jdk8-mips64-public/hotspot: comparison src/share/vm/opto/loopPredicate.cpp

--1:000000000000
+:f90c822e73f8
+/*
+* 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/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) {
+_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, Node* stride,
+Node* range, bool upper) {
+stringStream* predString = NULL;
+if (TraceLoopPredicate) {
+predString = new stringStream();
+predString->print("rc_predicate ");
+}
+Node* max_idx_expr  = init;
+int stride_con = stride->get_int();
+if ((stride_con > 0) == (scale > 0) == upper) {
+if (LoopLimitCheck) {
+// With LoopLimitCheck limit is not exact.
+// Calculate exact limit here.
+// Note, counted loop's test is '<' or '>'.
+limit = exact_limit(loop);
+max_idx_expr = new (C) SubINode(limit, stride);
+register_new_node(max_idx_expr, ctrl);
+if (TraceLoopPredicate) predString->print("(limit - stride) ");
+} else {
+max_idx_expr = new (C) SubINode(limit, stride);
+register_new_node(max_idx_expr, ctrl);
+if (TraceLoopPredicate) predString->print("(limit - stride) ");
+}
+} else {
+if (TraceLoopPredicate) predString->print("init ");
+}
+if (scale != 1) {
+ConNode* con_scale = _igvn.intcon(scale);
+max_idx_expr = new (C) MulINode(max_idx_expr, con_scale);
+register_new_node(max_idx_expr, ctrl);
+if (TraceLoopPredicate) predString->print("* %d ", scale);
+}
+if (offset && (!offset->is_Con() || offset->get_int() != 0)){
+max_idx_expr = new (C) AddINode(max_idx_expr, offset);
+register_new_node(max_idx_expr, ctrl);
+if (TraceLoopPredicate)
+if (offset->is_Con()) predString->print("+ %d ", offset->get_int());
+else predString->print("+ offset ");
+}
+CmpUNode* 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();
+Node* limit   = cl->limit();
+Node* stride  = cl->stride();
+// 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);
+}
+// Test the lower bound
+Node*  lower_bound_bol = rc_predicate(loop, ctrl, scale, offset, init, limit, stride, rng, false);
+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);
+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;
+}

Mercurial > jdk8-mips64-public > hotspot / file comparison

comparison: src/share/vm/opto/loopPredicate.cpp

src/share/vm/opto/loopPredicate.cpp