| /* |
| * Copyright (c) 2000, 2017, 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 "compiler/compileLog.hpp" |
| #include "memory/allocation.inline.hpp" |
| #include "opto/addnode.hpp" |
| #include "opto/callnode.hpp" |
| #include "opto/castnode.hpp" |
| #include "opto/connode.hpp" |
| #include "opto/convertnode.hpp" |
| #include "opto/divnode.hpp" |
| #include "opto/loopnode.hpp" |
| #include "opto/mulnode.hpp" |
| #include "opto/movenode.hpp" |
| #include "opto/opaquenode.hpp" |
| #include "opto/rootnode.hpp" |
| #include "opto/runtime.hpp" |
| #include "opto/subnode.hpp" |
| #include "opto/superword.hpp" |
| #include "opto/vectornode.hpp" |
| |
| //------------------------------is_loop_exit----------------------------------- |
| // Given an IfNode, return the loop-exiting projection or NULL if both |
| // arms remain in the loop. |
| Node *IdealLoopTree::is_loop_exit(Node *iff) const { |
| if( iff->outcnt() != 2 ) return NULL; // Ignore partially dead tests |
| PhaseIdealLoop *phase = _phase; |
| // Test is an IfNode, has 2 projections. If BOTH are in the loop |
| // we need loop unswitching instead of peeling. |
| if( !is_member(phase->get_loop( iff->raw_out(0) )) ) |
| return iff->raw_out(0); |
| if( !is_member(phase->get_loop( iff->raw_out(1) )) ) |
| return iff->raw_out(1); |
| return NULL; |
| } |
| |
| |
| //============================================================================= |
| |
| |
| //------------------------------record_for_igvn---------------------------- |
| // Put loop body on igvn work list |
| void IdealLoopTree::record_for_igvn() { |
| for( uint i = 0; i < _body.size(); i++ ) { |
| Node *n = _body.at(i); |
| _phase->_igvn._worklist.push(n); |
| } |
| } |
| |
| //------------------------------compute_exact_trip_count----------------------- |
| // Compute loop trip count if possible. Do not recalculate trip count for |
| // split loops (pre-main-post) which have their limits and inits behind Opaque node. |
| void IdealLoopTree::compute_trip_count(PhaseIdealLoop* phase) { |
| if (!_head->as_Loop()->is_valid_counted_loop()) { |
| return; |
| } |
| CountedLoopNode* cl = _head->as_CountedLoop(); |
| // Trip count may become nonexact for iteration split loops since |
| // RCE modifies limits. Note, _trip_count value is not reset since |
| // it is used to limit unrolling of main loop. |
| cl->set_nonexact_trip_count(); |
| |
| // Loop's test should be part of loop. |
| if (!phase->is_member(this, phase->get_ctrl(cl->loopexit()->in(CountedLoopEndNode::TestValue)))) |
| return; // Infinite loop |
| |
| #ifdef ASSERT |
| BoolTest::mask bt = cl->loopexit()->test_trip(); |
| assert(bt == BoolTest::lt || bt == BoolTest::gt || |
| bt == BoolTest::ne, "canonical test is expected"); |
| #endif |
| |
| Node* init_n = cl->init_trip(); |
| Node* limit_n = cl->limit(); |
| if (init_n != NULL && limit_n != NULL) { |
| // Use longs to avoid integer overflow. |
| int stride_con = cl->stride_con(); |
| jlong init_con = phase->_igvn.type(init_n)->is_int()->_lo; |
| jlong limit_con = phase->_igvn.type(limit_n)->is_int()->_hi; |
| int stride_m = stride_con - (stride_con > 0 ? 1 : -1); |
| jlong trip_count = (limit_con - init_con + stride_m)/stride_con; |
| if (trip_count > 0 && (julong)trip_count < (julong)max_juint) { |
| if (init_n->is_Con() && limit_n->is_Con()) { |
| // Set exact trip count. |
| cl->set_exact_trip_count((uint)trip_count); |
| } else if (cl->unrolled_count() == 1) { |
| // Set maximum trip count before unrolling. |
| cl->set_trip_count((uint)trip_count); |
| } |
| } |
| } |
| } |
| |
| //------------------------------compute_profile_trip_cnt---------------------------- |
| // Compute loop trip count from profile data as |
| // (backedge_count + loop_exit_count) / loop_exit_count |
| void IdealLoopTree::compute_profile_trip_cnt( PhaseIdealLoop *phase ) { |
| if (!_head->is_CountedLoop()) { |
| return; |
| } |
| CountedLoopNode* head = _head->as_CountedLoop(); |
| if (head->profile_trip_cnt() != COUNT_UNKNOWN) { |
| return; // Already computed |
| } |
| float trip_cnt = (float)max_jint; // default is big |
| |
| Node* back = head->in(LoopNode::LoopBackControl); |
| while (back != head) { |
| if ((back->Opcode() == Op_IfTrue || back->Opcode() == Op_IfFalse) && |
| back->in(0) && |
| back->in(0)->is_If() && |
| back->in(0)->as_If()->_fcnt != COUNT_UNKNOWN && |
| back->in(0)->as_If()->_prob != PROB_UNKNOWN) { |
| break; |
| } |
| back = phase->idom(back); |
| } |
| if (back != head) { |
| assert((back->Opcode() == Op_IfTrue || back->Opcode() == Op_IfFalse) && |
| back->in(0), "if-projection exists"); |
| IfNode* back_if = back->in(0)->as_If(); |
| float loop_back_cnt = back_if->_fcnt * back_if->_prob; |
| |
| // Now compute a loop exit count |
| float loop_exit_cnt = 0.0f; |
| for( uint i = 0; i < _body.size(); i++ ) { |
| Node *n = _body[i]; |
| if( n->is_If() ) { |
| IfNode *iff = n->as_If(); |
| if( iff->_fcnt != COUNT_UNKNOWN && iff->_prob != PROB_UNKNOWN ) { |
| Node *exit = is_loop_exit(iff); |
| if( exit ) { |
| float exit_prob = iff->_prob; |
| if (exit->Opcode() == Op_IfFalse) exit_prob = 1.0 - exit_prob; |
| if (exit_prob > PROB_MIN) { |
| float exit_cnt = iff->_fcnt * exit_prob; |
| loop_exit_cnt += exit_cnt; |
| } |
| } |
| } |
| } |
| } |
| if (loop_exit_cnt > 0.0f) { |
| trip_cnt = (loop_back_cnt + loop_exit_cnt) / loop_exit_cnt; |
| } else { |
| // No exit count so use |
| trip_cnt = loop_back_cnt; |
| } |
| } |
| #ifndef PRODUCT |
| if (TraceProfileTripCount) { |
| tty->print_cr("compute_profile_trip_cnt lp: %d cnt: %f\n", head->_idx, trip_cnt); |
| } |
| #endif |
| head->set_profile_trip_cnt(trip_cnt); |
| } |
| |
| //---------------------is_invariant_addition----------------------------- |
| // Return nonzero index of invariant operand for an Add or Sub |
| // of (nonconstant) invariant and variant values. Helper for reassociate_invariants. |
| int IdealLoopTree::is_invariant_addition(Node* n, PhaseIdealLoop *phase) { |
| int op = n->Opcode(); |
| if (op == Op_AddI || op == Op_SubI) { |
| bool in1_invar = this->is_invariant(n->in(1)); |
| bool in2_invar = this->is_invariant(n->in(2)); |
| if (in1_invar && !in2_invar) return 1; |
| if (!in1_invar && in2_invar) return 2; |
| } |
| return 0; |
| } |
| |
| //---------------------reassociate_add_sub----------------------------- |
| // Reassociate invariant add and subtract expressions: |
| // |
| // inv1 + (x + inv2) => ( inv1 + inv2) + x |
| // (x + inv2) + inv1 => ( inv1 + inv2) + x |
| // inv1 + (x - inv2) => ( inv1 - inv2) + x |
| // inv1 - (inv2 - x) => ( inv1 - inv2) + x |
| // (x + inv2) - inv1 => (-inv1 + inv2) + x |
| // (x - inv2) + inv1 => ( inv1 - inv2) + x |
| // (x - inv2) - inv1 => (-inv1 - inv2) + x |
| // inv1 + (inv2 - x) => ( inv1 + inv2) - x |
| // inv1 - (x - inv2) => ( inv1 + inv2) - x |
| // (inv2 - x) + inv1 => ( inv1 + inv2) - x |
| // (inv2 - x) - inv1 => (-inv1 + inv2) - x |
| // inv1 - (x + inv2) => ( inv1 - inv2) - x |
| // |
| Node* IdealLoopTree::reassociate_add_sub(Node* n1, PhaseIdealLoop *phase) { |
| if ((!n1->is_Add() && !n1->is_Sub()) || n1->outcnt() == 0) return NULL; |
| if (is_invariant(n1)) return NULL; |
| int inv1_idx = is_invariant_addition(n1, phase); |
| if (!inv1_idx) return NULL; |
| // Don't mess with add of constant (igvn moves them to expression tree root.) |
| if (n1->is_Add() && n1->in(2)->is_Con()) return NULL; |
| Node* inv1 = n1->in(inv1_idx); |
| Node* n2 = n1->in(3 - inv1_idx); |
| int inv2_idx = is_invariant_addition(n2, phase); |
| if (!inv2_idx) return NULL; |
| Node* x = n2->in(3 - inv2_idx); |
| Node* inv2 = n2->in(inv2_idx); |
| |
| bool neg_x = n2->is_Sub() && inv2_idx == 1; |
| bool neg_inv2 = n2->is_Sub() && inv2_idx == 2; |
| bool neg_inv1 = n1->is_Sub() && inv1_idx == 2; |
| if (n1->is_Sub() && inv1_idx == 1) { |
| neg_x = !neg_x; |
| neg_inv2 = !neg_inv2; |
| } |
| Node* inv1_c = phase->get_ctrl(inv1); |
| Node* inv2_c = phase->get_ctrl(inv2); |
| Node* n_inv1; |
| if (neg_inv1) { |
| Node *zero = phase->_igvn.intcon(0); |
| phase->set_ctrl(zero, phase->C->root()); |
| n_inv1 = new SubINode(zero, inv1); |
| phase->register_new_node(n_inv1, inv1_c); |
| } else { |
| n_inv1 = inv1; |
| } |
| Node* inv; |
| if (neg_inv2) { |
| inv = new SubINode(n_inv1, inv2); |
| } else { |
| inv = new AddINode(n_inv1, inv2); |
| } |
| phase->register_new_node(inv, phase->get_early_ctrl(inv)); |
| |
| Node* addx; |
| if (neg_x) { |
| addx = new SubINode(inv, x); |
| } else { |
| addx = new AddINode(x, inv); |
| } |
| phase->register_new_node(addx, phase->get_ctrl(x)); |
| phase->_igvn.replace_node(n1, addx); |
| assert(phase->get_loop(phase->get_ctrl(n1)) == this, ""); |
| _body.yank(n1); |
| return addx; |
| } |
| |
| //---------------------reassociate_invariants----------------------------- |
| // Reassociate invariant expressions: |
| void IdealLoopTree::reassociate_invariants(PhaseIdealLoop *phase) { |
| for (int i = _body.size() - 1; i >= 0; i--) { |
| Node *n = _body.at(i); |
| for (int j = 0; j < 5; j++) { |
| Node* nn = reassociate_add_sub(n, phase); |
| if (nn == NULL) break; |
| n = nn; // again |
| }; |
| } |
| } |
| |
| //------------------------------policy_peeling--------------------------------- |
| // Return TRUE or FALSE if the loop should be peeled or not. Peel if we can |
| // make some loop-invariant test (usually a null-check) happen before the loop. |
| bool IdealLoopTree::policy_peeling( PhaseIdealLoop *phase ) const { |
| Node *test = ((IdealLoopTree*)this)->tail(); |
| int body_size = ((IdealLoopTree*)this)->_body.size(); |
| // Peeling does loop cloning which can result in O(N^2) node construction |
| if( body_size > 255 /* Prevent overflow for large body_size */ |
| || (body_size * body_size + phase->C->live_nodes()) > phase->C->max_node_limit() ) { |
| return false; // too large to safely clone |
| } |
| |
| // check for vectorized loops, any peeling done was already applied |
| if (_head->is_CountedLoop() && _head->as_CountedLoop()->do_unroll_only()) return false; |
| |
| while( test != _head ) { // Scan till run off top of loop |
| if( test->is_If() ) { // Test? |
| Node *ctrl = phase->get_ctrl(test->in(1)); |
| if (ctrl->is_top()) |
| return false; // Found dead test on live IF? No peeling! |
| // Standard IF only has one input value to check for loop invariance |
| assert(test->Opcode() == Op_If || test->Opcode() == Op_CountedLoopEnd || test->Opcode() == Op_RangeCheck, "Check this code when new subtype is added"); |
| // Condition is not a member of this loop? |
| if( !is_member(phase->get_loop(ctrl)) && |
| is_loop_exit(test) ) |
| return true; // Found reason to peel! |
| } |
| // Walk up dominators to loop _head looking for test which is |
| // executed on every path thru loop. |
| test = phase->idom(test); |
| } |
| return false; |
| } |
| |
| //------------------------------peeled_dom_test_elim--------------------------- |
| // If we got the effect of peeling, either by actually peeling or by making |
| // a pre-loop which must execute at least once, we can remove all |
| // loop-invariant dominated tests in the main body. |
| void PhaseIdealLoop::peeled_dom_test_elim( IdealLoopTree *loop, Node_List &old_new ) { |
| bool progress = true; |
| while( progress ) { |
| progress = false; // Reset for next iteration |
| Node *prev = loop->_head->in(LoopNode::LoopBackControl);//loop->tail(); |
| Node *test = prev->in(0); |
| while( test != loop->_head ) { // Scan till run off top of loop |
| |
| int p_op = prev->Opcode(); |
| if( (p_op == Op_IfFalse || p_op == Op_IfTrue) && |
| test->is_If() && // Test? |
| !test->in(1)->is_Con() && // And not already obvious? |
| // Condition is not a member of this loop? |
| !loop->is_member(get_loop(get_ctrl(test->in(1))))){ |
| // Walk loop body looking for instances of this test |
| for( uint i = 0; i < loop->_body.size(); i++ ) { |
| Node *n = loop->_body.at(i); |
| if( n->is_If() && n->in(1) == test->in(1) /*&& n != loop->tail()->in(0)*/ ) { |
| // IfNode was dominated by version in peeled loop body |
| progress = true; |
| dominated_by( old_new[prev->_idx], n ); |
| } |
| } |
| } |
| prev = test; |
| test = idom(test); |
| } // End of scan tests in loop |
| |
| } // End of while( progress ) |
| } |
| |
| //------------------------------do_peeling------------------------------------- |
| // Peel the first iteration of the given loop. |
| // Step 1: Clone the loop body. The clone becomes the peeled iteration. |
| // The pre-loop illegally has 2 control users (old & new loops). |
| // Step 2: Make the old-loop fall-in edges point to the peeled iteration. |
| // Do this by making the old-loop fall-in edges act as if they came |
| // around the loopback from the prior iteration (follow the old-loop |
| // backedges) and then map to the new peeled iteration. This leaves |
| // the pre-loop with only 1 user (the new peeled iteration), but the |
| // peeled-loop backedge has 2 users. |
| // Step 3: Cut the backedge on the clone (so its not a loop) and remove the |
| // extra backedge user. |
| // |
| // orig |
| // |
| // stmt1 |
| // | |
| // v |
| // loop predicate |
| // | |
| // v |
| // loop<----+ |
| // | | |
| // stmt2 | |
| // | | |
| // v | |
| // if ^ |
| // / \ | |
| // / \ | |
| // v v | |
| // false true | |
| // / \ | |
| // / ----+ |
| // | |
| // v |
| // exit |
| // |
| // |
| // after clone loop |
| // |
| // stmt1 |
| // | |
| // v |
| // loop predicate |
| // / \ |
| // clone / \ orig |
| // / \ |
| // / \ |
| // v v |
| // +---->loop clone loop<----+ |
| // | | | | |
| // | stmt2 clone stmt2 | |
| // | | | | |
| // | v v | |
| // ^ if clone If ^ |
| // | / \ / \ | |
| // | / \ / \ | |
| // | v v v v | |
| // | true false false true | |
| // | / \ / \ | |
| // +---- \ / ----+ |
| // \ / |
| // 1v v2 |
| // region |
| // | |
| // v |
| // exit |
| // |
| // |
| // after peel and predicate move |
| // |
| // stmt1 |
| // / |
| // / |
| // clone / orig |
| // / |
| // / +----------+ |
| // / | | |
| // / loop predicate | |
| // / | | |
| // v v | |
| // TOP-->loop clone loop<----+ | |
| // | | | | |
| // stmt2 clone stmt2 | | |
| // | | | ^ |
| // v v | | |
| // if clone If ^ | |
| // / \ / \ | | |
| // / \ / \ | | |
| // v v v v | | |
| // true false false true | | |
| // | \ / \ | | |
| // | \ / ----+ ^ |
| // | \ / | |
| // | 1v v2 | |
| // v region | |
| // | | | |
| // | v | |
| // | exit | |
| // | | |
| // +--------------->-----------------+ |
| // |
| // |
| // final graph |
| // |
| // stmt1 |
| // | |
| // v |
| // stmt2 clone |
| // | |
| // v |
| // if clone |
| // / | |
| // / | |
| // v v |
| // false true |
| // | | |
| // | v |
| // | loop predicate |
| // | | |
| // | v |
| // | loop<----+ |
| // | | | |
| // | stmt2 | |
| // | | | |
| // | v | |
| // v if ^ |
| // | / \ | |
| // | / \ | |
| // | v v | |
| // | false true | |
| // | | \ | |
| // v v --+ |
| // region |
| // | |
| // v |
| // exit |
| // |
| void PhaseIdealLoop::do_peeling( IdealLoopTree *loop, Node_List &old_new ) { |
| |
| C->set_major_progress(); |
| // Peeling a 'main' loop in a pre/main/post situation obfuscates the |
| // 'pre' loop from the main and the 'pre' can no longer have its |
| // iterations adjusted. Therefore, we need to declare this loop as |
| // no longer a 'main' loop; it will need new pre and post loops before |
| // we can do further RCE. |
