| /* |
| * Copyright (c) 1999, 2023, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "opto/addnode.hpp" |
| #include "opto/node.hpp" |
| #include "precompiled.hpp" |
| #include "memory/allocation.inline.hpp" |
| #include "opto/callnode.hpp" |
| #include "opto/loopnode.hpp" |
| #include "opto/movenode.hpp" |
| #include "opto/opaquenode.hpp" |
| |
| |
| //------------------------------split_thru_region------------------------------ |
| // Split Node 'n' through merge point. |
| RegionNode* PhaseIdealLoop::split_thru_region(Node* n, RegionNode* region) { |
| assert(n->is_CFG(), ""); |
| RegionNode* r = new RegionNode(region->req()); |
| IdealLoopTree* loop = get_loop(n); |
| for (uint i = 1; i < region->req(); i++) { |
| Node* x = n->clone(); |
| Node* in0 = n->in(0); |
| if (in0->in(0) == region) x->set_req(0, in0->in(i)); |
| for (uint j = 1; j < n->req(); j++) { |
| Node* in = n->in(j); |
| if (get_ctrl(in) == region) { |
| x->set_req(j, in->in(i)); |
| } |
| } |
| _igvn.register_new_node_with_optimizer(x); |
| set_loop(x, loop); |
| set_idom(x, x->in(0), dom_depth(x->in(0))+1); |
| r->init_req(i, x); |
| } |
| |
| // Record region |
| r->set_req(0,region); // Not a TRUE RegionNode |
| _igvn.register_new_node_with_optimizer(r); |
| set_loop(r, loop); |
| if (!loop->_child) { |
| loop->_body.push(r); |
| } |
| return r; |
| } |
| |
| //------------------------------split_up--------------------------------------- |
| // Split block-local op up through the phis to empty the current block |
| bool PhaseIdealLoop::split_up( Node *n, Node *blk1, Node *blk2 ) { |
| if( n->is_CFG() ) { |
| assert( n->in(0) != blk1, "Lousy candidate for split-if" ); |
| return false; |
| } |
| if (!at_relevant_ctrl(n, blk1, blk2)) |
| return false; // Not block local |
| if( n->is_Phi() ) return false; // Local PHIs are expected |
| |
| // Recursively split-up inputs |
| for (uint i = 1; i < n->req(); i++) { |
| if( split_up( n->in(i), blk1, blk2 ) ) { |
| // Got split recursively and self went dead? |
| if (n->outcnt() == 0) |
| _igvn.remove_dead_node(n); |
| return true; |
| } |
| } |
| |
| if (clone_cmp_loadklass_down(n, blk1, blk2)) { |
| return true; |
| } |
| |
| // Check for needing to clone-up a compare. Can't do that, it forces |
| // another (nested) split-if transform. Instead, clone it "down". |
| if (clone_cmp_down(n, blk1, blk2)) { |
| return true; |
| } |
| |
| if (subgraph_has_opaque(n)) { |
| Unique_Node_List wq; |
| wq.push(n); |
| for (uint i = 0; i < wq.size(); i++) { |
| Node* m = wq.at(i); |
| if (m->is_If()) { |
| assert(assertion_predicate_has_loop_opaque_node(m->as_If()), "opaque node not reachable from if?"); |
| Node* bol = create_bool_from_template_assertion_predicate(m, nullptr, nullptr, m->in(0)); |
| _igvn.replace_input_of(m, 1, bol); |
| } else { |
| assert(!m->is_CFG(), "not CFG expected"); |
| for (DUIterator_Fast jmax, j = m->fast_outs(jmax); j < jmax; j++) { |
| Node* u = m->fast_out(j); |
| wq.push(u); |
| } |
| } |
| } |
| } |
| |
| if (n->Opcode() == Op_OpaqueZeroTripGuard) { |
| // If this Opaque1 is part of the zero trip guard for a loop: |
| // 1- it can't be shared |
| // 2- the zero trip guard can't be the if that's being split |
| // As a consequence, this node could be assigned control anywhere between its current control and the zero trip guard. |
| // Move it down to get it out of the way of split if and avoid breaking the zero trip guard shape. |
| Node* cmp = n->unique_out(); |
