| /* |
| * Copyright (c) 2011, 2014, 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 "precompiled.hpp" |
| #include "opto/loopnode.hpp" |
| #include "opto/addnode.hpp" |
| #include "opto/callnode.hpp" |
| #include "opto/connode.hpp" |
| #include "opto/loopnode.hpp" |
| #include "opto/matcher.hpp" |
| #include "opto/mulnode.hpp" |
| #include "opto/rootnode.hpp" |
| #include "opto/subnode.hpp" |
| |
| /* |
| * The general idea of Loop Predication is to insert a predicate on the entry |
| * path to a loop, and raise a uncommon trap if the check of the condition fails. |
| * The condition checks are promoted from inside the loop body, and thus |
| * the checks inside the loop could be eliminated. Currently, loop predication |
| * optimization has been applied to remove array range check and loop invariant |
| * checks (such as null checks). |
| */ |
| |
| //-------------------------------register_control------------------------- |
| void PhaseIdealLoop::register_control(Node* n, IdealLoopTree *loop, Node* pred) { |
| assert(n->is_CFG(), "must be control node"); |
| _igvn.register_new_node_with_optimizer(n); |
| loop->_body.push(n); |
| set_loop(n, loop); |
| // When called from beautify_loops() idom is not constructed yet. |
| if (_idom != NULL) { |
| set_idom(n, pred, dom_depth(pred)); |
| } |
| } |
| |
| //------------------------------create_new_if_for_predicate------------------------ |
| // create a new if above the uct_if_pattern for the predicate to be promoted. |
| // |
| // before after |
| // ---------- ---------- |
| // ctrl ctrl |
| // | | |
| // | | |
| // v v |
| // iff new_iff |
| // / \ / \ |
| // / \ / \ |
| // v v v v |
| // uncommon_proj cont_proj if_uct if_cont |
| // \ | | | | |
| // \ | | | | |
| // v v v | v |
| // rgn loop | iff |
| // | | / \ |
| // | | / \ |
| // v | v v |
| // uncommon_trap | uncommon_proj cont_proj |
| // \ \ | | |
| // \ \ | | |
| // v v v v |
| // rgn loop |
| // | |
| // | |
| // v |
| // uncommon_trap |
| // |
| // |
| // We will create a region to guard the uct call if there is no one there. |
| // The true projecttion (if_cont) of the new_iff is returned. |
| // This code is also used to clone predicates to clonned loops. |
| ProjNode* PhaseIdealLoop::create_new_if_for_predicate(ProjNode* cont_proj, Node* new_entry, |
| Deoptimization::DeoptReason reason) { |
| assert(cont_proj->is_uncommon_trap_if_pattern(reason), "must be a uct if pattern!"); |
| IfNode* iff = cont_proj->in(0)->as_If(); |
| |
| ProjNode *uncommon_proj = iff->proj_out(1 - cont_proj->_con); |
| Node *rgn = uncommon_proj->unique_ctrl_out(); |
| assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct"); |
| |
| uint proj_index = 1; // region's edge corresponding to uncommon_proj |
| if (!rgn->is_Region()) { // create a region to guard the call |
| assert(rgn->is_Call(), "must be call uct"); |
| CallNode* call = rgn->as_Call(); |
| IdealLoopTree* loop = get_loop(call); |
| rgn = new (C) RegionNode(1); |
| rgn->add_req(uncommon_proj); |
| register_control(rgn, loop, uncommon_proj); |
| _igvn.hash_delete(call); |
| call->set_req(0, rgn); |
| // When called from beautify_loops() idom is not constructed yet. |
| if (_idom != NULL) { |
| set_idom(call, rgn, dom_depth(rgn)); |
| } |
| } else { |
| // Find region's edge corresponding to uncommon_proj |
| for (; proj_index < rgn->req(); proj_index++) |
| if (rgn->in(proj_index) == uncommon_proj) break; |
| assert(proj_index < rgn->req(), "sanity"); |
| } |
| |
| Node* entry = iff->in(0); |
| if (new_entry != NULL) { |
| // Clonning the predicate to new location. |
| entry = new_entry; |
| } |
| // Create new_iff |
| IdealLoopTree* lp = get_loop(entry); |
| IfNode *new_iff = iff->clone()->as_If(); |
| new_iff->set_req(0, entry); |
| register_control(new_iff, lp, entry); |
| Node *if_cont = new (C) IfTrueNode(new_iff); |
| Node *if_uct = new (C) IfFalseNode(new_iff); |
| if (cont_proj->is_IfFalse()) { |
| // Swap |
| Node* tmp = if_uct; if_uct = if_cont; if_cont = tmp; |
| } |
| register_control(if_cont, lp, new_iff); |
| register_control(if_uct, get_loop(rgn), new_iff); |
| |
| // if_uct to rgn |
| _igvn.hash_delete(rgn); |
| rgn->add_req(if_uct); |
| // When called from beautify_loops() idom is not constructed yet. |
| if (_idom != NULL) { |
| Node* ridom = idom(rgn); |
| Node* nrdom = dom_lca(ridom, new_iff); |