| #ifndef PRODUCT |
| if (TraceLoopOpts) { |
| tty->print("Peel "); |
| loop->dump_head(); |
| } |
| #endif |
| Node* head = loop->_head; |
| bool counted_loop = head->is_CountedLoop(); |
| if (counted_loop) { |
| CountedLoopNode *cl = head->as_CountedLoop(); |
| assert(cl->trip_count() > 0, "peeling a fully unrolled loop"); |
| cl->set_trip_count(cl->trip_count() - 1); |
| if (cl->is_main_loop()) { |
| cl->set_normal_loop(); |
| #ifndef PRODUCT |
| if (PrintOpto && VerifyLoopOptimizations) { |
| tty->print("Peeling a 'main' loop; resetting to 'normal' "); |
| loop->dump_head(); |
| } |
| #endif |
| } |
| } |
| Node* entry = head->in(LoopNode::EntryControl); |
| |
| // Step 1: Clone the loop body. The clone becomes the peeled iteration. |
| // The pre-loop illegally has 2 control users (old & new loops). |
| clone_loop( loop, old_new, dom_depth(head) ); |
| |
| // Step 2: Make the old-loop fall-in edges point to the peeled iteration. |
| // Do this by making the old-loop fall-in edges act as if they came |
| // around the loopback from the prior iteration (follow the old-loop |
| // backedges) and then map to the new peeled iteration. This leaves |
| // the pre-loop with only 1 user (the new peeled iteration), but the |
| // peeled-loop backedge has 2 users. |
| Node* new_entry = old_new[head->in(LoopNode::LoopBackControl)->_idx]; |
| _igvn.hash_delete(head); |
| head->set_req(LoopNode::EntryControl, new_entry); |
| for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) { |
| Node* old = head->fast_out(j); |
| if (old->in(0) == loop->_head && old->req() == 3 && old->is_Phi()) { |
| Node* new_exit_value = old_new[old->in(LoopNode::LoopBackControl)->_idx]; |
| if (!new_exit_value ) // Backedge value is ALSO loop invariant? |
| // Then loop body backedge value remains the same. |
| new_exit_value = old->in(LoopNode::LoopBackControl); |
| _igvn.hash_delete(old); |
| old->set_req(LoopNode::EntryControl, new_exit_value); |
| } |
| } |
| |
| |
| // Step 3: Cut the backedge on the clone (so its not a loop) and remove the |
| // extra backedge user. |
| Node* new_head = old_new[head->_idx]; |
| _igvn.hash_delete(new_head); |
| new_head->set_req(LoopNode::LoopBackControl, C->top()); |
| for (DUIterator_Fast j2max, j2 = new_head->fast_outs(j2max); j2 < j2max; j2++) { |
| Node* use = new_head->fast_out(j2); |
| if (use->in(0) == new_head && use->req() == 3 && use->is_Phi()) { |
| _igvn.hash_delete(use); |
| use->set_req(LoopNode::LoopBackControl, C->top()); |
| } |
| } |
| |
| |
| // Step 4: Correct dom-depth info. Set to loop-head depth. |
| int dd = dom_depth(head); |
| set_idom(head, head->in(1), dd); |
| for (uint j3 = 0; j3 < loop->_body.size(); j3++) { |
| Node *old = loop->_body.at(j3); |
| Node *nnn = old_new[old->_idx]; |
| if (!has_ctrl(nnn)) |
| set_idom(nnn, idom(nnn), dd-1); |
| } |
| |
| // Now force out all loop-invariant dominating tests. The optimizer |
| // finds some, but we _know_ they are all useless. |
| peeled_dom_test_elim(loop,old_new); |
| |
| loop->record_for_igvn(); |
| } |
| |
| #define EMPTY_LOOP_SIZE 7 // number of nodes in an empty loop |
| |
| //------------------------------policy_maximally_unroll------------------------ |
| // Calculate exact loop trip count and return true if loop can be maximally |
| // unrolled. |
| bool IdealLoopTree::policy_maximally_unroll( PhaseIdealLoop *phase ) const { |
| CountedLoopNode *cl = _head->as_CountedLoop(); |
| assert(cl->is_normal_loop(), ""); |
| if (!cl->is_valid_counted_loop()) |
| return false; // Malformed counted loop |
| |
| if (!cl->has_exact_trip_count()) { |
| // Trip count is not exact. |
| return false; |
| } |
| |
| uint trip_count = cl->trip_count(); |
| // Note, max_juint is used to indicate unknown trip count. |
| assert(trip_count > 1, "one iteration loop should be optimized out already"); |
| assert(trip_count < max_juint, "exact trip_count should be less than max_uint."); |
| |
| // Real policy: if we maximally unroll, does it get too big? |
| // Allow the unrolled mess to get larger than standard loop |
| // size. After all, it will no longer be a loop. |
| uint body_size = _body.size(); |
| uint unroll_limit = (uint)LoopUnrollLimit * 4; |
| assert( (intx)unroll_limit == LoopUnrollLimit * 4, "LoopUnrollLimit must fit in 32bits"); |
| if (trip_count > unroll_limit || body_size > unroll_limit) { |
| return false; |
| } |
| |
| // Fully unroll a loop with few iterations regardless next |
| // conditions since following loop optimizations will split |
| // such loop anyway (pre-main-post). |
| if (trip_count <= 3) |
| return true; |
| |
| // Take into account that after unroll conjoined heads and tails will fold, |
| // otherwise policy_unroll() may allow more unrolling than max unrolling. |
| uint new_body_size = EMPTY_LOOP_SIZE + (body_size - EMPTY_LOOP_SIZE) * trip_count; |
| uint tst_body_size = (new_body_size - EMPTY_LOOP_SIZE) / trip_count + EMPTY_LOOP_SIZE; |
| if (body_size != tst_body_size) // Check for int overflow |
| return false; |
| if (new_body_size > unroll_limit || |
| // Unrolling can result in a large amount of node construction |
| new_body_size >= phase->C->max_node_limit() - phase->C->live_nodes()) { |
| return false; |
| } |
| |
| // Do not unroll a loop with String intrinsics code. |
| // String intrinsics are large and have loops. |
| for (uint k = 0; k < _body.size(); k++) { |
| Node* n = _body.at(k); |
| switch (n->Opcode()) { |
| case Op_StrComp: |
| case Op_StrEquals: |
| case Op_StrIndexOf: |
| case Op_StrIndexOfChar: |
| case Op_EncodeISOArray: |
| case Op_AryEq: |
| case Op_HasNegatives: { |
| return false; |
| } |
| #if INCLUDE_RTM_OPT |
| case Op_FastLock: |
| case Op_FastUnlock: { |
| // Don't unroll RTM locking code because it is large. |
| if (UseRTMLocking) { |
| return false; |
| } |
| } |
| #endif |
| } // switch |
| } |
| |
| return true; // Do maximally unroll |
| } |
| |
| |
| //------------------------------policy_unroll---------------------------------- |
| // Return TRUE or FALSE if the loop should be unrolled or not. Unroll if |
| // the loop is a CountedLoop and the body is small enough. |
| bool IdealLoopTree::policy_unroll(PhaseIdealLoop *phase) { |
| |
| CountedLoopNode *cl = _head->as_CountedLoop(); |
| assert(cl->is_normal_loop() || cl->is_main_loop(), ""); |
| |
| if (!cl->is_valid_counted_loop()) |
| return false; // Malformed counted loop |
| |
| // Protect against over-unrolling. |
| // After split at least one iteration will be executed in pre-loop. |
| if (cl->trip_count() <= (uint)(cl->is_normal_loop() ? 2 : 1)) return false; |
| |
| _local_loop_unroll_limit = LoopUnrollLimit; |
| _local_loop_unroll_factor = 4; |
| int future_unroll_ct = cl->unrolled_count() * 2; |
| if (!cl->do_unroll_only()) { |
| if (future_unroll_ct > LoopMaxUnroll) return false; |
| } else { |
| // obey user constraints on vector mapped loops with additional unrolling applied |
| int unroll_constraint = (cl->slp_max_unroll()) ? cl->slp_max_unroll() : 1; |
| if ((future_unroll_ct / unroll_constraint) > LoopMaxUnroll) return false; |
| } |
| |
| // Check for initial stride being a small enough constant |
| if (abs(cl->stride_con()) > (1<<2)*future_unroll_ct) return false; |
| |
| // Don't unroll if the next round of unrolling would push us |
| // over the expected trip count of the loop. One is subtracted |
| // from the expected trip count because the pre-loop normally |
| // executes 1 iteration. |
| if (UnrollLimitForProfileCheck > 0 && |
| cl->profile_trip_cnt() != COUNT_UNKNOWN && |
| future_unroll_ct > UnrollLimitForProfileCheck && |
| (float)future_unroll_ct > cl->profile_trip_cnt() - 1.0) { |
| return false; |
| } |
| |
| // When unroll count is greater than LoopUnrollMin, don't unroll if: |
| // the residual iterations are more than 10% of the trip count |
| // and rounds of "unroll,optimize" are not making significant progress |
| // Progress defined as current size less than 20% larger than previous size. |
| if (UseSuperWord && cl->node_count_before_unroll() > 0 && |
| future_unroll_ct > LoopUnrollMin && |
| (future_unroll_ct - 1) * (100 / LoopPercentProfileLimit) > cl->profile_trip_cnt() && |
| 1.2 * cl->node_count_before_unroll() < (double)_body.size()) { |
| return false; |
| } |
| |
| Node *init_n = cl->init_trip(); |
| Node *limit_n = cl->limit(); |
| int stride_con = cl->stride_con(); |
| // Non-constant bounds. |
| // Protect against over-unrolling when init or/and limit are not constant |
| // (so that trip_count's init value is maxint) but iv range is known. |
| if (init_n == NULL || !init_n->is_Con() || |
| limit_n == NULL || !limit_n->is_Con()) { |
| Node* phi = cl->phi(); |
| if (phi != NULL) { |
| assert(phi->is_Phi() && phi->in(0) == _head, "Counted loop should have iv phi."); |
| const TypeInt* iv_type = phase->_igvn.type(phi)->is_int(); |
| int next_stride = stride_con * 2; // stride after this unroll |
| if (next_stride > 0) { |
| if (iv_type->_lo + next_stride <= iv_type->_lo || // overflow |
| iv_type->_lo + next_stride > iv_type->_hi) { |
| return false; // over-unrolling |
| } |
| } else if (next_stride < 0) { |
| if (iv_type->_hi + next_stride >= iv_type->_hi || // overflow |
| iv_type->_hi + next_stride < iv_type->_lo) { |
| return false; // over-unrolling |
| } |
| } |
| } |
| } |
| |
| // After unroll limit will be adjusted: new_limit = limit-stride. |
| // Bailout if adjustment overflow. |
| const TypeInt* limit_type = phase->_igvn.type(limit_n)->is_int(); |
| if ((stride_con > 0 && ((limit_type->_hi - stride_con) >= limit_type->_hi)) || |
| (stride_con < 0 && ((limit_type->_lo - stride_con) <= limit_type->_lo))) |
| return false; // overflow |
| |
| // Adjust body_size to determine if we unroll or not |
| uint body_size = _body.size(); |
| // Key test to unroll loop in CRC32 java code |
| int xors_in_loop = 0; |
| // Also count ModL, DivL and MulL which expand mightly |
| for (uint k = 0; k < _body.size(); k++) { |
| Node* n = _body.at(k); |
| switch (n->Opcode()) { |
| case Op_XorI: xors_in_loop++; break; // CRC32 java code |
| case Op_ModL: body_size += 30; break; |
| case Op_DivL: body_size += 30; break; |
| case Op_MulL: body_size += 10; break; |
| case Op_StrComp: |
| case Op_StrEquals: |
| case Op_StrIndexOf: |
| case Op_StrIndexOfChar: |
| case Op_EncodeISOArray: |
| case Op_AryEq: |
| case Op_HasNegatives: { |
| // Do not unroll a loop with String intrinsics code. |
| // String intrinsics are large and have loops. |
| return false; |
| } |
| #if INCLUDE_RTM_OPT |
| case Op_FastLock: |
| case Op_FastUnlock: { |
| // Don't unroll RTM locking code because it is large. |
| if (UseRTMLocking) { |
| return false; |
| } |
| } |
| #endif |
| } // switch |
| } |
| |
| if (UseSuperWord) { |
| if (!cl->is_reduction_loop()) { |
| phase->mark_reductions(this); |
| } |
| |
| // Only attempt slp analysis when user controls do not prohibit it |
| if (LoopMaxUnroll > _local_loop_unroll_factor) { |
| // Once policy_slp_analysis succeeds, mark the loop with the |
| // maximal unroll factor so that we minimize analysis passes |
| if (future_unroll_ct >= _local_loop_unroll_factor) { |
| policy_unroll_slp_analysis(cl, phase, future_unroll_ct); |
| } |
| } |
| } |
| |
| int slp_max_unroll_factor = cl->slp_max_unroll(); |
| if ((LoopMaxUnroll < slp_max_unroll_factor) && FLAG_IS_DEFAULT(LoopMaxUnroll) && UseSubwordForMaxVector) { |
| LoopMaxUnroll = slp_max_unroll_factor; |
| } |
| if (cl->has_passed_slp()) { |
| if (slp_max_unroll_factor >= future_unroll_ct) return true; |
| // Normal case: loop too big |
| return false; |
| } |
| |
| // Check for being too big |
| if (body_size > (uint)_local_loop_unroll_limit) { |
| if ((UseSubwordForMaxVector || xors_in_loop >= 4) && body_size < (uint)LoopUnrollLimit * 4) return true; |
| // Normal case: loop too big |
| return false; |
| } |
| |
| if (cl->do_unroll_only()) { |
| if (TraceSuperWordLoopUnrollAnalysis) { |
| tty->print_cr("policy_unroll passed vector loop(vlen=%d,factor = %d)\n", slp_max_unroll_factor, future_unroll_ct); |
| } |
| } |
| |
| // Unroll once! (Each trip will soon do double iterations) |
| return true; |
| } |
| |
| void IdealLoopTree::policy_unroll_slp_analysis(CountedLoopNode *cl, PhaseIdealLoop *phase, int future_unroll_ct) { |
| // Enable this functionality target by target as needed |
| if (SuperWordLoopUnrollAnalysis) { |
| if (!cl->was_slp_analyzed()) { |
| SuperWord sw(phase); |
| sw.transform_loop(this, false); |
| |
| // If the loop is slp canonical analyze it |
| if (sw.early_return() == false) { |
| sw.unrolling_analysis(_local_loop_unroll_factor); |
| } |
| } |
| |
| if (cl->has_passed_slp()) { |
| int slp_max_unroll_factor = cl->slp_max_unroll(); |
| if (slp_max_unroll_factor >= future_unroll_ct) { |
| int new_limit = cl->node_count_before_unroll() * slp_max_unroll_factor; |
| if (new_limit > LoopUnrollLimit) { |
| if (TraceSuperWordLoopUnrollAnalysis) { |
| tty->print_cr("slp analysis unroll=%d, default limit=%d\n", new_limit, _local_loop_unroll_limit); |
| } |
| _local_loop_unroll_limit = new_limit; |
| } |
| } |
| } |
| } |
| } |
| |
| //------------------------------policy_align----------------------------------- |
| // Return TRUE or FALSE if the loop should be cache-line aligned. Gather the |
| // expression that does the alignment. Note that only one array base can be |
| // aligned in a loop (unless the VM guarantees mutual alignment). Note that |
| // if we vectorize short memory ops into longer memory ops, we may want to |
| // increase alignment. |
| bool IdealLoopTree::policy_align( PhaseIdealLoop *phase ) const { |
| return false; |
| } |
| |
| //------------------------------policy_range_check----------------------------- |
| // Return TRUE or FALSE if the loop should be range-check-eliminated. |
| // Actually we do iteration-splitting, a more powerful form of RCE. |
| bool IdealLoopTree::policy_range_check( PhaseIdealLoop *phase ) const { |
| if (!RangeCheckElimination) return false; |
| |
| CountedLoopNode *cl = _head->as_CountedLoop(); |
| // If we unrolled with no intention of doing RCE and we later |
| // changed our minds, we got no pre-loop. Either we need to |
| // make a new pre-loop, or we gotta disallow RCE. |
| if (cl->is_main_no_pre_loop()) return false; // Disallowed for now. |
| Node *trip_counter = cl->phi(); |
| |
| // check for vectorized loops, some opts are no longer needed |
| if (cl->do_unroll_only()) return false; |
| |
| // Check loop body for tests of trip-counter plus loop-invariant vs |
| // loop-invariant. |
| for (uint i = 0; i < _body.size(); i++) { |
| Node *iff = _body[i]; |
| if (iff->Opcode() == Op_If || |
| iff->Opcode() == Op_RangeCheck) { // Test? |
| |
| // Comparing trip+off vs limit |
| Node *bol = iff->in(1); |
| if (bol->req() != 2) continue; // dead constant test |
| if (!bol->is_Bool()) { |
| assert(bol->Opcode() == Op_Conv2B, "predicate check only"); |
| continue; |
| } |
| if (bol->as_Bool()->_test._test == BoolTest::ne) |
| continue; // not RC |
| |
| Node *cmp = bol->in(1); |
| Node *rc_exp = cmp->in(1); |
| Node *limit = cmp->in(2); |
| |
| Node *limit_c = phase->get_ctrl(limit); |
| if( limit_c == phase->C->top() ) |
| return false; // Found dead test on live IF? No RCE! |
| if( is_member(phase->get_loop(limit_c) ) ) { |
| // Compare might have operands swapped; commute them |
