| File: | jdk/src/hotspot/share/opto/split_if.cpp |
| Warning: | line 349, column 3 Value stored to 'prior_n' is never read |
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| 1 | /* |
| 2 | * Copyright (c) 1999, 2018, Oracle and/or its affiliates. All rights reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. |
| 8 | * |
| 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 12 | * version 2 for more details (a copy is included in the LICENSE file that |
| 13 | * accompanied this code). |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License version |
| 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 18 | * |
| 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| 20 | * or visit www.oracle.com if you need additional information or have any |
| 21 | * questions. |
| 22 | * |
| 23 | */ |
| 24 | |
| 25 | #include "precompiled.hpp" |
| 26 | #include "memory/allocation.inline.hpp" |
| 27 | #include "opto/callnode.hpp" |
| 28 | #include "opto/loopnode.hpp" |
| 29 | #include "opto/movenode.hpp" |
| 30 | |
| 31 | |
| 32 | //------------------------------split_thru_region------------------------------ |
| 33 | // Split Node 'n' through merge point. |
| 34 | Node *PhaseIdealLoop::split_thru_region( Node *n, Node *region ) { |
| 35 | uint wins = 0; |
| 36 | assert( n->is_CFG(), "" )do { if (!(n->is_CFG())) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 36, "assert(" "n->is_CFG()" ") failed", ""); ::breakpoint (); } } while (0); |
| 37 | assert( region->is_Region(), "" )do { if (!(region->is_Region())) { (*g_assert_poison) = 'X' ;; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 37, "assert(" "region->is_Region()" ") failed", ""); ::breakpoint (); } } while (0); |
| 38 | Node *r = new RegionNode( region->req() ); |
| 39 | IdealLoopTree *loop = get_loop( n ); |
| 40 | for( uint i = 1; i < region->req(); i++ ) { |
| 41 | Node *x = n->clone(); |
| 42 | Node *in0 = n->in(0); |
| 43 | if( in0->in(0) == region ) x->set_req( 0, in0->in(i) ); |
| 44 | for( uint j = 1; j < n->req(); j++ ) { |
| 45 | Node *in = n->in(j); |
| 46 | if( get_ctrl(in) == region ) |
| 47 | x->set_req( j, in->in(i) ); |
| 48 | } |
| 49 | _igvn.register_new_node_with_optimizer(x); |
| 50 | set_loop(x, loop); |
| 51 | set_idom(x, x->in(0), dom_depth(x->in(0))+1); |
| 52 | r->init_req(i, x); |
| 53 | } |
| 54 | |
| 55 | // Record region |
| 56 | r->set_req(0,region); // Not a TRUE RegionNode |
| 57 | _igvn.register_new_node_with_optimizer(r); |
| 58 | set_loop(r, loop); |
| 59 | if( !loop->_child ) |
| 60 | loop->_body.push(r); |
| 61 | return r; |
| 62 | } |
| 63 | |
| 64 | //------------------------------split_up--------------------------------------- |
| 65 | // Split block-local op up through the phis to empty the current block |
| 66 | bool PhaseIdealLoop::split_up( Node *n, Node *blk1, Node *blk2 ) { |
| 67 | if( n->is_CFG() ) { |
| 68 | assert( n->in(0) != blk1, "Lousy candidate for split-if" )do { if (!(n->in(0) != blk1)) { (*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 68, "assert(" "n->in(0) != blk1" ") failed", "Lousy candidate for split-if" ); ::breakpoint(); } } while (0); |
| 69 | return false; |
| 70 | } |
| 71 | if( get_ctrl(n) != blk1 && get_ctrl(n) != blk2 ) |
| 72 | return false; // Not block local |
| 73 | if( n->is_Phi() ) return false; // Local PHIs are expected |
| 74 | |
| 75 | // Recursively split-up inputs |
| 76 | for (uint i = 1; i < n->req(); i++) { |
| 77 | if( split_up( n->in(i), blk1, blk2 ) ) { |
| 78 | // Got split recursively and self went dead? |
| 79 | if (n->outcnt() == 0) |
| 80 | _igvn.remove_dead_node(n); |
| 81 | return true; |
| 82 | } |
| 83 | } |
| 84 | |
| 85 | // Check for needing to clone-up a compare. Can't do that, it forces |
| 86 | // another (nested) split-if transform. Instead, clone it "down". |
| 87 | if( n->is_Cmp() ) { |
