 | 1641 | bool should_maximally_unroll = policy_maximally_unroll(phase); |
duke@435 | 1642 | if( should_maximally_unroll ) { |
duke@435 | 1643 | // Here we did some unrolling and peeling. Eventually we will |
duke@435 | 1644 | // completely unroll this loop and it will no longer be a loop. |
duke@435 | 1645 | phase->do_maximally_unroll(this,old_new); |
never@836 | 1646 | return true; |
duke@435 | 1647 | } |
duke@435 | 1648 | } |
duke@435 | 1649 | |
duke@435 | 1650 | |
duke@435 | 1651 | // Counted loops may be peeled, may need some iterations run up |
duke@435 | 1652 | // front for RCE, and may want to align loop refs to a cache |
duke@435 | 1653 | // line. Thus we clone a full loop up front whose trip count is |
duke@435 | 1654 | // at least 1 (if peeling), but may be several more. |
duke@435 | 1655 | |
duke@435 | 1656 | // The main loop will start cache-line aligned with at least 1 |
duke@435 | 1657 | // iteration of the unrolled body (zero-trip test required) and |
duke@435 | 1658 | // will have some range checks removed. |
duke@435 | 1659 | |
duke@435 | 1660 | // A post-loop will finish any odd iterations (leftover after |
duke@435 | 1661 | // unrolling), plus any needed for RCE purposes. |
duke@435 | 1662 | |
duke@435 | 1663 | bool should_unroll = policy_unroll(phase); |
duke@435 | 1664 | |
duke@435 | 1665 | bool should_rce = policy_range_check(phase); |
duke@435 | 1666 | |
duke@435 | 1667 | bool should_align = policy_align(phase); |
duke@435 | 1668 | |
duke@435 | 1669 | // If not RCE'ing (iteration splitting) or Aligning, then we do not |
duke@435 | 1670 | // need a pre-loop. We may still need to peel an initial iteration but |
duke@435 | 1671 | // we will not be needing an unknown number of pre-iterations. |
duke@435 | 1672 | // |
duke@435 | 1673 | // Basically, if may_rce_align reports FALSE first time through, |
duke@435 | 1674 | // we will not be able to later do RCE or Aligning on this loop. |
duke@435 | 1675 | bool may_rce_align = !policy_peel_only(phase) || should_rce || should_align; |
duke@435 | 1676 | |
duke@435 | 1677 | // If we have any of these conditions (RCE, alignment, unrolling) met, then |
duke@435 | 1678 | // we switch to the pre-/main-/post-loop model. This model also covers |
duke@435 | 1679 | // peeling. |
duke@435 | 1680 | if( should_rce || should_align || should_unroll ) { |
duke@435 | 1681 | if( cl->is_normal_loop() ) // Convert to 'pre/main/post' loops |
duke@435 | 1682 | phase->insert_pre_post_loops(this,old_new, !may_rce_align); |
duke@435 | 1683 | |
duke@435 | 1684 | // Adjust the pre- and main-loop limits to let the pre and post loops run |
duke@435 | 1685 | // with full checks, but the main-loop with no checks. Remove said |
duke@435 | 1686 | // checks from the main body. |
duke@435 | 1687 | if( should_rce ) |
duke@435 | 1688 | phase->do_range_check(this,old_new); |
duke@435 | 1689 | |
duke@435 | 1690 | // Double loop body for unrolling. Adjust the minimum-trip test (will do |
duke@435 | 1691 | // twice as many iterations as before) and the main body limit (only do |
duke@435 | 1692 | // an even number of trips). If we are peeling, we might enable some RCE |
duke@435 | 1693 | // and we'd rather unroll the post-RCE'd loop SO... do not unroll if |
duke@435 | 1694 | // peeling. |
cfang@1607 | 1695 | if( should_unroll && !should_peel ) |
cfang@1607 | 1696 | phase->do_unroll(this,old_new, true); |
duke@435 | 1697 | |
duke@435 | 1698 | // Adjust the pre-loop limits to align the main body |
duke@435 | 1699 | // iterations. |
duke@435 | 1700 | if( should_align ) |
duke@435 | 1701 | Unimplemented(); |
duke@435 | 1702 | |
duke@435 | 1703 | } else { // Else we have an unchanged counted loop |
duke@435 | 1704 | if( should_peel ) // Might want to peel but do nothing else |
duke@435 | 1705 | phase->do_peeling(this,old_new); |
duke@435 | 1706 | } |
never@836 | 1707 | return true; |
duke@435 | 1708 | } |
duke@435 | 1709 | |
duke@435 | 1710 | |
duke@435 | 1711 | //============================================================================= |
duke@435 | 1712 | //------------------------------iteration_split-------------------------------- |
never@836 | 1713 | bool IdealLoopTree::iteration_split( PhaseIdealLoop *phase, Node_List &old_new ) { |
duke@435 | 1714 | // Recursively iteration split nested loops |
never@836 | 1715 | if( _child && !_child->iteration_split( phase, old_new )) |
never@836 | 1716 | return false; |
duke@435 | 1717 | |
duke@435 | 1718 | // Clean out prior deadwood |
duke@435 | 1719 | DCE_loop_body(); |