| assert(cmp->Opcode() == Op_CmpI, "bad zero trip guard shape"); |
| Node* bol = cmp->unique_out(); |
| assert(bol->Opcode() == Op_Bool, "bad zero trip guard shape"); |
| Node* iff = bol->unique_out(); |
| assert(iff->Opcode() == Op_If, "bad zero trip guard shape"); |
| set_ctrl(n, iff->in(0)); |
| set_ctrl(cmp, iff->in(0)); |
| set_ctrl(bol, iff->in(0)); |
| return true; |
| } |
| |
| // See if splitting-up a Store. Any anti-dep loads must go up as |
| // well. An anti-dep load might be in the wrong block, because in |
| // this particular layout/schedule we ignored anti-deps and allow |
| // memory to be alive twice. This only works if we do the same |
| // operations on anti-dep loads as we do their killing stores. |
| if( n->is_Store() && n->in(MemNode::Memory)->in(0) == n->in(0) ) { |
| // Get store's memory slice |
| int alias_idx = C->get_alias_index(_igvn.type(n->in(MemNode::Address))->is_ptr()); |
| |
| // Get memory-phi anti-dep loads will be using |
| Node *memphi = n->in(MemNode::Memory); |
| assert( memphi->is_Phi(), "" ); |
| // Hoist any anti-dep load to the splitting block; |
| // it will then "split-up". |
| for (DUIterator_Fast imax,i = memphi->fast_outs(imax); i < imax; i++) { |
| Node *load = memphi->fast_out(i); |
| if( load->is_Load() && alias_idx == C->get_alias_index(_igvn.type(load->in(MemNode::Address))->is_ptr()) ) |
| set_ctrl(load,blk1); |
| } |
| } |
| |
| // Found some other Node; must clone it up |
| #ifndef PRODUCT |
| if( PrintOpto && VerifyLoopOptimizations ) { |
| tty->print("Cloning up: "); |
| n->dump(); |
| } |
| #endif |
| |
| // ConvI2L may have type information on it which becomes invalid if |
| // it moves up in the graph so change any clones so widen the type |
| // to TypeLong::INT when pushing it up. |
| const Type* rtype = nullptr; |
| if (n->Opcode() == Op_ConvI2L && n->bottom_type() != TypeLong::INT) { |
| rtype = TypeLong::INT; |
| } |
| |
| // Now actually split-up this guy. One copy per control path merging. |
| Node *phi = PhiNode::make_blank(blk1, n); |
| for( uint j = 1; j < blk1->req(); j++ ) { |
| Node *x = n->clone(); |
| // Widen the type of the ConvI2L when pushing up. |
| if (rtype != nullptr) x->as_Type()->set_type(rtype); |
| if( n->in(0) && n->in(0) == blk1 ) |
| x->set_req( 0, blk1->in(j) ); |
| for( uint i = 1; i < n->req(); i++ ) { |
| Node *m = n->in(i); |
| if( get_ctrl(m) == blk1 ) { |
| assert( m->in(0) == blk1, "" ); |
| x->set_req( i, m->in(j) ); |
| } |
| } |
| register_new_node( x, blk1->in(j) ); |
| phi->init_req( j, x ); |
| } |
| // Announce phi to optimizer |
| register_new_node(phi, blk1); |
| |
| // Remove cloned-up value from optimizer; use phi instead |
| _igvn.replace_node( n, phi ); |
| |
| // (There used to be a self-recursive call to split_up() here, |
| // but it is not needed. All necessary forward walking is done |
| // by do_split_if() below.) |
| |
| return true; |
| } |
| |
| // Look for a (If .. (Bool(CmpP (LoadKlass .. (AddP obj ..)) ..))) and clone all of it down. |
| // There's likely a CheckCastPP on one of the branches of the If, with obj as input. |
| // If the (LoadKlass .. (AddP obj ..)) is not cloned down, then split if transforms this to: (If .. (Bool(CmpP phi1 ..))) |
| // and the CheckCastPP to (CheckCastPP phi2). It's possible then that phi2 is transformed to a CheckCastPP |
| // (through PhiNode::Ideal) and that that CheckCastPP is replaced by another narrower CheckCastPP at the same control |