| set_idom(rgn, nrdom, dom_depth(rgn)); |
| } |
| |
| // If rgn has phis add new edges which has the same |
| // value as on original uncommon_proj pass. |
| assert(rgn->in(rgn->req() -1) == if_uct, "new edge should be last"); |
| bool has_phi = false; |
| for (DUIterator_Fast imax, i = rgn->fast_outs(imax); i < imax; i++) { |
| Node* use = rgn->fast_out(i); |
| if (use->is_Phi() && use->outcnt() > 0) { |
| assert(use->in(0) == rgn, ""); |
| _igvn.rehash_node_delayed(use); |
| use->add_req(use->in(proj_index)); |
| has_phi = true; |
| } |
| } |
| assert(!has_phi || rgn->req() > 3, "no phis when region is created"); |
| |
| if (new_entry == NULL) { |
| // Attach if_cont to iff |
| _igvn.hash_delete(iff); |
| iff->set_req(0, if_cont); |
| if (_idom != NULL) { |
| set_idom(iff, if_cont, dom_depth(iff)); |
| } |
| } |
| return if_cont->as_Proj(); |
| } |
| |
| //------------------------------create_new_if_for_predicate------------------------ |
| // Create a new if below new_entry for the predicate to be cloned (IGVN optimization) |
| ProjNode* PhaseIterGVN::create_new_if_for_predicate(ProjNode* cont_proj, Node* new_entry, |
| Deoptimization::DeoptReason reason) { |
| assert(new_entry != 0, "only used for clone predicate"); |
| assert(cont_proj->is_uncommon_trap_if_pattern(reason), "must be a uct if pattern!"); |
| IfNode* iff = cont_proj->in(0)->as_If(); |
| |
| ProjNode *uncommon_proj = iff->proj_out(1 - cont_proj->_con); |
| Node *rgn = uncommon_proj->unique_ctrl_out(); |
| assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct"); |
| |
| uint proj_index = 1; // region's edge corresponding to uncommon_proj |
| if (!rgn->is_Region()) { // create a region to guard the call |
| assert(rgn->is_Call(), "must be call uct"); |
| CallNode* call = rgn->as_Call(); |
| rgn = new (C) RegionNode(1); |
| register_new_node_with_optimizer(rgn); |
| rgn->add_req(uncommon_proj); |
| hash_delete(call); |
| call->set_req(0, rgn); |
| } else { |
| // Find region's edge corresponding to uncommon_proj |
| for (; proj_index < rgn->req(); proj_index++) |
| if (rgn->in(proj_index) == uncommon_proj) break; |
| assert(proj_index < rgn->req(), "sanity"); |
| } |
| |
| // Create new_iff in new location. |
| IfNode *new_iff = iff->clone()->as_If(); |
| new_iff->set_req(0, new_entry); |
| |
| register_new_node_with_optimizer(new_iff); |
| Node *if_cont = new (C) IfTrueNode(new_iff); |
| Node *if_uct = new (C) IfFalseNode(new_iff); |
| if (cont_proj->is_IfFalse()) { |
| // Swap |
| Node* tmp = if_uct; if_uct = if_cont; if_cont = tmp; |
| } |
| register_new_node_with_optimizer(if_cont); |
| register_new_node_with_optimizer(if_uct); |
| |
| // if_uct to rgn |
| hash_delete(rgn); |
| rgn->add_req(if_uct); |
| |
| // If rgn has phis add corresponding new edges which has the same |
| // value as on original uncommon_proj pass. |
| assert(rgn->in(rgn->req() -1) == if_uct, "new edge should be last"); |
| bool has_phi = false; |
| for (DUIterator_Fast imax, i = rgn->fast_outs(imax); i < imax; i++) { |
| Node* use = rgn->fast_out(i); |
| if (use->is_Phi() && use->outcnt() > 0) { |
| rehash_node_delayed(use); |
| use->add_req(use->in(proj_index)); |
| has_phi = true; |
| } |
| } |
| assert(!has_phi || rgn->req() > 3, "no phis when region is created"); |
| |
| return if_cont->as_Proj(); |
| } |
| |
| //--------------------------clone_predicate----------------------- |
| ProjNode* PhaseIdealLoop::clone_predicate(ProjNode* predicate_proj, Node* new_entry, |
| Deoptimization::DeoptReason reason, |
| PhaseIdealLoop* loop_phase, |
| PhaseIterGVN* igvn) { |
| ProjNode* new_predicate_proj; |
| if (loop_phase != NULL) { |
| new_predicate_proj = loop_phase->create_new_if_for_predicate(predicate_proj, new_entry, reason); |
| } else { |
| new_predicate_proj = igvn->create_new_if_for_predicate(predicate_proj, new_entry, reason); |
| } |
| IfNode* iff = new_predicate_proj->in(0)->as_If(); |
| Node* ctrl = iff->in(0); |
| |
| // Match original condition since predicate's projections could be swapped. |
| assert(predicate_proj->in(0)->in(1)->in(1)->Opcode()==Op_Opaque1, "must be"); |
| Node* opq = new (igvn->C) Opaque1Node(igvn->C, predicate_proj->in(0)->in(1)->in(1)->in(1)); |
| igvn->C->add_predicate_opaq(opq); |
| |
| Node* bol = new (igvn->C) Conv2BNode(opq); |
| if (loop_phase != NULL) { |
| loop_phase->register_new_node(opq, ctrl); |