duke@435 | 1720 | |
duke@435 | 1721 | |
duke@435 | 1722 | // Look for loop-exit tests with my 50/50 guesses from the Parsing stage. |
duke@435 | 1723 | // Replace with a 1-in-10 exit guess. |
duke@435 | 1724 | if( _parent /*not the root loop*/ && |
duke@435 | 1725 | !_irreducible && |
duke@435 | 1726 | // Also ignore the occasional dead backedge |
duke@435 | 1727 | !tail()->is_top() ) { |
duke@435 | 1728 | adjust_loop_exit_prob(phase); |
duke@435 | 1729 | } |
duke@435 | 1730 | |
duke@435 | 1731 | |
duke@435 | 1732 | // Gate unrolling, RCE and peeling efforts. |
duke@435 | 1733 | if( !_child && // If not an inner loop, do not split |
duke@435 | 1734 | !_irreducible && |
kvn@474 | 1735 | _allow_optimizations && |
duke@435 | 1736 | !tail()->is_top() ) { // Also ignore the occasional dead backedge |
duke@435 | 1737 | if (!_has_call) { |
cfang@1607 | 1738 | if (!iteration_split_impl( phase, old_new )) { |
cfang@1607 | 1739 | return false; |
cfang@1607 | 1740 | } |
duke@435 | 1741 | } else if (policy_unswitching(phase)) { |
duke@435 | 1742 | phase->do_unswitching(this, old_new); |
duke@435 | 1743 | } |
duke@435 | 1744 | } |
duke@435 | 1745 | |
duke@435 | 1746 | // Minor offset re-organization to remove loop-fallout uses of |
duke@435 | 1747 | // trip counter. |
duke@435 | 1748 | if( _head->is_CountedLoop() ) phase->reorg_offsets( this ); |
never@836 | 1749 | if( _next && !_next->iteration_split( phase, old_new )) |
never@836 | 1750 | return false; |
never@836 | 1751 | return true; |
duke@435 | 1752 | } |
cfang@1607 | 1753 | |
cfang@1607 | 1754 | //-------------------------------is_uncommon_trap_proj---------------------------- |
cfang@1607 | 1755 | // Return true if proj is the form of "proj->[region->..]call_uct" |
cfang@1607 | 1756 | bool PhaseIdealLoop::is_uncommon_trap_proj(ProjNode* proj, bool must_reason_predicate) { |
cfang@1607 | 1757 | int path_limit = 10; |
cfang@1607 | 1758 | assert(proj, "invalid argument"); |
cfang@1607 | 1759 | Node* out = proj; |
cfang@1607 | 1760 | for (int ct = 0; ct < path_limit; ct++) { |
cfang@1607 | 1761 | out = out->unique_ctrl_out(); |
cfang@1607 | 1762 | if (out == NULL || out->is_Root() || out->is_Start()) |
cfang@1607 | 1763 | return false; |
cfang@1607 | 1764 | if (out->is_CallStaticJava()) { |
cfang@1607 | 1765 | int req = out->as_CallStaticJava()->uncommon_trap_request(); |
cfang@1607 | 1766 | if (req != 0) { |
cfang@1607 | 1767 | Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(req); |
cfang@1607 | 1768 | if (!must_reason_predicate || reason == Deoptimization::Reason_predicate){ |
cfang@1607 | 1769 | return true; |
cfang@1607 | 1770 | } |
cfang@1607 | 1771 | } |
cfang@1607 | 1772 | return false; // don't do further after call |
cfang@1607 | 1773 | } |
cfang@1607 | 1774 | } |
cfang@1607 | 1775 | return false; |
cfang@1607 | 1776 | } |
cfang@1607 | 1777 | |
cfang@1607 | 1778 | //-------------------------------is_uncommon_trap_if_pattern------------------------- |
cfang@1607 | 1779 | // Return true for "if(test)-> proj -> ... |
cfang@1607 | 1780 | // | |
cfang@1607 | 1781 | // V |
cfang@1607 | 1782 | // other_proj->[region->..]call_uct" |
cfang@1607 | 1783 | // |
cfang@1607 | 1784 | // "must_reason_predicate" means the uct reason must be Reason_predicate |
cfang@1607 | 1785 | bool PhaseIdealLoop::is_uncommon_trap_if_pattern(ProjNode *proj, bool must_reason_predicate) { |
cfang@1607 | 1786 | Node *in0 = proj->in(0); |
cfang@1607 | 1787 | if (!in0->is_If()) return false; |
cfang@1607 | 1788 | IfNode* iff = in0->as_If(); |
cfang@1607 | 1789 | |
cfang@1607 | 1790 | // we need "If(Conv2B(Opaque1(...)))" pattern for must_reason_predicate |
cfang@1607 | 1791 | if (must_reason_predicate) { |
cfang@1607 | 1792 | if (iff->in(1)->Opcode() != Op_Conv2B || |
cfang@1607 | 1793 | iff->in(1)->in(1)->Opcode() != Op_Opaque1) { |
cfang@1607 | 1794 | return false; |
cfang@1607 | 1795 | } |
cfang@1607 | 1796 | } |
cfang@1607 | 1797 | |
cfang@1607 | 1798 | ProjNode* other_proj = iff->proj_out(1-proj->_con)->as_Proj(); |
cfang@1607 | 1799 | return is_uncommon_trap_proj(other_proj, must_reason_predicate); |
cfang@1607 | 1800 | } |
cfang@1607 | 1801 | |
cfang@1607 | 1802 | //------------------------------create_new_if_for_predicate------------------------ |
cfang@1607 | 1803 | // create a new if above the uct_if_pattern for the predicate to be promoted. |
cfang@1607 | 1804 | // |
cfang@1607 | 1805 | // before after |
cfang@1607 | 1806 | // ---------- ---------- |
cfang@1607 | 1807 | // ctrl ctrl |
cfang@1607 | 1808 | // | | |