| rc_exp = cmp->in(2); |
| limit = cmp->in(1); |
| limit_c = phase->get_ctrl(limit); |
| if( is_member(phase->get_loop(limit_c) ) ) |
| continue; // Both inputs are loop varying; cannot RCE |
| } |
| |
| if (!phase->is_scaled_iv_plus_offset(rc_exp, trip_counter, NULL, NULL)) { |
| continue; |
| } |
| // Yeah! Found a test like 'trip+off vs limit' |
| // Test is an IfNode, has 2 projections. If BOTH are in the loop |
| // we need loop unswitching instead of iteration splitting. |
| if( is_loop_exit(iff) ) |
| return true; // Found reason to split iterations |
| } // End of is IF |
| } |
| |
| return false; |
| } |
| |
| //------------------------------policy_peel_only------------------------------- |
| // Return TRUE or FALSE if the loop should NEVER be RCE'd or aligned. Useful |
| // for unrolling loops with NO array accesses. |
| bool IdealLoopTree::policy_peel_only( PhaseIdealLoop *phase ) const { |
| // check for vectorized loops, any peeling done was already applied |
| if (_head->is_CountedLoop() && _head->as_CountedLoop()->do_unroll_only()) return false; |
| |
| for( uint i = 0; i < _body.size(); i++ ) |
| if( _body[i]->is_Mem() ) |
| return false; |
| |
| // No memory accesses at all! |
| return true; |
| } |
| |
| //------------------------------clone_up_backedge_goo-------------------------- |
| // If Node n lives in the back_ctrl block and cannot float, we clone a private |
| // version of n in preheader_ctrl block and return that, otherwise return n. |
| Node *PhaseIdealLoop::clone_up_backedge_goo( Node *back_ctrl, Node *preheader_ctrl, Node *n, VectorSet &visited, Node_Stack &clones ) { |
| if( get_ctrl(n) != back_ctrl ) return n; |
| |
| // Only visit once |
| if (visited.test_set(n->_idx)) { |
| Node *x = clones.find(n->_idx); |
| if (x != NULL) |
| return x; |
| return n; |
| } |
| |
| Node *x = NULL; // If required, a clone of 'n' |
| // Check for 'n' being pinned in the backedge. |
| if( n->in(0) && n->in(0) == back_ctrl ) { |
| assert(clones.find(n->_idx) == NULL, "dead loop"); |
| x = n->clone(); // Clone a copy of 'n' to preheader |
| clones.push(x, n->_idx); |
| x->set_req( 0, preheader_ctrl ); // Fix x's control input to preheader |
| } |
| |
| // Recursive fixup any other input edges into x. |
| // If there are no changes we can just return 'n', otherwise |
| // we need to clone a private copy and change it. |
| for( uint i = 1; i < n->req(); i++ ) { |
| Node *g = clone_up_backedge_goo( back_ctrl, preheader_ctrl, n->in(i), visited, clones ); |
| if( g != n->in(i) ) { |
| if( !x ) { |
| assert(clones.find(n->_idx) == NULL, "dead loop"); |
| x = n->clone(); |
| clones.push(x, n->_idx); |
| } |
| x->set_req(i, g); |
| } |
| } |
| if( x ) { // x can legally float to pre-header location |
| register_new_node( x, preheader_ctrl ); |
| return x; |
| } else { // raise n to cover LCA of uses |
| set_ctrl( n, find_non_split_ctrl(back_ctrl->in(0)) ); |
| } |
| return n; |
| } |
| |
| bool PhaseIdealLoop::cast_incr_before_loop(Node* incr, Node* ctrl, Node* loop) { |
| Node* castii = new CastIINode(incr, TypeInt::INT, true); |
| castii->set_req(0, ctrl); |
| register_new_node(castii, ctrl); |
| for (DUIterator_Fast imax, i = incr->fast_outs(imax); i < imax; i++) { |
| Node* n = incr->fast_out(i); |
| if (n->is_Phi() && n->in(0) == loop) { |
| int nrep = n->replace_edge(incr, castii); |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| //------------------------------insert_pre_post_loops-------------------------- |
| // Insert pre and post loops. If peel_only is set, the pre-loop can not have |
| // more iterations added. It acts as a 'peel' only, no lower-bound RCE, no |
| // alignment. Useful to unroll loops that do no array accesses. |
| void PhaseIdealLoop::insert_pre_post_loops( IdealLoopTree *loop, Node_List &old_new, bool peel_only ) { |
| |
| #ifndef PRODUCT |
| if (TraceLoopOpts) { |
| if (peel_only) |
| tty->print("PeelMainPost "); |
| else |
| tty->print("PreMainPost "); |
| loop->dump_head(); |
| } |
| #endif |
| C->set_major_progress(); |
| |
| // Find common pieces of the loop being guarded with pre & post loops |
| CountedLoopNode *main_head = loop->_head->as_CountedLoop(); |
| assert( main_head->is_normal_loop(), "" ); |
| CountedLoopEndNode *main_end = main_head->loopexit(); |
| guarantee(main_end != NULL, "no loop exit node"); |
| assert( main_end->outcnt() == 2, "1 true, 1 false path only" ); |
| uint dd_main_head = dom_depth(main_head); |
| uint max = main_head->outcnt(); |
| |
| Node *pre_header= main_head->in(LoopNode::EntryControl); |
| Node *init = main_head->init_trip(); |
| Node *incr = main_end ->incr(); |
| Node *limit = main_end ->limit(); |
| Node *stride = main_end ->stride(); |
| Node *cmp = main_end ->cmp_node(); |
| BoolTest::mask b_test = main_end->test_trip(); |
| |
| // Need only 1 user of 'bol' because I will be hacking the loop bounds. |
| Node *bol = main_end->in(CountedLoopEndNode::TestValue); |
| if( bol->outcnt() != 1 ) { |
| bol = bol->clone(); |
| register_new_node(bol,main_end->in(CountedLoopEndNode::TestControl)); |
| _igvn.replace_input_of(main_end, CountedLoopEndNode::TestValue, bol); |
| } |
| // Need only 1 user of 'cmp' because I will be hacking the loop bounds. |
| if( cmp->outcnt() != 1 ) { |
| cmp = cmp->clone(); |
| register_new_node(cmp,main_end->in(CountedLoopEndNode::TestControl)); |
| _igvn.replace_input_of(bol, 1, cmp); |
| } |
| |
| // Add the post loop |
| CountedLoopNode *post_head = NULL; |
| Node *main_exit = insert_post_loop(loop, old_new, main_head, main_end, incr, limit, post_head); |
| |
| //------------------------------ |
| // Step B: Create Pre-Loop. |
| |
| // Step B1: Clone the loop body. The clone becomes the pre-loop. The main |
| // loop pre-header illegally has 2 control users (old & new loops). |
| clone_loop( loop, old_new, dd_main_head ); |
| CountedLoopNode* pre_head = old_new[main_head->_idx]->as_CountedLoop(); |
| CountedLoopEndNode* pre_end = old_new[main_end ->_idx]->as_CountedLoopEnd(); |
| pre_head->set_pre_loop(main_head); |
| Node *pre_incr = old_new[incr->_idx]; |
| |
| // Reduce the pre-loop trip count. |
| pre_end->_prob = PROB_FAIR; |
| |
| // Find the pre-loop normal exit. |
| Node* pre_exit = pre_end->proj_out(false); |
| assert( pre_exit->Opcode() == Op_IfFalse, "" ); |
| IfFalseNode *new_pre_exit = new IfFalseNode(pre_end); |
| _igvn.register_new_node_with_optimizer( new_pre_exit ); |
| set_idom(new_pre_exit, pre_end, dd_main_head); |
| set_loop(new_pre_exit, loop->_parent); |
| |
| // Step B2: Build a zero-trip guard for the main-loop. After leaving the |
| // pre-loop, the main-loop may not execute at all. Later in life this |
| // zero-trip guard will become the minimum-trip guard when we unroll |
| // the main-loop. |
| Node *min_opaq = new Opaque1Node(C, limit); |
| Node *min_cmp = new CmpINode( pre_incr, min_opaq ); |
| Node *min_bol = new BoolNode( min_cmp, b_test ); |
| register_new_node( min_opaq, new_pre_exit ); |
| register_new_node( min_cmp , new_pre_exit ); |
| register_new_node( min_bol , new_pre_exit ); |
| |
| // Build the IfNode (assume the main-loop is executed always). |
| IfNode *min_iff = new IfNode( new_pre_exit, min_bol, PROB_ALWAYS, COUNT_UNKNOWN ); |
| _igvn.register_new_node_with_optimizer( min_iff ); |
| set_idom(min_iff, new_pre_exit, dd_main_head); |
| set_loop(min_iff, loop->_parent); |
| |
| // Plug in the false-path, taken if we need to skip main-loop |
| _igvn.hash_delete( pre_exit ); |
| pre_exit->set_req(0, min_iff); |
| set_idom(pre_exit, min_iff, dd_main_head); |
| set_idom(pre_exit->unique_out(), min_iff, dd_main_head); |
| // Make the true-path, must enter the main loop |
| Node *min_taken = new IfTrueNode( min_iff ); |
| _igvn.register_new_node_with_optimizer( min_taken ); |
| set_idom(min_taken, min_iff, dd_main_head); |
| set_loop(min_taken, loop->_parent); |
| // Plug in the true path |
| _igvn.hash_delete( main_head ); |
| main_head->set_req(LoopNode::EntryControl, min_taken); |
| set_idom(main_head, min_taken, dd_main_head); |
| |
| Arena *a = Thread::current()->resource_area(); |
| VectorSet visited(a); |
| Node_Stack clones(a, main_head->back_control()->outcnt()); |
| // Step B3: Make the fall-in values to the main-loop come from the |
| // fall-out values of the pre-loop. |
| for (DUIterator_Fast i2max, i2 = main_head->fast_outs(i2max); i2 < i2max; i2++) { |
| Node* main_phi = main_head->fast_out(i2); |
| if( main_phi->is_Phi() && main_phi->in(0) == main_head && main_phi->outcnt() > 0 ) { |
| Node *pre_phi = old_new[main_phi->_idx]; |
| Node *fallpre = clone_up_backedge_goo(pre_head->back_control(), |
| main_head->init_control(), |
| pre_phi->in(LoopNode::LoopBackControl), |
| visited, clones); |
| _igvn.hash_delete(main_phi); |
| main_phi->set_req( LoopNode::EntryControl, fallpre ); |
| } |
| } |
| |
| // Nodes inside the loop may be control dependent on a predicate |
| // that was moved before the preloop. If the back branch of the main |
| // or post loops becomes dead, those nodes won't be dependent on the |
| // test that guards that loop nest anymore which could lead to an |
| // incorrect array access because it executes independently of the |
| // test that was guarding the loop nest. We add a special CastII on |
| // the if branch that enters the loop, between the input induction |
| // variable value and the induction variable Phi to preserve correct |
| // dependencies. |
| |
| // CastII for the main loop: |
| bool inserted = cast_incr_before_loop( pre_incr, min_taken, main_head ); |
| assert(inserted, "no castII inserted"); |
| |
| // Step B4: Shorten the pre-loop to run only 1 iteration (for now). |
| // RCE and alignment may change this later. |
| Node *cmp_end = pre_end->cmp_node(); |
| assert( cmp_end->in(2) == limit, "" ); |
| Node *pre_limit = new AddINode( init, stride ); |
| |
| // Save the original loop limit in this Opaque1 node for |
| // use by range check elimination. |
| Node *pre_opaq = new Opaque1Node(C, pre_limit, limit); |
| |
| register_new_node( pre_limit, pre_head->in(0) ); |
| register_new_node( pre_opaq , pre_head->in(0) ); |
| |
| // Since no other users of pre-loop compare, I can hack limit directly |
| assert( cmp_end->outcnt() == 1, "no other users" ); |
| _igvn.hash_delete(cmp_end); |
| cmp_end->set_req(2, peel_only ? pre_limit : pre_opaq); |
| |
| // Special case for not-equal loop bounds: |
| // Change pre loop test, main loop test, and the |
| // main loop guard test to use lt or gt depending on stride |
| // direction: |
| // positive stride use < |
| // negative stride use > |
| // |
| // not-equal test is kept for post loop to handle case |
| // when init > limit when stride > 0 (and reverse). |
| |
| if (pre_end->in(CountedLoopEndNode::TestValue)->as_Bool()->_test._test == BoolTest::ne) { |
| |
| BoolTest::mask new_test = (main_end->stride_con() > 0) ? BoolTest::lt : BoolTest::gt; |
| // Modify pre loop end condition |
| Node* pre_bol = pre_end->in(CountedLoopEndNode::TestValue)->as_Bool(); |
| BoolNode* new_bol0 = new BoolNode(pre_bol->in(1), new_test); |
| register_new_node( new_bol0, pre_head->in(0) ); |
| _igvn.replace_input_of(pre_end, CountedLoopEndNode::TestValue, new_bol0); |
| // Modify main loop guard condition |
| assert(min_iff->in(CountedLoopEndNode::TestValue) == min_bol, "guard okay"); |
| BoolNode* new_bol1 = new BoolNode(min_bol->in(1), new_test); |
| register_new_node( new_bol1, new_pre_exit ); |
| _igvn.hash_delete(min_iff); |
| min_iff->set_req(CountedLoopEndNode::TestValue, new_bol1); |
| // Modify main loop end condition |
| BoolNode* main_bol = main_end->in(CountedLoopEndNode::TestValue)->as_Bool(); |
| BoolNode* new_bol2 = new BoolNode(main_bol->in(1), new_test); |
| register_new_node( new_bol2, main_end->in(CountedLoopEndNode::TestControl) ); |
| _igvn.replace_input_of(main_end, CountedLoopEndNode::TestValue, new_bol2); |
| } |
| |
| // Flag main loop |
| main_head->set_main_loop(); |
| if( peel_only ) main_head->set_main_no_pre_loop(); |
| |
| // Subtract a trip count for the pre-loop. |
| main_head->set_trip_count(main_head->trip_count() - 1); |
| |
| // It's difficult to be precise about the trip-counts |
| // for the pre/post loops. They are usually very short, |
| // so guess that 4 trips is a reasonable value. |
| post_head->set_profile_trip_cnt(4.0); |
| pre_head->set_profile_trip_cnt(4.0); |
| |
| // Now force out all loop-invariant dominating tests. The optimizer |
| // finds some, but we _know_ they are all useless. |
| peeled_dom_test_elim(loop,old_new); |
| loop->record_for_igvn(); |
| } |
| |
| //------------------------------insert_vector_post_loop------------------------ |
| // Insert a copy of the atomic unrolled vectorized main loop as a post loop, |
| // unroll_policy has already informed us that more unrolling is about to happen to |
| // the main loop. The resultant post loop will serve as a vectorized drain loop. |
| void PhaseIdealLoop::insert_vector_post_loop(IdealLoopTree *loop, Node_List &old_new) { |
| if (!loop->_head->is_CountedLoop()) return; |
| |
| CountedLoopNode *cl = loop->_head->as_CountedLoop(); |
| |
| // only process vectorized main loops |
| if (!cl->is_vectorized_loop() || !cl->is_main_loop()) return; |
| |
| int slp_max_unroll_factor = cl->slp_max_unroll(); |
| int cur_unroll = cl->unrolled_count(); |
| |
| if (slp_max_unroll_factor == 0) return; |
| |
| // only process atomic unroll vector loops (not super unrolled after vectorization) |
| if (cur_unroll != slp_max_unroll_factor) return; |
| |
| // we only ever process this one time |
| if (cl->has_atomic_post_loop()) return; |
| |
| #ifndef PRODUCT |
| if (TraceLoopOpts) { |
| tty->print("PostVector "); |
| loop->dump_head(); |
| } |
| #endif |
| C->set_major_progress(); |
| |
| // Find common pieces of the loop being guarded with pre & post loops |
| CountedLoopNode *main_head = loop->_head->as_CountedLoop(); |
| CountedLoopEndNode *main_end = main_head->loopexit(); |
| guarantee(main_end != NULL, "no loop exit node"); |
| // diagnostic to show loop end is not properly formed |
| assert(main_end->outcnt() == 2, "1 true, 1 false path only"); |
| |
| // mark this loop as processed |
| main_head->mark_has_atomic_post_loop(); |
| |
| Node *incr = main_end->incr(); |
| Node *limit = main_end->limit(); |
| |
| // In this case we throw away the result as we are not using it to connect anything else. |
| CountedLoopNode *post_head = NULL; |
| insert_post_loop(loop, old_new, main_head, main_end, incr, limit, post_head); |
| |
| // It's difficult to be precise about the trip-counts |
| // for post loops. They are usually very short, |
| // so guess that unit vector trips is a reasonable value. |
| post_head->set_profile_trip_cnt(cur_unroll); |
| |
| // Now force out all loop-invariant dominating tests. The optimizer |
| // finds some, but we _know_ they are all useless. |
| peeled_dom_test_elim(loop, old_new); |
| loop->record_for_igvn(); |
| } |
| |
| |
| //-------------------------insert_scalar_rced_post_loop------------------------ |
| // Insert a copy of the rce'd main loop as a post loop, |
| // We have not unrolled the main loop, so this is the right time to inject this. |
| // Later we will examine the partner of this post loop pair which still has range checks |
| // to see inject code which tests at runtime if the range checks are applicable. |