| loop_phase->register_new_node(bol, ctrl); |
| } else { |
| igvn->register_new_node_with_optimizer(opq); |
| igvn->register_new_node_with_optimizer(bol); |
| } |
| igvn->hash_delete(iff); |
| iff->set_req(1, bol); |
| return new_predicate_proj; |
| } |
| |
| |
| //--------------------------clone_loop_predicates----------------------- |
| // Interface from IGVN |
| Node* PhaseIterGVN::clone_loop_predicates(Node* old_entry, Node* new_entry, bool clone_limit_check) { |
| return PhaseIdealLoop::clone_loop_predicates(old_entry, new_entry, clone_limit_check, NULL, this); |
| } |
| |
| // Interface from PhaseIdealLoop |
| Node* PhaseIdealLoop::clone_loop_predicates(Node* old_entry, Node* new_entry, bool clone_limit_check) { |
| return clone_loop_predicates(old_entry, new_entry, clone_limit_check, this, &this->_igvn); |
| } |
| |
| // Clone loop predicates to cloned loops (peeled, unswitched, split_if). |
| Node* PhaseIdealLoop::clone_loop_predicates(Node* old_entry, Node* new_entry, |
| bool clone_limit_check, |
| PhaseIdealLoop* loop_phase, |
| PhaseIterGVN* igvn) { |
| #ifdef ASSERT |
| if (new_entry == NULL || !(new_entry->is_Proj() || new_entry->is_Region() || new_entry->is_SafePoint())) { |
| if (new_entry != NULL) |
| new_entry->dump(); |
| assert(false, "not IfTrue, IfFalse, Region or SafePoint"); |
| } |
| #endif |
| // Search original predicates |
| Node* entry = old_entry; |
| ProjNode* limit_check_proj = NULL; |
| if (LoopLimitCheck) { |
| limit_check_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check); |
| if (limit_check_proj != NULL) { |
| entry = entry->in(0)->in(0); |
| } |
| } |
| if (UseLoopPredicate) { |
| ProjNode* predicate_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); |
| if (predicate_proj != NULL) { // right pattern that can be used by loop predication |
| // clone predicate |
| new_entry = clone_predicate(predicate_proj, new_entry, |
| Deoptimization::Reason_predicate, |
| loop_phase, igvn); |
| assert(new_entry != NULL && new_entry->is_Proj(), "IfTrue or IfFalse after clone predicate"); |
| if (TraceLoopPredicate) { |
| tty->print("Loop Predicate cloned: "); |
| debug_only( new_entry->in(0)->dump(); ) |
| } |
| } |
| } |
| if (limit_check_proj != NULL && clone_limit_check) { |
| // Clone loop limit check last to insert it before loop. |
| // Don't clone a limit check which was already finalized |
| // for this counted loop (only one limit check is needed). |
| new_entry = clone_predicate(limit_check_proj, new_entry, |
| Deoptimization::Reason_loop_limit_check, |
| loop_phase, igvn); |
| assert(new_entry != NULL && new_entry->is_Proj(), "IfTrue or IfFalse after clone limit check"); |
| if (TraceLoopLimitCheck) { |
| tty->print("Loop Limit Check cloned: "); |
| debug_only( new_entry->in(0)->dump(); ) |
| } |
| } |
| return new_entry; |
| } |
| |
| //--------------------------skip_loop_predicates------------------------------ |
| // Skip related predicates. |
| Node* PhaseIdealLoop::skip_loop_predicates(Node* entry) { |
| Node* predicate = NULL; |
| if (LoopLimitCheck) { |
| predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check); |
| if (predicate != NULL) { |
| entry = entry->in(0)->in(0); |
| } |
| } |
| if (UseLoopPredicate) { |
| predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); |
| if (predicate != NULL) { // right pattern that can be used by loop predication |
| IfNode* iff = entry->in(0)->as_If(); |
| ProjNode* uncommon_proj = iff->proj_out(1 - entry->as_Proj()->_con); |
| Node* rgn = uncommon_proj->unique_ctrl_out(); |
| assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct"); |
| entry = entry->in(0)->in(0); |
| while (entry != NULL && entry->is_Proj() && entry->in(0)->is_If()) { |
| uncommon_proj = entry->in(0)->as_If()->proj_out(1 - entry->as_Proj()->_con); |
| if (uncommon_proj->unique_ctrl_out() != rgn) |
| break; |
| entry = entry->in(0)->in(0); |
| } |
| } |
| } |
| return entry; |
| } |
| |
| //--------------------------find_predicate_insertion_point------------------- |
| // Find a good location to insert a predicate |
| ProjNode* PhaseIdealLoop::find_predicate_insertion_point(Node* start_c, Deoptimization::DeoptReason reason) { |
| if (start_c == NULL || !start_c->is_Proj()) |
| return NULL; |
| if (start_c->as_Proj()->is_uncommon_trap_if_pattern(reason)) { |
| return start_c->as_Proj(); |
| } |
| return NULL; |
| } |
| |