cfang@1607 | 1809 | // | | |
cfang@1607 | 1810 | // v v |
cfang@1607 | 1811 | // iff new_iff |
cfang@1607 | 1812 | // / \ / \ |
cfang@1607 | 1813 | // / \ / \ |
cfang@1607 | 1814 | // v v v v |
cfang@1607 | 1815 | // uncommon_proj cont_proj if_uct if_cont |
cfang@1607 | 1816 | // \ | | | | |
cfang@1607 | 1817 | // \ | | | | |
cfang@1607 | 1818 | // v v v | v |
cfang@1607 | 1819 | // rgn loop | iff |
cfang@1607 | 1820 | // | | / \ |
cfang@1607 | 1821 | // | | / \ |
cfang@1607 | 1822 | // v | v v |
cfang@1607 | 1823 | // uncommon_trap | uncommon_proj cont_proj |
cfang@1607 | 1824 | // \ \ | | |
cfang@1607 | 1825 | // \ \ | | |
cfang@1607 | 1826 | // v v v v |
cfang@1607 | 1827 | // rgn loop |
cfang@1607 | 1828 | // | |
cfang@1607 | 1829 | // | |
cfang@1607 | 1830 | // v |
cfang@1607 | 1831 | // uncommon_trap |
cfang@1607 | 1832 | // |
cfang@1607 | 1833 | // |
cfang@1607 | 1834 | // We will create a region to guard the uct call if there is no one there. |
cfang@1607 | 1835 | // The true projecttion (if_cont) of the new_iff is returned. |
cfang@1607 | 1836 | ProjNode* PhaseIdealLoop::create_new_if_for_predicate(ProjNode* cont_proj) { |
cfang@1607 | 1837 | assert(is_uncommon_trap_if_pattern(cont_proj, true), "must be a uct if pattern!"); |
cfang@1607 | 1838 | IfNode* iff = cont_proj->in(0)->as_If(); |
cfang@1607 | 1839 | |
cfang@1607 | 1840 | ProjNode *uncommon_proj = iff->proj_out(1 - cont_proj->_con); |
cfang@1607 | 1841 | Node *rgn = uncommon_proj->unique_ctrl_out(); |
cfang@1607 | 1842 | assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct"); |
cfang@1607 | 1843 | |
cfang@1607 | 1844 | if (!rgn->is_Region()) { // create a region to guard the call |
cfang@1607 | 1845 | assert(rgn->is_Call(), "must be call uct"); |
cfang@1607 | 1846 | CallNode* call = rgn->as_Call(); |
cfang@1607 | 1847 | rgn = new (C, 1) RegionNode(1); |
cfang@1607 | 1848 | _igvn.set_type(rgn, rgn->bottom_type()); |
cfang@1607 | 1849 | rgn->add_req(uncommon_proj); |
cfang@1607 | 1850 | set_idom(rgn, idom(uncommon_proj), dom_depth(uncommon_proj)+1); |
cfang@1607 | 1851 | _igvn.hash_delete(call); |
cfang@1607 | 1852 | call->set_req(0, rgn); |
cfang@1607 | 1853 | } |
cfang@1607 | 1854 | |
cfang@1607 | 1855 | // Create new_iff |
cfang@1607 | 1856 | uint iffdd = dom_depth(iff); |
cfang@1607 | 1857 | IdealLoopTree* lp = get_loop(iff); |
cfang@1607 | 1858 | IfNode *new_iff = new (C, 2) IfNode(iff->in(0), NULL, iff->_prob, iff->_fcnt); |
cfang@1607 | 1859 | register_node(new_iff, lp, idom(iff), iffdd); |
cfang@1607 | 1860 | Node *if_cont = new (C, 1) IfTrueNode(new_iff); |
cfang@1607 | 1861 | Node *if_uct = new (C, 1) IfFalseNode(new_iff); |
cfang@1607 | 1862 | if (cont_proj->is_IfFalse()) { |
cfang@1607 | 1863 | // Swap |
cfang@1607 | 1864 | Node* tmp = if_uct; if_uct = if_cont; if_cont = tmp; |
cfang@1607 | 1865 | } |
cfang@1607 | 1866 | register_node(if_cont, lp, new_iff, iffdd); |
cfang@1607 | 1867 | register_node(if_uct, get_loop(rgn), new_iff, iffdd); |
cfang@1607 | 1868 | |
cfang@1607 | 1869 | // if_cont to iff |
cfang@1607 | 1870 | _igvn.hash_delete(iff); |
cfang@1607 | 1871 | iff->set_req(0, if_cont); |
cfang@1607 | 1872 | set_idom(iff, if_cont, dom_depth(iff)); |
cfang@1607 | 1873 | |
cfang@1607 | 1874 | // if_uct to rgn |
cfang@1607 | 1875 | _igvn.hash_delete(rgn); |
cfang@1607 | 1876 | rgn->add_req(if_uct); |
cfang@1607 | 1877 | Node* ridom = idom(rgn); |
cfang@1607 | 1878 | Node* nrdom = dom_lca(ridom, new_iff); |
cfang@1607 | 1879 | set_idom(rgn, nrdom, dom_depth(rgn)); |
cfang@1607 | 1880 | |
cfang@1607 | 1881 | // rgn must have no phis |
cfang@1607 | 1882 | assert(!rgn->as_Region()->has_phi(), "region must have no phis"); |
cfang@1607 | 1883 | |
cfang@1607 | 1884 | return if_cont->as_Proj(); |
cfang@1607 | 1885 | } |
cfang@1607 | 1886 | |
cfang@1607 | 1887 | //------------------------------find_predicate_insertion_point-------------------------- |
cfang@1607 | 1888 | // Find a good location to insert a predicate |
cfang@1607 | 1889 | ProjNode* PhaseIdealLoop::find_predicate_insertion_point(Node* start_c) { |
cfang@1607 | 1890 | if (start_c == C->root() || !start_c->is_Proj()) |
cfang@1607 | 1891 | return NULL; |
cfang@1607 | 1892 | if (is_uncommon_trap_if_pattern(start_c->as_Proj(), true/*Reason_Predicate*/)) { |
cfang@1607 | 1893 | return start_c->as_Proj(); |
cfang@1607 | 1894 | } |
cfang@1607 | 1895 | return NULL; |
cfang@1607 | 1896 | } |
cfang@1607 | 1897 | |
cfang@1607 | 1898 | //------------------------------Invariance----------------------------------- |