| // (through ConstraintCastNode::Identity). That could cause the CheckCastPP at the If to become top while (CmpP phi1) |
| // wouldn't constant fold because it's using a different data path. Cloning the whole subgraph down guarantees both the |
| // AddP and CheckCastPP have the same obj input after split if. |
| bool PhaseIdealLoop::clone_cmp_loadklass_down(Node* n, const Node* blk1, const Node* blk2) { |
| if (n->Opcode() == Op_AddP && at_relevant_ctrl(n, blk1, blk2)) { |
| Node_List cmp_nodes; |
| uint old = C->unique(); |
| for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { |
| Node* u1 = n->fast_out(i); |
| if (u1->Opcode() == Op_LoadNKlass && at_relevant_ctrl(u1, blk1, blk2)) { |
| for (DUIterator_Fast jmax, j = u1->fast_outs(jmax); j < jmax; j++) { |
| Node* u2 = u1->fast_out(j); |
| if (u2->Opcode() == Op_DecodeNKlass && at_relevant_ctrl(u2, blk1, blk2)) { |
| for (DUIterator k = u2->outs(); u2->has_out(k); k++) { |
| Node* u3 = u2->out(k); |
| if (at_relevant_ctrl(u3, blk1, blk2) && clone_cmp_down(u3, blk1, blk2)) { |
| --k; |
| } |
| } |
| for (DUIterator_Fast kmax, k = u2->fast_outs(kmax); k < kmax; k++) { |
| Node* u3 = u2->fast_out(k); |
| if (u3->_idx >= old) { |
| cmp_nodes.push(u3); |
| } |
| } |
| } |
| } |
| } else if (u1->Opcode() == Op_LoadKlass && at_relevant_ctrl(u1, blk1, blk2)) { |
| for (DUIterator j = u1->outs(); u1->has_out(j); j++) { |
| Node* u2 = u1->out(j); |
| if (at_relevant_ctrl(u2, blk1, blk2) && clone_cmp_down(u2, blk1, blk2)) { |
| --j; |
| } |
| } |
| for (DUIterator_Fast kmax, k = u1->fast_outs(kmax); k < kmax; k++) { |
| Node* u2 = u1->fast_out(k); |
| if (u2->_idx >= old) { |
| cmp_nodes.push(u2); |
| } |
| } |
| } |
| } |
| |
| for (uint i = 0; i < cmp_nodes.size(); ++i) { |
| Node* cmp = cmp_nodes.at(i); |
| clone_loadklass_nodes_at_cmp_index(n, cmp, 1); |
| clone_loadklass_nodes_at_cmp_index(n, cmp, 2); |
| } |
| if (n->outcnt() == 0) { |
| assert(n->is_dead(), ""); |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| bool PhaseIdealLoop::at_relevant_ctrl(Node* n, const Node* blk1, const Node* blk2) { |
| return ctrl_or_self(n) == blk1 || ctrl_or_self(n) == blk2; |
| } |
| |
| void PhaseIdealLoop::clone_loadklass_nodes_at_cmp_index(const Node* n, Node* cmp, int i) { |
| Node* decode = cmp->in(i); |
| if (decode->Opcode() == Op_DecodeNKlass) { |
| Node* loadklass = decode->in(1); |
| if (loadklass->Opcode() == Op_LoadNKlass) { |
| Node* addp = loadklass->in(MemNode::Address); |
| if (addp == n) { |
| Node* ctrl = get_ctrl(cmp); |
| Node* decode_clone = decode->clone(); |
| Node* loadklass_clone = loadklass->clone(); |
| Node* addp_clone = addp->clone(); |
| register_new_node(decode_clone, ctrl); |
| register_new_node(loadklass_clone, ctrl); |
| register_new_node(addp_clone, ctrl); |
| _igvn.replace_input_of(cmp, i, decode_clone); |
| _igvn.replace_input_of(decode_clone, 1, loadklass_clone); |
| _igvn.replace_input_of(loadklass_clone, MemNode::Address, addp_clone); |
| if (decode->outcnt() == 0) { |
| _igvn.remove_dead_node(decode); |
| } |
| } |
| } |
| } else { |
| Node* loadklass = cmp->in(i); |
| if (loadklass->Opcode() == Op_LoadKlass) { |
| Node* addp = loadklass->in(MemNode::Address); |
| if (addp == n) { |
| Node* ctrl = get_ctrl(cmp); |
| Node* loadklass_clone = loadklass->clone(); |
| Node* addp_clone = addp->clone(); |
| register_new_node(loadklass_clone, ctrl); |
| register_new_node(addp_clone, ctrl); |
| _igvn.replace_input_of(cmp, i, loadklass_clone); |