| void PhaseIdealLoop::insert_scalar_rced_post_loop(IdealLoopTree *loop, Node_List &old_new) { |
| if (!loop->_head->is_CountedLoop()) return; |
| |
| CountedLoopNode *cl = loop->_head->as_CountedLoop(); |
| |
| // only process RCE'd main loops |
| if (!cl->is_main_loop() || cl->range_checks_present()) return; |
| |
| #ifndef PRODUCT |
| if (TraceLoopOpts) { |
| tty->print("PostScalarRce "); |
| loop->dump_head(); |
| } |
| #endif |
| C->set_major_progress(); |
| |
| // Find common pieces of the loop being guarded with pre & post loops |
| CountedLoopNode *main_head = loop->_head->as_CountedLoop(); |
| CountedLoopEndNode *main_end = main_head->loopexit(); |
| guarantee(main_end != NULL, "no loop exit node"); |
| // diagnostic to show loop end is not properly formed |
| assert(main_end->outcnt() == 2, "1 true, 1 false path only"); |
| |
| Node *incr = main_end->incr(); |
| Node *limit = main_end->limit(); |
| |
| // In this case we throw away the result as we are not using it to connect anything else. |
| CountedLoopNode *post_head = NULL; |
| insert_post_loop(loop, old_new, main_head, main_end, incr, limit, post_head); |
| |
| // It's difficult to be precise about the trip-counts |
| // for post loops. They are usually very short, |
| // so guess that unit vector trips is a reasonable value. |
| post_head->set_profile_trip_cnt(4.0); |
| post_head->set_is_rce_post_loop(); |
| |
| // Now force out all loop-invariant dominating tests. The optimizer |
| // finds some, but we _know_ they are all useless. |
| peeled_dom_test_elim(loop, old_new); |
| loop->record_for_igvn(); |
| } |
| |
| |
| //------------------------------insert_post_loop------------------------------- |
| // Insert post loops. Add a post loop to the given loop passed. |
| Node *PhaseIdealLoop::insert_post_loop(IdealLoopTree *loop, Node_List &old_new, |
| CountedLoopNode *main_head, CountedLoopEndNode *main_end, |
| Node *incr, Node *limit, CountedLoopNode *&post_head) { |
| |
| //------------------------------ |
| // Step A: Create a new post-Loop. |
| Node* main_exit = main_end->proj_out(false); |
| assert(main_exit->Opcode() == Op_IfFalse, ""); |
| int dd_main_exit = dom_depth(main_exit); |
| |
| // Step A1: Clone the loop body of main. The clone becomes the post-loop. |
| // The main loop pre-header illegally has 2 control users (old & new loops). |
| clone_loop(loop, old_new, dd_main_exit); |
| assert(old_new[main_end->_idx]->Opcode() == Op_CountedLoopEnd, ""); |
| post_head = old_new[main_head->_idx]->as_CountedLoop(); |
| post_head->set_normal_loop(); |
| post_head->set_post_loop(main_head); |
| |
| // Reduce the post-loop trip count. |
| CountedLoopEndNode* post_end = old_new[main_end->_idx]->as_CountedLoopEnd(); |
| post_end->_prob = PROB_FAIR; |
| |
| // Build the main-loop normal exit. |
| IfFalseNode *new_main_exit = new IfFalseNode(main_end); |
| _igvn.register_new_node_with_optimizer(new_main_exit); |
| set_idom(new_main_exit, main_end, dd_main_exit); |
| set_loop(new_main_exit, loop->_parent); |
| |
| // Step A2: Build a zero-trip guard for the post-loop. After leaving the |
| // main-loop, the post-loop may not execute at all. We 'opaque' the incr |
| // (the previous loop trip-counter exit value) because we will be changing |
| // the exit value (via additional unrolling) so we cannot constant-fold away the zero |
| // trip guard until all unrolling is done. |
| Node *zer_opaq = new Opaque1Node(C, incr); |
| Node *zer_cmp = new CmpINode(zer_opaq, limit); |
| Node *zer_bol = new BoolNode(zer_cmp, main_end->test_trip()); |
| register_new_node(zer_opaq, new_main_exit); |
| register_new_node(zer_cmp, new_main_exit); |
| register_new_node(zer_bol, new_main_exit); |
| |
| // Build the IfNode |
| IfNode *zer_iff = new IfNode(new_main_exit, zer_bol, PROB_FAIR, COUNT_UNKNOWN); |
| _igvn.register_new_node_with_optimizer(zer_iff); |
| set_idom(zer_iff, new_main_exit, dd_main_exit); |
| set_loop(zer_iff, loop->_parent); |
| |
| // Plug in the false-path, taken if we need to skip this post-loop |
| _igvn.replace_input_of(main_exit, 0, zer_iff); |
| set_idom(main_exit, zer_iff, dd_main_exit); |
| set_idom(main_exit->unique_out(), zer_iff, dd_main_exit); |
| // Make the true-path, must enter this post loop |
| Node *zer_taken = new IfTrueNode(zer_iff); |
| _igvn.register_new_node_with_optimizer(zer_taken); |
| set_idom(zer_taken, zer_iff, dd_main_exit); |
| set_loop(zer_taken, loop->_parent); |
| // Plug in the true path |
| _igvn.hash_delete(post_head); |
| post_head->set_req(LoopNode::EntryControl, zer_taken); |
| set_idom(post_head, zer_taken, dd_main_exit); |
| |
| Arena *a = Thread::current()->resource_area(); |
| VectorSet visited(a); |
| Node_Stack clones(a, main_head->back_control()->outcnt()); |
| // Step A3: Make the fall-in values to the post-loop come from the |
| // fall-out values of the main-loop. |
| for (DUIterator_Fast imax, i = main_head->fast_outs(imax); i < imax; i++) { |
| Node* main_phi = main_head->fast_out(i); |
| if (main_phi->is_Phi() && main_phi->in(0) == main_head && main_phi->outcnt() >0) { |
| Node *cur_phi = old_new[main_phi->_idx]; |
| Node *fallnew = clone_up_backedge_goo(main_head->back_control(), |
| post_head->init_control(), |
| main_phi->in(LoopNode::LoopBackControl), |
| visited, clones); |
| _igvn.hash_delete(cur_phi); |
| cur_phi->set_req(LoopNode::EntryControl, fallnew); |
| } |
| } |
| |
| // CastII for the new post loop: |
| bool inserted = cast_incr_before_loop(zer_opaq->in(1), zer_taken, post_head); |
| assert(inserted, "no castII inserted"); |
| |
| return new_main_exit; |
| } |
| |
| //------------------------------is_invariant----------------------------- |
| // Return true if n is invariant |
| bool IdealLoopTree::is_invariant(Node* n) const { |
| Node *n_c = _phase->has_ctrl(n) ? _phase->get_ctrl(n) : n; |
| if (n_c->is_top()) return false; |
| return !is_member(_phase->get_loop(n_c)); |
| } |
| |
| |
| //------------------------------do_unroll-------------------------------------- |
| // Unroll the loop body one step - make each trip do 2 iterations. |
| void PhaseIdealLoop::do_unroll( IdealLoopTree *loop, Node_List &old_new, bool adjust_min_trip ) { |
| assert(LoopUnrollLimit, ""); |
| CountedLoopNode *loop_head = loop->_head->as_CountedLoop(); |
| CountedLoopEndNode *loop_end = loop_head->loopexit(); |
| assert(loop_end, ""); |
| #ifndef PRODUCT |
| if (PrintOpto && VerifyLoopOptimizations) { |
| tty->print("Unrolling "); |
| loop->dump_head(); |
| } else if (TraceLoopOpts) { |
| if (loop_head->trip_count() < (uint)LoopUnrollLimit) { |
| tty->print("Unroll %d(%2d) ", loop_head->unrolled_count()*2, loop_head->trip_count()); |
| } else { |
| tty->print("Unroll %d ", loop_head->unrolled_count()*2); |
| } |
| loop->dump_head(); |
| } |
| |
| if (C->do_vector_loop() && (PrintOpto && (VerifyLoopOptimizations || TraceLoopOpts))) { |
| Arena* arena = Thread::current()->resource_area(); |
| Node_Stack stack(arena, C->live_nodes() >> 2); |
| Node_List rpo_list; |
| VectorSet visited(arena); |
| visited.set(loop_head->_idx); |
| rpo( loop_head, stack, visited, rpo_list ); |
| dump(loop, rpo_list.size(), rpo_list ); |
| } |
| #endif |
| |
| // Remember loop node count before unrolling to detect |
| // if rounds of unroll,optimize are making progress |
| loop_head->set_node_count_before_unroll(loop->_body.size()); |
| |
| Node *ctrl = loop_head->in(LoopNode::EntryControl); |
| Node *limit = loop_head->limit(); |
| Node *init = loop_head->init_trip(); |
| Node *stride = loop_head->stride(); |
| |
| Node *opaq = NULL; |
| if (adjust_min_trip) { // If not maximally unrolling, need adjustment |
| // Search for zero-trip guard. |
| |
| // Check the shape of the graph at the loop entry. If an inappropriate |
| // graph shape is encountered, the compiler bails out loop unrolling; |
| // compilation of the method will still succeed. |
| if (!is_canonical_loop_entry(loop_head)) { |
| return; |
| } |
| opaq = ctrl->in(0)->in(1)->in(1)->in(2); |
| // Zero-trip test uses an 'opaque' node which is not shared. |
| assert(opaq->outcnt() == 1 && opaq->in(1) == limit, ""); |
| } |
| |
| C->set_major_progress(); |
| |
| Node* new_limit = NULL; |
| int stride_con = stride->get_int(); |
| int stride_p = (stride_con > 0) ? stride_con : -stride_con; |
| uint old_trip_count = loop_head->trip_count(); |
| // Verify that unroll policy result is still valid. |
| assert(old_trip_count > 1 && |
| (!adjust_min_trip || stride_p <= (1<<3)*loop_head->unrolled_count()), "sanity"); |
| |
| // Adjust loop limit to keep valid iterations number after unroll. |
| // Use (limit - stride) instead of (((limit - init)/stride) & (-2))*stride |
| // which may overflow. |
| if (!adjust_min_trip) { |
| assert(old_trip_count > 1 && (old_trip_count & 1) == 0, |
| "odd trip count for maximally unroll"); |
| // Don't need to adjust limit for maximally unroll since trip count is even. |
| } else if (loop_head->has_exact_trip_count() && init->is_Con()) { |
| // Loop's limit is constant. Loop's init could be constant when pre-loop |
| // become peeled iteration. |
| jlong init_con = init->get_int(); |
| // We can keep old loop limit if iterations count stays the same: |
| // old_trip_count == new_trip_count * 2 |
| // Note: since old_trip_count >= 2 then new_trip_count >= 1 |
| // so we also don't need to adjust zero trip test. |
| jlong limit_con = limit->get_int(); |
| // (stride_con*2) not overflow since stride_con <= 8. |
| int new_stride_con = stride_con * 2; |
| int stride_m = new_stride_con - (stride_con > 0 ? 1 : -1); |
| jlong trip_count = (limit_con - init_con + stride_m)/new_stride_con; |
| // New trip count should satisfy next conditions. |
| assert(trip_count > 0 && (julong)trip_count < (julong)max_juint/2, "sanity"); |
| uint new_trip_count = (uint)trip_count; |
| adjust_min_trip = (old_trip_count != new_trip_count*2); |
| } |
| |
| if (adjust_min_trip) { |
| // Step 2: Adjust the trip limit if it is called for. |
| // The adjustment amount is -stride. Need to make sure if the |
| // adjustment underflows or overflows, then the main loop is skipped. |
| Node* cmp = loop_end->cmp_node(); |
| assert(cmp->in(2) == limit, "sanity"); |
| assert(opaq != NULL && opaq->in(1) == limit, "sanity"); |
| |
| // Verify that policy_unroll result is still valid. |
| const TypeInt* limit_type = _igvn.type(limit)->is_int(); |
| assert(stride_con > 0 && ((limit_type->_hi - stride_con) < limit_type->_hi) || |
| stride_con < 0 && ((limit_type->_lo - stride_con) > limit_type->_lo), "sanity"); |
| |
| if (limit->is_Con()) { |
| // The check in policy_unroll and the assert above guarantee |
| // no underflow if limit is constant. |
| new_limit = _igvn.intcon(limit->get_int() - stride_con); |
| set_ctrl(new_limit, C->root()); |
| } else { |
| // Limit is not constant. |
| if (loop_head->unrolled_count() == 1) { // only for first unroll |
| // Separate limit by Opaque node in case it is an incremented |
| // variable from previous loop to avoid using pre-incremented |
| // value which could increase register pressure. |
| // Otherwise reorg_offsets() optimization will create a separate |
| // Opaque node for each use of trip-counter and as result |
| // zero trip guard limit will be different from loop limit. |
| assert(has_ctrl(opaq), "should have it"); |
| Node* opaq_ctrl = get_ctrl(opaq); |
| limit = new Opaque2Node( C, limit ); |
| register_new_node( limit, opaq_ctrl ); |
| } |
| if ((stride_con > 0 && (java_subtract(limit_type->_lo, stride_con) < limit_type->_lo)) || |
| (stride_con < 0 && (java_subtract(limit_type->_hi, stride_con) > limit_type->_hi))) { |
| // No underflow. |
| new_limit = new SubINode(limit, stride); |
| } else { |
| // (limit - stride) may underflow. |
| // Clamp the adjustment value with MININT or MAXINT: |
| // |
| // new_limit = limit-stride |
| // if (stride > 0) |
| // new_limit = (limit < new_limit) ? MININT : new_limit; |
| // else |
| // new_limit = (limit > new_limit) ? MAXINT : new_limit; |
| // |
| BoolTest::mask bt = loop_end->test_trip(); |
| assert(bt == BoolTest::lt || bt == BoolTest::gt, "canonical test is expected"); |
| Node* adj_max = _igvn.intcon((stride_con > 0) ? min_jint : max_jint); |
| set_ctrl(adj_max, C->root()); |
| Node* old_limit = NULL; |
| Node* adj_limit = NULL; |
| Node* bol = limit->is_CMove() ? limit->in(CMoveNode::Condition) : NULL; |
| if (loop_head->unrolled_count() > 1 && |
| limit->is_CMove() && limit->Opcode() == Op_CMoveI && |
| limit->in(CMoveNode::IfTrue) == adj_max && |
| bol->as_Bool()->_test._test == bt && |
| bol->in(1)->Opcode() == Op_CmpI && |
| bol->in(1)->in(2) == limit->in(CMoveNode::IfFalse)) { |
| // Loop was unrolled before. |
| // Optimize the limit to avoid nested CMove: |
| // use original limit as old limit. |
| old_limit = bol->in(1)->in(1); |
| // Adjust previous adjusted limit. |
| adj_limit = limit->in(CMoveNode::IfFalse); |
| adj_limit = new SubINode(adj_limit, stride); |
| } else { |
| old_limit = limit; |
| adj_limit = new SubINode(limit, stride); |
| } |
| assert(old_limit != NULL && adj_limit != NULL, ""); |
| register_new_node( adj_limit, ctrl ); // adjust amount |
| Node* adj_cmp = new CmpINode(old_limit, adj_limit); |
| register_new_node( adj_cmp, ctrl ); |
| Node* adj_bool = new BoolNode(adj_cmp, bt); |
| register_new_node( adj_bool, ctrl ); |
| new_limit = new CMoveINode(adj_bool, adj_limit, adj_max, TypeInt::INT); |
| } |
| register_new_node(new_limit, ctrl); |
| } |
| assert(new_limit != NULL, ""); |
| // Replace in loop test. |
| assert(loop_end->in(1)->in(1) == cmp, "sanity"); |
| if (cmp->outcnt() == 1 && loop_end->in(1)->outcnt() == 1) { |
| // Don't need to create new test since only one user. |
| _igvn.hash_delete(cmp); |
| cmp->set_req(2, new_limit); |
| } else { |
| // Create new test since it is shared. |
| Node* ctrl2 = loop_end->in(0); |
| Node* cmp2 = cmp->clone(); |
| cmp2->set_req(2, new_limit); |
| register_new_node(cmp2, ctrl2); |
| Node* bol2 = loop_end->in(1)->clone(); |
| bol2->set_req(1, cmp2); |
| register_new_node(bol2, ctrl2); |
| _igvn.replace_input_of(loop_end, 1, bol2); |
| } |
| // Step 3: Find the min-trip test guaranteed before a 'main' loop. |
| // Make it a 1-trip test (means at least 2 trips). |
| |
| // Guard test uses an 'opaque' node which is not shared. Hence I |
| // can edit it's inputs directly. Hammer in the new limit for the |
| // minimum-trip guard. |
| assert(opaq->outcnt() == 1, ""); |
| _igvn.replace_input_of(opaq, 1, new_limit); |
| } |
| |
| // Adjust max trip count. The trip count is intentionally rounded |
| // down here (e.g. 15-> 7-> 3-> 1) because if we unwittingly over-unroll, |
| // the main, unrolled, part of the loop will never execute as it is protected |
| // by the min-trip test. See bug 4834191 for a case where we over-unrolled |
| // and later determined that part of the unrolled loop was dead. |
| loop_head->set_trip_count(old_trip_count / 2); |
| |
| // Double the count of original iterations in the unrolled loop body. |
| loop_head->double_unrolled_count(); |
| |
| // --------- |
| // Step 4: Clone the loop body. Move it inside the loop. This loop body |
| // represents the odd iterations; since the loop trips an even number of |
| // times its backedge is never taken. Kill the backedge. |
| uint dd = dom_depth(loop_head); |