cfang@1607 | 1899 | // Helper class for loop_predication_impl to compute invariance on the fly and |
cfang@1607 | 1900 | // clone invariants. |
cfang@1607 | 1901 | class Invariance : public StackObj { |
cfang@1607 | 1902 | VectorSet _visited, _invariant; |
cfang@1607 | 1903 | Node_Stack _stack; |
cfang@1607 | 1904 | VectorSet _clone_visited; |
cfang@1607 | 1905 | Node_List _old_new; // map of old to new (clone) |
cfang@1607 | 1906 | IdealLoopTree* _lpt; |
cfang@1607 | 1907 | PhaseIdealLoop* _phase; |
cfang@1607 | 1908 | |
cfang@1607 | 1909 | // Helper function to set up the invariance for invariance computation |
cfang@1607 | 1910 | // If n is a known invariant, set up directly. Otherwise, look up the |
cfang@1607 | 1911 | // the possibility to push n onto the stack for further processing. |
cfang@1607 | 1912 | void visit(Node* use, Node* n) { |
cfang@1607 | 1913 | if (_lpt->is_invariant(n)) { // known invariant |
cfang@1607 | 1914 | _invariant.set(n->_idx); |
cfang@1607 | 1915 | } else if (!n->is_CFG()) { |
cfang@1607 | 1916 | Node *n_ctrl = _phase->ctrl_or_self(n); |
cfang@1607 | 1917 | Node *u_ctrl = _phase->ctrl_or_self(use); // self if use is a CFG |
cfang@1607 | 1918 | if (_phase->is_dominator(n_ctrl, u_ctrl)) { |
cfang@1607 | 1919 | _stack.push(n, n->in(0) == NULL ? 1 : 0); |
cfang@1607 | 1920 | } |
cfang@1607 | 1921 | } |
cfang@1607 | 1922 | } |
cfang@1607 | 1923 | |
cfang@1607 | 1924 | // Compute invariance for "the_node" and (possibly) all its inputs recursively |
cfang@1607 | 1925 | // on the fly |
cfang@1607 | 1926 | void compute_invariance(Node* n) { |
cfang@1607 | 1927 | assert(_visited.test(n->_idx), "must be"); |
cfang@1607 | 1928 | visit(n, n); |
cfang@1607 | 1929 | while (_stack.is_nonempty()) { |
cfang@1607 | 1930 | Node* n = _stack.node(); |
cfang@1607 | 1931 | uint idx = _stack.index(); |
cfang@1607 | 1932 | if (idx == n->req()) { // all inputs are processed |
cfang@1607 | 1933 | _stack.pop(); |
cfang@1607 | 1934 | // n is invariant if it's inputs are all invariant |
cfang@1607 | 1935 | bool all_inputs_invariant = true; |
cfang@1607 | 1936 | for (uint i = 0; i < n->req(); i++) { |
cfang@1607 | 1937 | Node* in = n->in(i); |
cfang@1607 | 1938 | if (in == NULL) continue; |
cfang@1607 | 1939 | assert(_visited.test(in->_idx), "must have visited input"); |
cfang@1607 | 1940 | if (!_invariant.test(in->_idx)) { // bad guy |
cfang@1607 | 1941 | all_inputs_invariant = false; |
cfang@1607 | 1942 | break; |
cfang@1607 | 1943 | } |
cfang@1607 | 1944 | } |
cfang@1607 | 1945 | if (all_inputs_invariant) { |
cfang@1607 | 1946 | _invariant.set(n->_idx); // I am a invariant too |
cfang@1607 | 1947 | } |
cfang@1607 | 1948 | } else { // process next input |
cfang@1607 | 1949 | _stack.set_index(idx + 1); |
cfang@1607 | 1950 | Node* m = n->in(idx); |
cfang@1607 | 1951 | if (m != NULL && !_visited.test_set(m->_idx)) { |
cfang@1607 | 1952 | visit(n, m); |
cfang@1607 | 1953 | } |
cfang@1607 | 1954 | } |
cfang@1607 | 1955 | } |
cfang@1607 | 1956 | } |
cfang@1607 | 1957 | |
cfang@1607 | 1958 | // Helper function to set up _old_new map for clone_nodes. |
cfang@1607 | 1959 | // If n is a known invariant, set up directly ("clone" of n == n). |
cfang@1607 | 1960 | // Otherwise, push n onto the stack for real cloning. |
cfang@1607 | 1961 | void clone_visit(Node* n) { |
cfang@1607 | 1962 | assert(_invariant.test(n->_idx), "must be invariant"); |
cfang@1607 | 1963 | if (_lpt->is_invariant(n)) { // known invariant |
cfang@1607 | 1964 | _old_new.map(n->_idx, n); |
cfang@1607 | 1965 | } else{ // to be cloned |
cfang@1607 | 1966 | assert (!n->is_CFG(), "should not see CFG here"); |
cfang@1607 | 1967 | _stack.push(n, n->in(0) == NULL ? 1 : 0); |
cfang@1607 | 1968 | } |
cfang@1607 | 1969 | } |
cfang@1607 | 1970 | |
cfang@1607 | 1971 | // Clone "n" and (possibly) all its inputs recursively |
cfang@1607 | 1972 | void clone_nodes(Node* n, Node* ctrl) { |
cfang@1607 | 1973 | clone_visit(n); |
cfang@1607 | 1974 | while (_stack.is_nonempty()) { |
cfang@1607 | 1975 | Node* n = _stack.node(); |
cfang@1607 | 1976 | uint idx = _stack.index(); |
cfang@1607 | 1977 | if (idx == n->req()) { // all inputs processed, clone n! |
cfang@1607 | 1978 | _stack.pop(); |
cfang@1607 | 1979 | // clone invariant node |
cfang@1607 | 1980 | Node* n_cl = n->clone(); |
cfang@1607 | 1981 | _old_new.map(n->_idx, n_cl); |
cfang@1607 | 1982 | _phase->register_new_node(n_cl, ctrl); |
cfang@1607 | 1983 | for (uint i = 0; i < n->req(); i++) { |
cfang@1607 | 1984 | Node* in = n_cl->in(i); |
cfang@1607 | 1985 | if (in == NULL) continue; |
