| /* |
| * Copyright (c) 1998, 2016, 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 "ci/ciMethodData.hpp" |
| #include "compiler/compileLog.hpp" |
| #include "libadt/vectset.hpp" |
| #include "memory/allocation.inline.hpp" |
| #include "memory/resourceArea.hpp" |
| #include "opto/addnode.hpp" |
| #include "opto/callnode.hpp" |
| #include "opto/connode.hpp" |
| #include "opto/convertnode.hpp" |
| #include "opto/divnode.hpp" |
| #include "opto/idealGraphPrinter.hpp" |
| #include "opto/loopnode.hpp" |
| #include "opto/mulnode.hpp" |
| #include "opto/rootnode.hpp" |
| #include "opto/superword.hpp" |
| |
| //============================================================================= |
| //------------------------------is_loop_iv------------------------------------- |
| // Determine if a node is Counted loop induction variable. |
| // The method is declared in node.hpp. |
| const Node* Node::is_loop_iv() const { |
| if (this->is_Phi() && !this->as_Phi()->is_copy() && |
| this->as_Phi()->region()->is_CountedLoop() && |
| this->as_Phi()->region()->as_CountedLoop()->phi() == this) { |
| return this; |
| } else { |
| return NULL; |
| } |
| } |
| |
| //============================================================================= |
| //------------------------------dump_spec-------------------------------------- |
| // Dump special per-node info |
| #ifndef PRODUCT |
| void LoopNode::dump_spec(outputStream *st) const { |
| if (is_inner_loop()) st->print( "inner " ); |
| if (is_partial_peel_loop()) st->print( "partial_peel " ); |
| if (partial_peel_has_failed()) st->print( "partial_peel_failed " ); |
| } |
| #endif |
| |
| //------------------------------is_valid_counted_loop------------------------- |
| bool LoopNode::is_valid_counted_loop() const { |
| if (is_CountedLoop()) { |
| CountedLoopNode* l = as_CountedLoop(); |
| CountedLoopEndNode* le = l->loopexit(); |
| if (le != NULL && |
| le->proj_out(1 /* true */) == l->in(LoopNode::LoopBackControl)) { |
| Node* phi = l->phi(); |
| Node* exit = le->proj_out(0 /* false */); |
| if (exit != NULL && exit->Opcode() == Op_IfFalse && |
| phi != NULL && phi->is_Phi() && |
| phi->in(LoopNode::LoopBackControl) == l->incr() && |
| le->loopnode() == l && le->stride_is_con()) { |
| return true; |
| } |
| } |
| } |
| return false; |
| } |
| |
| //------------------------------get_early_ctrl--------------------------------- |
| // Compute earliest legal control |
| Node *PhaseIdealLoop::get_early_ctrl( Node *n ) { |
| assert( !n->is_Phi() && !n->is_CFG(), "this code only handles data nodes" ); |
| uint i; |
| Node *early; |
| if (n->in(0) && !n->is_expensive()) { |
| early = n->in(0); |
| if (!early->is_CFG()) // Might be a non-CFG multi-def |
| early = get_ctrl(early); // So treat input as a straight data input |
| i = 1; |
| } else { |
| early = get_ctrl(n->in(1)); |
| i = 2; |
| } |
| uint e_d = dom_depth(early); |
| assert( early, "" ); |
| for (; i < n->req(); i++) { |
| Node *cin = get_ctrl(n->in(i)); |
| assert( cin, "" ); |
| // Keep deepest dominator depth |
| uint c_d = dom_depth(cin); |
| if (c_d > e_d) { // Deeper guy? |
| early = cin; // Keep deepest found so far |
| e_d = c_d; |
| } else if (c_d == e_d && // Same depth? |
| early != cin) { // If not equal, must use slower algorithm |
| // If same depth but not equal, one _must_ dominate the other |
| // and we want the deeper (i.e., dominated) guy. |
| Node *n1 = early; |
| Node *n2 = cin; |
| while (1) { |
| n1 = idom(n1); // Walk up until break cycle |
| n2 = idom(n2); |
| if (n1 == cin || // Walked early up to cin |
| dom_depth(n2) < c_d) |
| break; // early is deeper; keep him |
| if (n2 == early || // Walked cin up to early |
| dom_depth(n1) < c_d) { |
| early = cin; // cin is deeper; keep him |
| break; |
| } |
| } |
| e_d = dom_depth(early); // Reset depth register cache |
| } |
| } |
| |
| // Return earliest legal location |
| assert(early == find_non_split_ctrl(early), "unexpected early control"); |
| |
| if (n->is_expensive() && !_verify_only && !_verify_me) { |
| assert(n->in(0), "should have control input"); |
| early = get_early_ctrl_for_expensive(n, early); |
| } |
| |
| return early; |
| } |
| |
| //------------------------------get_early_ctrl_for_expensive--------------------------------- |
| // Move node up the dominator tree as high as legal while still beneficial |
| Node *PhaseIdealLoop::get_early_ctrl_for_expensive(Node *n, Node* earliest) { |
| assert(n->in(0) && n->is_expensive(), "expensive node with control input here"); |
| assert(OptimizeExpensiveOps, "optimization off?"); |
| |
| Node* ctl = n->in(0); |
| assert(ctl->is_CFG(), "expensive input 0 must be cfg"); |
| uint min_dom_depth = dom_depth(earliest); |
| #ifdef ASSERT |
| if (!is_dominator(ctl, earliest) && !is_dominator(earliest, ctl)) { |
| dump_bad_graph("Bad graph detected in get_early_ctrl_for_expensive", n, earliest, ctl); |
| assert(false, "Bad graph detected in get_early_ctrl_for_expensive"); |
| } |
| #endif |
| if (dom_depth(ctl) < min_dom_depth) { |
| return earliest; |
| } |
| |
| while (1) { |
| Node *next = ctl; |
| // Moving the node out of a loop on the projection of a If |
| // confuses loop predication. So once we hit a Loop in a If branch |
| // that doesn't branch to an UNC, we stop. The code that process |
| // expensive nodes will notice the loop and skip over it to try to |
| // move the node further up. |
| if (ctl->is_CountedLoop() && ctl->in(1) != NULL && ctl->in(1)->in(0) != NULL && ctl->in(1)->in(0)->is_If()) { |
| if (!ctl->in(1)->as_Proj()->is_uncommon_trap_if_pattern(Deoptimization::Reason_none)) { |
| break; |
| } |
| next = idom(ctl->in(1)->in(0)); |
| } else if (ctl->is_Proj()) { |
| // We only move it up along a projection if the projection is |
| // the single control projection for its parent: same code path, |
| // if it's a If with UNC or fallthrough of a call. |
| Node* parent_ctl = ctl->in(0); |
| if (parent_ctl == NULL) { |
| break; |
| } else if (parent_ctl->is_CountedLoopEnd() && parent_ctl->as_CountedLoopEnd()->loopnode() != NULL) { |
| next = parent_ctl->as_CountedLoopEnd()->loopnode()->init_control(); |
| } else if (parent_ctl->is_If()) { |
| if (!ctl->as_Proj()->is_uncommon_trap_if_pattern(Deoptimization::Reason_none)) { |
| break; |
| } |
| assert(idom(ctl) == parent_ctl, "strange"); |
| next = idom(parent_ctl); |
| } else if (ctl->is_CatchProj()) { |
| if (ctl->as_Proj()->_con != CatchProjNode::fall_through_index) { |
| break; |
| } |
| assert(parent_ctl->in(0)->in(0)->is_Call(), "strange graph"); |
| next = parent_ctl->in(0)->in(0)->in(0); |
| } else { |
| // Check if parent control has a single projection (this |
| // control is the only possible successor of the parent |
| // control). If so, we can try to move the node above the |
| // parent control. |
| int nb_ctl_proj = 0; |
| for (DUIterator_Fast imax, i = parent_ctl->fast_outs(imax); i < imax; i++) { |
| Node *p = parent_ctl->fast_out(i); |
| if (p->is_Proj() && p->is_CFG()) { |
| nb_ctl_proj++; |
| if (nb_ctl_proj > 1) { |
| break; |
| } |
| } |
| } |
| |
| if (nb_ctl_proj > 1) { |
| break; |
| } |
| assert(parent_ctl->is_Start() || parent_ctl->is_MemBar() || parent_ctl->is_Call(), "unexpected node"); |
| assert(idom(ctl) == parent_ctl, "strange"); |
| next = idom(parent_ctl); |
| } |
| } else { |
| next = idom(ctl); |
| } |
| if (next->is_Root() || next->is_Start() || dom_depth(next) < min_dom_depth) { |
| break; |
| } |
| ctl = next; |
| } |
| |
| if (ctl != n->in(0)) { |
| _igvn.replace_input_of(n, 0, ctl); |
| _igvn.hash_insert(n); |
| } |
| |
| return ctl; |
| } |
| |
| |
| //------------------------------set_early_ctrl--------------------------------- |
| // Set earliest legal control |
| void PhaseIdealLoop::set_early_ctrl( Node *n ) { |
| Node *early = get_early_ctrl(n); |
| |
| // Record earliest legal location |
| set_ctrl(n, early); |
| } |
| |
| //------------------------------set_subtree_ctrl------------------------------- |
| // set missing _ctrl entries on new nodes |
| void PhaseIdealLoop::set_subtree_ctrl( Node *n ) { |
| // Already set? Get out. |
| if( _nodes[n->_idx] ) return; |
| // Recursively set _nodes array to indicate where the Node goes |
| uint i; |
| for( i = 0; i < n->req(); ++i ) { |
| Node *m = n->in(i); |
| if( m && m != C->root() ) |
| set_subtree_ctrl( m ); |
| } |
| |
| // Fixup self |
| set_early_ctrl( n ); |
| } |
| |
| //------------------------------is_counted_loop-------------------------------- |
| bool PhaseIdealLoop::is_counted_loop( Node *x, IdealLoopTree *loop ) { |
| PhaseGVN *gvn = &_igvn; |
| |
| // Counted loop head must be a good RegionNode with only 3 not NULL |
| // control input edges: Self, Entry, LoopBack. |
| if (x->in(LoopNode::Self) == NULL || x->req() != 3 || loop->_irreducible) { |
| return false; |
| } |
| Node *init_control = x->in(LoopNode::EntryControl); |
| Node *back_control = x->in(LoopNode::LoopBackControl); |
| if (init_control == NULL || back_control == NULL) // Partially dead |
| return false; |
| // Must also check for TOP when looking for a dead loop |
| if (init_control->is_top() || back_control->is_top()) |
| return false; |
| |
| // Allow funny placement of Safepoint |
| if (back_control->Opcode() == Op_SafePoint) |
| back_control = back_control->in(TypeFunc::Control); |
| |
| // Controlling test for loop |
| Node *iftrue = back_control; |
| uint iftrue_op = iftrue->Opcode(); |
| if (iftrue_op != Op_IfTrue && |
| iftrue_op != Op_IfFalse) |
| // I have a weird back-control. Probably the loop-exit test is in |
| // the middle of the loop and I am looking at some trailing control-flow |
| // merge point. To fix this I would have to partially peel the loop. |
| return false; // Obscure back-control |
| |
| // Get boolean guarding loop-back test |
| Node *iff = iftrue->in(0); |
| if (get_loop(iff) != loop || !iff->in(1)->is_Bool()) |
| return false; |
| BoolNode *test = iff->in(1)->as_Bool(); |
| BoolTest::mask bt = test->_test._test; |
| float cl_prob = iff->as_If()->_prob; |
| if (iftrue_op == Op_IfFalse) { |
| bt = BoolTest(bt).negate(); |
| cl_prob = 1.0 - cl_prob; |
| } |
| // Get backedge compare |
| Node *cmp = test->in(1); |
| int cmp_op = cmp->Opcode(); |
| if (cmp_op != Op_CmpI) |
| return false; // Avoid pointer & float compares |
| |
| // Find the trip-counter increment & limit. Limit must be loop invariant. |
| Node *incr = cmp->in(1); |
| Node *limit = cmp->in(2); |
| |
| // --------- |
| // need 'loop()' test to tell if limit is loop invariant |
| // --------- |
| |
| if (!is_member(loop, get_ctrl(incr))) { // Swapped trip counter and limit? |
| Node *tmp = incr; // Then reverse order into the CmpI |
| incr = limit; |
| limit = tmp; |
| bt = BoolTest(bt).commute(); // And commute the exit test |
| } |
| if (is_member(loop, get_ctrl(limit))) // Limit must be loop-invariant |
| return false; |
| if (!is_member(loop, get_ctrl(incr))) // Trip counter must be loop-variant |
| return false; |
| |
| Node* phi_incr = NULL; |
| // Trip-counter increment must be commutative & associative. |
| if (incr->Opcode() == Op_CastII) { |
| incr = incr->in(1); |
| } |
| if (incr->is_Phi()) { |
| if (incr->as_Phi()->region() != x || incr->req() != 3) |
| return false; // Not simple trip counter expression |
| phi_incr = incr; |
| incr = phi_incr->in(LoopNode::LoopBackControl); // Assume incr is on backedge of Phi |
| if (!is_member(loop, get_ctrl(incr))) // Trip counter must be loop-variant |
| return false; |
| } |
| |
| Node* trunc1 = NULL; |
| Node* trunc2 = NULL; |
| const TypeInt* iv_trunc_t = NULL; |
| if (!(incr = CountedLoopNode::match_incr_with_optional_truncation(incr, &trunc1, &trunc2, &iv_trunc_t))) { |
| return false; // Funny increment opcode |
| } |
| assert(incr->Opcode() == Op_AddI, "wrong increment code"); |
| |
| // Get merge point |
| Node *xphi = incr->in(1); |
| Node *stride = incr->in(2); |
| if (!stride->is_Con()) { // Oops, swap these |
| if (!xphi->is_Con()) // Is the other guy a constant? |
| return false; // Nope, unknown stride, bail out |
| Node *tmp = xphi; // 'incr' is commutative, so ok to swap |
| xphi = stride; |
| stride = tmp; |
| } |
| if (xphi->Opcode() == Op_CastII) { |
| xphi = xphi->in(1); |
| } |
| // Stride must be constant |
| int stride_con = stride->get_int(); |
| if (stride_con == 0) |
| return false; // missed some peephole opt |