| 88 | assert(get_ctrl(n) == blk2 || get_ctrl(n) == blk1, "must be in block with IF")do { if (!(get_ctrl(n) == blk2 || get_ctrl(n) == blk1)) { (*g_assert_poison ) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 88, "assert(" "get_ctrl(n) == blk2 || get_ctrl(n) == blk1" ") failed" , "must be in block with IF"); ::breakpoint(); } } while (0); |
| 89 | // Check for simple Cmp/Bool/CMove which we can clone-up. Cmp/Bool/CMove |
| 90 | // sequence can have no other users and it must all reside in the split-if |
| 91 | // block. Non-simple Cmp/Bool/CMove sequences are 'cloned-down' below - |
| 92 | // private, per-use versions of the Cmp and Bool are made. These sink to |
| 93 | // the CMove block. If the CMove is in the split-if block, then in the |
| 94 | // next iteration this will become a simple Cmp/Bool/CMove set to clone-up. |
| 95 | Node *bol, *cmov; |
| 96 | if( !(n->outcnt() == 1 && n->unique_out()->is_Bool() && |
| 97 | (bol = n->unique_out()->as_Bool()) && |
| 98 | (get_ctrl(bol) == blk1 || |
| 99 | get_ctrl(bol) == blk2) && |
| 100 | bol->outcnt() == 1 && |
| 101 | bol->unique_out()->is_CMove() && |
| 102 | (cmov = bol->unique_out()->as_CMove()) && |
| 103 | (get_ctrl(cmov) == blk1 || |
| 104 | get_ctrl(cmov) == blk2) ) ) { |
| 105 | |
| 106 | // Must clone down |
| 107 | #ifndef PRODUCT |
| 108 | if( PrintOpto && VerifyLoopOptimizations ) { |
| 109 | tty->print("Cloning down: "); |
| 110 | n->dump(); |
| 111 | } |
| 112 | #endif |
| 113 | if (!n->is_FastLock()) { |
| 114 | // Clone down any block-local BoolNode uses of this CmpNode |
| 115 | for (DUIterator i = n->outs(); n->has_out(i); i++) { |
| 116 | Node* bol = n->out(i); |
| 117 | assert( bol->is_Bool(), "" )do { if (!(bol->is_Bool())) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 117, "assert(" "bol->is_Bool()" ") failed", ""); ::breakpoint (); } } while (0); |
| 118 | if (bol->outcnt() == 1) { |
| 119 | Node* use = bol->unique_out(); |
| 120 | if (use->Opcode() == Op_Opaque4) { |
| 121 | if (use->outcnt() == 1) { |
| 122 | Node* iff = use->unique_out(); |
| 123 | assert(iff->is_If(), "unexpected node type")do { if (!(iff->is_If())) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 123, "assert(" "iff->is_If()" ") failed", "unexpected node type" ); ::breakpoint(); } } while (0); |
| 124 | Node *use_c = iff->in(0); |
| 125 | if (use_c == blk1 || use_c == blk2) { |
| 126 | continue; |
| 127 | } |
| 128 | } |
| 129 | } else { |
| 130 | // We might see an Opaque1 from a loop limit check here |
| 131 | assert(use->is_If() || use->is_CMove() || use->Opcode() == Op_Opaque1, "unexpected node type")do { if (!(use->is_If() || use->is_CMove() || use->Opcode () == Op_Opaque1)) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 131, "assert(" "use->is_If() || use->is_CMove() || use->Opcode() == Op_Opaque1" ") failed", "unexpected node type"); ::breakpoint(); } } while (0); |
| 132 | Node *use_c = use->is_If() ? use->in(0) : get_ctrl(use); |
| 133 | if (use_c == blk1 || use_c == blk2) { |
| 134 | assert(use->is_CMove(), "unexpected node type")do { if (!(use->is_CMove())) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 134, "assert(" "use->is_CMove()" ") failed", "unexpected node type" ); ::breakpoint(); } } while (0); |
| 135 | continue; |
| 136 | } |
| 137 | } |
| 138 | } |
| 139 | if (get_ctrl(bol) == blk1 || get_ctrl(bol) == blk2) { |
| 140 | // Recursively sink any BoolNode |
| 141 | #ifndef PRODUCT |
| 142 | if( PrintOpto && VerifyLoopOptimizations ) { |
| 143 | tty->print("Cloning down: "); |
| 144 | bol->dump(); |
| 145 | } |
| 146 | #endif |
| 147 | for (DUIterator j = bol->outs(); bol->has_out(j); j++) { |
| 148 | Node* u = bol->out(j); |
| 149 | // Uses are either IfNodes, CMoves or Opaque4 |
| 150 | if (u->Opcode() == Op_Opaque4) { |
| 151 | assert(u->in(1) == bol, "bad input")do { if (!(u->in(1) == bol)) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 151, "assert(" "u->in(1) == bol" ") failed", "bad input" ); ::breakpoint(); } } while (0); |