cfang@1607 | 1986 | n_cl->set_req(i, _old_new[in->_idx]); |
cfang@1607 | 1987 | } |
cfang@1607 | 1988 | } else { // process next input |
cfang@1607 | 1989 | _stack.set_index(idx + 1); |
cfang@1607 | 1990 | Node* m = n->in(idx); |
cfang@1607 | 1991 | if (m != NULL && !_clone_visited.test_set(m->_idx)) { |
cfang@1607 | 1992 | clone_visit(m); // visit the input |
cfang@1607 | 1993 | } |
cfang@1607 | 1994 | } |
cfang@1607 | 1995 | } |
cfang@1607 | 1996 | } |
cfang@1607 | 1997 | |
cfang@1607 | 1998 | public: |
cfang@1607 | 1999 | Invariance(Arena* area, IdealLoopTree* lpt) : |
cfang@1607 | 2000 | _lpt(lpt), _phase(lpt->_phase), |
cfang@1607 | 2001 | _visited(area), _invariant(area), _stack(area, 10 /* guess */), |
cfang@1607 | 2002 | _clone_visited(area), _old_new(area) |
cfang@1607 | 2003 | {} |
cfang@1607 | 2004 | |
cfang@1607 | 2005 | // Map old to n for invariance computation and clone |
cfang@1607 | 2006 | void map_ctrl(Node* old, Node* n) { |
cfang@1607 | 2007 | assert(old->is_CFG() && n->is_CFG(), "must be"); |
cfang@1607 | 2008 | _old_new.map(old->_idx, n); // "clone" of old is n |
cfang@1607 | 2009 | _invariant.set(old->_idx); // old is invariant |
cfang@1607 | 2010 | _clone_visited.set(old->_idx); |
cfang@1607 | 2011 | } |
cfang@1607 | 2012 | |
cfang@1607 | 2013 | // Driver function to compute invariance |
cfang@1607 | 2014 | bool is_invariant(Node* n) { |
cfang@1607 | 2015 | if (!_visited.test_set(n->_idx)) |
cfang@1607 | 2016 | compute_invariance(n); |
cfang@1607 | 2017 | return (_invariant.test(n->_idx) != 0); |
cfang@1607 | 2018 | } |
cfang@1607 | 2019 | |
cfang@1607 | 2020 | // Driver function to clone invariant |
cfang@1607 | 2021 | Node* clone(Node* n, Node* ctrl) { |
cfang@1607 | 2022 | assert(ctrl->is_CFG(), "must be"); |
cfang@1607 | 2023 | assert(_invariant.test(n->_idx), "must be an invariant"); |
cfang@1607 | 2024 | if (!_clone_visited.test(n->_idx)) |
cfang@1607 | 2025 | clone_nodes(n, ctrl); |
cfang@1607 | 2026 | return _old_new[n->_idx]; |
cfang@1607 | 2027 | } |
cfang@1607 | 2028 | }; |
cfang@1607 | 2029 | |
cfang@1607 | 2030 | //------------------------------is_range_check_if ----------------------------------- |
cfang@1607 | 2031 | // Returns true if the predicate of iff is in "scale*iv + offset u< load_range(ptr)" format |
cfang@1607 | 2032 | // Note: this function is particularly designed for loop predication. We require load_range |
cfang@1607 | 2033 | // and offset to be loop invariant computed on the fly by "invar" |
cfang@1607 | 2034 | bool IdealLoopTree::is_range_check_if(IfNode *iff, PhaseIdealLoop *phase, Invariance& invar) const { |
cfang@1607 | 2035 | if (!is_loop_exit(iff)) { |
cfang@1607 | 2036 | return false; |
cfang@1607 | 2037 | } |
cfang@1607 | 2038 | if (!iff->in(1)->is_Bool()) { |
cfang@1607 | 2039 | return false; |
cfang@1607 | 2040 | } |
cfang@1607 | 2041 | const BoolNode *bol = iff->in(1)->as_Bool(); |
cfang@1607 | 2042 | if (bol->_test._test != BoolTest::lt) { |
cfang@1607 | 2043 | return false; |
cfang@1607 | 2044 | } |
cfang@1607 | 2045 | if (!bol->in(1)->is_Cmp()) { |
cfang@1607 | 2046 | return false; |
cfang@1607 | 2047 | } |
cfang@1607 | 2048 | const CmpNode *cmp = bol->in(1)->as_Cmp(); |
cfang@1607 | 2049 | if (cmp->Opcode() != Op_CmpU ) { |
cfang@1607 | 2050 | return false; |
cfang@1607 | 2051 | } |
cfang@1607 | 2052 | if (cmp->in(2)->Opcode() != Op_LoadRange) { |
cfang@1607 | 2053 | return false; |
cfang@1607 | 2054 | } |
cfang@1607 | 2055 | LoadRangeNode* lr = (LoadRangeNode*)cmp->in(2); |
cfang@1607 | 2056 | if (!invar.is_invariant(lr)) { // loadRange must be invariant |
cfang@1607 | 2057 | return false; |
cfang@1607 | 2058 | } |
cfang@1607 | 2059 | Node *iv = _head->as_CountedLoop()->phi(); |
cfang@1607 | 2060 | int scale = 0; |
cfang@1607 | 2061 | Node *offset = NULL; |
cfang@1607 | 2062 | if (!phase->is_scaled_iv_plus_offset(cmp->in(1), iv, &scale, &offset)) { |
cfang@1607 | 2063 | return false; |
cfang@1607 | 2064 | } |
cfang@1607 | 2065 | if(offset && !invar.is_invariant(offset)) { // offset must be invariant |
cfang@1607 | 2066 | return false; |
cfang@1607 | 2067 | } |
cfang@1607 | 2068 | return true; |
cfang@1607 | 2069 | } |
cfang@1607 | 2070 | |
cfang@1607 | 2071 | //------------------------------rc_predicate----------------------------------- |
cfang@1607 | 2072 | // Create a range check predicate |
cfang@1607 | 2073 | // |
cfang@1607 | 2074 | // for (i = init; i < limit; i += stride) { |
cfang@1607 | 2075 | // a[scale*i+offset] |
cfang@1607 | 2076 | // } |