| |
| if (!xphi->is_Phi()) |
| return false; // Too much math on the trip counter |
| if (phi_incr != NULL && phi_incr != xphi) |
| return false; |
| PhiNode *phi = xphi->as_Phi(); |
| |
| // Phi must be of loop header; backedge must wrap to increment |
| if (phi->region() != x) |
| return false; |
| if (trunc1 == NULL && phi->in(LoopNode::LoopBackControl) != incr || |
| trunc1 != NULL && phi->in(LoopNode::LoopBackControl) != trunc1) { |
| return false; |
| } |
| Node *init_trip = phi->in(LoopNode::EntryControl); |
| |
| // If iv trunc type is smaller than int, check for possible wrap. |
| if (!TypeInt::INT->higher_equal(iv_trunc_t)) { |
| assert(trunc1 != NULL, "must have found some truncation"); |
| |
| // Get a better type for the phi (filtered thru if's) |
| const TypeInt* phi_ft = filtered_type(phi); |
| |
| // Can iv take on a value that will wrap? |
| // |
| // Ensure iv's limit is not within "stride" of the wrap value. |
| // |
| // Example for "short" type |
| // Truncation ensures value is in the range -32768..32767 (iv_trunc_t) |
| // If the stride is +10, then the last value of the induction |
| // variable before the increment (phi_ft->_hi) must be |
| // <= 32767 - 10 and (phi_ft->_lo) must be >= -32768 to |
| // ensure no truncation occurs after the increment. |
| |
| if (stride_con > 0) { |
| if (iv_trunc_t->_hi - phi_ft->_hi < stride_con || |
| iv_trunc_t->_lo > phi_ft->_lo) { |
| return false; // truncation may occur |
| } |
| } else if (stride_con < 0) { |
| if (iv_trunc_t->_lo - phi_ft->_lo > stride_con || |
| iv_trunc_t->_hi < phi_ft->_hi) { |
| return false; // truncation may occur |
| } |
| } |
| // No possibility of wrap so truncation can be discarded |
| // Promote iv type to Int |
| } else { |
| assert(trunc1 == NULL && trunc2 == NULL, "no truncation for int"); |
| } |
| |
| // If the condition is inverted and we will be rolling |
| // through MININT to MAXINT, then bail out. |
| if (bt == BoolTest::eq || // Bail out, but this loop trips at most twice! |
| // Odd stride |
| bt == BoolTest::ne && stride_con != 1 && stride_con != -1 || |
| // Count down loop rolls through MAXINT |
| (bt == BoolTest::le || bt == BoolTest::lt) && stride_con < 0 || |
| // Count up loop rolls through MININT |
| (bt == BoolTest::ge || bt == BoolTest::gt) && stride_con > 0) { |
| return false; // Bail out |
| } |
| |
| const TypeInt* init_t = gvn->type(init_trip)->is_int(); |
| const TypeInt* limit_t = gvn->type(limit)->is_int(); |
| |
| if (stride_con > 0) { |
| jlong init_p = (jlong)init_t->_lo + stride_con; |
| if (init_p > (jlong)max_jint || init_p > (jlong)limit_t->_hi) |
| return false; // cyclic loop or this loop trips only once |
| } else { |
| jlong init_p = (jlong)init_t->_hi + stride_con; |
| if (init_p < (jlong)min_jint || init_p < (jlong)limit_t->_lo) |
| return false; // cyclic loop or this loop trips only once |
| } |
| |
| if (phi_incr != NULL) { |
| // check if there is a possiblity of IV overflowing after the first increment |
| if (stride_con > 0) { |
| if (init_t->_hi > max_jint - stride_con) { |
| return false; |
| } |
| } else { |
| if (init_t->_lo < min_jint - stride_con) { |
| return false; |
| } |
| } |
| } |
| |
| // ================================================= |
| // ---- SUCCESS! Found A Trip-Counted Loop! ----- |
| // |
| assert(x->Opcode() == Op_Loop, "regular loops only"); |
| C->print_method(PHASE_BEFORE_CLOOPS, 3); |
| |
| Node *hook = new Node(6); |
| |
| // =================================================== |
| // Generate loop limit check to avoid integer overflow |
| // in cases like next (cyclic loops): |
| // |
| // for (i=0; i <= max_jint; i++) {} |
| // for (i=0; i < max_jint; i+=2) {} |
| // |
| // |
| // Limit check predicate depends on the loop test: |
| // |
| // for(;i != limit; i++) --> limit <= (max_jint) |
| // for(;i < limit; i+=stride) --> limit <= (max_jint - stride + 1) |
| // for(;i <= limit; i+=stride) --> limit <= (max_jint - stride ) |
| // |
| |
| // Check if limit is excluded to do more precise int overflow check. |
| bool incl_limit = (bt == BoolTest::le || bt == BoolTest::ge); |
| int stride_m = stride_con - (incl_limit ? 0 : (stride_con > 0 ? 1 : -1)); |
| |
| // If compare points directly to the phi we need to adjust |
| // the compare so that it points to the incr. Limit have |
| // to be adjusted to keep trip count the same and the |
| // adjusted limit should be checked for int overflow. |
| if (phi_incr != NULL) { |
| stride_m += stride_con; |
| } |
| |
| if (limit->is_Con()) { |
| int limit_con = limit->get_int(); |
| if ((stride_con > 0 && limit_con > (max_jint - stride_m)) || |
| (stride_con < 0 && limit_con < (min_jint - stride_m))) { |
| // Bailout: it could be integer overflow. |
| return false; |
| } |
| } else if ((stride_con > 0 && limit_t->_hi <= (max_jint - stride_m)) || |
| (stride_con < 0 && limit_t->_lo >= (min_jint - stride_m))) { |
| // Limit's type may satisfy the condition, for example, |
| // when it is an array length. |
| } else { |
| // Generate loop's limit check. |
| // Loop limit check predicate should be near the loop. |
| ProjNode *limit_check_proj = find_predicate_insertion_point(init_control, Deoptimization::Reason_loop_limit_check); |
| if (!limit_check_proj) { |
| // The limit check predicate is not generated if this method trapped here before. |
| #ifdef ASSERT |
| if (TraceLoopLimitCheck) { |
| tty->print("missing loop limit check:"); |
| loop->dump_head(); |
| x->dump(1); |
| } |
| #endif |
| return false; |
| } |
| |
| IfNode* check_iff = limit_check_proj->in(0)->as_If(); |
| Node* cmp_limit; |
| Node* bol; |
| |
| if (stride_con > 0) { |
| cmp_limit = new CmpINode(limit, _igvn.intcon(max_jint - stride_m)); |
| bol = new BoolNode(cmp_limit, BoolTest::le); |
| } else { |
| cmp_limit = new CmpINode(limit, _igvn.intcon(min_jint - stride_m)); |
| bol = new BoolNode(cmp_limit, BoolTest::ge); |
| } |
| cmp_limit = _igvn.register_new_node_with_optimizer(cmp_limit); |
| bol = _igvn.register_new_node_with_optimizer(bol); |
| set_subtree_ctrl(bol); |
| |
| // Replace condition in original predicate but preserve Opaque node |
| // so that previous predicates could be found. |
| assert(check_iff->in(1)->Opcode() == Op_Conv2B && |
| check_iff->in(1)->in(1)->Opcode() == Op_Opaque1, ""); |
| Node* opq = check_iff->in(1)->in(1); |
| _igvn.replace_input_of(opq, 1, bol); |
| // Update ctrl. |
| set_ctrl(opq, check_iff->in(0)); |
| set_ctrl(check_iff->in(1), check_iff->in(0)); |
| |
| #ifndef PRODUCT |
| // report that the loop predication has been actually performed |
| // for this loop |
| if (TraceLoopLimitCheck) { |
| tty->print_cr("Counted Loop Limit Check generated:"); |
| debug_only( bol->dump(2); ) |
| } |
| #endif |
| } |
| |
| if (phi_incr != NULL) { |
| // If compare points directly to the phi we need to adjust |
| // the compare so that it points to the incr. Limit have |
| // to be adjusted to keep trip count the same and we |
| // should avoid int overflow. |
| // |
| // i = init; do {} while(i++ < limit); |
| // is converted to |
| // i = init; do {} while(++i < limit+1); |
| // |
| limit = gvn->transform(new AddINode(limit, stride)); |
| } |
| |
| // Now we need to canonicalize loop condition. |
| if (bt == BoolTest::ne) { |
| assert(stride_con == 1 || stride_con == -1, "simple increment only"); |
| // 'ne' can be replaced with 'lt' only when init < limit. |
| if (stride_con > 0 && init_t->_hi < limit_t->_lo) |
| bt = BoolTest::lt; |
| // 'ne' can be replaced with 'gt' only when init > limit. |
| if (stride_con < 0 && init_t->_lo > limit_t->_hi) |
| bt = BoolTest::gt; |
| } |
| |
| if (incl_limit) { |
| // The limit check guaranties that 'limit <= (max_jint - stride)' so |
| // we can convert 'i <= limit' to 'i < limit+1' since stride != 0. |
| // |
| Node* one = (stride_con > 0) ? gvn->intcon( 1) : gvn->intcon(-1); |
| limit = gvn->transform(new AddINode(limit, one)); |
| if (bt == BoolTest::le) |
| bt = BoolTest::lt; |
| else if (bt == BoolTest::ge) |
| bt = BoolTest::gt; |
| else |
| ShouldNotReachHere(); |
| } |
| set_subtree_ctrl( limit ); |
| |
| if (!UseCountedLoopSafepoints) { |
| // Check for SafePoint on backedge and remove |
| Node *sfpt = x->in(LoopNode::LoopBackControl); |
| if (sfpt->Opcode() == Op_SafePoint && is_deleteable_safept(sfpt)) { |
| lazy_replace( sfpt, iftrue ); |
| if (loop->_safepts != NULL) { |
| loop->_safepts->yank(sfpt); |
| } |
| loop->_tail = iftrue; |
| } |
| } |
| |
| // Build a canonical trip test. |
| // Clone code, as old values may be in use. |
| incr = incr->clone(); |
| incr->set_req(1,phi); |
| incr->set_req(2,stride); |
| incr = _igvn.register_new_node_with_optimizer(incr); |
| set_early_ctrl( incr ); |
| _igvn.rehash_node_delayed(phi); |
| phi->set_req_X( LoopNode::LoopBackControl, incr, &_igvn ); |
| |
| // If phi type is more restrictive than Int, raise to |
| // Int to prevent (almost) infinite recursion in igvn |
| // which can only handle integer types for constants or minint..maxint. |
| if (!TypeInt::INT->higher_equal(phi->bottom_type())) { |
| Node* nphi = PhiNode::make(phi->in(0), phi->in(LoopNode::EntryControl), TypeInt::INT); |
| nphi->set_req(LoopNode::LoopBackControl, phi->in(LoopNode::LoopBackControl)); |
| nphi = _igvn.register_new_node_with_optimizer(nphi); |
| set_ctrl(nphi, get_ctrl(phi)); |
| _igvn.replace_node(phi, nphi); |
| phi = nphi->as_Phi(); |
| } |
| cmp = cmp->clone(); |
| cmp->set_req(1,incr); |
| cmp->set_req(2,limit); |
| cmp = _igvn.register_new_node_with_optimizer(cmp); |
| set_ctrl(cmp, iff->in(0)); |
| |
| test = test->clone()->as_Bool(); |
| (*(BoolTest*)&test->_test)._test = bt; |
| test->set_req(1,cmp); |
| _igvn.register_new_node_with_optimizer(test); |
| set_ctrl(test, iff->in(0)); |
| |
| // Replace the old IfNode with a new LoopEndNode |
| Node *lex = _igvn.register_new_node_with_optimizer(new CountedLoopEndNode( iff->in(0), test, cl_prob, iff->as_If()->_fcnt )); |
| IfNode *le = lex->as_If(); |
| uint dd = dom_depth(iff); |
| set_idom(le, le->in(0), dd); // Update dominance for loop exit |
| set_loop(le, loop); |
| |
| // Get the loop-exit control |
| Node *iffalse = iff->as_If()->proj_out(!(iftrue_op == Op_IfTrue)); |
| |
| // Need to swap loop-exit and loop-back control? |
| if (iftrue_op == Op_IfFalse) { |
| Node *ift2=_igvn.register_new_node_with_optimizer(new IfTrueNode (le)); |
| Node *iff2=_igvn.register_new_node_with_optimizer(new IfFalseNode(le)); |
| |
| loop->_tail = back_control = ift2; |
| set_loop(ift2, loop); |
| set_loop(iff2, get_loop(iffalse)); |
| |
| // Lazy update of 'get_ctrl' mechanism. |
| lazy_replace(iffalse, iff2); |
| lazy_replace(iftrue, ift2); |
| |
| // Swap names |
| iffalse = iff2; |
| iftrue = ift2; |
| } else { |
| _igvn.rehash_node_delayed(iffalse); |
| _igvn.rehash_node_delayed(iftrue); |
| iffalse->set_req_X( 0, le, &_igvn ); |
| iftrue ->set_req_X( 0, le, &_igvn ); |
| } |
| |
| set_idom(iftrue, le, dd+1); |
| set_idom(iffalse, le, dd+1); |
| assert(iff->outcnt() == 0, "should be dead now"); |
| lazy_replace( iff, le ); // fix 'get_ctrl' |
| |
| // Now setup a new CountedLoopNode to replace the existing LoopNode |
| CountedLoopNode *l = new CountedLoopNode(init_control, back_control); |
| l->set_unswitch_count(x->as_Loop()->unswitch_count()); // Preserve |
| // The following assert is approximately true, and defines the intention |
| // of can_be_counted_loop. It fails, however, because phase->type |
| // is not yet initialized for this loop and its parts. |
| //assert(l->can_be_counted_loop(this), "sanity"); |
| _igvn.register_new_node_with_optimizer(l); |
| set_loop(l, loop); |
| loop->_head = l; |
| // Fix all data nodes placed at the old loop head. |
| // Uses the lazy-update mechanism of 'get_ctrl'. |
| lazy_replace( x, l ); |
| set_idom(l, init_control, dom_depth(x)); |
| |
| if (!UseCountedLoopSafepoints) { |
| // Check for immediately preceding SafePoint and remove |
| Node *sfpt2 = le->in(0); |
| if (sfpt2->Opcode() == Op_SafePoint && is_deleteable_safept(sfpt2)) { |
| lazy_replace( sfpt2, sfpt2->in(TypeFunc::Control)); |
| if (loop->_safepts != NULL) { |
| loop->_safepts->yank(sfpt2); |
| } |
| } |
| } |
| |
| // Free up intermediate goo |
| _igvn.remove_dead_node(hook); |
| |
| #ifdef ASSERT |
| assert(l->is_valid_counted_loop(), "counted loop shape is messed up"); |