| _igvn.replace_input_of(loadklass_clone, MemNode::Address, addp_clone); |
| if (loadklass->outcnt() == 0) { |
| _igvn.remove_dead_node(loadklass); |
| } |
| } |
| } |
| } |
| } |
| |
| bool PhaseIdealLoop::clone_cmp_down(Node* n, const Node* blk1, const Node* blk2) { |
| if( n->is_Cmp() ) { |
| assert(get_ctrl(n) == blk2 || get_ctrl(n) == blk1, "must be in block with IF"); |
| // Check for simple Cmp/Bool/CMove which we can clone-up. Cmp/Bool/CMove |
| // sequence can have no other users and it must all reside in the split-if |
| // block. Non-simple Cmp/Bool/CMove sequences are 'cloned-down' below - |
| // private, per-use versions of the Cmp and Bool are made. These sink to |
| // the CMove block. If the CMove is in the split-if block, then in the |
| // next iteration this will become a simple Cmp/Bool/CMove set to clone-up. |
| Node *bol, *cmov; |
| if (!(n->outcnt() == 1 && n->unique_out()->is_Bool() && |
| (bol = n->unique_out()->as_Bool()) && |
| (at_relevant_ctrl(bol, blk1, blk2) && |
| bol->outcnt() == 1 && |
| bol->unique_out()->is_CMove() && |
| (cmov = bol->unique_out()->as_CMove()) && |
| at_relevant_ctrl(cmov, blk1, blk2)))) { |
| |
| // Must clone down |
| #ifndef PRODUCT |
| if( PrintOpto && VerifyLoopOptimizations ) { |
| tty->print("Cloning down: "); |
| n->dump(); |
| } |
| #endif |
| if (!n->is_FastLock()) { |
| // Clone down any block-local BoolNode uses of this CmpNode |
| for (DUIterator i = n->outs(); n->has_out(i); i++) { |
| Node* bol = n->out(i); |
| assert( bol->is_Bool(), "" ); |
| if (bol->outcnt() == 1) { |
| Node* use = bol->unique_out(); |
| if (use->Opcode() == Op_Opaque4) { |
| if (use->outcnt() == 1) { |
| Node* iff = use->unique_out(); |
| assert(iff->is_If(), "unexpected node type"); |
| Node *use_c = iff->in(0); |
| if (use_c == blk1 || use_c == blk2) { |
| continue; |
| } |
| } |
| } else { |
| // We might see an Opaque1 from a loop limit check here |
| assert(use->is_If() || use->is_CMove() || use->Opcode() == Op_Opaque1 || use->is_AllocateArray(), "unexpected node type"); |
| Node *use_c = (use->is_If() || use->is_AllocateArray()) ? use->in(0) : get_ctrl(use); |
| if (use_c == blk1 || use_c == blk2) { |
| assert(use->is_CMove(), "unexpected node type"); |
| continue; |
| } |
| } |
| } |
| if (at_relevant_ctrl(bol, blk1, blk2)) { |
| // Recursively sink any BoolNode |
| #ifndef PRODUCT |
| if( PrintOpto && VerifyLoopOptimizations ) { |
| tty->print("Cloning down: "); |
| bol->dump(); |
| } |
| #endif |
| for (DUIterator j = bol->outs(); bol->has_out(j); j++) { |
| Node* u = bol->out(j); |
| // Uses are either IfNodes, CMoves or Opaque4 |
| if (u->Opcode() == Op_Opaque4) { |
| assert(u->in(1) == bol, "bad input"); |
| for (DUIterator_Last kmin, k = u->last_outs(kmin); k >= kmin; --k) { |
| Node* iff = u->last_out(k); |
| assert(iff->is_If() || iff->is_CMove(), "unexpected node type"); |
| assert( iff->in(1) == u, "" ); |
| // Get control block of either the CMove or the If input |
| Node *iff_ctrl = iff->is_If() ? iff->in(0) : get_ctrl(iff); |
| Node *x1 = bol->clone(); |
| Node *x2 = u->clone(); |
| register_new_node(x1, iff_ctrl); |
| register_new_node(x2, iff_ctrl); |
| _igvn.replace_input_of(x2, 1, x1); |
| _igvn.replace_input_of(iff, 1, x2); |
| } |
| _igvn.remove_dead_node(u); |
| --j; |
| } else { |
| // We might see an Opaque1 from a loop limit check here |
| assert(u->is_If() || u->is_CMove() || u->Opcode() == Op_Opaque1 || u->is_AllocateArray(), "unexpected node type"); |