cfang@1607 | 2077 | // |
cfang@1607 | 2078 | // Compute max(scale*i + offset) for init <= i < limit and build the predicate |
cfang@1607 | 2079 | // as "max(scale*i + offset) u< a.length". |
cfang@1607 | 2080 | // |
cfang@1607 | 2081 | // There are two cases for max(scale*i + offset): |
cfang@1607 | 2082 | // (1) stride*scale > 0 |
cfang@1607 | 2083 | // max(scale*i + offset) = scale*(limit-stride) + offset |
cfang@1607 | 2084 | // (2) stride*scale < 0 |
cfang@1607 | 2085 | // max(scale*i + offset) = scale*init + offset |
cfang@1607 | 2086 | BoolNode* PhaseIdealLoop::rc_predicate(Node* ctrl, |
cfang@1607 | 2087 | int scale, Node* offset, |
cfang@1607 | 2088 | Node* init, Node* limit, Node* stride, |
cfang@1607 | 2089 | Node* range) { |
cfang@1607 | 2090 | Node* max_idx_expr = init; |
cfang@1607 | 2091 | int stride_con = stride->get_int(); |
cfang@1607 | 2092 | if ((stride_con > 0) == (scale > 0)) { |
cfang@1607 | 2093 | max_idx_expr = new (C, 3) SubINode(limit, stride); |
cfang@1607 | 2094 | register_new_node(max_idx_expr, ctrl); |
cfang@1607 | 2095 | } |
cfang@1607 | 2096 | |
cfang@1607 | 2097 | if (scale != 1) { |
cfang@1607 | 2098 | ConNode* con_scale = _igvn.intcon(scale); |
cfang@1607 | 2099 | max_idx_expr = new (C, 3) MulINode(max_idx_expr, con_scale); |
cfang@1607 | 2100 | register_new_node(max_idx_expr, ctrl); |
cfang@1607 | 2101 | } |
cfang@1607 | 2102 | |
cfang@1607 | 2103 | if (offset && (!offset->is_Con() || offset->get_int() != 0)){ |
cfang@1607 | 2104 | max_idx_expr = new (C, 3) AddINode(max_idx_expr, offset); |
cfang@1607 | 2105 | register_new_node(max_idx_expr, ctrl); |
cfang@1607 | 2106 | } |
cfang@1607 | 2107 | |
cfang@1607 | 2108 | CmpUNode* cmp = new (C, 3) CmpUNode(max_idx_expr, range); |
cfang@1607 | 2109 | register_new_node(cmp, ctrl); |
cfang@1607 | 2110 | BoolNode* bol = new (C, 2) BoolNode(cmp, BoolTest::lt); |
cfang@1607 | 2111 | register_new_node(bol, ctrl); |
cfang@1607 | 2112 | return bol; |
cfang@1607 | 2113 | } |
cfang@1607 | 2114 | |
cfang@1607 | 2115 | //------------------------------ loop_predication_impl-------------------------- |
cfang@1607 | 2116 | // Insert loop predicates for null checks and range checks |
cfang@1607 | 2117 | bool PhaseIdealLoop::loop_predication_impl(IdealLoopTree *loop) { |
cfang@1607 | 2118 | if (!UseLoopPredicate) return false; |
cfang@1607 | 2119 | |
cfang@1607 | 2120 | // Too many traps seen? |
cfang@1607 | 2121 | bool tmt = C->too_many_traps(C->method(), 0, Deoptimization::Reason_predicate); |
cfang@1607 | 2122 | int tc = C->trap_count(Deoptimization::Reason_predicate); |
cfang@1607 | 2123 | if (tmt || tc > 0) { |
cfang@1607 | 2124 | if (TraceLoopPredicate) { |
cfang@1607 | 2125 | tty->print_cr("too many predicate traps: %d", tc); |
cfang@1607 | 2126 | C->method()->print(); // which method has too many predicate traps |
cfang@1607 | 2127 | tty->print_cr(""); |
cfang@1607 | 2128 | } |
cfang@1607 | 2129 | return false; |
cfang@1607 | 2130 | } |
cfang@1607 | 2131 | |
cfang@1607 | 2132 | CountedLoopNode *cl = NULL; |
cfang@1607 | 2133 | if (loop->_head->is_CountedLoop()) { |
cfang@1607 | 2134 | cl = loop->_head->as_CountedLoop(); |
cfang@1607 | 2135 | // do nothing for iteration-splitted loops |
cfang@1607 | 2136 | if(!cl->is_normal_loop()) return false; |
cfang@1607 | 2137 | } |
cfang@1607 | 2138 | |
cfang@1607 | 2139 | LoopNode *lpn = loop->_head->as_Loop(); |
cfang@1607 | 2140 | Node* entry = lpn->in(LoopNode::EntryControl); |
cfang@1607 | 2141 | |
cfang@1607 | 2142 | ProjNode *predicate_proj = find_predicate_insertion_point(entry); |
cfang@1607 | 2143 | if (!predicate_proj){ |
cfang@1607 | 2144 | #ifndef PRODUCT |
cfang@1607 | 2145 | if (TraceLoopPredicate) { |
cfang@1607 | 2146 | tty->print("missing predicate:"); |
cfang@1607 | 2147 | loop->dump_head(); |
cfang@1607 | 2148 | } |
cfang@1607 | 2149 | #endif |
cfang@1607 | 2150 | return false; |
cfang@1607 | 2151 | } |
cfang@1607 | 2152 | |
cfang@1607 | 2153 | ConNode* zero = _igvn.intcon(0); |
cfang@1607 | 2154 | set_ctrl(zero, C->root()); |
cfang@1607 | 2155 | Node *cond_false = new (C, 2) Conv2BNode(zero); |
cfang@1607 | 2156 | register_new_node(cond_false, C->root()); |
cfang@1607 | 2157 | ConNode* one = _igvn.intcon(1); |
cfang@1607 | 2158 | set_ctrl(one, C->root()); |
cfang@1607 | 2159 | Node *cond_true = new (C, 2) Conv2BNode(one); |
cfang@1607 | 2160 | register_new_node(cond_true, C->root()); |
cfang@1607 | 2161 | |
cfang@1607 | 2162 | ResourceArea *area = Thread::current()->resource_area(); |
cfang@1607 | 2163 | Invariance invar(area, loop); |