| clone_loop( loop, old_new, dd ); |
| |
| // Make backedges of the clone equal to backedges of the original. |
| // Make the fall-in from the original come from the fall-out of the clone. |
| for (DUIterator_Fast jmax, j = loop_head->fast_outs(jmax); j < jmax; j++) { |
| Node* phi = loop_head->fast_out(j); |
| if( phi->is_Phi() && phi->in(0) == loop_head && phi->outcnt() > 0 ) { |
| Node *newphi = old_new[phi->_idx]; |
| _igvn.hash_delete( phi ); |
| _igvn.hash_delete( newphi ); |
| |
| phi ->set_req(LoopNode:: EntryControl, newphi->in(LoopNode::LoopBackControl)); |
| newphi->set_req(LoopNode::LoopBackControl, phi ->in(LoopNode::LoopBackControl)); |
| phi ->set_req(LoopNode::LoopBackControl, C->top()); |
| } |
| } |
| Node *clone_head = old_new[loop_head->_idx]; |
| _igvn.hash_delete( clone_head ); |
| loop_head ->set_req(LoopNode:: EntryControl, clone_head->in(LoopNode::LoopBackControl)); |
| clone_head->set_req(LoopNode::LoopBackControl, loop_head ->in(LoopNode::LoopBackControl)); |
| loop_head ->set_req(LoopNode::LoopBackControl, C->top()); |
| loop->_head = clone_head; // New loop header |
| |
| set_idom(loop_head, loop_head ->in(LoopNode::EntryControl), dd); |
| set_idom(clone_head, clone_head->in(LoopNode::EntryControl), dd); |
| |
| // Kill the clone's backedge |
| Node *newcle = old_new[loop_end->_idx]; |
| _igvn.hash_delete( newcle ); |
| Node *one = _igvn.intcon(1); |
| set_ctrl(one, C->root()); |
| newcle->set_req(1, one); |
| // Force clone into same loop body |
| uint max = loop->_body.size(); |
| for( uint k = 0; k < max; k++ ) { |
| Node *old = loop->_body.at(k); |
| Node *nnn = old_new[old->_idx]; |
| loop->_body.push(nnn); |
| if (!has_ctrl(old)) |
| set_loop(nnn, loop); |
| } |
| |
| loop->record_for_igvn(); |
| |
| #ifndef PRODUCT |
| if (C->do_vector_loop() && (PrintOpto && (VerifyLoopOptimizations || TraceLoopOpts))) { |
| tty->print("\nnew loop after unroll\n"); loop->dump_head(); |
| for (uint i = 0; i < loop->_body.size(); i++) { |
| loop->_body.at(i)->dump(); |
| } |
| if(C->clone_map().is_debug()) { |
| tty->print("\nCloneMap\n"); |
| Dict* dict = C->clone_map().dict(); |
| DictI i(dict); |
| tty->print_cr("Dict@%p[%d] = ", dict, dict->Size()); |
| for (int ii = 0; i.test(); ++i, ++ii) { |
| NodeCloneInfo cl((uint64_t)dict->operator[]((void*)i._key)); |
| tty->print("%d->%d:%d,", (int)(intptr_t)i._key, cl.idx(), cl.gen()); |
| if (ii % 10 == 9) { |
| tty->print_cr(" "); |
| } |
| } |
| tty->print_cr(" "); |
| } |
| } |
| #endif |
| |
| } |
| |
| //------------------------------do_maximally_unroll---------------------------- |
| |
| void PhaseIdealLoop::do_maximally_unroll( IdealLoopTree *loop, Node_List &old_new ) { |
| CountedLoopNode *cl = loop->_head->as_CountedLoop(); |
| assert(cl->has_exact_trip_count(), "trip count is not exact"); |
| assert(cl->trip_count() > 0, ""); |
| #ifndef PRODUCT |
| if (TraceLoopOpts) { |
| tty->print("MaxUnroll %d ", cl->trip_count()); |
| loop->dump_head(); |
| } |
| #endif |
| |
| // If loop is tripping an odd number of times, peel odd iteration |
| if ((cl->trip_count() & 1) == 1) { |
| do_peeling(loop, old_new); |
| } |
| |
| // Now its tripping an even number of times remaining. Double loop body. |
| // Do not adjust pre-guards; they are not needed and do not exist. |
| if (cl->trip_count() > 0) { |
| assert((cl->trip_count() & 1) == 0, "missed peeling"); |
| do_unroll(loop, old_new, false); |
| } |
| } |
| |
| void PhaseIdealLoop::mark_reductions(IdealLoopTree *loop) { |
| if (SuperWordReductions == false) return; |
| |
| CountedLoopNode* loop_head = loop->_head->as_CountedLoop(); |
| if (loop_head->unrolled_count() > 1) { |
| return; |
| } |
| |
| Node* trip_phi = loop_head->phi(); |
| for (DUIterator_Fast imax, i = loop_head->fast_outs(imax); i < imax; i++) { |
| Node* phi = loop_head->fast_out(i); |
| if (phi->is_Phi() && phi->outcnt() > 0 && phi != trip_phi) { |
| // For definitions which are loop inclusive and not tripcounts. |
| Node* def_node = phi->in(LoopNode::LoopBackControl); |
| |
| if (def_node != NULL) { |
| Node* n_ctrl = get_ctrl(def_node); |
| if (n_ctrl != NULL && loop->is_member(get_loop(n_ctrl))) { |
| // Now test it to see if it fits the standard pattern for a reduction operator. |
| int opc = def_node->Opcode(); |
| if (opc != ReductionNode::opcode(opc, def_node->bottom_type()->basic_type())) { |
| if (!def_node->is_reduction()) { // Not marked yet |
| // To be a reduction, the arithmetic node must have the phi as input and provide a def to it |
| bool ok = false; |
| for (unsigned j = 1; j < def_node->req(); j++) { |
| Node* in = def_node->in(j); |
| if (in == phi) { |
| ok = true; |
| break; |
| } |
| } |
| |
| // do nothing if we did not match the initial criteria |
| if (ok == false) { |
| continue; |
| } |
| |
| // The result of the reduction must not be used in the loop |
| for (DUIterator_Fast imax, i = def_node->fast_outs(imax); i < imax && ok; i++) { |
| Node* u = def_node->fast_out(i); |
| if (!loop->is_member(get_loop(ctrl_or_self(u)))) { |
| continue; |
| } |
| if (u == phi) { |
| continue; |
| } |
| ok = false; |
| } |
| |
| // iff the uses conform |
| if (ok) { |
| def_node->add_flag(Node::Flag_is_reduction); |
| loop_head->mark_has_reductions(); |
| } |
| } |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| //------------------------------adjust_limit----------------------------------- |
| // Helper function for add_constraint(). |
| Node* PhaseIdealLoop::adjust_limit(int stride_con, Node * scale, Node *offset, Node *rc_limit, Node *loop_limit, Node *pre_ctrl) { |
| // Compute "I :: (limit-offset)/scale" |
| Node *con = new SubINode(rc_limit, offset); |
| register_new_node(con, pre_ctrl); |
| Node *X = new DivINode(0, con, scale); |
| register_new_node(X, pre_ctrl); |
| |
| // Adjust loop limit |
| loop_limit = (stride_con > 0) |
| ? (Node*)(new MinINode(loop_limit, X)) |
| : (Node*)(new MaxINode(loop_limit, X)); |
| register_new_node(loop_limit, pre_ctrl); |
| return loop_limit; |
| } |
| |
| //------------------------------add_constraint--------------------------------- |
| // Constrain the main loop iterations so the conditions: |
| // low_limit <= scale_con * I + offset < upper_limit |
| // always holds true. That is, either increase the number of iterations in |
| // the pre-loop or the post-loop until the condition holds true in the main |
| // loop. Stride, scale, offset and limit are all loop invariant. Further, |
| // stride and scale are constants (offset and limit often are). |
| void PhaseIdealLoop::add_constraint( int stride_con, int scale_con, Node *offset, Node *low_limit, Node *upper_limit, Node *pre_ctrl, Node **pre_limit, Node **main_limit ) { |
| // For positive stride, the pre-loop limit always uses a MAX function |
| // and the main loop a MIN function. For negative stride these are |
| // reversed. |
| |
| // Also for positive stride*scale the affine function is increasing, so the |
| // pre-loop must check for underflow and the post-loop for overflow. |
| // Negative stride*scale reverses this; pre-loop checks for overflow and |
| // post-loop for underflow. |
| |
| Node *scale = _igvn.intcon(scale_con); |
| set_ctrl(scale, C->root()); |
| |
| if ((stride_con^scale_con) >= 0) { // Use XOR to avoid overflow |
| // The overflow limit: scale*I+offset < upper_limit |
| // For main-loop compute |
| // ( if (scale > 0) /* and stride > 0 */ |
| // I < (upper_limit-offset)/scale |
| // else /* scale < 0 and stride < 0 */ |
| // I > (upper_limit-offset)/scale |
| // ) |
| // |
| // (upper_limit-offset) may overflow or underflow. |
| // But it is fine since main loop will either have |
| // less iterations or will be skipped in such case. |
| *main_limit = adjust_limit(stride_con, scale, offset, upper_limit, *main_limit, pre_ctrl); |
| |
| // The underflow limit: low_limit <= scale*I+offset. |
| // For pre-loop compute |
| // NOT(scale*I+offset >= low_limit) |
| // scale*I+offset < low_limit |
| // ( if (scale > 0) /* and stride > 0 */ |
| // I < (low_limit-offset)/scale |
| // else /* scale < 0 and stride < 0 */ |
| // I > (low_limit-offset)/scale |
| // ) |
| |
| if (low_limit->get_int() == -max_jint) { |
| // We need this guard when scale*pre_limit+offset >= limit |
| // due to underflow. So we need execute pre-loop until |
| // scale*I+offset >= min_int. But (min_int-offset) will |
| // underflow when offset > 0 and X will be > original_limit |
| // when stride > 0. To avoid it we replace positive offset with 0. |
| // |
| // Also (min_int+1 == -max_int) is used instead of min_int here |
| // to avoid problem with scale == -1 (min_int/(-1) == min_int). |
| Node* shift = _igvn.intcon(31); |
| set_ctrl(shift, C->root()); |
| Node* sign = new RShiftINode(offset, shift); |
| register_new_node(sign, pre_ctrl); |
| offset = new AndINode(offset, sign); |
| register_new_node(offset, pre_ctrl); |
| } else { |
| assert(low_limit->get_int() == 0, "wrong low limit for range check"); |
| // The only problem we have here when offset == min_int |
| // since (0-min_int) == min_int. It may be fine for stride > 0 |
| // but for stride < 0 X will be < original_limit. To avoid it |
| // max(pre_limit, original_limit) is used in do_range_check(). |
| } |
| // Pass (-stride) to indicate pre_loop_cond = NOT(main_loop_cond); |
| *pre_limit = adjust_limit((-stride_con), scale, offset, low_limit, *pre_limit, pre_ctrl); |
| |
| } else { // stride_con*scale_con < 0 |
| // For negative stride*scale pre-loop checks for overflow and |
| // post-loop for underflow. |
| // |
| // The overflow limit: scale*I+offset < upper_limit |
| // For pre-loop compute |
| // NOT(scale*I+offset < upper_limit) |
| // scale*I+offset >= upper_limit |
| // scale*I+offset+1 > upper_limit |
| // ( if (scale < 0) /* and stride > 0 */ |
| // I < (upper_limit-(offset+1))/scale |
| // else /* scale > 0 and stride < 0 */ |
| // I > (upper_limit-(offset+1))/scale |
| // ) |
| // |
| // (upper_limit-offset-1) may underflow or overflow. |
| // To avoid it min(pre_limit, original_limit) is used |
| // in do_range_check() for stride > 0 and max() for < 0. |
| Node *one = _igvn.intcon(1); |
| set_ctrl(one, C->root()); |
| |
| Node *plus_one = new AddINode(offset, one); |
| register_new_node( plus_one, pre_ctrl ); |
| // Pass (-stride) to indicate pre_loop_cond = NOT(main_loop_cond); |
| *pre_limit = adjust_limit((-stride_con), scale, plus_one, upper_limit, *pre_limit, pre_ctrl); |
| |
| if (low_limit->get_int() == -max_jint) { |
| // We need this guard when scale*main_limit+offset >= limit |
| // due to underflow. So we need execute main-loop while |
| // scale*I+offset+1 > min_int. But (min_int-offset-1) will |
| // underflow when (offset+1) > 0 and X will be < main_limit |
| // when scale < 0 (and stride > 0). To avoid it we replace |
| // positive (offset+1) with 0. |
| // |
| // Also (min_int+1 == -max_int) is used instead of min_int here |
| // to avoid problem with scale == -1 (min_int/(-1) == min_int). |
| Node* shift = _igvn.intcon(31); |
| set_ctrl(shift, C->root()); |
| Node* sign = new RShiftINode(plus_one, shift); |
| register_new_node(sign, pre_ctrl); |
| plus_one = new AndINode(plus_one, sign); |
| register_new_node(plus_one, pre_ctrl); |
| } else { |
| assert(low_limit->get_int() == 0, "wrong low limit for range check"); |
| // The only problem we have here when offset == max_int |
| // since (max_int+1) == min_int and (0-min_int) == min_int. |
| // But it is fine since main loop will either have |
| // less iterations or will be skipped in such case. |
| } |
| // The underflow limit: low_limit <= scale*I+offset. |
| // For main-loop compute |
| // scale*I+offset+1 > low_limit |
| // ( if (scale < 0) /* and stride > 0 */ |
| // I < (low_limit-(offset+1))/scale |
| // else /* scale > 0 and stride < 0 */ |
| // I > (low_limit-(offset+1))/scale |
| // ) |
| |
| *main_limit = adjust_limit(stride_con, scale, plus_one, low_limit, *main_limit, pre_ctrl); |
| } |
| } |
| |
| |
| //------------------------------is_scaled_iv--------------------------------- |
| // Return true if exp is a constant times an induction var |
| bool PhaseIdealLoop::is_scaled_iv(Node* exp, Node* iv, int* p_scale) { |
| if (exp == iv) { |
| if (p_scale != NULL) { |
| *p_scale = 1; |
| } |
| return true; |
| } |
| int opc = exp->Opcode(); |
| if (opc == Op_MulI) { |
| if (exp->in(1) == iv && exp->in(2)->is_Con()) { |
| if (p_scale != NULL) { |
| *p_scale = exp->in(2)->get_int(); |
| } |
| return true; |
| } |
| if (exp->in(2) == iv && exp->in(1)->is_Con()) { |
| if (p_scale != NULL) { |
| *p_scale = exp->in(1)->get_int(); |
| } |
| return true; |
| } |
| } else if (opc == Op_LShiftI) { |
| if (exp->in(1) == iv && exp->in(2)->is_Con()) { |
| if (p_scale != NULL) { |
| *p_scale = 1 << exp->in(2)->get_int(); |
| } |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| //-----------------------------is_scaled_iv_plus_offset------------------------------ |
| // Return true if exp is a simple induction variable expression: k1*iv + (invar + k2) |
| bool PhaseIdealLoop::is_scaled_iv_plus_offset(Node* exp, Node* iv, int* p_scale, Node** p_offset, int depth) { |
| if (is_scaled_iv(exp, iv, p_scale)) { |
| if (p_offset != NULL) { |
| Node *zero = _igvn.intcon(0); |
| set_ctrl(zero, C->root()); |
| *p_offset = zero; |
| } |
| return true; |
| } |
| int opc = exp->Opcode(); |
| if (opc == Op_AddI) { |
| if (is_scaled_iv(exp->in(1), iv, p_scale)) { |
| if (p_offset != NULL) { |
| *p_offset = exp->in(2); |
| } |
| return true; |
| } |
| if (is_scaled_iv(exp->in(2), iv, p_scale)) { |
| if (p_offset != NULL) { |
| *p_offset = exp->in(1); |
| } |
| return true; |
| } |
| if (exp->in(2)->is_Con()) { |
| Node* offset2 = NULL; |
| if (depth < 2 && |
| is_scaled_iv_plus_offset(exp->in(1), iv, p_scale, |
| p_offset != NULL ? &offset2 : NULL, depth+1)) { |
| if (p_offset != NULL) { |
| Node *ctrl_off2 = get_ctrl(offset2); |
| Node* offset = new AddINode(offset2, exp->in(2)); |
| register_new_node(offset, ctrl_off2); |
| *p_offset = offset; |
| } |
| return true; |
| } |
| } |
| } else if (opc == Op_SubI) { |
| if (is_scaled_iv(exp->in(1), iv, p_scale)) { |
| if (p_offset != NULL) { |
| Node *zero = _igvn.intcon(0); |
| set_ctrl(zero, C->root()); |
| Node *ctrl_off = get_ctrl(exp->in(2)); |
| Node* offset = new SubINode(zero, exp->in(2)); |
| register_new_node(offset, ctrl_off); |
| *p_offset = offset; |
| } |
| return true; |
| } |
| if (is_scaled_iv(exp->in(2), iv, p_scale)) { |
| if (p_offset != NULL) { |
| *p_scale *= -1; |
| *p_offset = exp->in(1); |
| } |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| //------------------------------do_range_check--------------------------------- |
| // Eliminate range-checks and other trip-counter vs loop-invariant tests. |
| int PhaseIdealLoop::do_range_check( IdealLoopTree *loop, Node_List &old_new ) { |
| #ifndef PRODUCT |
| if (PrintOpto && VerifyLoopOptimizations) { |
| tty->print("Range Check Elimination "); |
| loop->dump_head(); |
| } else if (TraceLoopOpts) { |
| tty->print("RangeCheck "); |
| loop->dump_head(); |
| } |
| #endif |
| assert(RangeCheckElimination, ""); |
| CountedLoopNode *cl = loop->_head->as_CountedLoop(); |
| // If we fail before trying to eliminate range checks, set multiversion state |
| int closed_range_checks = 1; |
| |
| // protect against stride not being a constant |