| assert(u->is_AllocateArray() || u->in(1) == bol, ""); |
| assert(!u->is_AllocateArray() || u->in(AllocateNode::ValidLengthTest) == bol, "wrong input to AllocateArray"); |
| // Get control block of either the CMove or the If input |
| Node *u_ctrl = (u->is_If() || u->is_AllocateArray()) ? u->in(0) : get_ctrl(u); |
| assert((u_ctrl != blk1 && u_ctrl != blk2) || u->is_CMove(), "won't converge"); |
| Node *x = bol->clone(); |
| register_new_node(x, u_ctrl); |
| _igvn.replace_input_of(u, u->is_AllocateArray() ? AllocateNode::ValidLengthTest : 1, x); |
| --j; |
| } |
| } |
| _igvn.remove_dead_node(bol); |
| --i; |
| } |
| } |
| } |
| // Clone down this CmpNode |
| for (DUIterator_Last jmin, j = n->last_outs(jmin); j >= jmin; --j) { |
| Node* use = n->last_out(j); |
| uint pos = 1; |
| if (n->is_FastLock()) { |
| pos = TypeFunc::Parms + 2; |
| assert(use->is_Lock(), "FastLock only used by LockNode"); |
| } |
| assert(use->in(pos) == n, "" ); |
| Node *x = n->clone(); |
| register_new_node(x, ctrl_or_self(use)); |
| _igvn.replace_input_of(use, pos, x); |
| } |
| _igvn.remove_dead_node(n); |
| |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| //------------------------------register_new_node------------------------------ |
| void PhaseIdealLoop::register_new_node( Node *n, Node *blk ) { |
| assert(!n->is_CFG(), "must be data node"); |
| _igvn.register_new_node_with_optimizer(n); |
| set_ctrl(n, blk); |
| IdealLoopTree *loop = get_loop(blk); |
| if( !loop->_child ) |
| loop->_body.push(n); |
| } |
| |
| //------------------------------small_cache------------------------------------ |
| struct small_cache : public Dict { |
| |
| small_cache() : Dict( cmpkey, hashptr ) {} |
| Node *probe( Node *use_blk ) { return (Node*)((*this)[use_blk]); } |
| void lru_insert( Node *use_blk, Node *new_def ) { Insert(use_blk,new_def); } |
| }; |
| |
| //------------------------------spinup----------------------------------------- |
| // "Spin up" the dominator tree, starting at the use site and stopping when we |
| // find the post-dominating point. |
| |
| // We must be at the merge point which post-dominates 'new_false' and |
| // 'new_true'. Figure out which edges into the RegionNode eventually lead up |
| // to false and which to true. Put in a PhiNode to merge values; plug in |
| // the appropriate false-arm or true-arm values. If some path leads to the |
| // original IF, then insert a Phi recursively. |
| Node *PhaseIdealLoop::spinup( Node *iff_dom, Node *new_false, Node *new_true, Node *use_blk, Node *def, small_cache *cache ) { |
| if (use_blk->is_top()) // Handle dead uses |
| return use_blk; |
| Node *prior_n = (Node*)((intptr_t)0xdeadbeef); |
| Node *n = use_blk; // Get path input |
| assert( use_blk != iff_dom, "" ); |
| // Here's the "spinup" the dominator tree loop. Do a cache-check |
| // along the way, in case we've come this way before. |
| while( n != iff_dom ) { // Found post-dominating point? |
| prior_n = n; |
| n = idom(n); // Search higher |
| Node *s = cache->probe( prior_n ); // Check cache |
| if( s ) return s; // Cache hit! |
| } |
| |
| Node *phi_post; |
| if( prior_n == new_false || prior_n == new_true ) { |
| phi_post = def->clone(); |
| phi_post->set_req(0, prior_n ); |
| register_new_node(phi_post, prior_n); |
| } else { |
| // This method handles both control uses (looking for Regions) or data |
| // uses (looking for Phis). If looking for a control use, then we need |