| assert(l == loop->_head && l->phi() == phi && l->loopexit() == lex, "" ); |
| #endif |
| #ifndef PRODUCT |
| if (TraceLoopOpts) { |
| tty->print("Counted "); |
| loop->dump_head(); |
| } |
| #endif |
| |
| C->print_method(PHASE_AFTER_CLOOPS, 3); |
| |
| // Capture bounds of the loop in the induction variable Phi before |
| // subsequent transformation (iteration splitting) obscures the |
| // bounds |
| l->phi()->as_Phi()->set_type(l->phi()->Value(&_igvn)); |
| |
| return true; |
| } |
| |
| //----------------------exact_limit------------------------------------------- |
| Node* PhaseIdealLoop::exact_limit( IdealLoopTree *loop ) { |
| assert(loop->_head->is_CountedLoop(), ""); |
| CountedLoopNode *cl = loop->_head->as_CountedLoop(); |
| assert(cl->is_valid_counted_loop(), ""); |
| |
| if (ABS(cl->stride_con()) == 1 || |
| cl->limit()->Opcode() == Op_LoopLimit) { |
| // Old code has exact limit (it could be incorrect in case of int overflow). |
| // Loop limit is exact with stride == 1. And loop may already have exact limit. |
| return cl->limit(); |
| } |
| Node *limit = NULL; |
| #ifdef ASSERT |
| BoolTest::mask bt = cl->loopexit()->test_trip(); |
| assert(bt == BoolTest::lt || bt == BoolTest::gt, "canonical test is expected"); |
| #endif |
| if (cl->has_exact_trip_count()) { |
| // Simple case: loop has constant boundaries. |
| // Use jlongs to avoid integer overflow. |
| int stride_con = cl->stride_con(); |
| jlong init_con = cl->init_trip()->get_int(); |
| jlong limit_con = cl->limit()->get_int(); |
| julong trip_cnt = cl->trip_count(); |
| jlong final_con = init_con + trip_cnt*stride_con; |
| int final_int = (int)final_con; |
| // The final value should be in integer range since the loop |
| // is counted and the limit was checked for overflow. |
| assert(final_con == (jlong)final_int, "final value should be integer"); |
| limit = _igvn.intcon(final_int); |
| } else { |
| // Create new LoopLimit node to get exact limit (final iv value). |
| limit = new LoopLimitNode(C, cl->init_trip(), cl->limit(), cl->stride()); |
| register_new_node(limit, cl->in(LoopNode::EntryControl)); |
| } |
| assert(limit != NULL, "sanity"); |
| return limit; |
| } |
| |
| //------------------------------Ideal------------------------------------------ |
| // Return a node which is more "ideal" than the current node. |
| // Attempt to convert into a counted-loop. |
| Node *LoopNode::Ideal(PhaseGVN *phase, bool can_reshape) { |
| if (!can_be_counted_loop(phase)) { |
| phase->C->set_major_progress(); |
| } |
| return RegionNode::Ideal(phase, can_reshape); |
| } |
| |
| |
| //============================================================================= |
| //------------------------------Ideal------------------------------------------ |
| // Return a node which is more "ideal" than the current node. |
| // Attempt to convert into a counted-loop. |
| Node *CountedLoopNode::Ideal(PhaseGVN *phase, bool can_reshape) { |
| return RegionNode::Ideal(phase, can_reshape); |
| } |
| |
| //------------------------------dump_spec-------------------------------------- |
| // Dump special per-node info |
| #ifndef PRODUCT |
| void CountedLoopNode::dump_spec(outputStream *st) const { |
| LoopNode::dump_spec(st); |
| if (stride_is_con()) { |
| st->print("stride: %d ",stride_con()); |
| } |
| if (is_pre_loop ()) st->print("pre of N%d" , _main_idx); |
| if (is_main_loop()) st->print("main of N%d", _idx); |
| if (is_post_loop()) st->print("post of N%d", _main_idx); |
| } |
| #endif |
| |
| //============================================================================= |
| int CountedLoopEndNode::stride_con() const { |
| return stride()->bottom_type()->is_int()->get_con(); |
| } |
| |
| //============================================================================= |
| //------------------------------Value----------------------------------------- |
| const Type* LoopLimitNode::Value(PhaseGVN* phase) const { |
| const Type* init_t = phase->type(in(Init)); |
| const Type* limit_t = phase->type(in(Limit)); |
| const Type* stride_t = phase->type(in(Stride)); |
| // Either input is TOP ==> the result is TOP |
| if (init_t == Type::TOP) return Type::TOP; |
| if (limit_t == Type::TOP) return Type::TOP; |
| if (stride_t == Type::TOP) return Type::TOP; |
| |
| int stride_con = stride_t->is_int()->get_con(); |
| if (stride_con == 1) |
| return NULL; // Identity |
| |
| if (init_t->is_int()->is_con() && limit_t->is_int()->is_con()) { |
| // Use jlongs to avoid integer overflow. |
| jlong init_con = init_t->is_int()->get_con(); |
| jlong limit_con = limit_t->is_int()->get_con(); |
| int stride_m = stride_con - (stride_con > 0 ? 1 : -1); |
| jlong trip_count = (limit_con - init_con + stride_m)/stride_con; |
| jlong final_con = init_con + stride_con*trip_count; |
| int final_int = (int)final_con; |
| // The final value should be in integer range since the loop |
| // is counted and the limit was checked for overflow. |
| assert(final_con == (jlong)final_int, "final value should be integer"); |
| return TypeInt::make(final_int); |
| } |
| |
| return bottom_type(); // TypeInt::INT |
| } |
| |
| //------------------------------Ideal------------------------------------------ |
| // Return a node which is more "ideal" than the current node. |
| Node *LoopLimitNode::Ideal(PhaseGVN *phase, bool can_reshape) { |
| if (phase->type(in(Init)) == Type::TOP || |
| phase->type(in(Limit)) == Type::TOP || |
| phase->type(in(Stride)) == Type::TOP) |
| return NULL; // Dead |
| |
| int stride_con = phase->type(in(Stride))->is_int()->get_con(); |
| if (stride_con == 1) |
| return NULL; // Identity |
| |
| if (in(Init)->is_Con() && in(Limit)->is_Con()) |
| return NULL; // Value |
| |
| // Delay following optimizations until all loop optimizations |
| // done to keep Ideal graph simple. |
| if (!can_reshape || phase->C->major_progress()) |
| return NULL; |
| |
| const TypeInt* init_t = phase->type(in(Init) )->is_int(); |
| const TypeInt* limit_t = phase->type(in(Limit))->is_int(); |
| int stride_p; |
| jlong lim, ini; |
| julong max; |
| if (stride_con > 0) { |
| stride_p = stride_con; |
| lim = limit_t->_hi; |
| ini = init_t->_lo; |
| max = (julong)max_jint; |
| } else { |
| stride_p = -stride_con; |
| lim = init_t->_hi; |
| ini = limit_t->_lo; |
| max = (julong)min_jint; |
| } |
| julong range = lim - ini + stride_p; |
| if (range <= max) { |
| // Convert to integer expression if it is not overflow. |
| Node* stride_m = phase->intcon(stride_con - (stride_con > 0 ? 1 : -1)); |
| Node *range = phase->transform(new SubINode(in(Limit), in(Init))); |
| Node *bias = phase->transform(new AddINode(range, stride_m)); |
| Node *trip = phase->transform(new DivINode(0, bias, in(Stride))); |
| Node *span = phase->transform(new MulINode(trip, in(Stride))); |
| return new AddINode(span, in(Init)); // exact limit |
| } |
| |
| if (is_power_of_2(stride_p) || // divisor is 2^n |
| !Matcher::has_match_rule(Op_LoopLimit)) { // or no specialized Mach node? |
| // Convert to long expression to avoid integer overflow |
| // and let igvn optimizer convert this division. |
| // |
| Node* init = phase->transform( new ConvI2LNode(in(Init))); |
| Node* limit = phase->transform( new ConvI2LNode(in(Limit))); |
| Node* stride = phase->longcon(stride_con); |
| Node* stride_m = phase->longcon(stride_con - (stride_con > 0 ? 1 : -1)); |
| |
| Node *range = phase->transform(new SubLNode(limit, init)); |
| Node *bias = phase->transform(new AddLNode(range, stride_m)); |
| Node *span; |
| if (stride_con > 0 && is_power_of_2(stride_p)) { |
| // bias >= 0 if stride >0, so if stride is 2^n we can use &(-stride) |
| // and avoid generating rounding for division. Zero trip guard should |
| // guarantee that init < limit but sometimes the guard is missing and |
| // we can get situation when init > limit. Note, for the empty loop |
| // optimization zero trip guard is generated explicitly which leaves |
| // only RCE predicate where exact limit is used and the predicate |
| // will simply fail forcing recompilation. |
| Node* neg_stride = phase->longcon(-stride_con); |
| span = phase->transform(new AndLNode(bias, neg_stride)); |
| } else { |
| Node *trip = phase->transform(new DivLNode(0, bias, stride)); |
| span = phase->transform(new MulLNode(trip, stride)); |
| } |
| // Convert back to int |
| Node *span_int = phase->transform(new ConvL2INode(span)); |
| return new AddINode(span_int, in(Init)); // exact limit |
| } |
| |
| return NULL; // No progress |
| } |
| |
| //------------------------------Identity--------------------------------------- |
| // If stride == 1 return limit node. |
| Node* LoopLimitNode::Identity(PhaseGVN* phase) { |
| int stride_con = phase->type(in(Stride))->is_int()->get_con(); |
| if (stride_con == 1 || stride_con == -1) |
| return in(Limit); |
| return this; |
| } |
| |
| //============================================================================= |
| //----------------------match_incr_with_optional_truncation-------------------- |
| // Match increment with optional truncation: |
| // CHAR: (i+1)&0x7fff, BYTE: ((i+1)<<8)>>8, or SHORT: ((i+1)<<16)>>16 |
| // Return NULL for failure. Success returns the increment node. |
| Node* CountedLoopNode::match_incr_with_optional_truncation( |
| Node* expr, Node** trunc1, Node** trunc2, const TypeInt** trunc_type) { |
| // Quick cutouts: |
| if (expr == NULL || expr->req() != 3) return NULL; |
| |
| Node *t1 = NULL; |
| Node *t2 = NULL; |
| const TypeInt* trunc_t = TypeInt::INT; |
| Node* n1 = expr; |
| int n1op = n1->Opcode(); |
| |
| // Try to strip (n1 & M) or (n1 << N >> N) from n1. |
| if (n1op == Op_AndI && |
| n1->in(2)->is_Con() && |
| n1->in(2)->bottom_type()->is_int()->get_con() == 0x7fff) { |
| // %%% This check should match any mask of 2**K-1. |
| t1 = n1; |
| n1 = t1->in(1); |
| n1op = n1->Opcode(); |
| trunc_t = TypeInt::CHAR; |
| } else if (n1op == Op_RShiftI && |
| n1->in(1) != NULL && |
| n1->in(1)->Opcode() == Op_LShiftI && |
| n1->in(2) == n1->in(1)->in(2) && |
| n1->in(2)->is_Con()) { |
| jint shift = n1->in(2)->bottom_type()->is_int()->get_con(); |
| // %%% This check should match any shift in [1..31]. |
| if (shift == 16 || shift == 8) { |
| t1 = n1; |
| t2 = t1->in(1); |
| n1 = t2->in(1); |
| n1op = n1->Opcode(); |
| if (shift == 16) { |
| trunc_t = TypeInt::SHORT; |
| } else if (shift == 8) { |
| trunc_t = TypeInt::BYTE; |
| } |
| } |
| } |
| |
| // If (maybe after stripping) it is an AddI, we won: |
| if (n1op == Op_AddI) { |
| *trunc1 = t1; |
| *trunc2 = t2; |
| *trunc_type = trunc_t; |
| return n1; |
| } |
| |
| // failed |
| return NULL; |
| } |
| |
| |
| //------------------------------filtered_type-------------------------------- |
| // Return a type based on condition control flow |
| // A successful return will be a type that is restricted due |
| // to a series of dominating if-tests, such as: |
| // if (i < 10) { |
| // if (i > 0) { |
| // here: "i" type is [1..10) |
| // } |
| // } |
| // or a control flow merge |
| // if (i < 10) { |
| // do { |
| // phi( , ) -- at top of loop type is [min_int..10) |
| // i = ? |
| // } while ( i < 10) |
| // |
| const TypeInt* PhaseIdealLoop::filtered_type( Node *n, Node* n_ctrl) { |
| assert(n && n->bottom_type()->is_int(), "must be int"); |
| const TypeInt* filtered_t = NULL; |
| if (!n->is_Phi()) { |
| assert(n_ctrl != NULL || n_ctrl == C->top(), "valid control"); |
| filtered_t = filtered_type_from_dominators(n, n_ctrl); |
| |
| } else { |
| Node* phi = n->as_Phi(); |
| Node* region = phi->in(0); |
| assert(n_ctrl == NULL || n_ctrl == region, "ctrl parameter must be region"); |
| if (region && region != C->top()) { |
| for (uint i = 1; i < phi->req(); i++) { |
| Node* val = phi->in(i); |
| Node* use_c = region->in(i); |
| const TypeInt* val_t = filtered_type_from_dominators(val, use_c); |
| if (val_t != NULL) { |
| if (filtered_t == NULL) { |
| filtered_t = val_t; |
| } else { |
| filtered_t = filtered_t->meet(val_t)->is_int(); |
| } |
| } |
| } |
| } |
| } |
| const TypeInt* n_t = _igvn.type(n)->is_int(); |
| if (filtered_t != NULL) { |
| n_t = n_t->join(filtered_t)->is_int(); |
| } |
| return n_t; |
| } |
| |
| |
| //------------------------------filtered_type_from_dominators-------------------------------- |
| // Return a possibly more restrictive type for val based on condition control flow of dominators |