| 152 | for (DUIterator_Last kmin, k = u->last_outs(kmin); k >= kmin; --k) { |
| 153 | Node* iff = u->last_out(k); |
| 154 | assert(iff->is_If() || iff->is_CMove(), "unexpected node type")do { if (!(iff->is_If() || iff->is_CMove())) { (*g_assert_poison ) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 154, "assert(" "iff->is_If() || iff->is_CMove()" ") failed" , "unexpected node type"); ::breakpoint(); } } while (0); |
| 155 | assert( iff->in(1) == u, "" )do { if (!(iff->in(1) == u)) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 155, "assert(" "iff->in(1) == u" ") failed", ""); ::breakpoint (); } } while (0); |
| 156 | // Get control block of either the CMove or the If input |
| 157 | Node *iff_ctrl = iff->is_If() ? iff->in(0) : get_ctrl(iff); |
| 158 | Node *x1 = bol->clone(); |
| 159 | Node *x2 = u->clone(); |
| 160 | register_new_node(x1, iff_ctrl); |
| 161 | register_new_node(x2, iff_ctrl); |
| 162 | _igvn.replace_input_of(x2, 1, x1); |
| 163 | _igvn.replace_input_of(iff, 1, x2); |
| 164 | } |
| 165 | _igvn.remove_dead_node(u); |
| 166 | --j; |
| 167 | } else { |
| 168 | // We might see an Opaque1 from a loop limit check here |
| 169 | assert(u->is_If() || u->is_CMove() || u->Opcode() == Op_Opaque1, "unexpected node type")do { if (!(u->is_If() || u->is_CMove() || u->Opcode( ) == Op_Opaque1)) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 169, "assert(" "u->is_If() || u->is_CMove() || u->Opcode() == Op_Opaque1" ") failed", "unexpected node type"); ::breakpoint(); } } while (0); |
| 170 | assert(u->in(1) == bol, "")do { if (!(u->in(1) == bol)) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 170, "assert(" "u->in(1) == bol" ") failed", ""); ::breakpoint (); } } while (0); |
| 171 | // Get control block of either the CMove or the If input |
| 172 | Node *u_ctrl = u->is_If() ? u->in(0) : get_ctrl(u); |
| 173 | assert((u_ctrl != blk1 && u_ctrl != blk2) || u->is_CMove(), "won't converge")do { if (!((u_ctrl != blk1 && u_ctrl != blk2) || u-> is_CMove())) { (*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 173, "assert(" "(u_ctrl != blk1 && u_ctrl != blk2) || u->is_CMove()" ") failed", "won't converge"); ::breakpoint(); } } while (0); |
| 174 | Node *x = bol->clone(); |
| 175 | register_new_node(x, u_ctrl); |
| 176 | _igvn.replace_input_of(u, 1, x); |
| 177 | --j; |
| 178 | } |
| 179 | } |
| 180 | _igvn.remove_dead_node(bol); |
| 181 | --i; |
| 182 | } |
| 183 | } |
| 184 | } |
| 185 | // Clone down this CmpNode |
| 186 | for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin; --j) { |
| 187 | Node* use = n->last_out(j); |
| 188 | uint pos = 1; |
| 189 | if (n->is_FastLock()) { |
| 190 | pos = TypeFunc::Parms + 2; |
| 191 | assert(use->is_Lock(), "FastLock only used by LockNode")do { if (!(use->is_Lock())) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 191, "assert(" "use->is_Lock()" ") failed", "FastLock only used by LockNode" ); ::breakpoint(); } } while (0); |
| 192 | } |
| 193 | assert(use->in(pos) == n, "" )do { if (!(use->in(pos) == n)) { (*g_assert_poison) = 'X'; ; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 193, "assert(" "use->in(pos) == n" ") failed", ""); ::breakpoint (); } } while (0); |
| 194 | Node *x = n->clone(); |
| 195 | register_new_node(x, ctrl_or_self(use)); |
| 196 | _igvn.replace_input_of(use, pos, x); |
| 197 | } |
| 198 | _igvn.remove_dead_node( n ); |
| 199 | |
| 200 | return true; |
| 201 | } |
| 202 | } |
| 203 | |
| 204 | // See if splitting-up a Store. Any anti-dep loads must go up as |
| 205 | // well. An anti-dep load might be in the wrong block, because in |
| 206 | // this particular layout/schedule we ignored anti-deps and allow |
| 207 | // memory to be alive twice. This only works if we do the same |
| 208 | // operations on anti-dep loads as we do their killing stores. |
| 209 | if( n->is_Store() && n->in(MemNode::Memory)->in(0) == n->in(0) ) { |