| //--------------------------find_predicate------------------------------------ |
| // Find a predicate |
| Node* PhaseIdealLoop::find_predicate(Node* entry) { |
| Node* predicate = NULL; |
| if (LoopLimitCheck) { |
| predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check); |
| if (predicate != NULL) { // right pattern that can be used by loop predication |
| return entry; |
| } |
| } |
| if (UseLoopPredicate) { |
| predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); |
| if (predicate != NULL) { // right pattern that can be used by loop predication |
| return entry; |
| } |
| } |
| return NULL; |
| } |
| |
| //------------------------------Invariance----------------------------------- |
| // Helper class for loop_predication_impl to compute invariance on the fly and |
| // clone invariants. |
| class Invariance : public StackObj { |
| VectorSet _visited, _invariant; |
| Node_Stack _stack; |
| VectorSet _clone_visited; |
| Node_List _old_new; // map of old to new (clone) |
| IdealLoopTree* _lpt; |
| PhaseIdealLoop* _phase; |
| |
| // Helper function to set up the invariance for invariance computation |
| // If n is a known invariant, set up directly. Otherwise, look up the |
| // the possibility to push n onto the stack for further processing. |
| void visit(Node* use, Node* n) { |
| if (_lpt->is_invariant(n)) { // known invariant |
| _invariant.set(n->_idx); |
| } else if (!n->is_CFG()) { |
| Node *n_ctrl = _phase->ctrl_or_self(n); |
| Node *u_ctrl = _phase->ctrl_or_self(use); // self if use is a CFG |
| if (_phase->is_dominator(n_ctrl, u_ctrl)) { |
| _stack.push(n, n->in(0) == NULL ? 1 : 0); |
| } |
| } |
| } |
| |
| // Compute invariance for "the_node" and (possibly) all its inputs recursively |
| // on the fly |
| void compute_invariance(Node* n) { |
| assert(_visited.test(n->_idx), "must be"); |
| visit(n, n); |
| while (_stack.is_nonempty()) { |
| Node* n = _stack.node(); |
| uint idx = _stack.index(); |
| if (idx == n->req()) { // all inputs are processed |
| _stack.pop(); |
| // n is invariant if it's inputs are all invariant |
| bool all_inputs_invariant = true; |
| for (uint i = 0; i < n->req(); i++) { |
| Node* in = n->in(i); |
| if (in == NULL) continue; |
| assert(_visited.test(in->_idx), "must have visited input"); |
| if (!_invariant.test(in->_idx)) { // bad guy |
| all_inputs_invariant = false; |
| break; |
| } |
| } |
| if (all_inputs_invariant) { |
| // If n's control is a predicate that was moved out of the |
| // loop, it was marked invariant but n is only invariant if |
| // it depends only on that test. Otherwise, unless that test |
| // is out of the loop, it's not invariant. |
| if (n->is_CFG() || n->depends_only_on_test() || n->in(0) == NULL || !_phase->is_member(_lpt, n->in(0))) { |
| _invariant.set(n->_idx); // I am a invariant too |
| } |
| } |
| } else { // process next input |
| _stack.set_index(idx + 1); |
| Node* m = n->in(idx); |
| if (m != NULL && !_visited.test_set(m->_idx)) { |
| visit(n, m); |
| } |
| } |
| } |
| } |
| |
| // Helper function to set up _old_new map for clone_nodes. |
| // If n is a known invariant, set up directly ("clone" of n == n). |
| // Otherwise, push n onto the stack for real cloning. |
| void clone_visit(Node* n) { |
| assert(_invariant.test(n->_idx), "must be invariant"); |
| if (_lpt->is_invariant(n)) { // known invariant |
| _old_new.map(n->_idx, n); |
| } else { // to be cloned |
| assert(!n->is_CFG(), "should not see CFG here"); |
| _stack.push(n, n->in(0) == NULL ? 1 : 0); |
| } |
| } |
| |
| // Clone "n" and (possibly) all its inputs recursively |
| void clone_nodes(Node* n, Node* ctrl) { |
| clone_visit(n); |
| while (_stack.is_nonempty()) { |
| Node* n = _stack.node(); |
| uint idx = _stack.index(); |
| if (idx == n->req()) { // all inputs processed, clone n! |
| _stack.pop(); |
| // clone invariant node |
| Node* n_cl = n->clone(); |
| _old_new.map(n->_idx, n_cl); |
| _phase->register_new_node(n_cl, ctrl); |
| for (uint i = 0; i < n->req(); i++) { |
| Node* in = n_cl->in(i); |
| if (in == NULL) continue; |
| n_cl->set_req(i, _old_new[in->_idx]); |
| } |
| } else { // process next input |
| _stack.set_index(idx + 1); |
| Node* m = n->in(idx); |
| if (m != NULL && !_clone_visited.test_set(m->_idx)) { |
| clone_visit(m); // visit the input |
| } |
| } |
| } |
| } |
| |
| public: |
| Invariance(Arena* area, IdealLoopTree* lpt) : |