| const TypeInt* PhaseIdealLoop::filtered_type_from_dominators( Node* val, Node *use_ctrl) { |
| if (val->is_Con()) { |
| return val->bottom_type()->is_int(); |
| } |
| uint if_limit = 10; // Max number of dominating if's visited |
| const TypeInt* rtn_t = NULL; |
| |
| if (use_ctrl && use_ctrl != C->top()) { |
| Node* val_ctrl = get_ctrl(val); |
| uint val_dom_depth = dom_depth(val_ctrl); |
| Node* pred = use_ctrl; |
| uint if_cnt = 0; |
| while (if_cnt < if_limit) { |
| if ((pred->Opcode() == Op_IfTrue || pred->Opcode() == Op_IfFalse)) { |
| if_cnt++; |
| const TypeInt* if_t = IfNode::filtered_int_type(&_igvn, val, pred); |
| if (if_t != NULL) { |
| if (rtn_t == NULL) { |
| rtn_t = if_t; |
| } else { |
| rtn_t = rtn_t->join(if_t)->is_int(); |
| } |
| } |
| } |
| pred = idom(pred); |
| if (pred == NULL || pred == C->top()) { |
| break; |
| } |
| // Stop if going beyond definition block of val |
| if (dom_depth(pred) < val_dom_depth) { |
| break; |
| } |
| } |
| } |
| return rtn_t; |
| } |
| |
| |
| //------------------------------dump_spec-------------------------------------- |
| // Dump special per-node info |
| #ifndef PRODUCT |
| void CountedLoopEndNode::dump_spec(outputStream *st) const { |
| if( in(TestValue) != NULL && in(TestValue)->is_Bool() ) { |
| BoolTest bt( test_trip()); // Added this for g++. |
| |
| st->print("["); |
| bt.dump_on(st); |
| st->print("]"); |
| } |
| st->print(" "); |
| IfNode::dump_spec(st); |
| } |
| #endif |
| |
| //============================================================================= |
| //------------------------------is_member-------------------------------------- |
| // Is 'l' a member of 'this'? |
| bool IdealLoopTree::is_member(const IdealLoopTree *l) const { |
| while( l->_nest > _nest ) l = l->_parent; |
| return l == this; |
| } |
| |
| //------------------------------set_nest--------------------------------------- |
| // Set loop tree nesting depth. Accumulate _has_call bits. |
| int IdealLoopTree::set_nest( uint depth ) { |
| _nest = depth; |
| int bits = _has_call; |
| if( _child ) bits |= _child->set_nest(depth+1); |
| if( bits ) _has_call = 1; |
| if( _next ) bits |= _next ->set_nest(depth ); |
| return bits; |
| } |
| |
| //------------------------------split_fall_in---------------------------------- |
| // Split out multiple fall-in edges from the loop header. Move them to a |
| // private RegionNode before the loop. This becomes the loop landing pad. |
| void IdealLoopTree::split_fall_in( PhaseIdealLoop *phase, int fall_in_cnt ) { |
| PhaseIterGVN &igvn = phase->_igvn; |
| uint i; |
| |
| // Make a new RegionNode to be the landing pad. |
| Node *landing_pad = new RegionNode( fall_in_cnt+1 ); |
| phase->set_loop(landing_pad,_parent); |
| // Gather all the fall-in control paths into the landing pad |
| uint icnt = fall_in_cnt; |
| uint oreq = _head->req(); |
| for( i = oreq-1; i>0; i-- ) |
| if( !phase->is_member( this, _head->in(i) ) ) |
| landing_pad->set_req(icnt--,_head->in(i)); |
| |
| // Peel off PhiNode edges as well |
| for (DUIterator_Fast jmax, j = _head->fast_outs(jmax); j < jmax; j++) { |
| Node *oj = _head->fast_out(j); |
| if( oj->is_Phi() ) { |
| PhiNode* old_phi = oj->as_Phi(); |
| assert( old_phi->region() == _head, "" ); |
| igvn.hash_delete(old_phi); // Yank from hash before hacking edges |
| Node *p = PhiNode::make_blank(landing_pad, old_phi); |
| uint icnt = fall_in_cnt; |
| for( i = oreq-1; i>0; i-- ) { |
| if( !phase->is_member( this, _head->in(i) ) ) { |
| p->init_req(icnt--, old_phi->in(i)); |
| // Go ahead and clean out old edges from old phi |
| old_phi->del_req(i); |
| } |
| } |
| // Search for CSE's here, because ZKM.jar does a lot of |
| // loop hackery and we need to be a little incremental |
| // with the CSE to avoid O(N^2) node blow-up. |
| Node *p2 = igvn.hash_find_insert(p); // Look for a CSE |
| if( p2 ) { // Found CSE |
| p->destruct(); // Recover useless new node |
| p = p2; // Use old node |
| } else { |
| igvn.register_new_node_with_optimizer(p, old_phi); |
| } |
| // Make old Phi refer to new Phi. |
| old_phi->add_req(p); |
| // Check for the special case of making the old phi useless and |
| // disappear it. In JavaGrande I have a case where this useless |
| // Phi is the loop limit and prevents recognizing a CountedLoop |
| // which in turn prevents removing an empty loop. |
| Node *id_old_phi = old_phi->Identity( &igvn ); |
| if( id_old_phi != old_phi ) { // Found a simple identity? |
| // Note that I cannot call 'replace_node' here, because |
| // that will yank the edge from old_phi to the Region and |
| // I'm mid-iteration over the Region's uses. |
| for (DUIterator_Last imin, i = old_phi->last_outs(imin); i >= imin; ) { |
| Node* use = old_phi->last_out(i); |
| igvn.rehash_node_delayed(use); |
| uint uses_found = 0; |
| for (uint j = 0; j < use->len(); j++) { |
| if (use->in(j) == old_phi) { |
| if (j < use->req()) use->set_req (j, id_old_phi); |
| else use->set_prec(j, id_old_phi); |
| uses_found++; |
| } |
| } |
| i -= uses_found; // we deleted 1 or more copies of this edge |
| } |
| } |
| igvn._worklist.push(old_phi); |
| } |
| } |
| // Finally clean out the fall-in edges from the RegionNode |
| for( i = oreq-1; i>0; i-- ) { |
| if( !phase->is_member( this, _head->in(i) ) ) { |
| _head->del_req(i); |
| } |
| } |
| igvn.rehash_node_delayed(_head); |
| // Transform landing pad |
| igvn.register_new_node_with_optimizer(landing_pad, _head); |
| // Insert landing pad into the header |
| _head->add_req(landing_pad); |
| } |
| |
| //------------------------------split_outer_loop------------------------------- |
| // Split out the outermost loop from this shared header. |
| void IdealLoopTree::split_outer_loop( PhaseIdealLoop *phase ) { |
| PhaseIterGVN &igvn = phase->_igvn; |
| |
| // Find index of outermost loop; it should also be my tail. |
| uint outer_idx = 1; |
| while( _head->in(outer_idx) != _tail ) outer_idx++; |
| |
| // Make a LoopNode for the outermost loop. |
| Node *ctl = _head->in(LoopNode::EntryControl); |
| Node *outer = new LoopNode( ctl, _head->in(outer_idx) ); |
| outer = igvn.register_new_node_with_optimizer(outer, _head); |
| phase->set_created_loop_node(); |
| |
| // Outermost loop falls into '_head' loop |
| _head->set_req(LoopNode::EntryControl, outer); |
| _head->del_req(outer_idx); |
| // Split all the Phis up between '_head' loop and 'outer' loop. |
| for (DUIterator_Fast jmax, j = _head->fast_outs(jmax); j < jmax; j++) { |
| Node *out = _head->fast_out(j); |
| if( out->is_Phi() ) { |
| PhiNode *old_phi = out->as_Phi(); |
| assert( old_phi->region() == _head, "" ); |
| Node *phi = PhiNode::make_blank(outer, old_phi); |
| phi->init_req(LoopNode::EntryControl, old_phi->in(LoopNode::EntryControl)); |
| phi->init_req(LoopNode::LoopBackControl, old_phi->in(outer_idx)); |
| phi = igvn.register_new_node_with_optimizer(phi, old_phi); |
| // Make old Phi point to new Phi on the fall-in path |
| igvn.replace_input_of(old_phi, LoopNode::EntryControl, phi); |
| old_phi->del_req(outer_idx); |
| } |
| } |
| |
| // Use the new loop head instead of the old shared one |
| _head = outer; |
| phase->set_loop(_head, this); |
| } |
| |
| //------------------------------fix_parent------------------------------------- |
| static void fix_parent( IdealLoopTree *loop, IdealLoopTree *parent ) { |
| loop->_parent = parent; |
| if( loop->_child ) fix_parent( loop->_child, loop ); |
| if( loop->_next ) fix_parent( loop->_next , parent ); |
| } |
| |
| //------------------------------estimate_path_freq----------------------------- |
| static float estimate_path_freq( Node *n ) { |
| // Try to extract some path frequency info |
| IfNode *iff; |
| for( int i = 0; i < 50; i++ ) { // Skip through a bunch of uncommon tests |
| uint nop = n->Opcode(); |
| if( nop == Op_SafePoint ) { // Skip any safepoint |
| n = n->in(0); |
| continue; |
| } |
| if( nop == Op_CatchProj ) { // Get count from a prior call |
| // Assume call does not always throw exceptions: means the call-site |
| // count is also the frequency of the fall-through path. |
| assert( n->is_CatchProj(), "" ); |
| if( ((CatchProjNode*)n)->_con != CatchProjNode::fall_through_index ) |
| return 0.0f; // Assume call exception path is rare |
| Node *call = n->in(0)->in(0)->in(0); |
| assert( call->is_Call(), "expect a call here" ); |
| const JVMState *jvms = ((CallNode*)call)->jvms(); |
| ciMethodData* methodData = jvms->method()->method_data(); |
| if (!methodData->is_mature()) return 0.0f; // No call-site data |
| ciProfileData* data = methodData->bci_to_data(jvms->bci()); |
| if ((data == NULL) || !data->is_CounterData()) { |
| // no call profile available, try call's control input |
| n = n->in(0); |
| continue; |
| } |
| return data->as_CounterData()->count()/FreqCountInvocations; |
| } |
| // See if there's a gating IF test |
| Node *n_c = n->in(0); |
| if( !n_c->is_If() ) break; // No estimate available |
| iff = n_c->as_If(); |
| if( iff->_fcnt != COUNT_UNKNOWN ) // Have a valid count? |
| // Compute how much count comes on this path |
| return ((nop == Op_IfTrue) ? iff->_prob : 1.0f - iff->_prob) * iff->_fcnt; |
| // Have no count info. Skip dull uncommon-trap like branches. |
| if( (nop == Op_IfTrue && iff->_prob < PROB_LIKELY_MAG(5)) || |
| (nop == Op_IfFalse && iff->_prob > PROB_UNLIKELY_MAG(5)) ) |
| break; |
| // Skip through never-taken branch; look for a real loop exit. |
| n = iff->in(0); |
| } |
| return 0.0f; // No estimate available |
| } |
| |
| //------------------------------merge_many_backedges--------------------------- |
| // Merge all the backedges from the shared header into a private Region. |
| // Feed that region as the one backedge to this loop. |
| void IdealLoopTree::merge_many_backedges( PhaseIdealLoop *phase ) { |
| uint i; |
| |
| // Scan for the top 2 hottest backedges |
| float hotcnt = 0.0f; |
| float warmcnt = 0.0f; |
| uint hot_idx = 0; |
| // Loop starts at 2 because slot 1 is the fall-in path |
| for( i = 2; i < _head->req(); i++ ) { |
| float cnt = estimate_path_freq(_head->in(i)); |
| if( cnt > hotcnt ) { // Grab hottest path |
| warmcnt = hotcnt; |
| hotcnt = cnt; |
| hot_idx = i; |
| } else if( cnt > warmcnt ) { // And 2nd hottest path |
| warmcnt = cnt; |
| } |
| } |
| |
| // See if the hottest backedge is worthy of being an inner loop |
| // by being much hotter than the next hottest backedge. |
| if( hotcnt <= 0.0001 || |
| hotcnt < 2.0*warmcnt ) hot_idx = 0;// No hot backedge |
| |
| // Peel out the backedges into a private merge point; peel |
| // them all except optionally hot_idx. |
| PhaseIterGVN &igvn = phase->_igvn; |
| |
| Node *hot_tail = NULL; |
| // Make a Region for the merge point |
| Node *r = new RegionNode(1); |
| for( i = 2; i < _head->req(); i++ ) { |
| if( i != hot_idx ) |
| r->add_req( _head->in(i) ); |
| else hot_tail = _head->in(i); |
| } |
| igvn.register_new_node_with_optimizer(r, _head); |
| // Plug region into end of loop _head, followed by hot_tail |
| while( _head->req() > 3 ) _head->del_req( _head->req()-1 ); |
| igvn.replace_input_of(_head, 2, r); |
| if( hot_idx ) _head->add_req(hot_tail); |
| |
| // Split all the Phis up between '_head' loop and the Region 'r' |
| for (DUIterator_Fast jmax, j = _head->fast_outs(jmax); j < jmax; j++) { |
| Node *out = _head->fast_out(j); |
| if( out->is_Phi() ) { |
| PhiNode* n = out->as_Phi(); |
| igvn.hash_delete(n); // Delete from hash before hacking edges |
| Node *hot_phi = NULL; |
| Node *phi = new PhiNode(r, n->type(), n->adr_type()); |
| // Check all inputs for the ones to peel out |
| uint j = 1; |
| for( uint i = 2; i < n->req(); i++ ) { |
| if( i != hot_idx ) |
| phi->set_req( j++, n->in(i) ); |
| else hot_phi = n->in(i); |
| } |
| // Register the phi but do not transform until whole place transforms |
| igvn.register_new_node_with_optimizer(phi, n); |
| // Add the merge phi to the old Phi |
| while( n->req() > 3 ) n->del_req( n->req()-1 ); |
| igvn.replace_input_of(n, 2, phi); |
| if( hot_idx ) n->add_req(hot_phi); |
| } |
| } |
| |
| |
| // Insert a new IdealLoopTree inserted below me. Turn it into a clone |
| // of self loop tree. Turn self into a loop headed by _head and with |
| // tail being the new merge point. |
| IdealLoopTree *ilt = new IdealLoopTree( phase, _head, _tail ); |
| phase->set_loop(_tail,ilt); // Adjust tail |