| 210 | // Get store's memory slice |
| 211 | int alias_idx = C->get_alias_index(_igvn.type(n->in(MemNode::Address))->is_ptr()); |
| 212 | |
| 213 | // Get memory-phi anti-dep loads will be using |
| 214 | Node *memphi = n->in(MemNode::Memory); |
| 215 | assert( memphi->is_Phi(), "" )do { if (!(memphi->is_Phi())) { (*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 215, "assert(" "memphi->is_Phi()" ") failed", ""); ::breakpoint (); } } while (0); |
| 216 | // Hoist any anti-dep load to the splitting block; |
| 217 | // it will then "split-up". |
| 218 | for (DUIterator_Fast imax,i = memphi->fast_outs(imax); i < imax; i++) { |
| 219 | Node *load = memphi->fast_out(i); |
| 220 | if( load->is_Load() && alias_idx == C->get_alias_index(_igvn.type(load->in(MemNode::Address))->is_ptr()) ) |
| 221 | set_ctrl(load,blk1); |
| 222 | } |
| 223 | } |
| 224 | |
| 225 | // Found some other Node; must clone it up |
| 226 | #ifndef PRODUCT |
| 227 | if( PrintOpto && VerifyLoopOptimizations ) { |
| 228 | tty->print("Cloning up: "); |
| 229 | n->dump(); |
| 230 | } |
| 231 | #endif |
| 232 | |
| 233 | // ConvI2L may have type information on it which becomes invalid if |
| 234 | // it moves up in the graph so change any clones so widen the type |
| 235 | // to TypeLong::INT when pushing it up. |
| 236 | const Type* rtype = NULL__null; |
| 237 | if (n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::INT) { |
| 238 | rtype = TypeLong::INT; |
| 239 | } |
| 240 | |
| 241 | // Now actually split-up this guy. One copy per control path merging. |
| 242 | Node *phi = PhiNode::make_blank(blk1, n); |
| 243 | for( uint j = 1; j < blk1->req(); j++ ) { |
| 244 | Node *x = n->clone(); |
| 245 | // Widen the type of the ConvI2L when pushing up. |
| 246 | if (rtype != NULL__null) x->as_Type()->set_type(rtype); |
| 247 | if( n->in(0) && n->in(0) == blk1 ) |
| 248 | x->set_req( 0, blk1->in(j) ); |
| 249 | for( uint i = 1; i < n->req(); i++ ) { |
| 250 | Node *m = n->in(i); |
| 251 | if( get_ctrl(m) == blk1 ) { |
| 252 | assert( m->in(0) == blk1, "" )do { if (!(m->in(0) == blk1)) { (*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 252, "assert(" "m->in(0) == blk1" ") failed", ""); ::breakpoint (); } } while (0); |
| 253 | x->set_req( i, m->in(j) ); |
| 254 | } |
| 255 | } |
| 256 | register_new_node( x, blk1->in(j) ); |
| 257 | phi->init_req( j, x ); |
| 258 | } |
| 259 | // Announce phi to optimizer |
| 260 | register_new_node(phi, blk1); |
| 261 | |
| 262 | // Remove cloned-up value from optimizer; use phi instead |
| 263 | _igvn.replace_node( n, phi ); |
| 264 | |
| 265 | // (There used to be a self-recursive call to split_up() here, |
| 266 | // but it is not needed. All necessary forward walking is done |
| 267 | // by do_split_if() below.) |
| 268 | |
| 269 | return true; |
| 270 | } |
| 271 | |
| 272 | //------------------------------register_new_node------------------------------ |
| 273 | void PhaseIdealLoop::register_new_node( Node *n, Node *blk ) { |
| 274 | assert(!n->is_CFG(), "must be data node")do { if (!(!n->is_CFG())) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 274, "assert(" "!n->is_CFG()" ") failed", "must be data node" ); ::breakpoint(); } } while (0); |
| 275 | _igvn.register_new_node_with_optimizer(n); |
| 276 | set_ctrl(n, blk); |
| 277 | IdealLoopTree *loop = get_loop(blk); |
| 278 | if( !loop->_child ) |
| 279 | loop->_body.push(n); |
| 280 | } |
| 281 | |
| 282 | //------------------------------small_cache------------------------------------ |
| 283 | struct small_cache : public Dict { |
| 284 | |
| 285 | small_cache() : Dict( cmpkey, hashptr ) {} |
| 286 | Node *probe( Node *use_blk ) { return (Node*)((*this)[use_blk]); } |
| 287 | void lru_insert( Node *use_blk, Node *new_def ) { Insert(use_blk,new_def); } |
| 288 | }; |
| 289 | |
| 290 | //------------------------------spinup----------------------------------------- |