cfang@1607 | 2164 | |
cfang@1607 | 2165 | // Create list of if-projs such that a newer proj dominates all older |
cfang@1607 | 2166 | // projs in the list, and they all dominate loop->tail() |
cfang@1607 | 2167 | Node_List if_proj_list(area); |
cfang@1607 | 2168 | LoopNode *head = loop->_head->as_Loop(); |
cfang@1607 | 2169 | Node *current_proj = loop->tail(); //start from tail |
cfang@1607 | 2170 | while ( current_proj != head ) { |
cfang@1607 | 2171 | if (loop == get_loop(current_proj) && // still in the loop ? |
cfang@1607 | 2172 | current_proj->is_Proj() && // is a projection ? |
cfang@1607 | 2173 | current_proj->in(0)->Opcode() == Op_If) { // is a if projection ? |
cfang@1607 | 2174 | if_proj_list.push(current_proj); |
cfang@1607 | 2175 | } |
cfang@1607 | 2176 | current_proj = idom(current_proj); |
cfang@1607 | 2177 | } |
cfang@1607 | 2178 | |
cfang@1607 | 2179 | bool hoisted = false; // true if at least one proj is promoted |
cfang@1607 | 2180 | while (if_proj_list.size() > 0) { |
cfang@1607 | 2181 | // Following are changed to nonnull when a predicate can be hoisted |
cfang@1607 | 2182 | ProjNode* new_predicate_proj = NULL; |
cfang@1607 | 2183 | BoolNode* new_predicate_bol = NULL; |
cfang@1607 | 2184 | |
cfang@1607 | 2185 | ProjNode* proj = if_proj_list.pop()->as_Proj(); |
cfang@1607 | 2186 | IfNode* iff = proj->in(0)->as_If(); |
cfang@1607 | 2187 | |
cfang@1607 | 2188 | if (!is_uncommon_trap_if_pattern(proj)) { |
cfang@1607 | 2189 | if (loop->is_loop_exit(iff)) { |
cfang@1607 | 2190 | // stop processing the remaining projs in the list because the execution of them |
cfang@1607 | 2191 | // depends on the condition of "iff" (iff->in(1)). |
cfang@1607 | 2192 | break; |
cfang@1607 | 2193 | } else { |
cfang@1607 | 2194 | // Both arms are inside the loop. There are two cases: |
cfang@1607 | 2195 | // (1) there is one backward branch. In this case, any remaining proj |
cfang@1607 | 2196 | // in the if_proj list post-dominates "iff". So, the condition of "iff" |
cfang@1607 | 2197 | // does not determine the execution the remining projs directly, and we |
cfang@1607 | 2198 | // can safely continue. |
cfang@1607 | 2199 | // (2) both arms are forwarded, i.e. a diamond shape. In this case, "proj" |
cfang@1607 | 2200 | // does not dominate loop->tail(), so it can not be in the if_proj list. |
cfang@1607 | 2201 | continue; |
cfang@1607 | 2202 | } |
cfang@1607 | 2203 | } |
cfang@1607 | 2204 | |
cfang@1607 | 2205 | Node* test = iff->in(1); |
cfang@1607 | 2206 | if (!test->is_Bool()){ //Conv2B, ... |
cfang@1607 | 2207 | continue; |
cfang@1607 | 2208 | } |
cfang@1607 | 2209 | BoolNode* bol = test->as_Bool(); |
cfang@1607 | 2210 | if (invar.is_invariant(bol)) { |
cfang@1607 | 2211 | // Invariant test |
cfang@1607 | 2212 | new_predicate_proj = create_new_if_for_predicate(predicate_proj); |
cfang@1607 | 2213 | Node* ctrl = new_predicate_proj->in(0)->as_If()->in(0); |
cfang@1607 | 2214 | new_predicate_bol = invar.clone(bol, ctrl)->as_Bool(); |
cfang@1607 | 2215 | if (TraceLoopPredicate) tty->print("invariant"); |
cfang@1607 | 2216 | } else if (cl != NULL && loop->is_range_check_if(iff, this, invar)) { |
cfang@1607 | 2217 | // Range check (only for counted loops) |
cfang@1607 | 2218 | new_predicate_proj = create_new_if_for_predicate(predicate_proj); |
cfang@1607 | 2219 | Node *ctrl = new_predicate_proj->in(0)->as_If()->in(0); |
cfang@1607 | 2220 | const Node* cmp = bol->in(1)->as_Cmp(); |
cfang@1607 | 2221 | Node* idx = cmp->in(1); |
cfang@1607 | 2222 | assert(!invar.is_invariant(idx), "index is variant"); |
cfang@1607 | 2223 | assert(cmp->in(2)->Opcode() == Op_LoadRange, "must be"); |
cfang@1607 | 2224 | LoadRangeNode* ld_rng = (LoadRangeNode*)cmp->in(2); // LoadRangeNode |
cfang@1607 | 2225 | assert(invar.is_invariant(ld_rng), "load range must be invariant"); |
cfang@1607 | 2226 | ld_rng = (LoadRangeNode*)invar.clone(ld_rng, ctrl); |
cfang@1607 | 2227 | int scale = 1; |
cfang@1607 | 2228 | Node* offset = zero; |
cfang@1607 | 2229 | bool ok = is_scaled_iv_plus_offset(idx, cl->phi(), &scale, &offset); |
cfang@1607 | 2230 | assert(ok, "must be index expression"); |
cfang@1607 | 2231 | if (offset && offset != zero) { |
cfang@1607 | 2232 | assert(invar.is_invariant(offset), "offset must be loop invariant"); |
cfang@1607 | 2233 | offset = invar.clone(offset, ctrl); |
cfang@1607 | 2234 | } |
cfang@1607 | 2235 | Node* init = cl->init_trip(); |
cfang@1607 | 2236 | Node* limit = cl->limit(); |
cfang@1607 | 2237 | Node* stride = cl->stride(); |