| _tail = r; // Self's tail is new merge point |
| phase->set_loop(r,this); |
| ilt->_child = _child; // New guy has my children |
| _child = ilt; // Self has new guy as only child |
| ilt->_parent = this; // new guy has self for parent |
| ilt->_nest = _nest; // Same nesting depth (for now) |
| |
| // Starting with 'ilt', look for child loop trees using the same shared |
| // header. Flatten these out; they will no longer be loops in the end. |
| IdealLoopTree **pilt = &_child; |
| while( ilt ) { |
| if( ilt->_head == _head ) { |
| uint i; |
| for( i = 2; i < _head->req(); i++ ) |
| if( _head->in(i) == ilt->_tail ) |
| break; // Still a loop |
| if( i == _head->req() ) { // No longer a loop |
| // Flatten ilt. Hang ilt's "_next" list from the end of |
| // ilt's '_child' list. Move the ilt's _child up to replace ilt. |
| IdealLoopTree **cp = &ilt->_child; |
| while( *cp ) cp = &(*cp)->_next; // Find end of child list |
| *cp = ilt->_next; // Hang next list at end of child list |
| *pilt = ilt->_child; // Move child up to replace ilt |
| ilt->_head = NULL; // Flag as a loop UNIONED into parent |
| ilt = ilt->_child; // Repeat using new ilt |
| continue; // do not advance over ilt->_child |
| } |
| assert( ilt->_tail == hot_tail, "expected to only find the hot inner loop here" ); |
| phase->set_loop(_head,ilt); |
| } |
| pilt = &ilt->_child; // Advance to next |
| ilt = *pilt; |
| } |
| |
| if( _child ) fix_parent( _child, this ); |
| } |
| |
| //------------------------------beautify_loops--------------------------------- |
| // Split shared headers and insert loop landing pads. |
| // Insert a LoopNode to replace the RegionNode. |
| // Return TRUE if loop tree is structurally changed. |
| bool IdealLoopTree::beautify_loops( PhaseIdealLoop *phase ) { |
| bool result = false; |
| // Cache parts in locals for easy |
| PhaseIterGVN &igvn = phase->_igvn; |
| |
| igvn.hash_delete(_head); // Yank from hash before hacking edges |
| |
| // Check for multiple fall-in paths. Peel off a landing pad if need be. |
| int fall_in_cnt = 0; |
| for( uint i = 1; i < _head->req(); i++ ) |
| if( !phase->is_member( this, _head->in(i) ) ) |
| fall_in_cnt++; |
| assert( fall_in_cnt, "at least 1 fall-in path" ); |
| if( fall_in_cnt > 1 ) // Need a loop landing pad to merge fall-ins |
| split_fall_in( phase, fall_in_cnt ); |
| |
| // Swap inputs to the _head and all Phis to move the fall-in edge to |
| // the left. |
| fall_in_cnt = 1; |
| while( phase->is_member( this, _head->in(fall_in_cnt) ) ) |
| fall_in_cnt++; |
| if( fall_in_cnt > 1 ) { |
| // Since I am just swapping inputs I do not need to update def-use info |
| Node *tmp = _head->in(1); |
| igvn.rehash_node_delayed(_head); |
| _head->set_req( 1, _head->in(fall_in_cnt) ); |
| _head->set_req( fall_in_cnt, tmp ); |
| // Swap also all Phis |
| for (DUIterator_Fast imax, i = _head->fast_outs(imax); i < imax; i++) { |
| Node* phi = _head->fast_out(i); |
| if( phi->is_Phi() ) { |
| igvn.rehash_node_delayed(phi); // Yank from hash before hacking edges |
| tmp = phi->in(1); |
| phi->set_req( 1, phi->in(fall_in_cnt) ); |
| phi->set_req( fall_in_cnt, tmp ); |
| } |
| } |
| } |
| assert( !phase->is_member( this, _head->in(1) ), "left edge is fall-in" ); |
| assert( phase->is_member( this, _head->in(2) ), "right edge is loop" ); |
| |
| // If I am a shared header (multiple backedges), peel off the many |
| // backedges into a private merge point and use the merge point as |
| // the one true backedge. |
| if( _head->req() > 3 ) { |
| // Merge the many backedges into a single backedge but leave |
| // the hottest backedge as separate edge for the following peel. |
| merge_many_backedges( phase ); |
| result = true; |
| } |
| |
| // If I have one hot backedge, peel off myself loop. |
| // I better be the outermost loop. |
| if (_head->req() > 3 && !_irreducible) { |
| split_outer_loop( phase ); |
| result = true; |
| |
| } else if (!_head->is_Loop() && !_irreducible) { |
| // Make a new LoopNode to replace the old loop head |
| Node *l = new LoopNode( _head->in(1), _head->in(2) ); |
| l = igvn.register_new_node_with_optimizer(l, _head); |
| phase->set_created_loop_node(); |
| // Go ahead and replace _head |
| phase->_igvn.replace_node( _head, l ); |
| _head = l; |
| phase->set_loop(_head, this); |
| } |
| |
| // Now recursively beautify nested loops |
| if( _child ) result |= _child->beautify_loops( phase ); |
| if( _next ) result |= _next ->beautify_loops( phase ); |
| return result; |
| } |
| |
| //------------------------------allpaths_check_safepts---------------------------- |
| // Allpaths backwards scan from loop tail, terminating each path at first safepoint |
| // encountered. Helper for check_safepts. |
| void IdealLoopTree::allpaths_check_safepts(VectorSet &visited, Node_List &stack) { |
| assert(stack.size() == 0, "empty stack"); |
| stack.push(_tail); |
| visited.Clear(); |
| visited.set(_tail->_idx); |
| while (stack.size() > 0) { |
| Node* n = stack.pop(); |
| if (n->is_Call() && n->as_Call()->guaranteed_safepoint()) { |
| // Terminate this path |
| } else if (n->Opcode() == Op_SafePoint) { |
| if (_phase->get_loop(n) != this) { |
| if (_required_safept == NULL) _required_safept = new Node_List(); |
| _required_safept->push(n); // save the one closest to the tail |
| } |
| // Terminate this path |
| } else { |
| uint start = n->is_Region() ? 1 : 0; |
| uint end = n->is_Region() && !n->is_Loop() ? n->req() : start + 1; |
| for (uint i = start; i < end; i++) { |
| Node* in = n->in(i); |
| assert(in->is_CFG(), "must be"); |
| if (!visited.test_set(in->_idx) && is_member(_phase->get_loop(in))) { |
| stack.push(in); |
| } |
| } |
| } |
| } |
| } |
| |
| //------------------------------check_safepts---------------------------- |
| // Given dominators, try to find loops with calls that must always be |
| // executed (call dominates loop tail). These loops do not need non-call |
| // safepoints (ncsfpt). |
| // |
| // A complication is that a safepoint in a inner loop may be needed |
| // by an outer loop. In the following, the inner loop sees it has a |
| // call (block 3) on every path from the head (block 2) to the |
| // backedge (arc 3->2). So it deletes the ncsfpt (non-call safepoint) |
| // in block 2, _but_ this leaves the outer loop without a safepoint. |
| // |
| // entry 0 |
| // | |
| // v |
| // outer 1,2 +->1 |
| // | | |
| // | v |
| // | 2<---+ ncsfpt in 2 |
| // |_/|\ | |
| // | v | |
| // inner 2,3 / 3 | call in 3 |
| // / | | |
| // v +--+ |
| // exit 4 |
| // |
| // |
| // This method creates a list (_required_safept) of ncsfpt nodes that must |
| // be protected is created for each loop. When a ncsfpt maybe deleted, it |
| // is first looked for in the lists for the outer loops of the current loop. |
| // |
| // The insights into the problem: |
| // A) counted loops are okay |
| // B) innermost loops are okay (only an inner loop can delete |
| // a ncsfpt needed by an outer loop) |
| // C) a loop is immune from an inner loop deleting a safepoint |
| // if the loop has a call on the idom-path |
| // D) a loop is also immune if it has a ncsfpt (non-call safepoint) on the |
| // idom-path that is not in a nested loop |
| // E) otherwise, an ncsfpt on the idom-path that is nested in an inner |
| // loop needs to be prevented from deletion by an inner loop |
| // |
| // There are two analyses: |
| // 1) The first, and cheaper one, scans the loop body from |
| // tail to head following the idom (immediate dominator) |
| // chain, looking for the cases (C,D,E) above. |
| // Since inner loops are scanned before outer loops, there is summary |
| // information about inner loops. Inner loops can be skipped over |
| // when the tail of an inner loop is encountered. |
| // |
| // 2) The second, invoked if the first fails to find a call or ncsfpt on |
| // the idom path (which is rare), scans all predecessor control paths |
| // from the tail to the head, terminating a path when a call or sfpt |
| // is encountered, to find the ncsfpt's that are closest to the tail. |
| // |
| void IdealLoopTree::check_safepts(VectorSet &visited, Node_List &stack) { |
| // Bottom up traversal |
| IdealLoopTree* ch = _child; |
| if (_child) _child->check_safepts(visited, stack); |
| if (_next) _next ->check_safepts(visited, stack); |
| |
| if (!_head->is_CountedLoop() && !_has_sfpt && _parent != NULL && !_irreducible) { |
| bool has_call = false; // call on dom-path |
| bool has_local_ncsfpt = false; // ncsfpt on dom-path at this loop depth |
| Node* nonlocal_ncsfpt = NULL; // ncsfpt on dom-path at a deeper depth |
| // Scan the dom-path nodes from tail to head |
| for (Node* n = tail(); n != _head; n = _phase->idom(n)) { |
| if (n->is_Call() && n->as_Call()->guaranteed_safepoint()) { |
| has_call = true; |
| _has_sfpt = 1; // Then no need for a safept! |
| break; |
| } else if (n->Opcode() == Op_SafePoint) { |
| if (_phase->get_loop(n) == this) { |
| has_local_ncsfpt = true; |
| break; |
| } |
| if (nonlocal_ncsfpt == NULL) { |
| nonlocal_ncsfpt = n; // save the one closest to the tail |
| } |
| } else { |
| IdealLoopTree* nlpt = _phase->get_loop(n); |
| if (this != nlpt) { |
| // If at an inner loop tail, see if the inner loop has already |
| // recorded seeing a call on the dom-path (and stop.) If not, |
| // jump to the head of the inner loop. |
| assert(is_member(nlpt), "nested loop"); |
| Node* tail = nlpt->_tail; |
| if (tail->in(0)->is_If()) tail = tail->in(0); |
| if (n == tail) { |
| // If inner loop has call on dom-path, so does outer loop |
| if (nlpt->_has_sfpt) { |
| has_call = true; |
| _has_sfpt = 1; |
| break; |
| } |
| // Skip to head of inner loop |
| assert(_phase->is_dominator(_head, nlpt->_head), "inner head dominated by outer head"); |
| n = nlpt->_head; |
| } |
| } |
| } |
| } |
| // Record safept's that this loop needs preserved when an |
| // inner loop attempts to delete it's safepoints. |
| if (_child != NULL && !has_call && !has_local_ncsfpt) { |
| if (nonlocal_ncsfpt != NULL) { |
| if (_required_safept == NULL) _required_safept = new Node_List(); |
| _required_safept->push(nonlocal_ncsfpt); |
| } else { |
| // Failed to find a suitable safept on the dom-path. Now use |
| // an all paths walk from tail to head, looking for safepoints to preserve. |
| allpaths_check_safepts(visited, stack); |
| } |
| } |
| } |
| } |
| |
| //---------------------------is_deleteable_safept---------------------------- |
| // Is safept not required by an outer loop? |
| bool PhaseIdealLoop::is_deleteable_safept(Node* sfpt) { |
| assert(sfpt->Opcode() == Op_SafePoint, ""); |
| IdealLoopTree* lp = get_loop(sfpt)->_parent; |
| while (lp != NULL) { |
| Node_List* sfpts = lp->_required_safept; |
| if (sfpts != NULL) { |
| for (uint i = 0; i < sfpts->size(); i++) { |
| if (sfpt == sfpts->at(i)) |
| return false; |
| } |
| } |
| lp = lp->_parent; |
| } |
| return true; |
| } |
| |
| //---------------------------replace_parallel_iv------------------------------- |
| // Replace parallel induction variable (parallel to trip counter) |
| void PhaseIdealLoop::replace_parallel_iv(IdealLoopTree *loop) { |
| assert(loop->_head->is_CountedLoop(), ""); |
| CountedLoopNode *cl = loop->_head->as_CountedLoop(); |
| if (!cl->is_valid_counted_loop()) |
| return; // skip malformed counted loop |
| Node *incr = cl->incr(); |
| if (incr == NULL) |
| return; // Dead loop? |
| Node *init = cl->init_trip(); |
| Node *phi = cl->phi(); |
| int stride_con = cl->stride_con(); |
| |
| // Visit all children, looking for Phis |
| for (DUIterator i = cl->outs(); cl->has_out(i); i++) { |
| Node *out = cl->out(i); |
| // Look for other phis (secondary IVs). Skip dead ones |
| if (!out->is_Phi() || out == phi || !has_node(out)) |
| continue; |
| PhiNode* phi2 = out->as_Phi(); |
| Node *incr2 = phi2->in( LoopNode::LoopBackControl ); |
| // Look for induction variables of the form: X += constant |
| if (phi2->region() != loop->_head || |
| incr2->req() != 3 || |
| incr2->in(1) != phi2 || |
| incr2 == incr || |
| incr2->Opcode() != Op_AddI || |
| !incr2->in(2)->is_Con()) |
| continue; |
| |
| // Check for parallel induction variable (parallel to trip counter) |
| // via an affine function. In particular, count-down loops with |
| // count-up array indices are common. We only RCE references off |
| // the trip-counter, so we need to convert all these to trip-counter |