| _lpt(lpt), _phase(lpt->_phase), |
| _visited(area), _invariant(area), _stack(area, 10 /* guess */), |
| _clone_visited(area), _old_new(area) |
| {} |
| |
| // Map old to n for invariance computation and clone |
| void map_ctrl(Node* old, Node* n) { |
| assert(old->is_CFG() && n->is_CFG(), "must be"); |
| _old_new.map(old->_idx, n); // "clone" of old is n |
| _invariant.set(old->_idx); // old is invariant |
| _clone_visited.set(old->_idx); |
| } |
| |
| // Driver function to compute invariance |
| bool is_invariant(Node* n) { |
| if (!_visited.test_set(n->_idx)) |
| compute_invariance(n); |
| return (_invariant.test(n->_idx) != 0); |
| } |
| |
| // Driver function to clone invariant |
| Node* clone(Node* n, Node* ctrl) { |
| assert(ctrl->is_CFG(), "must be"); |
| assert(_invariant.test(n->_idx), "must be an invariant"); |
| if (!_clone_visited.test(n->_idx)) |
| clone_nodes(n, ctrl); |
| return _old_new[n->_idx]; |
| } |
| }; |
| |
| //------------------------------is_range_check_if ----------------------------------- |
| // Returns true if the predicate of iff is in "scale*iv + offset u< load_range(ptr)" format |
| // Note: this function is particularly designed for loop predication. We require load_range |
| // and offset to be loop invariant computed on the fly by "invar" |
| bool IdealLoopTree::is_range_check_if(IfNode *iff, PhaseIdealLoop *phase, Invariance& invar) const { |
| if (!is_loop_exit(iff)) { |
| return false; |
| } |
| if (!iff->in(1)->is_Bool()) { |
| return false; |
| } |
| const BoolNode *bol = iff->in(1)->as_Bool(); |
| if (bol->_test._test != BoolTest::lt) { |
| return false; |
| } |
| if (!bol->in(1)->is_Cmp()) { |
| return false; |
| } |
| const CmpNode *cmp = bol->in(1)->as_Cmp(); |
| if (cmp->Opcode() != Op_CmpU) { |
| return false; |
| } |
| Node* range = cmp->in(2); |
| if (range->Opcode() != Op_LoadRange) { |
| const TypeInt* tint = phase->_igvn.type(range)->isa_int(); |
| if (tint == NULL || tint->empty() || tint->_lo < 0) { |
| // Allow predication on positive values that aren't LoadRanges. |
| // This allows optimization of loops where the length of the |
| // array is a known value and doesn't need to be loaded back |
| // from the array. |
| return false; |
| } |
| } |
| if (!invar.is_invariant(range)) { |
| return false; |
| } |
| Node *iv = _head->as_CountedLoop()->phi(); |
| int scale = 0; |
| Node *offset = NULL; |
| if (!phase->is_scaled_iv_plus_offset(cmp->in(1), iv, &scale, &offset)) { |
| return false; |
| } |
| if (offset && !invar.is_invariant(offset)) { // offset must be invariant |
| return false; |
| } |
| return true; |
| } |
| |
| //------------------------------rc_predicate----------------------------------- |
| // Create a range check predicate |
| // |
| // for (i = init; i < limit; i += stride) { |
| // a[scale*i+offset] |
| // } |
| // |
| // Compute max(scale*i + offset) for init <= i < limit and build the predicate |
| // as "max(scale*i + offset) u< a.length". |
| // |
| // There are two cases for max(scale*i + offset): |
| // (1) stride*scale > 0 |
| // max(scale*i + offset) = scale*(limit-stride) + offset |
| // (2) stride*scale < 0 |
| // max(scale*i + offset) = scale*init + offset |
| BoolNode* PhaseIdealLoop::rc_predicate(IdealLoopTree *loop, Node* ctrl, |
| int scale, Node* offset, |
| Node* init, Node* limit, jint stride, |
| Node* range, bool upper, bool &overflow) { |
| jint con_limit = limit->is_Con() ? limit->get_int() : 0; |
| jint con_init = init->is_Con() ? init->get_int() : 0; |
| jint con_offset = offset->is_Con() ? offset->get_int() : 0; |
| |
| stringStream* predString = NULL; |
| if (TraceLoopPredicate) { |
| predString = new stringStream(); |
| predString->print("rc_predicate "); |
| } |
| |
| overflow = false; |
| Node* max_idx_expr = NULL; |
| const TypeInt* idx_type = TypeInt::INT; |
| if ((stride > 0) == (scale > 0) == upper) { |
| if (TraceLoopPredicate) { |
| predString->print(limit->is_Con() ? "(%d " : "(limit ", con_limit); |
| predString->print("- %d) ", stride); |
| } |
| // Check if (limit - stride) may overflow |
| const TypeInt* limit_type = _igvn.type(limit)->isa_int(); |
| jint limit_lo = limit_type->_lo; |
| jint limit_hi = limit_type->_hi; |
| jint res_lo = limit_lo - stride; |
| jint res_hi = limit_hi - stride; |
| if ((stride > 0 && (res_lo < limit_lo)) || |