| 291 | // "Spin up" the dominator tree, starting at the use site and stopping when we |
| 292 | // find the post-dominating point. |
| 293 | |
| 294 | // We must be at the merge point which post-dominates 'new_false' and |
| 295 | // 'new_true'. Figure out which edges into the RegionNode eventually lead up |
| 296 | // to false and which to true. Put in a PhiNode to merge values; plug in |
| 297 | // the appropriate false-arm or true-arm values. If some path leads to the |
| 298 | // original IF, then insert a Phi recursively. |
| 299 | Node *PhaseIdealLoop::spinup( Node *iff_dom, Node *new_false, Node *new_true, Node *use_blk, Node *def, small_cache *cache ) { |
| 300 | if (use_blk->is_top()) // Handle dead uses |
| 301 | return use_blk; |
| 302 | Node *prior_n = (Node*)((intptr_t)0xdeadbeef); |
| 303 | Node *n = use_blk; // Get path input |
| 304 | assert( use_blk != iff_dom, "" )do { if (!(use_blk != iff_dom)) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 304, "assert(" "use_blk != iff_dom" ") failed", ""); ::breakpoint (); } } while (0); |
| 305 | // Here's the "spinup" the dominator tree loop. Do a cache-check |
| 306 | // along the way, in case we've come this way before. |
| 307 | while( n != iff_dom ) { // Found post-dominating point? |
| 308 | prior_n = n; |
| 309 | n = idom(n); // Search higher |
| 310 | Node *s = cache->probe( prior_n ); // Check cache |
| 311 | if( s ) return s; // Cache hit! |
| 312 | } |
| 313 | |
| 314 | Node *phi_post; |
| 315 | if( prior_n == new_false || prior_n == new_true ) { |
| 316 | phi_post = def->clone(); |
| 317 | phi_post->set_req(0, prior_n ); |
| 318 | register_new_node(phi_post, prior_n); |
| 319 | } else { |
| 320 | // This method handles both control uses (looking for Regions) or data |
| 321 | // uses (looking for Phis). If looking for a control use, then we need |
| 322 | // to insert a Region instead of a Phi; however Regions always exist |
| 323 | // previously (the hash_find_insert below would always hit) so we can |
| 324 | // return the existing Region. |
| 325 | if( def->is_CFG() ) { |
| 326 | phi_post = prior_n; // If looking for CFG, return prior |
| 327 | } else { |
| 328 | assert( def->is_Phi(), "" )do { if (!(def->is_Phi())) { (*g_assert_poison) = 'X';; report_vm_error ("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 328, "assert(" "def->is_Phi()" ") failed", ""); ::breakpoint (); } } while (0); |
| 329 | assert( prior_n->is_Region(), "must be a post-dominating merge point" )do { if (!(prior_n->is_Region())) { (*g_assert_poison) = 'X' ;; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 329, "assert(" "prior_n->is_Region()" ") failed", "must be a post-dominating merge point" ); ::breakpoint(); } } while (0); |
| 330 | |
| 331 | // Need a Phi here |
| 332 | phi_post = PhiNode::make_blank(prior_n, def); |
| 333 | // Search for both true and false on all paths till find one. |
| 334 | for( uint i = 1; i < phi_post->req(); i++ ) // For all paths |
| 335 | phi_post->init_req( i, spinup( iff_dom, new_false, new_true, prior_n->in(i), def, cache ) ); |
| 336 | Node *t = _igvn.hash_find_insert(phi_post); |
| 337 | if( t ) { // See if we already have this one |
| 338 | // phi_post will not be used, so kill it |
| 339 | _igvn.remove_dead_node(phi_post); |
| 340 | phi_post->destruct(&_igvn); |
| 341 | phi_post = t; |
| 342 | } else { |
| 343 | register_new_node( phi_post, prior_n ); |
| 344 | } |
| 345 | } |
| 346 | } |
| 347 | |
| 348 | // Update cache everywhere |
| 349 | prior_n = (Node*)((intptr_t)0xdeadbeef); // Reset IDOM walk |
Value stored to 'prior_n' is never read | |
| 350 | n = use_blk; // Get path input |
| 351 | // Spin-up the idom tree again, basically doing path-compression. |
| 352 | // Insert cache entries along the way, so that if we ever hit this |
| 353 | // point in the IDOM tree again we'll stop immediately on a cache hit. |