| // expressions. |
| Node *init2 = phi2->in( LoopNode::EntryControl ); |
| int stride_con2 = incr2->in(2)->get_int(); |
| |
| // The general case here gets a little tricky. We want to find the |
| // GCD of all possible parallel IV's and make a new IV using this |
| // GCD for the loop. Then all possible IVs are simple multiples of |
| // the GCD. In practice, this will cover very few extra loops. |
| // Instead we require 'stride_con2' to be a multiple of 'stride_con', |
| // where +/-1 is the common case, but other integer multiples are |
| // also easy to handle. |
| int ratio_con = stride_con2/stride_con; |
| |
| if ((ratio_con * stride_con) == stride_con2) { // Check for exact |
| #ifndef PRODUCT |
| if (TraceLoopOpts) { |
| tty->print("Parallel IV: %d ", phi2->_idx); |
| loop->dump_head(); |
| } |
| #endif |
| // Convert to using the trip counter. The parallel induction |
| // variable differs from the trip counter by a loop-invariant |
| // amount, the difference between their respective initial values. |
| // It is scaled by the 'ratio_con'. |
| Node* ratio = _igvn.intcon(ratio_con); |
| set_ctrl(ratio, C->root()); |
| Node* ratio_init = new MulINode(init, ratio); |
| _igvn.register_new_node_with_optimizer(ratio_init, init); |
| set_early_ctrl(ratio_init); |
| Node* diff = new SubINode(init2, ratio_init); |
| _igvn.register_new_node_with_optimizer(diff, init2); |
| set_early_ctrl(diff); |
| Node* ratio_idx = new MulINode(phi, ratio); |
| _igvn.register_new_node_with_optimizer(ratio_idx, phi); |
| set_ctrl(ratio_idx, cl); |
| Node* add = new AddINode(ratio_idx, diff); |
| _igvn.register_new_node_with_optimizer(add); |
| set_ctrl(add, cl); |
| _igvn.replace_node( phi2, add ); |
| // Sometimes an induction variable is unused |
| if (add->outcnt() == 0) { |
| _igvn.remove_dead_node(add); |
| } |
| --i; // deleted this phi; rescan starting with next position |
| continue; |
| } |
| } |
| } |
| |
| void IdealLoopTree::remove_safepoints(PhaseIdealLoop* phase, bool keep_one) { |
| Node* keep = NULL; |
| if (keep_one) { |
| // Look for a safepoint on the idom-path. |
| for (Node* i = tail(); i != _head; i = phase->idom(i)) { |
| if (i->Opcode() == Op_SafePoint && phase->get_loop(i) == this) { |
| keep = i; |
| break; // Found one |
| } |
| } |
| } |
| |
| // Don't remove any safepoints if it is requested to keep a single safepoint and |
| // no safepoint was found on idom-path. It is not safe to remove any safepoint |
| // in this case since there's no safepoint dominating all paths in the loop body. |
| bool prune = !keep_one || keep != NULL; |
| |
| // Delete other safepoints in this loop. |
| Node_List* sfpts = _safepts; |
| if (prune && sfpts != NULL) { |
| assert(keep == NULL || keep->Opcode() == Op_SafePoint, "not safepoint"); |
| for (uint i = 0; i < sfpts->size(); i++) { |
| Node* n = sfpts->at(i); |
| assert(phase->get_loop(n) == this, ""); |
| if (n != keep && phase->is_deleteable_safept(n)) { |
| phase->lazy_replace(n, n->in(TypeFunc::Control)); |
| } |
| } |
| } |
| } |
| |
| //------------------------------counted_loop----------------------------------- |
| // Convert to counted loops where possible |
| void IdealLoopTree::counted_loop( PhaseIdealLoop *phase ) { |
| |
| // For grins, set the inner-loop flag here |
| if (!_child) { |
| if (_head->is_Loop()) _head->as_Loop()->set_inner_loop(); |
| } |
| |
| if (_head->is_CountedLoop() || |
| phase->is_counted_loop(_head, this)) { |
| |
| if (!UseCountedLoopSafepoints) { |
| // Indicate we do not need a safepoint here |
| _has_sfpt = 1; |
| } |
| |
| // Remove safepoints |
| bool keep_one_sfpt = !(_has_call || _has_sfpt); |
| remove_safepoints(phase, keep_one_sfpt); |
| |
| // Look for induction variables |
| phase->replace_parallel_iv(this); |
| |
| } else if (_parent != NULL && !_irreducible) { |
| // Not a counted loop. Keep one safepoint. |
| bool keep_one_sfpt = true; |
| remove_safepoints(phase, keep_one_sfpt); |
| } |
| |
| // Recursively |
| if (_child) _child->counted_loop( phase ); |
| if (_next) _next ->counted_loop( phase ); |
| } |
| |
| #ifndef PRODUCT |
| //------------------------------dump_head-------------------------------------- |
| // Dump 1 liner for loop header info |
| void IdealLoopTree::dump_head( ) const { |
| for (uint i=0; i<_nest; i++) |
| tty->print(" "); |
| tty->print("Loop: N%d/N%d ",_head->_idx,_tail->_idx); |
| if (_irreducible) tty->print(" IRREDUCIBLE"); |
| Node* entry = _head->in(LoopNode::EntryControl); |
| Node* predicate = PhaseIdealLoop::find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check); |
| if (predicate != NULL ) { |
| tty->print(" limit_check"); |
| entry = entry->in(0)->in(0); |
| } |
| if (UseLoopPredicate) { |
| entry = PhaseIdealLoop::find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); |
| if (entry != NULL) { |
| tty->print(" predicated"); |
| } |
| } |
| if (_head->is_CountedLoop()) { |
| CountedLoopNode *cl = _head->as_CountedLoop(); |
| tty->print(" counted"); |
| |
| Node* init_n = cl->init_trip(); |
| if (init_n != NULL && init_n->is_Con()) |
| tty->print(" [%d,", cl->init_trip()->get_int()); |
| else |
| tty->print(" [int,"); |
| Node* limit_n = cl->limit(); |
| if (limit_n != NULL && limit_n->is_Con()) |
| tty->print("%d),", cl->limit()->get_int()); |
| else |
| tty->print("int),"); |
| int stride_con = cl->stride_con(); |
| if (stride_con > 0) tty->print("+"); |
| tty->print("%d", stride_con); |
| |
| tty->print(" (%0.f iters) ", cl->profile_trip_cnt()); |
| |
| if (cl->is_pre_loop ()) tty->print(" pre" ); |
| if (cl->is_main_loop()) tty->print(" main"); |
| if (cl->is_post_loop()) tty->print(" post"); |
| if (cl->is_vectorized_loop()) tty->print(" vector"); |
| if (cl->range_checks_present()) tty->print(" rc "); |
| if (cl->is_multiversioned()) tty->print(" multi "); |
| } |
| if (_has_call) tty->print(" has_call"); |
| if (_has_sfpt) tty->print(" has_sfpt"); |
| if (_rce_candidate) tty->print(" rce"); |
| if (_safepts != NULL && _safepts->size() > 0) { |
| tty->print(" sfpts={"); _safepts->dump_simple(); tty->print(" }"); |
| } |
| if (_required_safept != NULL && _required_safept->size() > 0) { |
| tty->print(" req={"); _required_safept->dump_simple(); tty->print(" }"); |
| } |
| tty->cr(); |
| } |
| |
| //------------------------------dump------------------------------------------- |
| // Dump loops by loop tree |
| void IdealLoopTree::dump( ) const { |
| dump_head(); |
| if (_child) _child->dump(); |
| if (_next) _next ->dump(); |
| } |
| |
| #endif |
| |
| static void log_loop_tree(IdealLoopTree* root, IdealLoopTree* loop, CompileLog* log) { |
| if (loop == root) { |
| if (loop->_child != NULL) { |
| log->begin_head("loop_tree"); |
| log->end_head(); |
| if( loop->_child ) log_loop_tree(root, loop->_child, log); |
| log->tail("loop_tree"); |
| assert(loop->_next == NULL, "what?"); |
| } |
| } else { |
| Node* head = loop->_head; |
| log->begin_head("loop"); |
| log->print(" idx='%d' ", head->_idx); |
| if (loop->_irreducible) log->print("irreducible='1' "); |
| if (head->is_Loop()) { |
| if (head->as_Loop()->is_inner_loop()) log->print("inner_loop='1' "); |
| if (head->as_Loop()->is_partial_peel_loop()) log->print("partial_peel_loop='1' "); |
| } |
| if (head->is_CountedLoop()) { |
| CountedLoopNode* cl = head->as_CountedLoop(); |
| if (cl->is_pre_loop()) log->print("pre_loop='%d' ", cl->main_idx()); |
| if (cl->is_main_loop()) log->print("main_loop='%d' ", cl->_idx); |
| if (cl->is_post_loop()) log->print("post_loop='%d' ", cl->main_idx()); |
| } |
| log->end_head(); |
| if( loop->_child ) log_loop_tree(root, loop->_child, log); |
| log->tail("loop"); |
| if( loop->_next ) log_loop_tree(root, loop->_next, log); |
| } |
| } |
| |
| //---------------------collect_potentially_useful_predicates----------------------- |
| // Helper function to collect potentially useful predicates to prevent them from |
| // being eliminated by PhaseIdealLoop::eliminate_useless_predicates |
| void PhaseIdealLoop::collect_potentially_useful_predicates( |
| IdealLoopTree * loop, Unique_Node_List &useful_predicates) { |
| if (loop->_child) { // child |
| collect_potentially_useful_predicates(loop->_child, useful_predicates); |
| } |
| |
| // self (only loops that we can apply loop predication may use their predicates) |
| if (loop->_head->is_Loop() && |
| !loop->_irreducible && |
| !loop->tail()->is_top()) { |
| LoopNode* lpn = loop->_head->as_Loop(); |
| Node* entry = lpn->in(LoopNode::EntryControl); |
| Node* predicate_proj = find_predicate(entry); // loop_limit_check first |
| if (predicate_proj != NULL ) { // right pattern that can be used by loop predication |
| assert(entry->in(0)->in(1)->in(1)->Opcode() == Op_Opaque1, "must be"); |
| useful_predicates.push(entry->in(0)->in(1)->in(1)); // good one |
| entry = entry->in(0)->in(0); |
| } |
| predicate_proj = find_predicate(entry); // Predicate |
| if (predicate_proj != NULL ) { |
| useful_predicates.push(entry->in(0)->in(1)->in(1)); // good one |
| } |
| } |
| |
| if (loop->_next) { // sibling |
| collect_potentially_useful_predicates(loop->_next, useful_predicates); |
| } |
| } |
| |
| //------------------------eliminate_useless_predicates----------------------------- |
| // Eliminate all inserted predicates if they could not be used by loop predication. |
| // Note: it will also eliminates loop limits check predicate since it also uses |
| // Opaque1 node (see Parse::add_predicate()). |
| void PhaseIdealLoop::eliminate_useless_predicates() { |
| if (C->predicate_count() == 0) |
| return; // no predicate left |
| |
| Unique_Node_List useful_predicates; // to store useful predicates |
| if (C->has_loops()) { |
| collect_potentially_useful_predicates(_ltree_root->_child, useful_predicates); |
| } |
| |
| for (int i = C->predicate_count(); i > 0; i--) { |
| Node * n = C->predicate_opaque1_node(i-1); |
| assert(n->Opcode() == Op_Opaque1, "must be"); |
| if (!useful_predicates.member(n)) { // not in the useful list |
| _igvn.replace_node(n, n->in(1)); |
| } |
| } |
| } |
| |
| //------------------------process_expensive_nodes----------------------------- |
| // Expensive nodes have their control input set to prevent the GVN |
| // from commoning them and as a result forcing the resulting node to |
| // be in a more frequent path. Use CFG information here, to change the |
| // control inputs so that some expensive nodes can be commoned while |
| // not executed more frequently. |
| bool PhaseIdealLoop::process_expensive_nodes() { |
| assert(OptimizeExpensiveOps, "optimization off?"); |
| |
| // Sort nodes to bring similar nodes together |
| C->sort_expensive_nodes(); |
| |
| bool progress = false; |
| |
| for (int i = 0; i < C->expensive_count(); ) { |
| Node* n = C->expensive_node(i); |
| int start = i; |
| // Find nodes similar to n |
| i++; |
| for (; i < C->expensive_count() && Compile::cmp_expensive_nodes(n, C->expensive_node(i)) == 0; i++); |
| int end = i; |
| // And compare them two by two |
| for (int j = start; j < end; j++) { |
| Node* n1 = C->expensive_node(j); |
| if (is_node_unreachable(n1)) { |
| continue; |
| } |
| for (int k = j+1; k < end; k++) { |
| Node* n2 = C->expensive_node(k); |
| if (is_node_unreachable(n2)) { |
| continue; |
| } |
| |
| assert(n1 != n2, "should be pair of nodes"); |
| |
| Node* c1 = n1->in(0); |
| Node* c2 = n2->in(0); |
| |
| Node* parent_c1 = c1; |
| Node* parent_c2 = c2; |
| |
| // The call to get_early_ctrl_for_expensive() moves the |
| // expensive nodes up but stops at loops that are in a if |
| // branch. See whether we can exit the loop and move above the |
| // If. |
| if (c1->is_Loop()) { |
| parent_c1 = c1->in(1); |
| } |
| if (c2->is_Loop()) { |
| parent_c2 = c2->in(1); |
| } |
| |
| if (parent_c1 == parent_c2) { |
| _igvn._worklist.push(n1); |
| _igvn._worklist.push(n2); |
| continue; |
| } |
| |
| // Look for identical expensive node up the dominator chain. |
| if (is_dominator(c1, c2)) { |
| c2 = c1; |
| } else if (is_dominator(c2, c1)) { |
| c1 = c2; |
| } else if (parent_c1->is_Proj() && parent_c1->in(0)->is_If() && |
| parent_c2->is_Proj() && parent_c1->in(0) == parent_c2->in(0)) { |
| // Both branches have the same expensive node so move it up |
| // before the if. |
| c1 = c2 = idom(parent_c1->in(0)); |
| } |
| // Do the actual moves |
| if (n1->in(0) != c1) { |
| _igvn.hash_delete(n1); |