| (stride < 0 && (res_hi > limit_hi))) { |
| // No overflow possible |
| ConINode* con_stride = _igvn.intcon(stride); |
| set_ctrl(con_stride, C->root()); |
| max_idx_expr = new (C) SubINode(limit, con_stride); |
| idx_type = TypeInt::make(limit_lo - stride, limit_hi - stride, limit_type->_widen); |
| } else { |
| // May overflow |
| overflow = true; |
| limit = new (C) ConvI2LNode(limit); |
| register_new_node(limit, ctrl); |
| ConLNode* con_stride = _igvn.longcon(stride); |
| set_ctrl(con_stride, C->root()); |
| max_idx_expr = new (C) SubLNode(limit, con_stride); |
| } |
| register_new_node(max_idx_expr, ctrl); |
| } else { |
| if (TraceLoopPredicate) { |
| predString->print(init->is_Con() ? "%d " : "init ", con_init); |
| } |
| idx_type = _igvn.type(init)->isa_int(); |
| max_idx_expr = init; |
| } |
| |
| if (scale != 1) { |
| ConNode* con_scale = _igvn.intcon(scale); |
| set_ctrl(con_scale, C->root()); |
| if (TraceLoopPredicate) { |
| predString->print("* %d ", scale); |
| } |
| // Check if (scale * max_idx_expr) may overflow |
| const TypeInt* scale_type = TypeInt::make(scale); |
| MulINode* mul = new (C) MulINode(max_idx_expr, con_scale); |
| idx_type = (TypeInt*)mul->mul_ring(idx_type, scale_type); |
| if (overflow || TypeInt::INT->higher_equal(idx_type)) { |
| // May overflow |
| mul->destruct(); |
| if (!overflow) { |
| max_idx_expr = new (C) ConvI2LNode(max_idx_expr); |
| register_new_node(max_idx_expr, ctrl); |
| } |
| overflow = true; |
| con_scale = _igvn.longcon(scale); |
| set_ctrl(con_scale, C->root()); |
| max_idx_expr = new (C) MulLNode(max_idx_expr, con_scale); |
| } else { |
| // No overflow possible |
| max_idx_expr = mul; |
| } |
| register_new_node(max_idx_expr, ctrl); |
| } |
| |
| if (offset && (!offset->is_Con() || con_offset != 0)){ |
| if (TraceLoopPredicate) { |
| predString->print(offset->is_Con() ? "+ %d " : "+ offset", con_offset); |
| } |
| // Check if (max_idx_expr + offset) may overflow |
| const TypeInt* offset_type = _igvn.type(offset)->isa_int(); |
| jint lo = idx_type->_lo + offset_type->_lo; |
| jint hi = idx_type->_hi + offset_type->_hi; |
| if (overflow || (lo > hi) || |
| ((idx_type->_lo & offset_type->_lo) < 0 && lo >= 0) || |
| ((~(idx_type->_hi | offset_type->_hi)) < 0 && hi < 0)) { |
| // May overflow |
| if (!overflow) { |
| max_idx_expr = new (C) ConvI2LNode(max_idx_expr); |
| register_new_node(max_idx_expr, ctrl); |
| } |
| overflow = true; |
| offset = new (C) ConvI2LNode(offset); |
| register_new_node(offset, ctrl); |
| max_idx_expr = new (C) AddLNode(max_idx_expr, offset); |
| } else { |
| // No overflow possible |
| max_idx_expr = new (C) AddINode(max_idx_expr, offset); |
| } |
| register_new_node(max_idx_expr, ctrl); |
| } |
| |
| CmpNode* cmp = NULL; |
| if (overflow) { |
| // Integer expressions may overflow, do long comparison |
| range = new (C) ConvI2LNode(range); |
| register_new_node(range, ctrl); |
| if (!Matcher::has_match_rule(Op_CmpUL)) { |
| // We don't support unsigned long comparisons. Set 'max_idx_expr' |
| // to max_julong if < 0 to make the signed comparison fail. |
| ConINode* sign_pos = _igvn.intcon(BitsPerLong - 1); |
| set_ctrl(sign_pos, C->root()); |
| Node* sign_bit_mask = new (C) RShiftLNode(max_idx_expr, sign_pos); |
| register_new_node(sign_bit_mask, ctrl); |
| // OR with sign bit to set all bits to 1 if negative (otherwise no change) |
| max_idx_expr = new (C) OrLNode(max_idx_expr, sign_bit_mask); |
| register_new_node(max_idx_expr, ctrl); |
| // AND with 0x7ff... to unset the sign bit |
| ConLNode* remove_sign_mask = _igvn.longcon(max_jlong); |
| set_ctrl(remove_sign_mask, C->root()); |
| max_idx_expr = new (C) AndLNode(max_idx_expr, remove_sign_mask); |
| register_new_node(max_idx_expr, ctrl); |
| |
| cmp = new (C) CmpLNode(max_idx_expr, range); |
| } else { |
| cmp = new (C) CmpULNode(max_idx_expr, range); |
| } |
| } else { |
| cmp = new (C) CmpUNode(max_idx_expr, range); |
| } |
| register_new_node(cmp, ctrl); |
| BoolNode* bol = new (C) BoolNode(cmp, BoolTest::lt); |
| register_new_node(bol, ctrl); |
| |
| if (TraceLoopPredicate) { |
| predString->print_cr("<u range"); |
| tty->print("%s", predString->as_string()); |
| } |
| return bol; |
| } |
| |
| //------------------------------ loop_predication_impl-------------------------- |
| // Insert loop predicates for null checks and range checks |