| if (!cl->stride_is_con()) |
| return closed_range_checks; |
| |
| // Find the trip counter; we are iteration splitting based on it |
| Node *trip_counter = cl->phi(); |
| // Find the main loop limit; we will trim it's iterations |
| // to not ever trip end tests |
| Node *main_limit = cl->limit(); |
| |
| // Check graph shape. Cannot optimize a loop if zero-trip |
| // Opaque1 node is optimized away and then another round |
| // of loop opts attempted. |
| if (!is_canonical_loop_entry(cl)) { |
| return closed_range_checks; |
| } |
| |
| // Need to find the main-loop zero-trip guard |
| Node *ctrl = cl->in(LoopNode::EntryControl); |
| Node *iffm = ctrl->in(0); |
| Node *opqzm = iffm->in(1)->in(1)->in(2); |
| assert(opqzm->in(1) == main_limit, "do not understand situation"); |
| |
| // Find the pre-loop limit; we will expand its iterations to |
| // not ever trip low tests. |
| Node *p_f = iffm->in(0); |
| // pre loop may have been optimized out |
| if (p_f->Opcode() != Op_IfFalse) { |
| return closed_range_checks; |
| } |
| CountedLoopEndNode *pre_end = p_f->in(0)->as_CountedLoopEnd(); |
| assert(pre_end->loopnode()->is_pre_loop(), ""); |
| Node *pre_opaq1 = pre_end->limit(); |
| // Occasionally it's possible for a pre-loop Opaque1 node to be |
| // optimized away and then another round of loop opts attempted. |
| // We can not optimize this particular loop in that case. |
| if (pre_opaq1->Opcode() != Op_Opaque1) |
| return closed_range_checks; |
| Opaque1Node *pre_opaq = (Opaque1Node*)pre_opaq1; |
| Node *pre_limit = pre_opaq->in(1); |
| |
| // Where do we put new limit calculations |
| Node *pre_ctrl = pre_end->loopnode()->in(LoopNode::EntryControl); |
| |
| // Ensure the original loop limit is available from the |
| // pre-loop Opaque1 node. |
| Node *orig_limit = pre_opaq->original_loop_limit(); |
| if (orig_limit == NULL || _igvn.type(orig_limit) == Type::TOP) |
| return closed_range_checks; |
| |
| // Must know if its a count-up or count-down loop |
| |
| int stride_con = cl->stride_con(); |
| Node *zero = _igvn.intcon(0); |
| Node *one = _igvn.intcon(1); |
| // Use symmetrical int range [-max_jint,max_jint] |
| Node *mini = _igvn.intcon(-max_jint); |
| set_ctrl(zero, C->root()); |
| set_ctrl(one, C->root()); |
| set_ctrl(mini, C->root()); |
| |
| // Range checks that do not dominate the loop backedge (ie. |
| // conditionally executed) can lengthen the pre loop limit beyond |
| // the original loop limit. To prevent this, the pre limit is |
| // (for stride > 0) MINed with the original loop limit (MAXed |
| // stride < 0) when some range_check (rc) is conditionally |
| // executed. |
| bool conditional_rc = false; |
| |
| // Count number of range checks and reduce by load range limits, if zero, |
| // the loop is in canonical form to multiversion. |
| closed_range_checks = 0; |
| |
| // Check loop body for tests of trip-counter plus loop-invariant vs loop-variant. |
| for( uint i = 0; i < loop->_body.size(); i++ ) { |
| Node *iff = loop->_body[i]; |
| if (iff->Opcode() == Op_If || |
| iff->Opcode() == Op_RangeCheck) { // Test? |
| // Test is an IfNode, has 2 projections. If BOTH are in the loop |
| // we need loop unswitching instead of iteration splitting. |
| closed_range_checks++; |
| Node *exit = loop->is_loop_exit(iff); |
| if( !exit ) continue; |
| int flip = (exit->Opcode() == Op_IfTrue) ? 1 : 0; |
| |
| // Get boolean condition to test |
| Node *i1 = iff->in(1); |
| if( !i1->is_Bool() ) continue; |
| BoolNode *bol = i1->as_Bool(); |
| BoolTest b_test = bol->_test; |
| // Flip sense of test if exit condition is flipped |
| if( flip ) |
| b_test = b_test.negate(); |
| |
| // Get compare |
| Node *cmp = bol->in(1); |
| |
| // Look for trip_counter + offset vs limit |
| Node *rc_exp = cmp->in(1); |
| Node *limit = cmp->in(2); |
| jint scale_con= 1; // Assume trip counter not scaled |
| |
| Node *limit_c = get_ctrl(limit); |
| if( loop->is_member(get_loop(limit_c) ) ) { |
| // Compare might have operands swapped; commute them |
| b_test = b_test.commute(); |
| rc_exp = cmp->in(2); |
| limit = cmp->in(1); |
| limit_c = get_ctrl(limit); |
| if( loop->is_member(get_loop(limit_c) ) ) |
| continue; // Both inputs are loop varying; cannot RCE |
| } |
| // Here we know 'limit' is loop invariant |
| |
| // 'limit' maybe pinned below the zero trip test (probably from a |
| // previous round of rce), in which case, it can't be used in the |
| // zero trip test expression which must occur before the zero test's if. |
| if( limit_c == ctrl ) { |
| continue; // Don't rce this check but continue looking for other candidates. |
| } |
| |
| // Check for scaled induction variable plus an offset |
| Node *offset = NULL; |
| |
| if (!is_scaled_iv_plus_offset(rc_exp, trip_counter, &scale_con, &offset)) { |
| continue; |
| } |
| |
| Node *offset_c = get_ctrl(offset); |
| if( loop->is_member( get_loop(offset_c) ) ) |
| continue; // Offset is not really loop invariant |
| // Here we know 'offset' is loop invariant. |
| |
| // As above for the 'limit', the 'offset' maybe pinned below the |
| // zero trip test. |
| if( offset_c == ctrl ) { |
| continue; // Don't rce this check but continue looking for other candidates. |
| } |
| #ifdef ASSERT |
| if (TraceRangeLimitCheck) { |
| tty->print_cr("RC bool node%s", flip ? " flipped:" : ":"); |
| bol->dump(2); |
| } |
| #endif |
| // At this point we have the expression as: |
| // scale_con * trip_counter + offset :: limit |
| // where scale_con, offset and limit are loop invariant. Trip_counter |
| // monotonically increases by stride_con, a constant. Both (or either) |
| // stride_con and scale_con can be negative which will flip about the |
| // sense of the test. |
| |
| // Adjust pre and main loop limits to guard the correct iteration set |
| if( cmp->Opcode() == Op_CmpU ) {// Unsigned compare is really 2 tests |
| if( b_test._test == BoolTest::lt ) { // Range checks always use lt |
| // The underflow and overflow limits: 0 <= scale*I+offset < limit |
| add_constraint( stride_con, scale_con, offset, zero, limit, pre_ctrl, &pre_limit, &main_limit ); |
| // (0-offset)/scale could be outside of loop iterations range. |
| conditional_rc = true; |
| } else { |
| if (PrintOpto) { |
| tty->print_cr("missed RCE opportunity"); |
| } |
| continue; // In release mode, ignore it |
| } |
| } else { // Otherwise work on normal compares |
| switch( b_test._test ) { |
| case BoolTest::gt: |
| // Fall into GE case |
| case BoolTest::ge: |
| // Convert (I*scale+offset) >= Limit to (I*(-scale)+(-offset)) <= -Limit |
| scale_con = -scale_con; |
| offset = new SubINode( zero, offset ); |
| register_new_node( offset, pre_ctrl ); |
| limit = new SubINode( zero, limit ); |
| register_new_node( limit, pre_ctrl ); |
| // Fall into LE case |
| case BoolTest::le: |
| if (b_test._test != BoolTest::gt) { |
| // Convert X <= Y to X < Y+1 |
| limit = new AddINode( limit, one ); |
| register_new_node( limit, pre_ctrl ); |
| } |
| // Fall into LT case |
| case BoolTest::lt: |
| // The underflow and overflow limits: MIN_INT <= scale*I+offset < limit |
| // Note: (MIN_INT+1 == -MAX_INT) is used instead of MIN_INT here |
| // to avoid problem with scale == -1: MIN_INT/(-1) == MIN_INT. |
| add_constraint( stride_con, scale_con, offset, mini, limit, pre_ctrl, &pre_limit, &main_limit ); |
| // ((MIN_INT+1)-offset)/scale could be outside of loop iterations range. |
| // Note: negative offset is replaced with 0 but (MIN_INT+1)/scale could |
| // still be outside of loop range. |
| conditional_rc = true; |
| break; |
| default: |
| if (PrintOpto) { |
| tty->print_cr("missed RCE opportunity"); |
| } |
| continue; // Unhandled case |
| } |
| } |
| |
| // Kill the eliminated test |
| C->set_major_progress(); |
| Node *kill_con = _igvn.intcon( 1-flip ); |
| set_ctrl(kill_con, C->root()); |
| _igvn.replace_input_of(iff, 1, kill_con); |
| // Find surviving projection |
| assert(iff->is_If(), ""); |
| ProjNode* dp = ((IfNode*)iff)->proj_out(1-flip); |
| // Find loads off the surviving projection; remove their control edge |
| for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) { |
| Node* cd = dp->fast_out(i); // Control-dependent node |
| if (cd->is_Load() && cd->depends_only_on_test()) { // Loads can now float around in the loop |
| // Allow the load to float around in the loop, or before it |
| // but NOT before the pre-loop. |
| _igvn.replace_input_of(cd, 0, ctrl); // ctrl, not NULL |
| --i; |
| --imax; |
| } |
| } |
| if (limit->Opcode() == Op_LoadRange) { |
| closed_range_checks--; |
| } |
| |
| } // End of is IF |
| |
| } |
| |
| // Update loop limits |
| if (conditional_rc) { |
| pre_limit = (stride_con > 0) ? (Node*)new MinINode(pre_limit, orig_limit) |
| : (Node*)new MaxINode(pre_limit, orig_limit); |
| register_new_node(pre_limit, pre_ctrl); |
| } |
| _igvn.replace_input_of(pre_opaq, 1, pre_limit); |
| |
| // Note:: we are making the main loop limit no longer precise; |
| // need to round up based on stride. |
| cl->set_nonexact_trip_count(); |
| Node *main_cle = cl->loopexit(); |
| Node *main_bol = main_cle->in(1); |
| // Hacking loop bounds; need private copies of exit test |
| if( main_bol->outcnt() > 1 ) {// BoolNode shared? |
| main_bol = main_bol->clone();// Clone a private BoolNode |
| register_new_node( main_bol, main_cle->in(0) ); |
| _igvn.replace_input_of(main_cle, 1, main_bol); |
| } |
| Node *main_cmp = main_bol->in(1); |
| if( main_cmp->outcnt() > 1 ) { // CmpNode shared? |
| main_cmp = main_cmp->clone();// Clone a private CmpNode |
| register_new_node( main_cmp, main_cle->in(0) ); |
| _igvn.replace_input_of(main_bol, 1, main_cmp); |
| } |
| // Hack the now-private loop bounds |
| _igvn.replace_input_of(main_cmp, 2, main_limit); |
| // The OpaqueNode is unshared by design |
| assert( opqzm->outcnt() == 1, "cannot hack shared node" ); |
| _igvn.replace_input_of(opqzm, 1, main_limit); |
| |
| return closed_range_checks; |
| } |
| |
| //------------------------------has_range_checks------------------------------- |
| // Check to see if RCE cleaned the current loop of range-checks. |
| void PhaseIdealLoop::has_range_checks(IdealLoopTree *loop) { |
| assert(RangeCheckElimination, ""); |
| |
| // skip if not a counted loop |
| if (!loop->is_counted()) return; |
| |
| CountedLoopNode *cl = loop->_head->as_CountedLoop(); |
| |
| // skip this loop if it is already checked |
| if (cl->has_been_range_checked()) return; |
| |
| // Now check for existence of range checks |
| for (uint i = 0; i < loop->_body.size(); i++) { |
| Node *iff = loop->_body[i]; |
| int iff_opc = iff->Opcode(); |
| if (iff_opc == Op_If || iff_opc == Op_RangeCheck) { |
| cl->mark_has_range_checks(); |
| break; |
| } |
| } |
| cl->set_has_been_range_checked(); |
| } |
| |
| //-------------------------multi_version_post_loops---------------------------- |
| // Check the range checks that remain, if simple, use the bounds to guard |
| // which version to a post loop we execute, one with range checks or one without |
| bool PhaseIdealLoop::multi_version_post_loops(IdealLoopTree *rce_loop, IdealLoopTree *legacy_loop) { |
| bool multi_version_succeeded = false; |
| assert(RangeCheckElimination, ""); |
| CountedLoopNode *legacy_cl = legacy_loop->_head->as_CountedLoop(); |
| assert(legacy_cl->is_post_loop(), ""); |
| |
| // Check for existence of range checks using the unique instance to make a guard with |
| Unique_Node_List worklist; |
| for (uint i = 0; i < legacy_loop->_body.size(); i++) { |
| Node *iff = legacy_loop->_body[i]; |
| int iff_opc = iff->Opcode(); |
| if (iff_opc == Op_If || iff_opc == Op_RangeCheck) { |
| worklist.push(iff); |
| } |
| } |
| |
| // Find RCE'd post loop so that we can stage its guard. |
| if (!is_canonical_loop_entry(legacy_cl)) return multi_version_succeeded; |
| Node* ctrl = legacy_cl->in(LoopNode::EntryControl); |
| Node* iffm = ctrl->in(0); |
| |
| // Now we test that both the post loops are connected |
| Node* post_loop_region = iffm->in(0); |
| if (post_loop_region == NULL) return multi_version_succeeded; |
| if (!post_loop_region->is_Region()) return multi_version_succeeded; |
| Node* covering_region = post_loop_region->in(RegionNode::Control+1); |
| if (covering_region == NULL) return multi_version_succeeded; |
| if (!covering_region->is_Region()) return multi_version_succeeded; |
| Node* p_f = covering_region->in(RegionNode::Control); |
| if (p_f == NULL) return multi_version_succeeded; |
| if (!p_f->is_IfFalse()) return multi_version_succeeded; |
| if (!p_f->in(0)->is_CountedLoopEnd()) return multi_version_succeeded; |
| CountedLoopEndNode* rce_loop_end = p_f->in(0)->as_CountedLoopEnd(); |
| if (rce_loop_end == NULL) return multi_version_succeeded; |
| CountedLoopNode* rce_cl = rce_loop_end->loopnode(); |
| if (rce_cl == NULL || !rce_cl->is_post_loop()) return multi_version_succeeded; |
| CountedLoopNode *known_rce_cl = rce_loop->_head->as_CountedLoop(); |
| if (rce_cl != known_rce_cl) return multi_version_succeeded; |
| |
| // Then we fetch the cover entry test |
| ctrl = rce_cl->in(LoopNode::EntryControl); |
| if (!ctrl->is_IfTrue() && !ctrl->is_IfFalse()) return multi_version_succeeded; |
| |
| #ifndef PRODUCT |
| if (TraceLoopOpts) { |
| tty->print("PostMultiVersion\n"); |
| rce_loop->dump_head(); |
| legacy_loop->dump_head(); |
| } |
| #endif |
| |
| // Now fetch the limit we want to compare against |
| Node *limit = rce_cl->limit(); |
| bool first_time = true; |
| |
| // If we got this far, we identified the post loop which has been RCE'd and |
| // we have a work list. Now we will try to transform the if guard to cause |
| // the loop pair to be multi version executed with the determination left to runtime |
| // or the optimizer if full information is known about the given arrays at compile time. |
| Node *last_min = NULL; |
| multi_version_succeeded = true; |
| while (worklist.size()) { |
| Node* rc_iffm = worklist.pop(); |
| if (rc_iffm->is_If()) { |
| Node *rc_bolzm = rc_iffm->in(1); |
| if (rc_bolzm->is_Bool()) { |
| Node *rc_cmpzm = rc_bolzm->in(1); |
| if (rc_cmpzm->is_Cmp()) { |
| Node *rc_left = rc_cmpzm->in(2); |
| if (rc_left->Opcode() != Op_LoadRange) { |
| multi_version_succeeded = false; |
| break; |
| } |
| if (first_time) { |
| last_min = rc_left; |
| first_time = false; |
| } else { |
| Node *cur_min = new MinINode(last_min, rc_left); |
| last_min = cur_min; |
| _igvn.register_new_node_with_optimizer(last_min); |
| } |
| } |
| } |
| } |
| } |
| |
| // All we have to do is update the limit of the rce loop |
| // with the min of our expression and the current limit. |
| // We will use this expression to replace the current limit. |
| if (last_min && multi_version_succeeded) { |
| Node *cur_min = new MinINode(last_min, limit); |
| _igvn.register_new_node_with_optimizer(cur_min); |
| Node *cmp_node = rce_loop_end->cmp_node(); |
| _igvn.replace_input_of(cmp_node, 2, cur_min); |
| set_idom(cmp_node, cur_min, dom_depth(ctrl)); |
| set_ctrl(cur_min, ctrl); |
| set_loop(cur_min, rce_loop->_parent); |
| |
| legacy_cl->mark_is_multiversioned(); |
| rce_cl->mark_is_multiversioned(); |
| multi_version_succeeded = true; |
| |
| C->set_major_progress(); |
| } |
| |
| return multi_version_succeeded; |
| } |
| |
| //-------------------------poison_rce_post_loop-------------------------------- |