| n1->set_req(0, c1); |
| _igvn.hash_insert(n1); |
| _igvn._worklist.push(n1); |
| progress = true; |
| } |
| if (n2->in(0) != c2) { |
| _igvn.hash_delete(n2); |
| n2->set_req(0, c2); |
| _igvn.hash_insert(n2); |
| _igvn._worklist.push(n2); |
| progress = true; |
| } |
| } |
| } |
| } |
| |
| return progress; |
| } |
| |
| |
| //============================================================================= |
| //----------------------------build_and_optimize------------------------------- |
| // Create a PhaseLoop. Build the ideal Loop tree. Map each Ideal Node to |
| // its corresponding LoopNode. If 'optimize' is true, do some loop cleanups. |
| void PhaseIdealLoop::build_and_optimize(bool do_split_ifs, bool skip_loop_opts) { |
| ResourceMark rm; |
| |
| int old_progress = C->major_progress(); |
| uint orig_worklist_size = _igvn._worklist.size(); |
| |
| // Reset major-progress flag for the driver's heuristics |
| C->clear_major_progress(); |
| |
| #ifndef PRODUCT |
| // Capture for later assert |
| uint unique = C->unique(); |
| _loop_invokes++; |
| _loop_work += unique; |
| #endif |
| |
| // True if the method has at least 1 irreducible loop |
| _has_irreducible_loops = false; |
| |
| _created_loop_node = false; |
| |
| Arena *a = Thread::current()->resource_area(); |
| VectorSet visited(a); |
| // Pre-grow the mapping from Nodes to IdealLoopTrees. |
| _nodes.map(C->unique(), NULL); |
| memset(_nodes.adr(), 0, wordSize * C->unique()); |
| |
| // Pre-build the top-level outermost loop tree entry |
| _ltree_root = new IdealLoopTree( this, C->root(), C->root() ); |
| // Do not need a safepoint at the top level |
| _ltree_root->_has_sfpt = 1; |
| |
| // Initialize Dominators. |
| // Checked in clone_loop_predicate() during beautify_loops(). |
| _idom_size = 0; |
| _idom = NULL; |
| _dom_depth = NULL; |
| _dom_stk = NULL; |
| |
| // Empty pre-order array |
| allocate_preorders(); |
| |
| // Build a loop tree on the fly. Build a mapping from CFG nodes to |
| // IdealLoopTree entries. Data nodes are NOT walked. |
| build_loop_tree(); |
| // Check for bailout, and return |
| if (C->failing()) { |
| return; |
| } |
| |
| // No loops after all |
| if( !_ltree_root->_child && !_verify_only ) C->set_has_loops(false); |
| |
| // There should always be an outer loop containing the Root and Return nodes. |
| // If not, we have a degenerate empty program. Bail out in this case. |
| if (!has_node(C->root())) { |
| if (!_verify_only) { |
| C->clear_major_progress(); |
| C->record_method_not_compilable("empty program detected during loop optimization"); |
| } |
| return; |
| } |
| |
| // Nothing to do, so get out |
| bool stop_early = !C->has_loops() && !skip_loop_opts && !do_split_ifs && !_verify_me && !_verify_only; |
| bool do_expensive_nodes = C->should_optimize_expensive_nodes(_igvn); |
| if (stop_early && !do_expensive_nodes) { |
| _igvn.optimize(); // Cleanup NeverBranches |
| return; |
| } |
| |
| // Set loop nesting depth |
| _ltree_root->set_nest( 0 ); |
| |
| // Split shared headers and insert loop landing pads. |
| // Do not bother doing this on the Root loop of course. |
| if( !_verify_me && !_verify_only && _ltree_root->_child ) { |
| C->print_method(PHASE_BEFORE_BEAUTIFY_LOOPS, 3); |
| if( _ltree_root->_child->beautify_loops( this ) ) { |
| // Re-build loop tree! |
| _ltree_root->_child = NULL; |
| _nodes.clear(); |
| reallocate_preorders(); |
| build_loop_tree(); |
| // Check for bailout, and return |
| if (C->failing()) { |
| return; |
| } |
| // Reset loop nesting depth |
| _ltree_root->set_nest( 0 ); |
| |
| C->print_method(PHASE_AFTER_BEAUTIFY_LOOPS, 3); |
| } |
| } |
| |
| // Build Dominators for elision of NULL checks & loop finding. |
| // Since nodes do not have a slot for immediate dominator, make |
| // a persistent side array for that info indexed on node->_idx. |
| _idom_size = C->unique(); |
| _idom = NEW_RESOURCE_ARRAY( Node*, _idom_size ); |
| _dom_depth = NEW_RESOURCE_ARRAY( uint, _idom_size ); |
| _dom_stk = NULL; // Allocated on demand in recompute_dom_depth |
| memset( _dom_depth, 0, _idom_size * sizeof(uint) ); |
| |
| Dominators(); |
| |
| if (!_verify_only) { |
| // As a side effect, Dominators removed any unreachable CFG paths |
| // into RegionNodes. It doesn't do this test against Root, so |
| // we do it here. |
| for( uint i = 1; i < C->root()->req(); i++ ) { |
| if( !_nodes[C->root()->in(i)->_idx] ) { // Dead path into Root? |
| _igvn.delete_input_of(C->root(), i); |
| i--; // Rerun same iteration on compressed edges |
| } |
| } |
| |
| // Given dominators, try to find inner loops with calls that must |
| // always be executed (call dominates loop tail). These loops do |
| // not need a separate safepoint. |
| Node_List cisstack(a); |
| _ltree_root->check_safepts(visited, cisstack); |
| } |
| |
| // Walk the DATA nodes and place into loops. Find earliest control |
| // node. For CFG nodes, the _nodes array starts out and remains |
| // holding the associated IdealLoopTree pointer. For DATA nodes, the |
| // _nodes array holds the earliest legal controlling CFG node. |
| |
| // Allocate stack with enough space to avoid frequent realloc |
| int stack_size = (C->live_nodes() >> 1) + 16; // (live_nodes>>1)+16 from Java2D stats |
| Node_Stack nstack( a, stack_size ); |
| |
| visited.Clear(); |
| Node_List worklist(a); |
| // Don't need C->root() on worklist since |
| // it will be processed among C->top() inputs |
| worklist.push( C->top() ); |
| visited.set( C->top()->_idx ); // Set C->top() as visited now |
| build_loop_early( visited, worklist, nstack ); |
| |
| // Given early legal placement, try finding counted loops. This placement |
| // is good enough to discover most loop invariants. |
| if( !_verify_me && !_verify_only ) |
| _ltree_root->counted_loop( this ); |
| |
| // Find latest loop placement. Find ideal loop placement. |
| visited.Clear(); |
| init_dom_lca_tags(); |
| // Need C->root() on worklist when processing outs |
| worklist.push( C->root() ); |
| NOT_PRODUCT( C->verify_graph_edges(); ) |
| worklist.push( C->top() ); |
| build_loop_late( visited, worklist, nstack ); |
| |
| if (_verify_only) { |
| // restore major progress flag |
| for (int i = 0; i < old_progress; i++) |
| C->set_major_progress(); |
| assert(C->unique() == unique, "verification mode made Nodes? ? ?"); |
| assert(_igvn._worklist.size() == orig_worklist_size, "shouldn't push anything"); |
| return; |
| } |
| |
| // clear out the dead code after build_loop_late |
| while (_deadlist.size()) { |
| _igvn.remove_globally_dead_node(_deadlist.pop()); |
| } |
| |
| if (stop_early) { |
| assert(do_expensive_nodes, "why are we here?"); |
| if (process_expensive_nodes()) { |
| // If we made some progress when processing expensive nodes then |
| // the IGVN may modify the graph in a way that will allow us to |
| // make some more progress: we need to try processing expensive |
| // nodes again. |
| C->set_major_progress(); |
| } |
| _igvn.optimize(); |
| return; |
| } |
| |
| // Some parser-inserted loop predicates could never be used by loop |
| // predication or they were moved away from loop during some optimizations. |
| // For example, peeling. Eliminate them before next loop optimizations. |
| if (UseLoopPredicate) { |
| eliminate_useless_predicates(); |
| } |
| |
| #ifndef PRODUCT |
| C->verify_graph_edges(); |
| if (_verify_me) { // Nested verify pass? |
| // Check to see if the verify mode is broken |
| assert(C->unique() == unique, "non-optimize mode made Nodes? ? ?"); |
| return; |
| } |
| if(VerifyLoopOptimizations) verify(); |
| if(TraceLoopOpts && C->has_loops()) { |
| _ltree_root->dump(); |
| } |
| #endif |
| |
| if (skip_loop_opts) { |
| // restore major progress flag |
| for (int i = 0; i < old_progress; i++) { |
| C->set_major_progress(); |
| } |
| |
| // Cleanup any modified bits |
| _igvn.optimize(); |
| |
| if (C->log() != NULL) { |
| log_loop_tree(_ltree_root, _ltree_root, C->log()); |
| } |
| return; |
| } |
| |
| if (ReassociateInvariants) { |
| // Reassociate invariants and prep for split_thru_phi |
| for (LoopTreeIterator iter(_ltree_root); !iter.done(); iter.next()) { |
| IdealLoopTree* lpt = iter.current(); |
| bool is_counted = lpt->is_counted(); |
| if (!is_counted || !lpt->is_inner()) continue; |
| |
| // check for vectorized loops, any reassociation of invariants was already done |
| if (is_counted && lpt->_head->as_CountedLoop()->do_unroll_only()) continue; |
| |
| lpt->reassociate_invariants(this); |
| |
| // Because RCE opportunities can be masked by split_thru_phi, |
| // look for RCE candidates and inhibit split_thru_phi |
| // on just their loop-phi's for this pass of loop opts |
| if (SplitIfBlocks && do_split_ifs) { |
| if (lpt->policy_range_check(this)) { |
| lpt->_rce_candidate = 1; // = true |
| } |
| } |
| } |
| } |
| |
| // Check for aggressive application of split-if and other transforms |
| // that require basic-block info (like cloning through Phi's) |
| if( SplitIfBlocks && do_split_ifs ) { |
| visited.Clear(); |
| split_if_with_blocks( visited, nstack ); |
| NOT_PRODUCT( if( VerifyLoopOptimizations ) verify(); ); |
| } |
| |
| if (!C->major_progress() && do_expensive_nodes && process_expensive_nodes()) { |
| C->set_major_progress(); |
| } |
| |
| // Perform loop predication before iteration splitting |
| if (C->has_loops() && !C->major_progress() && (C->predicate_count() > 0)) { |
| _ltree_root->_child->loop_predication(this); |
| } |
| |
| if (OptimizeFill && UseLoopPredicate && C->has_loops() && !C->major_progress()) { |
| if (do_intrinsify_fill()) { |
| C->set_major_progress(); |
| } |
| } |
| |
| // Perform iteration-splitting on inner loops. Split iterations to avoid |
| // range checks or one-shot null checks. |
| |
| // If split-if's didn't hack the graph too bad (no CFG changes) |
| // then do loop opts. |
| if (C->has_loops() && !C->major_progress()) { |
| memset( worklist.adr(), 0, worklist.Size()*sizeof(Node*) ); |
| _ltree_root->_child->iteration_split( this, worklist ); |
| // No verify after peeling! GCM has hoisted code out of the loop. |
| // After peeling, the hoisted code could sink inside the peeled area. |
| // The peeling code does not try to recompute the best location for |
| // all the code before the peeled area, so the verify pass will always |
| // complain about it. |
| } |
| // Do verify graph edges in any case |
| NOT_PRODUCT( C->verify_graph_edges(); ); |
| |
| if (!do_split_ifs) { |
| // We saw major progress in Split-If to get here. We forced a |
| // pass with unrolling and not split-if, however more split-if's |
| // might make progress. If the unrolling didn't make progress |
| // then the major-progress flag got cleared and we won't try |
| // another round of Split-If. In particular the ever-common |
| // instance-of/check-cast pattern requires at least 2 rounds of |
| // Split-If to clear out. |
| C->set_major_progress(); |
| } |
| |
| // Repeat loop optimizations if new loops were seen |
| if (created_loop_node()) { |
| C->set_major_progress(); |
| } |
| |
| // Keep loop predicates and perform optimizations with them |
| // until no more loop optimizations could be done. |
| // After that switch predicates off and do more loop optimizations. |
| if (!C->major_progress() && (C->predicate_count() > 0)) { |
| C->cleanup_loop_predicates(_igvn); |
| if (TraceLoopOpts) { |
| tty->print_cr("PredicatesOff"); |
| } |
| C->set_major_progress(); |
| } |
| |
| // Convert scalar to superword operations at the end of all loop opts. |
| if (UseSuperWord && C->has_loops() && !C->major_progress()) { |
| // SuperWord transform |
| SuperWord sw(this); |
| for (LoopTreeIterator iter(_ltree_root); !iter.done(); iter.next()) { |
| IdealLoopTree* lpt = iter.current(); |
| if (lpt->is_counted()) { |
| CountedLoopNode *cl = lpt->_head->as_CountedLoop(); |
| |
| if (PostLoopMultiversioning && cl->is_rce_post_loop() && !cl->is_vectorized_loop()) { |
| // Check that the rce'd post loop is encountered first, multiversion after all |
| // major main loop optimization are concluded |
| if (!C->major_progress()) { |
| IdealLoopTree *lpt_next = lpt->_next; |
| if (lpt_next && lpt_next->is_counted()) { |
| CountedLoopNode *cl = lpt_next->_head->as_CountedLoop(); |
| has_range_checks(lpt_next); |
| if (cl->is_post_loop() && cl->range_checks_present()) { |