| 354 | while( n != iff_dom ) { // Found post-dominating point? |
| 355 | prior_n = n; |
| 356 | n = idom(n); // Search higher |
| 357 | cache->lru_insert( prior_n, phi_post ); // Fill cache |
| 358 | } // End of while not gone high enough |
| 359 | |
| 360 | return phi_post; |
| 361 | } |
| 362 | |
| 363 | //------------------------------find_use_block--------------------------------- |
| 364 | // Find the block a USE is in. Normally USE's are in the same block as the |
| 365 | // using instruction. For Phi-USE's, the USE is in the predecessor block |
| 366 | // along the corresponding path. |
| 367 | Node *PhaseIdealLoop::find_use_block( Node *use, Node *def, Node *old_false, Node *new_false, Node *old_true, Node *new_true ) { |
| 368 | // CFG uses are their own block |
| 369 | if( use->is_CFG() ) |
| 370 | return use; |
| 371 | |
| 372 | if( use->is_Phi() ) { // Phi uses in prior block |
| 373 | // Grab the first Phi use; there may be many. |
| 374 | // Each will be handled as a separate iteration of |
| 375 | // the "while( phi->outcnt() )" loop. |
| 376 | uint j; |
| 377 | for( j = 1; j < use->req(); j++ ) |
| 378 | if( use->in(j) == def ) |
| 379 | break; |
| 380 | assert( j < use->req(), "def should be among use's inputs" )do { if (!(j < use->req())) { (*g_assert_poison) = 'X'; ; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 380, "assert(" "j < use->req()" ") failed", "def should be among use's inputs" ); ::breakpoint(); } } while (0); |
| 381 | return use->in(0)->in(j); |
| 382 | } |
| 383 | // Normal (non-phi) use |
| 384 | Node *use_blk = get_ctrl(use); |
| 385 | // Some uses are directly attached to the old (and going away) |
| 386 | // false and true branches. |
| 387 | if( use_blk == old_false ) { |
| 388 | use_blk = new_false; |
| 389 | set_ctrl(use, new_false); |
| 390 | } |
| 391 | if( use_blk == old_true ) { |
| 392 | use_blk = new_true; |
| 393 | set_ctrl(use, new_true); |
| 394 | } |
| 395 | |
| 396 | if (use_blk == NULL__null) { // He's dead, Jim |
| 397 | _igvn.replace_node(use, C->top()); |
| 398 | } |
| 399 | |
| 400 | return use_blk; |
| 401 | } |
| 402 | |
| 403 | //------------------------------handle_use------------------------------------- |
| 404 | // Handle uses of the merge point. Basically, split-if makes the merge point |
| 405 | // go away so all uses of the merge point must go away as well. Most block |
| 406 | // local uses have already been split-up, through the merge point. Uses from |
| 407 | // far below the merge point can't always be split up (e.g., phi-uses are |
| 408 | // pinned) and it makes too much stuff live. Instead we use a path-based |
| 409 | // solution to move uses down. |
| 410 | // |
| 411 | // If the use is along the pre-split-CFG true branch, then the new use will |
| 412 | // be from the post-split-CFG true merge point. Vice-versa for the false |
| 413 | // path. Some uses will be along both paths; then we sink the use to the |
| 414 | // post-dominating location; we may need to insert a Phi there. |
| 415 | void PhaseIdealLoop::handle_use( Node *use, Node *def, small_cache *cache, Node *region_dom, Node *new_false, Node *new_true, Node *old_false, Node *old_true ) { |
| 416 | |
| 417 | Node *use_blk = find_use_block(use,def,old_false,new_false,old_true,new_true); |
| 418 | if( !use_blk ) return; // He's dead, Jim |
| 419 | |
| 420 | // Walk up the dominator tree until I hit either the old IfFalse, the old |
| 421 | // IfTrue or the old If. Insert Phis where needed. |
| 422 | Node *new_def = spinup( region_dom, new_false, new_true, use_blk, def, cache ); |
| 423 | |
| 424 | // Found where this USE goes. Re-point him. |
| 425 | uint i; |
| 426 | for( i = 0; i < use->req(); i++ ) |
| 427 | if( use->in(i) == def ) |
| 428 | break; |
| 429 | assert( i < use->req(), "def should be among use's inputs" )do { if (!(i < use->req())) { (*g_assert_poison) = 'X'; ; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 429, "assert(" "i < use->req()" ") failed", "def should be among use's inputs" ); ::breakpoint(); } } while (0); |