| // Causes the rce'd post loop to be optimized away if multiversioning fails |
| void PhaseIdealLoop::poison_rce_post_loop(IdealLoopTree *rce_loop) { |
| CountedLoopNode *rce_cl = rce_loop->_head->as_CountedLoop(); |
| Node* ctrl = rce_cl->in(LoopNode::EntryControl); |
| if (ctrl->is_IfTrue() || ctrl->is_IfFalse()) { |
| Node* iffm = ctrl->in(0); |
| if (iffm->is_If()) { |
| Node* cur_bool = iffm->in(1); |
| if (cur_bool->is_Bool()) { |
| Node* cur_cmp = cur_bool->in(1); |
| if (cur_cmp->is_Cmp()) { |
| BoolTest::mask new_test = BoolTest::gt; |
| BoolNode *new_bool = new BoolNode(cur_cmp, new_test); |
| _igvn.replace_node(cur_bool, new_bool); |
| _igvn._worklist.push(new_bool); |
| Node* left_op = cur_cmp->in(1); |
| _igvn.replace_input_of(cur_cmp, 2, left_op); |
| C->set_major_progress(); |
| } |
| } |
| } |
| } |
| } |
| |
| //------------------------------DCE_loop_body---------------------------------- |
| // Remove simplistic dead code from loop body |
| void IdealLoopTree::DCE_loop_body() { |
| for( uint i = 0; i < _body.size(); i++ ) |
| if( _body.at(i)->outcnt() == 0 ) |
| _body.map( i--, _body.pop() ); |
| } |
| |
| |
| //------------------------------adjust_loop_exit_prob-------------------------- |
| // Look for loop-exit tests with the 50/50 (or worse) guesses from the parsing stage. |
| // Replace with a 1-in-10 exit guess. |
| void IdealLoopTree::adjust_loop_exit_prob( PhaseIdealLoop *phase ) { |
| Node *test = tail(); |
| while( test != _head ) { |
| uint top = test->Opcode(); |
| if( top == Op_IfTrue || top == Op_IfFalse ) { |
| int test_con = ((ProjNode*)test)->_con; |
| assert(top == (uint)(test_con? Op_IfTrue: Op_IfFalse), "sanity"); |
| IfNode *iff = test->in(0)->as_If(); |
| if( iff->outcnt() == 2 ) { // Ignore dead tests |
| Node *bol = iff->in(1); |
| if( bol && bol->req() > 1 && bol->in(1) && |
| ((bol->in(1)->Opcode() == Op_StorePConditional ) || |
| (bol->in(1)->Opcode() == Op_StoreIConditional ) || |
| (bol->in(1)->Opcode() == Op_StoreLConditional ) || |
| (bol->in(1)->Opcode() == Op_CompareAndExchangeB ) || |
| (bol->in(1)->Opcode() == Op_CompareAndExchangeS ) || |
| (bol->in(1)->Opcode() == Op_CompareAndExchangeI ) || |
| (bol->in(1)->Opcode() == Op_CompareAndExchangeL ) || |
| (bol->in(1)->Opcode() == Op_CompareAndExchangeP ) || |
| (bol->in(1)->Opcode() == Op_CompareAndExchangeN ) || |
| (bol->in(1)->Opcode() == Op_WeakCompareAndSwapB ) || |
| (bol->in(1)->Opcode() == Op_WeakCompareAndSwapS ) || |
| (bol->in(1)->Opcode() == Op_WeakCompareAndSwapI ) || |
| (bol->in(1)->Opcode() == Op_WeakCompareAndSwapL ) || |
| (bol->in(1)->Opcode() == Op_WeakCompareAndSwapP ) || |
| (bol->in(1)->Opcode() == Op_WeakCompareAndSwapN ) || |
| (bol->in(1)->Opcode() == Op_CompareAndSwapB ) || |
| (bol->in(1)->Opcode() == Op_CompareAndSwapS ) || |
| (bol->in(1)->Opcode() == Op_CompareAndSwapI ) || |
| (bol->in(1)->Opcode() == Op_CompareAndSwapL ) || |
| (bol->in(1)->Opcode() == Op_CompareAndSwapP ) || |
| (bol->in(1)->Opcode() == Op_CompareAndSwapN ))) |
| return; // Allocation loops RARELY take backedge |
| // Find the OTHER exit path from the IF |
| Node* ex = iff->proj_out(1-test_con); |
| float p = iff->_prob; |
| if( !phase->is_member( this, ex ) && iff->_fcnt == COUNT_UNKNOWN ) { |
| if( top == Op_IfTrue ) { |
| if( p < (PROB_FAIR + PROB_UNLIKELY_MAG(3))) { |
| iff->_prob = PROB_STATIC_FREQUENT; |
| } |
| } else { |
| if( p > (PROB_FAIR - PROB_UNLIKELY_MAG(3))) { |
| iff->_prob = PROB_STATIC_INFREQUENT; |
| } |
| } |
| } |
| } |
| } |
| test = phase->idom(test); |
| } |
| } |
| |
| #ifdef ASSERT |
| static CountedLoopNode* locate_pre_from_main(CountedLoopNode *cl) { |
| Node *ctrl = cl->in(LoopNode::EntryControl); |
| assert(ctrl->Opcode() == Op_IfTrue || ctrl->Opcode() == Op_IfFalse, ""); |
| Node *iffm = ctrl->in(0); |
| assert(iffm->Opcode() == Op_If, ""); |
| Node *p_f = iffm->in(0); |
| assert(p_f->Opcode() == Op_IfFalse, ""); |
| CountedLoopEndNode *pre_end = p_f->in(0)->as_CountedLoopEnd(); |
| assert(pre_end->loopnode()->is_pre_loop(), ""); |
| return pre_end->loopnode(); |
| } |
| #endif |
| |
| // Remove the main and post loops and make the pre loop execute all |
| // iterations. Useful when the pre loop is found empty. |
| void IdealLoopTree::remove_main_post_loops(CountedLoopNode *cl, PhaseIdealLoop *phase) { |
| CountedLoopEndNode* pre_end = cl->loopexit(); |
| Node* pre_cmp = pre_end->cmp_node(); |
| if (pre_cmp->in(2)->Opcode() != Op_Opaque1) { |
| // Only safe to remove the main loop if the compiler optimized it |
| // out based on an unknown number of iterations |
| return; |
| } |
| |
| // Can we find the main loop? |
| if (_next == NULL) { |
| return; |
| } |
| |
| Node* next_head = _next->_head; |
| if (!next_head->is_CountedLoop()) { |
| return; |
| } |
| |
| CountedLoopNode* main_head = next_head->as_CountedLoop(); |
| if (!main_head->is_main_loop()) { |
| return; |
| } |
| |
| assert(locate_pre_from_main(main_head) == cl, "bad main loop"); |
| Node* main_iff = main_head->in(LoopNode::EntryControl)->in(0); |
| |
| // Remove the Opaque1Node of the pre loop and make it execute all iterations |
| phase->_igvn.replace_input_of(pre_cmp, 2, pre_cmp->in(2)->in(2)); |
| // Remove the Opaque1Node of the main loop so it can be optimized out |
| Node* main_cmp = main_iff->in(1)->in(1); |
| assert(main_cmp->in(2)->Opcode() == Op_Opaque1, "main loop has no opaque node?"); |
| phase->_igvn.replace_input_of(main_cmp, 2, main_cmp->in(2)->in(1)); |
| } |
| |
| //------------------------------policy_do_remove_empty_loop-------------------- |
| // Micro-benchmark spamming. Policy is to always remove empty loops. |
| // The 'DO' part is to replace the trip counter with the value it will |
| // have on the last iteration. This will break the loop. |
| bool IdealLoopTree::policy_do_remove_empty_loop( PhaseIdealLoop *phase ) { |
| // Minimum size must be empty loop |
| if (_body.size() > EMPTY_LOOP_SIZE) |
| return false; |
| |
| if (!_head->is_CountedLoop()) |
| return false; // Dead loop |
| CountedLoopNode *cl = _head->as_CountedLoop(); |
| if (!cl->is_valid_counted_loop()) |
| return false; // Malformed loop |
| if (!phase->is_member(this, phase->get_ctrl(cl->loopexit()->in(CountedLoopEndNode::TestValue)))) |
| return false; // Infinite loop |
| |
| if (cl->is_pre_loop()) { |
| // If the loop we are removing is a pre-loop then the main and |
| // post loop can be removed as well |
| remove_main_post_loops(cl, phase); |
| } |
| |
| #ifdef ASSERT |
| // Ensure only one phi which is the iv. |
| Node* iv = NULL; |
| for (DUIterator_Fast imax, i = cl->fast_outs(imax); i < imax; i++) { |
| Node* n = cl->fast_out(i); |
| if (n->Opcode() == Op_Phi) { |
| assert(iv == NULL, "Too many phis" ); |
| iv = n; |
| } |
| } |
| assert(iv == cl->phi(), "Wrong phi" ); |
| #endif |
| |
| // main and post loops have explicitly created zero trip guard |
| bool needs_guard = !cl->is_main_loop() && !cl->is_post_loop(); |
| if (needs_guard) { |
| // Skip guard if values not overlap. |
| const TypeInt* init_t = phase->_igvn.type(cl->init_trip())->is_int(); |
| const TypeInt* limit_t = phase->_igvn.type(cl->limit())->is_int(); |
| int stride_con = cl->stride_con(); |
| if (stride_con > 0) { |
| needs_guard = (init_t->_hi >= limit_t->_lo); |
| } else { |
| needs_guard = (init_t->_lo <= limit_t->_hi); |
| } |
| } |
| if (needs_guard) { |
| // Check for an obvious zero trip guard. |
| Node* inctrl = PhaseIdealLoop::skip_loop_predicates(cl->in(LoopNode::EntryControl)); |
| if (inctrl->Opcode() == Op_IfTrue || inctrl->Opcode() == Op_IfFalse) { |
| bool maybe_swapped = (inctrl->Opcode() == Op_IfFalse); |
| // The test should look like just the backedge of a CountedLoop |
| Node* iff = inctrl->in(0); |
| if (iff->is_If()) { |
| Node* bol = iff->in(1); |
| if (bol->is_Bool()) { |
| BoolTest test = bol->as_Bool()->_test; |
| if (maybe_swapped) { |
| test._test = test.commute(); |
| test._test = test.negate(); |
| } |
| if (test._test == cl->loopexit()->test_trip()) { |
| Node* cmp = bol->in(1); |
| int init_idx = maybe_swapped ? 2 : 1; |
| int limit_idx = maybe_swapped ? 1 : 2; |
| if (cmp->is_Cmp() && cmp->in(init_idx) == cl->init_trip() && cmp->in(limit_idx) == cl->limit()) { |
| needs_guard = false; |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| #ifndef PRODUCT |
| if (PrintOpto) { |
| tty->print("Removing empty loop with%s zero trip guard", needs_guard ? "out" : ""); |
| this->dump_head(); |
| } else if (TraceLoopOpts) { |
| tty->print("Empty with%s zero trip guard ", needs_guard ? "out" : ""); |
| this->dump_head(); |
| } |
| #endif |
| |
| if (needs_guard) { |
| // Peel the loop to ensure there's a zero trip guard |
| Node_List old_new; |
| phase->do_peeling(this, old_new); |
| } |
| |
| // Replace the phi at loop head with the final value of the last |
| // iteration. Then the CountedLoopEnd will collapse (backedge never |
| // taken) and all loop-invariant uses of the exit values will be correct. |
| Node *phi = cl->phi(); |
| Node *exact_limit = phase->exact_limit(this); |
| if (exact_limit != cl->limit()) { |
| // We also need to replace the original limit to collapse loop exit. |
| Node* cmp = cl->loopexit()->cmp_node(); |
| assert(cl->limit() == cmp->in(2), "sanity"); |
| phase->_igvn._worklist.push(cmp->in(2)); // put limit on worklist |
| phase->_igvn.replace_input_of(cmp, 2, exact_limit); // put cmp on worklist |
| } |
| // Note: the final value after increment should not overflow since |
| // counted loop has limit check predicate. |
| Node *final = new SubINode( exact_limit, cl->stride() ); |
| phase->register_new_node(final,cl->in(LoopNode::EntryControl)); |
| phase->_igvn.replace_node(phi,final); |
| phase->C->set_major_progress(); |
| return true; |
| } |
| |
| //------------------------------policy_do_one_iteration_loop------------------- |
| // Convert one iteration loop into normal code. |
| bool IdealLoopTree::policy_do_one_iteration_loop( PhaseIdealLoop *phase ) { |
| if (!_head->as_Loop()->is_valid_counted_loop()) |
| return false; // Only for counted loop |
| |
| CountedLoopNode *cl = _head->as_CountedLoop(); |
| if (!cl->has_exact_trip_count() || cl->trip_count() != 1) { |
| return false; |
| } |
| |
| #ifndef PRODUCT |
| if(TraceLoopOpts) { |
| tty->print("OneIteration "); |
| this->dump_head(); |
| } |
| #endif |
| |
| Node *init_n = cl->init_trip(); |
| #ifdef ASSERT |
| // Loop boundaries should be constant since trip count is exact. |
| assert(init_n->get_int() + cl->stride_con() >= cl->limit()->get_int(), "should be one iteration"); |
| #endif |
| // Replace the phi at loop head with the value of the init_trip. |
| // Then the CountedLoopEnd will collapse (backedge will not be taken) |
| // and all loop-invariant uses of the exit values will be correct. |
| phase->_igvn.replace_node(cl->phi(), cl->init_trip()); |
| phase->C->set_major_progress(); |
| return true; |
| } |
| |
| //============================================================================= |
| //------------------------------iteration_split_impl--------------------------- |
| bool IdealLoopTree::iteration_split_impl( PhaseIdealLoop *phase, Node_List &old_new ) { |
| // Compute loop trip count if possible. |
| compute_trip_count(phase); |
| |
| // Convert one iteration loop into normal code. |
| if (policy_do_one_iteration_loop(phase)) |
| return true; |
| |
| // Check and remove empty loops (spam micro-benchmarks) |
| if (policy_do_remove_empty_loop(phase)) |
| return true; // Here we removed an empty loop |
| |
| bool should_peel = policy_peeling(phase); // Should we peel? |
| |
| bool should_unswitch = policy_unswitching(phase); |
| |
| // Non-counted loops may be peeled; exactly 1 iteration is peeled. |
| // This removes loop-invariant tests (usually null checks). |
| if (!_head->is_CountedLoop()) { // Non-counted loop |
| if (PartialPeelLoop && phase->partial_peel(this, old_new)) { |
| // Partial peel succeeded so terminate this round of loop opts |
| return false; |
| } |
| if (should_peel) { // Should we peel? |
| if (PrintOpto) { tty->print_cr("should_peel"); } |
| phase->do_peeling(this,old_new); |
| } else if (should_unswitch) { |
| phase->do_unswitching(this, old_new); |
| } |
| return true; |
| } |
| CountedLoopNode *cl = _head->as_CountedLoop(); |
| |
| if (!cl->is_valid_counted_loop()) return true; // Ignore various kinds of broken loops |
| |
| // Do nothing special to pre- and post- loops |
| if (cl->is_pre_loop() || cl->is_post_loop()) return true; |
| |
| // Compute loop trip count from profile data |
| compute_profile_trip_cnt(phase); |
| |
| // Before attempting fancy unrolling, RCE or alignment, see if we want |
| // to completely unroll this loop or do loop unswitching. |
| if (cl->is_normal_loop()) { |
| if (should_unswitch) { |
| phase->do_unswitching(this, old_new); |
| return true; |
| } |
| bool should_maximally_unroll = policy_maximally_unroll(phase); |
| if (should_maximally_unroll) { |
| // Here we did some unrolling and peeling. Eventually we will |
| // completely unroll this loop and it will no longer be a loop. |
| phase->do_maximally_unroll(this,old_new); |
| return true; |
| } |
| } |
| |
| // Skip next optimizations if running low on nodes. Note that |
| // policy_unswitching and policy_maximally_unroll have this check. |
| int nodes_left = phase->C->max_node_limit() - phase->C->live_nodes(); |
| if ((int)(2 * _body.size()) > nodes_left) { |
| return true; |
| } |
| |
| // Counted loops may be peeled, may need some iterations run up |
| // front for RCE, and may want to align loop refs to a cache |
| // line. Thus we clone a full loop up front whose trip count is |
| // at least 1 (if peeling), but may be several more. |
| |
| // The main loop will start cache-line aligned with at least 1 |
| // iteration of the unrolled body (zero-trip test required) and |
| // will have some range checks removed. |
| |
| // A post-loop will finish any odd iterations (leftover after |
| // unrolling), plus any needed for RCE purposes. |
| |
| bool should_unroll = policy_unroll(phase); |
| |
| bool should_rce = policy_range_check(phase); |
| |
| bool should_align = policy_align(phase); |
| |
| // If not RCE'ing (iteration splitting) or Aligning, then we do not |
| // need a pre-loop. We may still need to peel an initial iteration but |
| // we will not be needing an unknown number of pre-iterations. |
| // |
| // Basically, if may_rce_align reports FALSE first time through, |
| // we will not be able to later do RCE or Aligning on this loop. |
| bool may_rce_align = !policy_peel_only(phase) || should_rce || should_align; |
| |
| // If we have any of these conditions (RCE, alignment, unrolling) met, then |
| // we switch to the pre-/main-/post-loop model. This model also covers |
| // peeling. |
| if (should_rce || should_align || should_unroll) { |
| if (cl->is_normal_loop()) // Convert to 'pre/main/post' loops |
| phase->insert_pre_post_loops(this,old_new, !may_rce_align); |
| |
| // Adjust the pre- and main-loop limits to let the pre and post loops run |
| // with full checks, but the main-loop with no checks. Remove said |
| // checks from the main body. |
| if (should_rce) { |
| if (phase->do_range_check(this, old_new) != 0) { |
| cl->mark_has_range_checks(); |
| } |
| } else if (PostLoopMultiversioning) { |
| phase->has_range_checks(this); |
| } |
| |