| // to insert a Region instead of a Phi; however Regions always exist |
| // previously (the hash_find_insert below would always hit) so we can |
| // return the existing Region. |
| if( def->is_CFG() ) { |
| phi_post = prior_n; // If looking for CFG, return prior |
| } else { |
| assert( def->is_Phi(), "" ); |
| assert( prior_n->is_Region(), "must be a post-dominating merge point" ); |
| |
| // Need a Phi here |
| phi_post = PhiNode::make_blank(prior_n, def); |
| // Search for both true and false on all paths till find one. |
| for( uint i = 1; i < phi_post->req(); i++ ) // For all paths |
| phi_post->init_req( i, spinup( iff_dom, new_false, new_true, prior_n->in(i), def, cache ) ); |
| Node *t = _igvn.hash_find_insert(phi_post); |
| if( t ) { // See if we already have this one |
| // phi_post will not be used, so kill it |
| _igvn.remove_dead_node(phi_post); |
| phi_post->destruct(&_igvn); |
| phi_post = t; |
| } else { |
| register_new_node( phi_post, prior_n ); |
| } |
| } |
| } |
| |
| // Update cache everywhere |
| prior_n = (Node*)((intptr_t)0xdeadbeef); // Reset IDOM walk |
| n = use_blk; // Get path input |
| // Spin-up the idom tree again, basically doing path-compression. |
| // Insert cache entries along the way, so that if we ever hit this |
| // point in the IDOM tree again we'll stop immediately on a cache hit. |
| while( n != iff_dom ) { // Found post-dominating point? |
| prior_n = n; |
| n = idom(n); // Search higher |
| cache->lru_insert( prior_n, phi_post ); // Fill cache |
| } // End of while not gone high enough |
| |
| return phi_post; |
| } |
| |
| //------------------------------find_use_block--------------------------------- |
| // Find the block a USE is in. Normally USE's are in the same block as the |
| // using instruction. For Phi-USE's, the USE is in the predecessor block |
| // along the corresponding path. |
| Node *PhaseIdealLoop::find_use_block( Node *use, Node *def, Node *old_false, Node *new_false, Node *old_true, Node *new_true ) { |
| // CFG uses are their own block |
| if( use->is_CFG() ) |
| return use; |
| |
| if( use->is_Phi() ) { // Phi uses in prior block |
| // Grab the first Phi use; there may be many. |
| // Each will be handled as a separate iteration of |
| // the "while( phi->outcnt() )" loop. |
| uint j; |
| for( j = 1; j < use->req(); j++ ) |
| if( use->in(j) == def ) |
| break; |
| assert( j < use->req(), "def should be among use's inputs" ); |
| return use->in(0)->in(j); |
| } |
| // Normal (non-phi) use |
| Node *use_blk = get_ctrl(use); |
| // Some uses are directly attached to the old (and going away) |
| // false and true branches. |
| if( use_blk == old_false ) { |
| use_blk = new_false; |
| set_ctrl(use, new_false); |
| } |
| if( use_blk == old_true ) { |
| use_blk = new_true; |
| set_ctrl(use, new_true); |
| } |
| |
| if (use_blk == nullptr) { // He's dead, Jim |
| _igvn.replace_node(use, C->top()); |
| } |
| |
| return use_blk; |
| } |
| |
| //------------------------------handle_use------------------------------------- |
| // Handle uses of the merge point. Basically, split-if makes the merge point |
| // go away so all uses of the merge point must go away as well. Most block |
| // local uses have already been split-up, through the merge point. Uses from |
| // far below the merge point can't always be split up (e.g., phi-uses are |
| // pinned) and it makes too much stuff live. Instead we use a path-based |
| // solution to move uses down. |
| // |