| 430 | _igvn.replace_input_of(use, i, new_def); |
| 431 | } |
| 432 | |
| 433 | //------------------------------do_split_if------------------------------------ |
| 434 | // Found an If getting its condition-code input from a Phi in the same block. |
| 435 | // Split thru the Region. |
| 436 | void PhaseIdealLoop::do_split_if( Node *iff ) { |
| 437 | if (PrintOpto && VerifyLoopOptimizations) { |
| 438 | tty->print_cr("Split-if"); |
| 439 | } |
| 440 | if (TraceLoopOpts) { |
| 441 | tty->print_cr("SplitIf"); |
| 442 | } |
| 443 | |
| 444 | C->set_major_progress(); |
| 445 | Node *region = iff->in(0); |
| 446 | Node *region_dom = idom(region); |
| 447 | |
| 448 | // We are going to clone this test (and the control flow with it) up through |
| 449 | // the incoming merge point. We need to empty the current basic block. |
| 450 | // Clone any instructions which must be in this block up through the merge |
| 451 | // point. |
| 452 | DUIterator i, j; |
| 453 | bool progress = true; |
| 454 | while (progress) { |
| 455 | progress = false; |
| 456 | for (i = region->outs(); region->has_out(i); i++) { |
| 457 | Node* n = region->out(i); |
| 458 | if( n == region ) continue; |
| 459 | // The IF to be split is OK. |
| 460 | if( n == iff ) continue; |
| 461 | if( !n->is_Phi() ) { // Found pinned memory op or such |
| 462 | if (split_up(n, region, iff)) { |
| 463 | i = region->refresh_out_pos(i); |
| 464 | progress = true; |
| 465 | } |
| 466 | continue; |
| 467 | } |
| 468 | assert( n->in(0) == region, "" )do { if (!(n->in(0) == region)) { (*g_assert_poison) = 'X' ;; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 468, "assert(" "n->in(0) == region" ") failed", ""); ::breakpoint (); } } while (0); |
| 469 | |
| 470 | // Recursively split up all users of a Phi |
| 471 | for (j = n->outs(); n->has_out(j); j++) { |
| 472 | Node* m = n->out(j); |
| 473 | // If m is dead, throw it away, and declare progress |
| 474 | if (_nodes[m->_idx] == NULL__null) { |
| 475 | _igvn.remove_dead_node(m); |
| 476 | // fall through |
| 477 | } |
| 478 | else if (m != iff && split_up(m, region, iff)) { |
| 479 | // fall through |
| 480 | } else { |
| 481 | continue; |
| 482 | } |
| 483 | // Something unpredictable changed. |
| 484 | // Tell the iterators to refresh themselves, and rerun the loop. |
| 485 | i = region->refresh_out_pos(i); |
| 486 | j = region->refresh_out_pos(j); |
| 487 | progress = true; |
| 488 | } |
| 489 | } |
| 490 | } |
| 491 | |
| 492 | // Now we have no instructions in the block containing the IF. |
| 493 | // Split the IF. |
| 494 | Node *new_iff = split_thru_region( iff, region ); |
| 495 | |
| 496 | // Replace both uses of 'new_iff' with Regions merging True/False |
| 497 | // paths. This makes 'new_iff' go dead. |
| 498 | Node *old_false = NULL__null, *old_true = NULL__null; |
| 499 | Node *new_false = NULL__null, *new_true = NULL__null; |
| 500 | for (DUIterator_Last j2min, j2 = iff->last_outs(j2min); j2 >= j2min; --j2) { |
| 501 | Node *ifp = iff->last_out(j2); |
| 502 | assert( ifp->Opcode() == Op_IfFalse || ifp->Opcode() == Op_IfTrue, "" )do { if (!(ifp->Opcode() == Op_IfFalse || ifp->Opcode() == Op_IfTrue)) { (*g_assert_poison) = 'X';; report_vm_error( "/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 502, "assert(" "ifp->Opcode() == Op_IfFalse || ifp->Opcode() == Op_IfTrue" ") failed", ""); ::breakpoint(); } } while (0); |
| 503 | ifp->set_req(0, new_iff); |
| 504 | Node *ifpx = split_thru_region( ifp, region ); |
| 505 | |
| 506 | // Replace 'If' projection of a Region with a Region of |
| 507 | // 'If' projections. |
| 508 | ifpx->set_req(0, ifpx); // A TRUE RegionNode |
| 509 | |
| 510 | // Setup dominator info |
| 511 | set_idom(ifpx, region_dom, dom_depth(region_dom) + 1); |