| if (should_unroll && !should_peel && PostLoopMultiversioning) { |
| // Try to setup multiversioning on main loops before they are unrolled |
| if (cl->is_main_loop() && (cl->unrolled_count() == 1)) { |
| phase->insert_scalar_rced_post_loop(this, old_new); |
| } |
| } |
| |
| // Double loop body for unrolling. Adjust the minimum-trip test (will do |
| // twice as many iterations as before) and the main body limit (only do |
| // an even number of trips). If we are peeling, we might enable some RCE |
| // and we'd rather unroll the post-RCE'd loop SO... do not unroll if |
| // peeling. |
| if (should_unroll && !should_peel) { |
| if (SuperWordLoopUnrollAnalysis) { |
| phase->insert_vector_post_loop(this, old_new); |
| } |
| phase->do_unroll(this, old_new, true); |
| } |
| |
| // Adjust the pre-loop limits to align the main body |
| // iterations. |
| if (should_align) |
| Unimplemented(); |
| |
| } else { // Else we have an unchanged counted loop |
| if (should_peel) // Might want to peel but do nothing else |
| phase->do_peeling(this,old_new); |
| } |
| return true; |
| } |
| |
| |
| //============================================================================= |
| //------------------------------iteration_split-------------------------------- |
| bool IdealLoopTree::iteration_split( PhaseIdealLoop *phase, Node_List &old_new ) { |
| // Recursively iteration split nested loops |
| if (_child && !_child->iteration_split(phase, old_new)) |
| return false; |
| |
| // Clean out prior deadwood |
| DCE_loop_body(); |
| |
| |
| // Look for loop-exit tests with my 50/50 guesses from the Parsing stage. |
| // Replace with a 1-in-10 exit guess. |
| if (_parent /*not the root loop*/ && |
| !_irreducible && |
| // Also ignore the occasional dead backedge |
| !tail()->is_top()) { |
| adjust_loop_exit_prob(phase); |
| } |
| |
| // Gate unrolling, RCE and peeling efforts. |
| if (!_child && // If not an inner loop, do not split |
| !_irreducible && |
| _allow_optimizations && |
| !tail()->is_top()) { // Also ignore the occasional dead backedge |
| if (!_has_call) { |
| if (!iteration_split_impl(phase, old_new)) { |
| return false; |
| } |
| } else if (policy_unswitching(phase)) { |
| phase->do_unswitching(this, old_new); |
| } |
| } |
| |
| // Minor offset re-organization to remove loop-fallout uses of |
| // trip counter when there was no major reshaping. |
| phase->reorg_offsets(this); |
| |
| if (_next && !_next->iteration_split(phase, old_new)) |
| return false; |
| return true; |
| } |
| |
| |
| //============================================================================= |
| // Process all the loops in the loop tree and replace any fill |
| // patterns with an intrinsic version. |
| bool PhaseIdealLoop::do_intrinsify_fill() { |
| bool changed = false; |
| for (LoopTreeIterator iter(_ltree_root); !iter.done(); iter.next()) { |
| IdealLoopTree* lpt = iter.current(); |
| changed |= intrinsify_fill(lpt); |
| } |
| return changed; |
| } |
| |
| |
| // Examine an inner loop looking for a a single store of an invariant |
| // value in a unit stride loop, |
| bool PhaseIdealLoop::match_fill_loop(IdealLoopTree* lpt, Node*& store, Node*& store_value, |
| Node*& shift, Node*& con) { |
| const char* msg = NULL; |
| Node* msg_node = NULL; |
| |
| store_value = NULL; |
| con = NULL; |
| shift = NULL; |
| |
| // Process the loop looking for stores. If there are multiple |
| // stores or extra control flow give at this point. |
| CountedLoopNode* head = lpt->_head->as_CountedLoop(); |
| for (uint i = 0; msg == NULL && i < lpt->_body.size(); i++) { |
| Node* n = lpt->_body.at(i); |
| if (n->outcnt() == 0) continue; // Ignore dead |
| if (n->is_Store()) { |
| if (store != NULL) { |
| msg = "multiple stores"; |
| break; |
| } |
| int opc = n->Opcode(); |
| if (opc == Op_StoreP || opc == Op_StoreN || opc == Op_StoreNKlass || opc == Op_StoreCM) { |
| msg = "oop fills not handled"; |
| break; |
| } |
| Node* value = n->in(MemNode::ValueIn); |
| if (!lpt->is_invariant(value)) { |
| msg = "variant store value"; |
| } else if (!_igvn.type(n->in(MemNode::Address))->isa_aryptr()) { |
| msg = "not array address"; |
| } |
| store = n; |
| store_value = value; |
| } else if (n->is_If() && n != head->loopexit()) { |
| msg = "extra control flow"; |
| msg_node = n; |
| } |
| } |
| |
| if (store == NULL) { |
| // No store in loop |
| return false; |
| } |
| |
| if (msg == NULL && head->stride_con() != 1) { |
| // could handle negative strides too |
| if (head->stride_con() < 0) { |
| msg = "negative stride"; |
| } else { |
| msg = "non-unit stride"; |
| } |
| } |
| |
| if (msg == NULL && !store->in(MemNode::Address)->is_AddP()) { |
| msg = "can't handle store address"; |
| msg_node = store->in(MemNode::Address); |
| } |
| |
| if (msg == NULL && |
| (!store->in(MemNode::Memory)->is_Phi() || |
| store->in(MemNode::Memory)->in(LoopNode::LoopBackControl) != store)) { |
| msg = "store memory isn't proper phi"; |
| msg_node = store->in(MemNode::Memory); |
| } |
| |
| // Make sure there is an appropriate fill routine |
| BasicType t = store->as_Mem()->memory_type(); |
| const char* fill_name; |
| if (msg == NULL && |
| StubRoutines::select_fill_function(t, false, fill_name) == NULL) { |
| msg = "unsupported store"; |
| msg_node = store; |
| } |
| |
| if (msg != NULL) { |
| #ifndef PRODUCT |
| if (TraceOptimizeFill) { |
| tty->print_cr("not fill intrinsic candidate: %s", msg); |
| if (msg_node != NULL) msg_node->dump(); |
| } |
| #endif |
| return false; |
| } |
| |
| // Make sure the address expression can be handled. It should be |
| // head->phi * elsize + con. head->phi might have a ConvI2L(CastII()). |
| Node* elements[4]; |
| Node* cast = NULL; |
| Node* conv = NULL; |
| bool found_index = false; |
| int count = store->in(MemNode::Address)->as_AddP()->unpack_offsets(elements, ARRAY_SIZE(elements)); |
| for (int e = 0; e < count; e++) { |
| Node* n = elements[e]; |
| if (n->is_Con() && con == NULL) { |
| con = n; |
| } else if (n->Opcode() == Op_LShiftX && shift == NULL) { |
| Node* value = n->in(1); |
| #ifdef _LP64 |
| if (value->Opcode() == Op_ConvI2L) { |
| conv = value; |
| value = value->in(1); |
| } |
| if (value->Opcode() == Op_CastII && |
| value->as_CastII()->has_range_check()) { |
| // Skip range check dependent CastII nodes |
| cast = value; |
| value = value->in(1); |
| } |
| #endif |
| if (value != head->phi()) { |
| msg = "unhandled shift in address"; |
| } else { |
| if (type2aelembytes(store->as_Mem()->memory_type(), true) != (1 << n->in(2)->get_int())) { |
| msg = "scale doesn't match"; |
| } else { |
| found_index = true; |
| shift = n; |
| } |
| } |
| } else if (n->Opcode() == Op_ConvI2L && conv == NULL) { |
| conv = n; |
| n = n->in(1); |
| if (n->Opcode() == Op_CastII && |
| n->as_CastII()->has_range_check()) { |
| // Skip range check dependent CastII nodes |
| cast = n; |
| n = n->in(1); |
| } |
| if (n == head->phi()) { |
| found_index = true; |
| } else { |
| msg = "unhandled input to ConvI2L"; |
| } |
| } else if (n == head->phi()) { |
| // no shift, check below for allowed cases |
| found_index = true; |
| } else { |
| msg = "unhandled node in address"; |
| msg_node = n; |
| } |
| } |
| |
| if (count == -1) { |
| msg = "malformed address expression"; |
| msg_node = store; |
| } |
| |
| if (!found_index) { |
| msg = "missing use of index"; |
| } |
| |
| // byte sized items won't have a shift |
| if (msg == NULL && shift == NULL && t != T_BYTE && t != T_BOOLEAN) { |
| msg = "can't find shift"; |
| msg_node = store; |
| } |
| |
| if (msg != NULL) { |
| #ifndef PRODUCT |
| if (TraceOptimizeFill) { |
| tty->print_cr("not fill intrinsic: %s", msg); |
| if (msg_node != NULL) msg_node->dump(); |
| } |
| #endif |
| return false; |
| } |
| |
| // No make sure all the other nodes in the loop can be handled |
| VectorSet ok(Thread::current()->resource_area()); |
| |
| // store related values are ok |
| ok.set(store->_idx); |
| ok.set(store->in(MemNode::Memory)->_idx); |
| |
| CountedLoopEndNode* loop_exit = head->loopexit(); |
| guarantee(loop_exit != NULL, "no loop exit node"); |
| |
| // Loop structure is ok |
| ok.set(head->_idx); |
| ok.set(loop_exit->_idx); |
| ok.set(head->phi()->_idx); |
| ok.set(head->incr()->_idx); |
| ok.set(loop_exit->cmp_node()->_idx); |
| ok.set(loop_exit->in(1)->_idx); |
| |
| // Address elements are ok |
| if (con) ok.set(con->_idx); |
| if (shift) ok.set(shift->_idx); |
| if (cast) ok.set(cast->_idx); |
| if (conv) ok.set(conv->_idx); |
| |
| for (uint i = 0; msg == NULL && i < lpt->_body.size(); i++) { |
| Node* n = lpt->_body.at(i); |
| if (n->outcnt() == 0) continue; // Ignore dead |
| if (ok.test(n->_idx)) continue; |
| // Backedge projection is ok |
| if (n->is_IfTrue() && n->in(0) == loop_exit) continue; |
| if (!n->is_AddP()) { |
| msg = "unhandled node"; |
| msg_node = n; |
| break; |
| } |
| } |
| |
| // Make sure no unexpected values are used outside the loop |
| for (uint i = 0; msg == NULL && i < lpt->_body.size(); i++) { |
| Node* n = lpt->_body.at(i); |
| // These values can be replaced with other nodes if they are used |
| // outside the loop. |
| if (n == store || n == loop_exit || n == head->incr() || n == store->in(MemNode::Memory)) continue; |
| for (SimpleDUIterator iter(n); iter.has_next(); iter.next()) { |
| Node* use = iter.get(); |
| if (!lpt->_body.contains(use)) { |
| msg = "node is used outside loop"; |
| // lpt->_body.dump(); |
| msg_node = n; |
| break; |
| } |
| } |
| } |
| |
| #ifdef ASSERT |
| if (TraceOptimizeFill) { |
| if (msg != NULL) { |
| tty->print_cr("no fill intrinsic: %s", msg); |
| if (msg_node != NULL) msg_node->dump(); |
| } else { |
| tty->print_cr("fill intrinsic for:"); |
| } |
| store->dump(); |
| if (Verbose) { |
| lpt->_body.dump(); |
| } |
| } |
| #endif |
| |
| return msg == NULL; |
| } |
| |
| |
| |
| bool PhaseIdealLoop::intrinsify_fill(IdealLoopTree* lpt) { |
| // Only for counted inner loops |
| if (!lpt->is_counted() || !lpt->is_inner()) { |
| return false; |
| } |
| |
| // Must have constant stride |
| CountedLoopNode* head = lpt->_head->as_CountedLoop(); |
| if (!head->is_valid_counted_loop() || !head->is_normal_loop()) { |
| return false; |
| } |
| |
| // Check that the body only contains a store of a loop invariant |
| // value that is indexed by the loop phi. |
| Node* store = NULL; |
| Node* store_value = NULL; |
| Node* shift = NULL; |
| Node* offset = NULL; |
| if (!match_fill_loop(lpt, store, store_value, shift, offset)) { |
| return false; |
| } |
| |
| Node* exit = head->loopexit()->proj_out(0); |
| if (exit == NULL) { |
| return false; |
| } |
| |
| #ifndef PRODUCT |
| if (TraceLoopOpts) { |
| tty->print("ArrayFill "); |
| lpt->dump_head(); |
| } |
| #endif |
| |
| // Now replace the whole loop body by a call to a fill routine that |
| // covers the same region as the loop. |
| Node* base = store->in(MemNode::Address)->as_AddP()->in(AddPNode::Base); |
| |
| // Build an expression for the beginning of the copy region |
| Node* index = head->init_trip(); |
| #ifdef _LP64 |
| index = new ConvI2LNode(index); |
| _igvn.register_new_node_with_optimizer(index); |
| #endif |
| if (shift != NULL) { |
| // byte arrays don't require a shift but others do. |
| index = new LShiftXNode(index, shift->in(2)); |
| _igvn.register_new_node_with_optimizer(index); |
| } |
| index = new AddPNode(base, base, index); |
| _igvn.register_new_node_with_optimizer(index); |
| Node* from = new AddPNode(base, index, offset); |
| _igvn.register_new_node_with_optimizer(from); |
| // Compute the number of elements to copy |
| Node* len = new SubINode(head->limit(), head->init_trip()); |
| _igvn.register_new_node_with_optimizer(len); |
| |
| BasicType t = store->as_Mem()->memory_type(); |
| bool aligned = false; |
| if (offset != NULL && head->init_trip()->is_Con()) { |
| int element_size = type2aelembytes(t); |
| aligned = (offset->find_intptr_t_type()->get_con() + head->init_trip()->get_int() * element_size) % HeapWordSize == 0; |
| } |
| |
| // Build a call to the fill routine |
| const char* fill_name; |
| address fill = StubRoutines::select_fill_function(t, aligned, fill_name); |
| assert(fill != NULL, "what?"); |
| |
| // Convert float/double to int/long for fill routines |
| if (t == T_FLOAT) { |
| store_value = new MoveF2INode(store_value); |
| _igvn.register_new_node_with_optimizer(store_value); |
| } else if (t == T_DOUBLE) { |
| store_value = new MoveD2LNode(store_value); |
| _igvn.register_new_node_with_optimizer(store_value); |
| } |
| |
| Node* mem_phi = store->in(MemNode::Memory); |
| Node* result_ctrl; |
| Node* result_mem; |
| const TypeFunc* call_type = OptoRuntime::array_fill_Type(); |
| CallLeafNode *call = new CallLeafNoFPNode(call_type, fill, |
| fill_name, TypeAryPtr::get_array_body_type(t)); |
| uint cnt = 0; |
| call->init_req(TypeFunc::Parms + cnt++, from); |
| call->init_req(TypeFunc::Parms + cnt++, store_value); |
| #ifdef _LP64 |
| len = new ConvI2LNode(len); |
| _igvn.register_new_node_with_optimizer(len); |
| #endif |
| call->init_req(TypeFunc::Parms + cnt++, len); |
| #ifdef _LP64 |
| call->init_req(TypeFunc::Parms + cnt++, C->top()); |
| #endif |
| call->init_req(TypeFunc::Control, head->init_control()); |
| call->init_req(TypeFunc::I_O, C->top()); // Does no I/O. |
| call->init_req(TypeFunc::Memory, mem_phi->in(LoopNode::EntryControl)); |
| call->init_req(TypeFunc::ReturnAdr, C->start()->proj_out(TypeFunc::ReturnAdr)); |
| call->init_req(TypeFunc::FramePtr, C->start()->proj_out(TypeFunc::FramePtr)); |
| _igvn.register_new_node_with_optimizer(call); |
| result_ctrl = new ProjNode(call,TypeFunc::Control); |
| _igvn.register_new_node_with_optimizer(result_ctrl); |
| result_mem = new ProjNode(call,TypeFunc::Memory); |
| _igvn.register_new_node_with_optimizer(result_mem); |
| |
| /* Disable following optimization until proper fix (add missing checks). |
| |
| // If this fill is tightly coupled to an allocation and overwrites |
| // the whole body, allow it to take over the zeroing. |
| AllocateNode* alloc = AllocateNode::Ideal_allocation(base, this); |
| if (alloc != NULL && alloc->is_AllocateArray()) { |
| Node* length = alloc->as_AllocateArray()->Ideal_length(); |
| if (head->limit() == length && |
| head->init_trip() == _igvn.intcon(0)) { |
| if (TraceOptimizeFill) { |
| tty->print_cr("Eliminated zeroing in allocation"); |
| } |
| alloc->maybe_set_complete(&_igvn); |
| } else { |
| #ifdef ASSERT |
| if (TraceOptimizeFill) { |
| tty->print_cr("filling array but bounds don't match"); |
| alloc->dump(); |
| head->init_trip()->dump(); |
| head->limit()->dump(); |
| length->dump(); |
| } |
| #endif |
| } |
| } |
| */ |
| |
| // Redirect the old control and memory edges that are outside the loop. |
| // Sometimes the memory phi of the head is used as the outgoing |
| // state of the loop. It's safe in this case to replace it with the |
| // result_mem. |
| _igvn.replace_node(store->in(MemNode::Memory), result_mem); |
| lazy_replace(exit, result_ctrl); |
| _igvn.replace_node(store, result_mem); |
| // Any uses the increment outside of the loop become the loop limit. |
| _igvn.replace_node(head->incr(), head->limit()); |
| |
| // Disconnect the head from the loop. |
| for (uint i = 0; i < lpt->_body.size(); i++) { |
| Node* n = lpt->_body.at(i); |
| _igvn.replace_node(n, C->top()); |
| } |
| |
| return true; |
| } |