| // If the use is along the pre-split-CFG true branch, then the new use will |
| // be from the post-split-CFG true merge point. Vice-versa for the false |
| // path. Some uses will be along both paths; then we sink the use to the |
| // post-dominating location; we may need to insert a Phi there. |
| 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 ) { |
| |
| Node *use_blk = find_use_block(use,def,old_false,new_false,old_true,new_true); |
| if( !use_blk ) return; // He's dead, Jim |
| |
| // Walk up the dominator tree until I hit either the old IfFalse, the old |
| // IfTrue or the old If. Insert Phis where needed. |
| Node *new_def = spinup( region_dom, new_false, new_true, use_blk, def, cache ); |
| |
| // Found where this USE goes. Re-point him. |
| uint i; |
| for( i = 0; i < use->req(); i++ ) |
| if( use->in(i) == def ) |
| break; |
| assert( i < use->req(), "def should be among use's inputs" ); |
| _igvn.replace_input_of(use, i, new_def); |
| } |
| |
| //------------------------------do_split_if------------------------------------ |
| // Found an If getting its condition-code input from a Phi in the same block. |
| // Split thru the Region. |
| void PhaseIdealLoop::do_split_if(Node* iff, RegionNode** new_false_region, RegionNode** new_true_region) { |
| if (PrintOpto && VerifyLoopOptimizations) { |
| tty->print_cr("Split-if"); |
| } |
| if (TraceLoopOpts) { |
| tty->print_cr("SplitIf"); |
| } |
| |
| C->set_major_progress(); |
| RegionNode *region = iff->in(0)->as_Region(); |
| Node *region_dom = idom(region); |
| |
| // We are going to clone this test (and the control flow with it) up through |
| // the incoming merge point. We need to empty the current basic block. |
| // Clone any instructions which must be in this block up through the merge |
| // point. |
| DUIterator i, j; |
| bool progress = true; |
| while (progress) { |
| progress = false; |
| for (i = region->outs(); region->has_out(i); i++) { |
| Node* n = region->out(i); |
| if( n == region ) continue; |
| // The IF to be split is OK. |
| if( n == iff ) continue; |
| if( !n->is_Phi() ) { // Found pinned memory op or such |
| if (split_up(n, region, iff)) { |
| i = region->refresh_out_pos(i); |
| progress = true; |
| } |
| continue; |
| } |
| assert( n->in(0) == region, "" ); |
| |
| // Recursively split up all users of a Phi |
| for (j = n->outs(); n->has_out(j); j++) { |
| Node* m = n->out(j); |
| // If m is dead, throw it away, and declare progress |
| if (_loop_or_ctrl[m->_idx] == nullptr) { |
| _igvn.remove_dead_node(m); |
| // fall through |
| } |
| else if (m != iff && split_up(m, region, iff)) { |
| // fall through |
| } else { |
| continue; |
| } |
| // Something unpredictable changed. |
| // Tell the iterators to refresh themselves, and rerun the loop. |
| i = region->refresh_out_pos(i); |
| j = region->refresh_out_pos(j); |
| progress = true; |
| } |
| } |
| } |
| |
| // Now we have no instructions in the block containing the IF. |
| // Split the IF. |
| RegionNode *new_iff = split_thru_region(iff, region); |
| |
| // Replace both uses of 'new_iff' with Regions merging True/False |
| // paths. This makes 'new_iff' go dead. |
| Node *old_false = nullptr, *old_true = nullptr; |
| RegionNode* new_false = nullptr; |
| RegionNode* new_true = nullptr; |
| for (DUIterator_Last j2min, j2 = iff->last_outs(j2min); j2 >= j2min; --j2) { |
| Node *ifp = iff->last_out(j2); |
| assert( ifp->Opcode() == Op_IfFalse || ifp->Opcode() == Op_IfTrue, "" ); |