| 512 | |
| 513 | // Check for splitting loop tails |
| 514 | if( get_loop(iff)->tail() == ifp ) |
| 515 | get_loop(iff)->_tail = ifpx; |
| 516 | |
| 517 | // Replace in the graph with lazy-update mechanism |
| 518 | new_iff->set_req(0, new_iff); // hook self so it does not go dead |
| 519 | lazy_replace(ifp, ifpx); |
| 520 | new_iff->set_req(0, region); |
| 521 | |
| 522 | // Record bits for later xforms |
| 523 | if( ifp->Opcode() == Op_IfFalse ) { |
| 524 | old_false = ifp; |
| 525 | new_false = ifpx; |
| 526 | } else { |
| 527 | old_true = ifp; |
| 528 | new_true = ifpx; |
| 529 | } |
| 530 | } |
| 531 | _igvn.remove_dead_node(new_iff); |
| 532 | // Lazy replace IDOM info with the region's dominator |
| 533 | lazy_replace(iff, region_dom); |
| 534 | lazy_update(region, region_dom); // idom must be update before handle_uses |
| 535 | region->set_req(0, NULL__null); // Break the self-cycle. Required for lazy_update to work on region |
| 536 | |
| 537 | // Now make the original merge point go dead, by handling all its uses. |
| 538 | small_cache region_cache; |
| 539 | // Preload some control flow in region-cache |
| 540 | region_cache.lru_insert( new_false, new_false ); |
| 541 | region_cache.lru_insert( new_true , new_true ); |
| 542 | // Now handle all uses of the splitting block |
| 543 | for (DUIterator k = region->outs(); region->has_out(k); k++) { |
| 544 | Node* phi = region->out(k); |
| 545 | if (!phi->in(0)) { // Dead phi? Remove it |
| 546 | _igvn.remove_dead_node(phi); |
| 547 | } else if (phi == region) { // Found the self-reference |
| 548 | continue; // No roll-back of DUIterator |
| 549 | } else if (phi->is_Phi()) { // Expected common case: Phi hanging off of Region |
| 550 | assert(phi->in(0) == region, "Inconsistent graph")do { if (!(phi->in(0) == region)) { (*g_assert_poison) = 'X' ;; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 550, "assert(" "phi->in(0) == region" ") failed", "Inconsistent graph" ); ::breakpoint(); } } while (0); |
| 551 | // Need a per-def cache. Phi represents a def, so make a cache |
| 552 | small_cache phi_cache; |
| 553 | |
| 554 | // Inspect all Phi uses to make the Phi go dead |
| 555 | for (DUIterator_Last lmin, l = phi->last_outs(lmin); l >= lmin; --l) { |
| 556 | Node* use = phi->last_out(l); |
| 557 | // Compute the new DEF for this USE. New DEF depends on the path |
| 558 | // taken from the original DEF to the USE. The new DEF may be some |
| 559 | // collection of PHI's merging values from different paths. The Phis |
| 560 | // inserted depend only on the location of the USE. We use a |
| 561 | // 2-element cache to handle multiple uses from the same block. |
| 562 | handle_use(use, phi, &phi_cache, region_dom, new_false, new_true, old_false, old_true); |
| 563 | } // End of while phi has uses |
| 564 | // Remove the dead Phi |
| 565 | _igvn.remove_dead_node( phi ); |
| 566 | } else { |
| 567 | assert(phi->in(0) == region, "Inconsistent graph")do { if (!(phi->in(0) == region)) { (*g_assert_poison) = 'X' ;; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/opto/split_if.cpp" , 567, "assert(" "phi->in(0) == region" ") failed", "Inconsistent graph" ); ::breakpoint(); } } while (0); |
| 568 | // Random memory op guarded by Region. Compute new DEF for USE. |
| 569 | handle_use(phi, region, ®ion_cache, region_dom, new_false, new_true, old_false, old_true); |
| 570 | } |
| 571 | // Every path above deletes a use of the region, except for the region |
| 572 | // self-cycle (which is needed by handle_use calling find_use_block |
| 573 | // calling get_ctrl calling get_ctrl_no_update looking for dead |
| 574 | // regions). So roll back the DUIterator innards. |
| 575 | --k; |
| 576 | } // End of while merge point has phis |
| 577 | |
| 578 | _igvn.remove_dead_node(region); |
| 579 | |
| 580 | #ifndef PRODUCT |
| 581 | if( VerifyLoopOptimizations ) verify(); |
| 582 | #endif |
| 583 | } |