| bool PhaseIdealLoop::loop_predication_impl(IdealLoopTree *loop) { |
| if (!UseLoopPredicate) return false; |
| |
| if (!loop->_head->is_Loop()) { |
| // Could be a simple region when irreducible loops are present. |
| return false; |
| } |
| LoopNode* head = loop->_head->as_Loop(); |
| |
| if (head->unique_ctrl_out()->Opcode() == Op_NeverBranch) { |
| // do nothing for infinite loops |
| return false; |
| } |
| |
| CountedLoopNode *cl = NULL; |
| if (head->is_valid_counted_loop()) { |
| cl = head->as_CountedLoop(); |
| // do nothing for iteration-splitted loops |
| if (!cl->is_normal_loop()) return false; |
| // Avoid RCE if Counted loop's test is '!='. |
| BoolTest::mask bt = cl->loopexit()->test_trip(); |
| if (bt != BoolTest::lt && bt != BoolTest::gt) |
| cl = NULL; |
| } |
| |
| Node* entry = head->in(LoopNode::EntryControl); |
| ProjNode *predicate_proj = NULL; |
| // Loop limit check predicate should be near the loop. |
| if (LoopLimitCheck) { |
| predicate_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check); |
| if (predicate_proj != NULL) |
| entry = predicate_proj->in(0)->in(0); |
| } |
| |
| predicate_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); |
| if (!predicate_proj) { |
| #ifndef PRODUCT |
| if (TraceLoopPredicate) { |
| tty->print("missing predicate:"); |
| loop->dump_head(); |
| head->dump(1); |
| } |
| #endif |
| return false; |
| } |
| ConNode* zero = _igvn.intcon(0); |
| set_ctrl(zero, C->root()); |
| |
| ResourceArea *area = Thread::current()->resource_area(); |
| Invariance invar(area, loop); |
| |
| // Create list of if-projs such that a newer proj dominates all older |
| // projs in the list, and they all dominate loop->tail() |
| Node_List if_proj_list(area); |
| Node *current_proj = loop->tail(); //start from tail |
| while (current_proj != head) { |
| if (loop == get_loop(current_proj) && // still in the loop ? |
| current_proj->is_Proj() && // is a projection ? |
| current_proj->in(0)->Opcode() == Op_If) { // is a if projection ? |
| if_proj_list.push(current_proj); |
| } |
| current_proj = idom(current_proj); |
| } |
| |
| bool hoisted = false; // true if at least one proj is promoted |
| while (if_proj_list.size() > 0) { |
| // Following are changed to nonnull when a predicate can be hoisted |
| ProjNode* new_predicate_proj = NULL; |
| |
| ProjNode* proj = if_proj_list.pop()->as_Proj(); |
| IfNode* iff = proj->in(0)->as_If(); |
| |
| if (!proj->is_uncommon_trap_if_pattern(Deoptimization::Reason_none)) { |
| if (loop->is_loop_exit(iff)) { |
| // stop processing the remaining projs in the list because the execution of them |
| // depends on the condition of "iff" (iff->in(1)). |
| break; |
| } else { |
| // Both arms are inside the loop. There are two cases: |
| // (1) there is one backward branch. In this case, any remaining proj |
| // in the if_proj list post-dominates "iff". So, the condition of "iff" |
| // does not determine the execution the remining projs directly, and we |
| // can safely continue. |
| // (2) both arms are forwarded, i.e. a diamond shape. In this case, "proj" |
| // does not dominate loop->tail(), so it can not be in the if_proj list. |
| continue; |
| } |
| } |
| |
| Node* test = iff->in(1); |
| if (!test->is_Bool()){ //Conv2B, ... |
| continue; |
| } |
| BoolNode* bol = test->as_Bool(); |
| if (invar.is_invariant(bol)) { |
| // Invariant test |
| new_predicate_proj = create_new_if_for_predicate(predicate_proj, NULL, |
| Deoptimization::Reason_predicate); |
| Node* ctrl = new_predicate_proj->in(0)->as_If()->in(0); |
| BoolNode* new_predicate_bol = invar.clone(bol, ctrl)->as_Bool(); |
| |
| // Negate test if necessary |
| bool negated = false; |
| if (proj->_con != predicate_proj->_con) { |
| new_predicate_bol = new (C) BoolNode(new_predicate_bol->in(1), new_predicate_bol->_test.negate()); |
| register_new_node(new_predicate_bol, ctrl); |
| negated = true; |
| } |
| IfNode* new_predicate_iff = new_predicate_proj->in(0)->as_If(); |
| _igvn.hash_delete(new_predicate_iff); |
| new_predicate_iff->set_req(1, new_predicate_bol); |
| #ifndef PRODUCT |
| if (TraceLoopPredicate) { |
| tty->print("Predicate invariant if%s: %d ", negated ? " negated" : "", new_predicate_iff->_idx); |
| loop->dump_head(); |
| } else if (TraceLoopOpts) { |
| tty->print("Predicate IC "); |
| loop->dump_head(); |
| } |
| #endif |
| } else if ((cl != NULL) && (proj->_con == predicate_proj->_con) && |