| ifp->set_req(0, new_iff); |
| RegionNode* ifpx = split_thru_region(ifp, region); |
| |
| // Replace 'If' projection of a Region with a Region of |
| // 'If' projections. |
| ifpx->set_req(0, ifpx); // A TRUE RegionNode |
| |
| // Setup dominator info |
| set_idom(ifpx, region_dom, dom_depth(region_dom) + 1); |
| |
| // Check for splitting loop tails |
| if( get_loop(iff)->tail() == ifp ) |
| get_loop(iff)->_tail = ifpx; |
| |
| // Replace in the graph with lazy-update mechanism |
| new_iff->set_req(0, new_iff); // hook self so it does not go dead |
| lazy_replace(ifp, ifpx); |
| new_iff->set_req(0, region); |
| |
| // Record bits for later xforms |
| if( ifp->Opcode() == Op_IfFalse ) { |
| old_false = ifp; |
| new_false = ifpx; |
| } else { |
| old_true = ifp; |
| new_true = ifpx; |
| } |
| } |
| _igvn.remove_dead_node(new_iff); |
| // Lazy replace IDOM info with the region's dominator |
| lazy_replace(iff, region_dom); |
| lazy_update(region, region_dom); // idom must be update before handle_uses |
| region->set_req(0, nullptr); // Break the self-cycle. Required for lazy_update to work on region |
| |
| // Now make the original merge point go dead, by handling all its uses. |
| small_cache region_cache; |
| // Preload some control flow in region-cache |
| region_cache.lru_insert( new_false, new_false ); |
| region_cache.lru_insert( new_true , new_true ); |
| // Now handle all uses of the splitting block |
| for (DUIterator k = region->outs(); region->has_out(k); k++) { |
| Node* phi = region->out(k); |
| if (!phi->in(0)) { // Dead phi? Remove it |
| _igvn.remove_dead_node(phi); |
| } else if (phi == region) { // Found the self-reference |
| continue; // No roll-back of DUIterator |
| } else if (phi->is_Phi()) { // Expected common case: Phi hanging off of Region |
| assert(phi->in(0) == region, "Inconsistent graph"); |
| // Need a per-def cache. Phi represents a def, so make a cache |
| small_cache phi_cache; |
| |
| // Inspect all Phi uses to make the Phi go dead |
| for (DUIterator_Last lmin, l = phi->last_outs(lmin); l >= lmin; --l) { |
| Node* use = phi->last_out(l); |
| // Compute the new DEF for this USE. New DEF depends on the path |
| // taken from the original DEF to the USE. The new DEF may be some |
| // collection of PHI's merging values from different paths. The Phis |
| // inserted depend only on the location of the USE. We use a |
| // 2-element cache to handle multiple uses from the same block. |
| handle_use(use, phi, &phi_cache, region_dom, new_false, new_true, old_false, old_true); |
| } // End of while phi has uses |
| // Remove the dead Phi |
| _igvn.remove_dead_node( phi ); |
| } else { |
| assert(phi->in(0) == region, "Inconsistent graph"); |
| // Random memory op guarded by Region. Compute new DEF for USE. |
| handle_use(phi, region, ®ion_cache, region_dom, new_false, new_true, old_false, old_true); |
| } |
| // Every path above deletes a use of the region, except for the region |
| // self-cycle (which is needed by handle_use calling find_use_block |
| // calling get_ctrl calling get_ctrl_no_update looking for dead |
| // regions). So roll back the DUIterator innards. |
| --k; |
| } // End of while merge point has phis |
| |
| _igvn.remove_dead_node(region); |
| |
| if (new_false_region != nullptr) { |
| *new_false_region = new_false; |
| } |
| if (new_true_region != nullptr) { |
| *new_true_region = new_true; |
| } |
| |
| DEBUG_ONLY( if (VerifyLoopOptimizations) { verify(); } ); |
| } |