cfang@1607 | 2238 | new_predicate_bol = rc_predicate(ctrl, scale, offset, init, limit, stride, ld_rng); |
cfang@1607 | 2239 | if (TraceLoopPredicate) tty->print("range check"); |
cfang@1607 | 2240 | } |
cfang@1607 | 2241 | |
cfang@1607 | 2242 | if (new_predicate_proj == NULL) { |
cfang@1607 | 2243 | // The other proj of the "iff" is a uncommon trap projection, and we can assume |
cfang@1607 | 2244 | // the other proj will not be executed ("executed" means uct raised). |
cfang@1607 | 2245 | continue; |
cfang@1607 | 2246 | } else { |
cfang@1607 | 2247 | // Success - attach condition (new_predicate_bol) to predicate if |
cfang@1607 | 2248 | invar.map_ctrl(proj, new_predicate_proj); // so that invariance test can be appropriate |
cfang@1607 | 2249 | IfNode* new_iff = new_predicate_proj->in(0)->as_If(); |
cfang@1607 | 2250 | |
cfang@1607 | 2251 | // Negate test if necessary |
cfang@1607 | 2252 | if (proj->_con != predicate_proj->_con) { |
cfang@1607 | 2253 | new_predicate_bol = new (C, 2) BoolNode(new_predicate_bol->in(1), new_predicate_bol->_test.negate()); |
cfang@1607 | 2254 | register_new_node(new_predicate_bol, new_iff->in(0)); |
cfang@1607 | 2255 | if (TraceLoopPredicate) tty->print_cr(" if negated: %d", iff->_idx); |
cfang@1607 | 2256 | } else { |
cfang@1607 | 2257 | if (TraceLoopPredicate) tty->print_cr(" if: %d", iff->_idx); |
cfang@1607 | 2258 | } |
cfang@1607 | 2259 | |
cfang@1607 | 2260 | _igvn.hash_delete(new_iff); |
cfang@1607 | 2261 | new_iff->set_req(1, new_predicate_bol); |
cfang@1607 | 2262 | |
cfang@1607 | 2263 | _igvn.hash_delete(iff); |
cfang@1607 | 2264 | iff->set_req(1, proj->is_IfFalse() ? cond_false : cond_true); |
cfang@1607 | 2265 | |
cfang@1607 | 2266 | Node* ctrl = new_predicate_proj; // new control |
cfang@1607 | 2267 | ProjNode* dp = proj; // old control |
cfang@1607 | 2268 | assert(get_loop(dp) == loop, "guarenteed at the time of collecting proj"); |
cfang@1607 | 2269 | // Find nodes (depends only on the test) off the surviving projection; |
cfang@1607 | 2270 | // move them outside the loop with the control of proj_clone |
cfang@1607 | 2271 | for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) { |
cfang@1607 | 2272 | Node* cd = dp->fast_out(i); // Control-dependent node |
cfang@1607 | 2273 | if (cd->depends_only_on_test()) { |
cfang@1607 | 2274 | assert(cd->in(0) == dp, ""); |
cfang@1607 | 2275 | _igvn.hash_delete(cd); |
cfang@1607 | 2276 | cd->set_req(0, ctrl); // ctrl, not NULL |
cfang@1607 | 2277 | set_early_ctrl(cd); |
cfang@1607 | 2278 | _igvn._worklist.push(cd); |
cfang@1607 | 2279 | IdealLoopTree *new_loop = get_loop(get_ctrl(cd)); |
cfang@1607 | 2280 | if (new_loop != loop) { |
cfang@1607 | 2281 | if (!loop->_child) loop->_body.yank(cd); |
cfang@1607 | 2282 | if (!new_loop->_child ) new_loop->_body.push(cd); |
cfang@1607 | 2283 | } |
cfang@1607 | 2284 | --i; |
cfang@1607 | 2285 | --imax; |
cfang@1607 | 2286 | } |
cfang@1607 | 2287 | } |
cfang@1607 | 2288 | |
cfang@1607 | 2289 | hoisted = true; |
cfang@1607 | 2290 | C->set_major_progress(); |
cfang@1607 | 2291 | } |
cfang@1607 | 2292 | } // end while |
cfang@1607 | 2293 | |
cfang@1607 | 2294 | #ifndef PRODUCT |
cfang@1607 | 2295 | // report that the loop predication has been actually performed |
cfang@1607 | 2296 | // for this loop |
cfang@1607 | 2297 | if (TraceLoopPredicate && hoisted) { |
cfang@1607 | 2298 | tty->print("Loop Predication Performed:"); |
cfang@1607 | 2299 | loop->dump_head(); |
cfang@1607 | 2300 | } |
cfang@1607 | 2301 | #endif |
cfang@1607 | 2302 | |
cfang@1607 | 2303 | return hoisted; |
cfang@1607 | 2304 | } |
cfang@1607 | 2305 | |
cfang@1607 | 2306 | //------------------------------loop_predication-------------------------------- |
cfang@1607 | 2307 | // driver routine for loop predication optimization |
cfang@1607 | 2308 | bool IdealLoopTree::loop_predication( PhaseIdealLoop *phase) { |
cfang@1607 | 2309 | bool hoisted = false; |
cfang@1607 | 2310 | // Recursively promote predicates |
cfang@1607 | 2311 | if ( _child ) { |
cfang@1607 | 2312 | hoisted = _child->loop_predication( phase); |
cfang@1607 | 2313 | } |
cfang@1607 | 2314 | |
cfang@1607 | 2315 | // self |
cfang@1607 | 2316 | if (!_irreducible && !tail()->is_top()) { |
cfang@1607 | 2317 | hoisted |= phase->loop_predication_impl(this); |
cfang@1607 | 2318 | } |
cfang@1607 | 2319 | |
cfang@1607 | 2320 | if ( _next ) { //sibling |
cfang@1607 | 2321 | hoisted |= _next->loop_predication( phase); |
cfang@1607 | 2322 | } |
cfang@1607 | 2323 | |
cfang@1607 | 2324 | return hoisted; |
cfang@1607 | 2325 | } |