| loop->is_range_check_if(iff, this, invar)) { |
| |
| // Range check for counted loops |
| const Node* cmp = bol->in(1)->as_Cmp(); |
| Node* idx = cmp->in(1); |
| assert(!invar.is_invariant(idx), "index is variant"); |
| Node* rng = cmp->in(2); |
| assert(rng->Opcode() == Op_LoadRange || _igvn.type(rng)->is_int() >= 0, "must be"); |
| assert(invar.is_invariant(rng), "range must be invariant"); |
| int scale = 1; |
| Node* offset = zero; |
| bool ok = is_scaled_iv_plus_offset(idx, cl->phi(), &scale, &offset); |
| assert(ok, "must be index expression"); |
| |
| Node* init = cl->init_trip(); |
| // Limit is not exact. |
| // Calculate exact limit here. |
| // Note, counted loop's test is '<' or '>'. |
| Node* limit = exact_limit(loop); |
| int stride = cl->stride()->get_int(); |
| |
| // Build if's for the upper and lower bound tests. The |
| // lower_bound test will dominate the upper bound test and all |
| // cloned or created nodes will use the lower bound test as |
| // their declared control. |
| ProjNode* lower_bound_proj = create_new_if_for_predicate(predicate_proj, NULL, Deoptimization::Reason_predicate); |
| ProjNode* upper_bound_proj = create_new_if_for_predicate(predicate_proj, NULL, Deoptimization::Reason_predicate); |
| assert(upper_bound_proj->in(0)->as_If()->in(0) == lower_bound_proj, "should dominate"); |
| Node *ctrl = lower_bound_proj->in(0)->as_If()->in(0); |
| |
| // Perform cloning to keep Invariance state correct since the |
| // late schedule will place invariant things in the loop. |
| rng = invar.clone(rng, ctrl); |
| if (offset && offset != zero) { |
| assert(invar.is_invariant(offset), "offset must be loop invariant"); |
| offset = invar.clone(offset, ctrl); |
| } |
| // If predicate expressions may overflow in the integer range, longs are used. |
| bool overflow = false; |
| |
| // Test the lower bound |
| Node* lower_bound_bol = rc_predicate(loop, ctrl, scale, offset, init, limit, stride, rng, false, overflow); |
| IfNode* lower_bound_iff = lower_bound_proj->in(0)->as_If(); |
| _igvn.hash_delete(lower_bound_iff); |
| lower_bound_iff->set_req(1, lower_bound_bol); |
| if (TraceLoopPredicate) tty->print_cr("lower bound check if: %d", lower_bound_iff->_idx); |
| |
| // Test the upper bound |
| Node* upper_bound_bol = rc_predicate(loop, lower_bound_proj, scale, offset, init, limit, stride, rng, true, overflow); |
| IfNode* upper_bound_iff = upper_bound_proj->in(0)->as_If(); |
| _igvn.hash_delete(upper_bound_iff); |
| upper_bound_iff->set_req(1, upper_bound_bol); |
| if (TraceLoopPredicate) tty->print_cr("upper bound check if: %d", lower_bound_iff->_idx); |
| |
| // Fall through into rest of the clean up code which will move |
| // any dependent nodes onto the upper bound test. |
| new_predicate_proj = upper_bound_proj; |
| |
| #ifndef PRODUCT |
| if (TraceLoopOpts && !TraceLoopPredicate) { |
| tty->print("Predicate RC "); |
| loop->dump_head(); |
| } |
| #endif |
| } else { |
| // Loop variant check (for example, range check in non-counted loop) |
| // with uncommon trap. |
| continue; |
| } |
| assert(new_predicate_proj != NULL, "sanity"); |
| // Success - attach condition (new_predicate_bol) to predicate if |
| invar.map_ctrl(proj, new_predicate_proj); // so that invariance test can be appropriate |
| |
| // Eliminate the old If in the loop body |
| dominated_by( new_predicate_proj, iff, proj->_con != new_predicate_proj->_con ); |
| |
| hoisted = true; |
| C->set_major_progress(); |
| } // end while |
| |
| #ifndef PRODUCT |
| // report that the loop predication has been actually performed |
| // for this loop |
| if (TraceLoopPredicate && hoisted) { |
| tty->print("Loop Predication Performed:"); |
| loop->dump_head(); |
| } |
| #endif |
| |
| return hoisted; |
| } |
| |
| //------------------------------loop_predication-------------------------------- |
| // driver routine for loop predication optimization |
| bool IdealLoopTree::loop_predication( PhaseIdealLoop *phase) { |
| bool hoisted = false; |
| // Recursively promote predicates |
| if (_child) { |
| hoisted = _child->loop_predication( phase); |
| } |
| |
| // self |
| if (!_irreducible && !tail()->is_top()) { |
| hoisted |= phase->loop_predication_impl(this); |
| } |
| |
| if (_next) { //sibling |
| hoisted |= _next->loop_predication( phase); |
| } |
| |
| return hoisted; |
| } |