| if (!cl->is_multiversioned()) { |
| if (multi_version_post_loops(lpt, lpt_next) == false) { |
| // Cause the rce loop to be optimized away if we fail |
| cl->mark_is_multiversioned(); |
| poison_rce_post_loop(lpt); |
| } |
| } |
| } |
| } |
| } |
| } else if (cl->is_main_loop()) { |
| sw.transform_loop(lpt, true); |
| } |
| } |
| } |
| } |
| |
| // Cleanup any modified bits |
| _igvn.optimize(); |
| |
| // disable assert until issue with split_flow_path is resolved (6742111) |
| // assert(!_has_irreducible_loops || C->parsed_irreducible_loop() || C->is_osr_compilation(), |
| // "shouldn't introduce irreducible loops"); |
| |
| if (C->log() != NULL) { |
| log_loop_tree(_ltree_root, _ltree_root, C->log()); |
| } |
| } |
| |
| #ifndef PRODUCT |
| //------------------------------print_statistics------------------------------- |
| int PhaseIdealLoop::_loop_invokes=0;// Count of PhaseIdealLoop invokes |
| int PhaseIdealLoop::_loop_work=0; // Sum of PhaseIdealLoop x unique |
| void PhaseIdealLoop::print_statistics() { |
| tty->print_cr("PhaseIdealLoop=%d, sum _unique=%d", _loop_invokes, _loop_work); |
| } |
| |
| //------------------------------verify----------------------------------------- |
| // Build a verify-only PhaseIdealLoop, and see that it agrees with me. |
| static int fail; // debug only, so its multi-thread dont care |
| void PhaseIdealLoop::verify() const { |
| int old_progress = C->major_progress(); |
| ResourceMark rm; |
| PhaseIdealLoop loop_verify( _igvn, this ); |
| VectorSet visited(Thread::current()->resource_area()); |
| |
| fail = 0; |
| verify_compare( C->root(), &loop_verify, visited ); |
| assert( fail == 0, "verify loops failed" ); |
| // Verify loop structure is the same |
| _ltree_root->verify_tree(loop_verify._ltree_root, NULL); |
| // Reset major-progress. It was cleared by creating a verify version of |
| // PhaseIdealLoop. |
| for( int i=0; i<old_progress; i++ ) |
| C->set_major_progress(); |
| } |
| |
| //------------------------------verify_compare--------------------------------- |
| // Make sure me and the given PhaseIdealLoop agree on key data structures |
| void PhaseIdealLoop::verify_compare( Node *n, const PhaseIdealLoop *loop_verify, VectorSet &visited ) const { |
| if( !n ) return; |
| if( visited.test_set( n->_idx ) ) return; |
| if( !_nodes[n->_idx] ) { // Unreachable |
| assert( !loop_verify->_nodes[n->_idx], "both should be unreachable" ); |
| return; |
| } |
| |
| uint i; |
| for( i = 0; i < n->req(); i++ ) |
| verify_compare( n->in(i), loop_verify, visited ); |
| |
| // Check the '_nodes' block/loop structure |
| i = n->_idx; |
| if( has_ctrl(n) ) { // We have control; verify has loop or ctrl |
| if( _nodes[i] != loop_verify->_nodes[i] && |
| get_ctrl_no_update(n) != loop_verify->get_ctrl_no_update(n) ) { |
| tty->print("Mismatched control setting for: "); |
| n->dump(); |
| if( fail++ > 10 ) return; |
| Node *c = get_ctrl_no_update(n); |
| tty->print("We have it as: "); |
| if( c->in(0) ) c->dump(); |
| else tty->print_cr("N%d",c->_idx); |
| tty->print("Verify thinks: "); |
| if( loop_verify->has_ctrl(n) ) |
| loop_verify->get_ctrl_no_update(n)->dump(); |
| else |
| loop_verify->get_loop_idx(n)->dump(); |
| tty->cr(); |
| } |
| } else { // We have a loop |
| IdealLoopTree *us = get_loop_idx(n); |
| if( loop_verify->has_ctrl(n) ) { |
| tty->print("Mismatched loop setting for: "); |
| n->dump(); |
| if( fail++ > 10 ) return; |
| tty->print("We have it as: "); |
| us->dump(); |
| tty->print("Verify thinks: "); |
| loop_verify->get_ctrl_no_update(n)->dump(); |
| tty->cr(); |
| } else if (!C->major_progress()) { |
| // Loop selection can be messed up if we did a major progress |
| // operation, like split-if. Do not verify in that case. |
| IdealLoopTree *them = loop_verify->get_loop_idx(n); |
| if( us->_head != them->_head || us->_tail != them->_tail ) { |
| tty->print("Unequals loops for: "); |
| n->dump(); |
| if( fail++ > 10 ) return; |
| tty->print("We have it as: "); |
| us->dump(); |
| tty->print("Verify thinks: "); |
| them->dump(); |
| tty->cr(); |
| } |
| } |
| } |
| |
| // Check for immediate dominators being equal |
| if( i >= _idom_size ) { |
| if( !n->is_CFG() ) return; |
| tty->print("CFG Node with no idom: "); |
| n->dump(); |
| return; |
| } |
| if( !n->is_CFG() ) return; |
| if( n == C->root() ) return; // No IDOM here |
| |
| assert(n->_idx == i, "sanity"); |
| Node *id = idom_no_update(n); |
| if( id != loop_verify->idom_no_update(n) ) { |
| tty->print("Unequals idoms for: "); |
| n->dump(); |
| if( fail++ > 10 ) return; |
| tty->print("We have it as: "); |
| id->dump(); |
| tty->print("Verify thinks: "); |
| loop_verify->idom_no_update(n)->dump(); |
| tty->cr(); |
| } |
| |
| } |
| |
| //------------------------------verify_tree------------------------------------ |
| // Verify that tree structures match. Because the CFG can change, siblings |
| // within the loop tree can be reordered. We attempt to deal with that by |
| // reordering the verify's loop tree if possible. |
| void IdealLoopTree::verify_tree(IdealLoopTree *loop, const IdealLoopTree *parent) const { |
| assert( _parent == parent, "Badly formed loop tree" ); |
| |
| // Siblings not in same order? Attempt to re-order. |
| if( _head != loop->_head ) { |
| // Find _next pointer to update |
| IdealLoopTree **pp = &loop->_parent->_child; |
| while( *pp != loop ) |
| pp = &((*pp)->_next); |
| // Find proper sibling to be next |
| IdealLoopTree **nn = &loop->_next; |
| while( (*nn) && (*nn)->_head != _head ) |
| nn = &((*nn)->_next); |
| |
| // Check for no match. |
| if( !(*nn) ) { |
| // Annoyingly, irreducible loops can pick different headers |
| // after a major_progress operation, so the rest of the loop |
| // tree cannot be matched. |
| if (_irreducible && Compile::current()->major_progress()) return; |
| assert( 0, "failed to match loop tree" ); |
| } |
| |
| // Move (*nn) to (*pp) |
| IdealLoopTree *hit = *nn; |
| *nn = hit->_next; |
| hit->_next = loop; |
| *pp = loop; |
| loop = hit; |
| // Now try again to verify |
| } |
| |
| assert( _head == loop->_head , "mismatched loop head" ); |
| Node *tail = _tail; // Inline a non-updating version of |
| while( !tail->in(0) ) // the 'tail()' call. |
| tail = tail->in(1); |
| assert( tail == loop->_tail, "mismatched loop tail" ); |
| |
| // Counted loops that are guarded should be able to find their guards |
| if( _head->is_CountedLoop() && _head->as_CountedLoop()->is_main_loop() ) { |
| CountedLoopNode *cl = _head->as_CountedLoop(); |
| Node *init = cl->init_trip(); |
| Node *ctrl = cl->in(LoopNode::EntryControl); |
| assert( ctrl->Opcode() == Op_IfTrue || ctrl->Opcode() == Op_IfFalse, "" ); |
| Node *iff = ctrl->in(0); |
| assert( iff->Opcode() == Op_If, "" ); |
| Node *bol = iff->in(1); |
| assert( bol->Opcode() == Op_Bool, "" ); |
| Node *cmp = bol->in(1); |
| assert( cmp->Opcode() == Op_CmpI, "" ); |
| Node *add = cmp->in(1); |
| Node *opaq; |
| if( add->Opcode() == Op_Opaque1 ) { |
| opaq = add; |
| } else { |
| assert( add->Opcode() == Op_AddI || add->Opcode() == Op_ConI , "" ); |
| assert( add == init, "" ); |
| opaq = cmp->in(2); |
| } |
| assert( opaq->Opcode() == Op_Opaque1, "" ); |
| |
| } |
| |
| if (_child != NULL) _child->verify_tree(loop->_child, this); |
| if (_next != NULL) _next ->verify_tree(loop->_next, parent); |
| // Innermost loops need to verify loop bodies, |
| // but only if no 'major_progress' |
| int fail = 0; |
| if (!Compile::current()->major_progress() && _child == NULL) { |
| for( uint i = 0; i < _body.size(); i++ ) { |
| Node *n = _body.at(i); |
| if (n->outcnt() == 0) continue; // Ignore dead |
| uint j; |
| for( j = 0; j < loop->_body.size(); j++ ) |
| if( loop->_body.at(j) == n ) |
| break; |
| if( j == loop->_body.size() ) { // Not found in loop body |
| // Last ditch effort to avoid assertion: Its possible that we |
| // have some users (so outcnt not zero) but are still dead. |
| // Try to find from root. |
| if (Compile::current()->root()->find(n->_idx)) { |
| fail++; |
| tty->print("We have that verify does not: "); |
| n->dump(); |
| } |
| } |
| } |
| for( uint i2 = 0; i2 < loop->_body.size(); i2++ ) { |
| Node *n = loop->_body.at(i2); |
| if (n->outcnt() == 0) continue; // Ignore dead |
| uint j; |
| for( j = 0; j < _body.size(); j++ ) |
| if( _body.at(j) == n ) |
| break; |
| if( j == _body.size() ) { // Not found in loop body |
| // Last ditch effort to avoid assertion: Its possible that we |
| // have some users (so outcnt not zero) but are still dead. |
| // Try to find from root. |
| if (Compile::current()->root()->find(n->_idx)) { |
| fail++; |
| tty->print("Verify has that we do not: "); |
| n->dump(); |
| } |
| } |
| } |
| assert( !fail, "loop body mismatch" ); |
| } |
| } |
| |
| #endif |
| |
| //------------------------------set_idom--------------------------------------- |
| void PhaseIdealLoop::set_idom(Node* d, Node* n, uint dom_depth) { |
| uint idx = d->_idx; |
| if (idx >= _idom_size) { |
| uint newsize = _idom_size<<1; |
| while( idx >= newsize ) { |
| newsize <<= 1; |
| } |
| _idom = REALLOC_RESOURCE_ARRAY( Node*, _idom,_idom_size,newsize); |
| _dom_depth = REALLOC_RESOURCE_ARRAY( uint, _dom_depth,_idom_size,newsize); |
| memset( _dom_depth + _idom_size, 0, (newsize - _idom_size) * sizeof(uint) ); |
| _idom_size = newsize; |
| } |
| _idom[idx] = n; |
| _dom_depth[idx] = dom_depth; |
| } |
| |
| //------------------------------recompute_dom_depth--------------------------------------- |
| // The dominator tree is constructed with only parent pointers. |
| // This recomputes the depth in the tree by first tagging all |
| // nodes as "no depth yet" marker. The next pass then runs up |
| // the dom tree from each node marked "no depth yet", and computes |
| // the depth on the way back down. |
| void PhaseIdealLoop::recompute_dom_depth() { |
| uint no_depth_marker = C->unique(); |
| uint i; |
| // Initialize depth to "no depth yet" |
| for (i = 0; i < _idom_size; i++) { |
| if (_dom_depth[i] > 0 && _idom[i] != NULL) { |
| _dom_depth[i] = no_depth_marker; |
| } |
| } |
| if (_dom_stk == NULL) { |
| uint init_size = C->live_nodes() / 100; // Guess that 1/100 is a reasonable initial size. |
| if (init_size < 10) init_size = 10; |
| _dom_stk = new GrowableArray<uint>(init_size); |
| } |
| // Compute new depth for each node. |
| for (i = 0; i < _idom_size; i++) { |
| uint j = i; |
| // Run up the dom tree to find a node with a depth |
| while (_dom_depth[j] == no_depth_marker) { |
| _dom_stk->push(j); |
| j = _idom[j]->_idx; |
| } |
| // Compute the depth on the way back down this tree branch |
| uint dd = _dom_depth[j] + 1; |
| while (_dom_stk->length() > 0) { |
| uint j = _dom_stk->pop(); |
| _dom_depth[j] = dd; |
| dd++; |
| } |
| } |
| } |
| |
| //------------------------------sort------------------------------------------- |
| // Insert 'loop' into the existing loop tree. 'innermost' is a leaf of the |
| // loop tree, not the root. |
| IdealLoopTree *PhaseIdealLoop::sort( IdealLoopTree *loop, IdealLoopTree *innermost ) { |
| if( !innermost ) return loop; // New innermost loop |
| |
| int loop_preorder = get_preorder(loop->_head); // Cache pre-order number |
| assert( loop_preorder, "not yet post-walked loop" ); |
| IdealLoopTree **pp = &innermost; // Pointer to previous next-pointer |
| IdealLoopTree *l = *pp; // Do I go before or after 'l'? |
| |
| // Insert at start of list |
| while( l ) { // Insertion sort based on pre-order |
| if( l == loop ) return innermost; // Already on list! |
| int l_preorder = get_preorder(l->_head); // Cache pre-order number |
| assert( l_preorder, "not yet post-walked l" ); |
| // Check header pre-order number to figure proper nesting |
| if( loop_preorder > l_preorder ) |
| break; // End of insertion |
| // If headers tie (e.g., shared headers) check tail pre-order numbers. |
| // Since I split shared headers, you'd think this could not happen. |
| // BUT: I must first do the preorder numbering before I can discover I |
| // have shared headers, so the split headers all get the same preorder |
| // number as the RegionNode they split from. |
| if( loop_preorder == l_preorder && |
| get_preorder(loop->_tail) < get_preorder(l->_tail) ) |
| break; // Also check for shared headers (same pre#) |
| pp = &l->_parent; // Chain up list |
| l = *pp; |
| } |
| // Link into list |
| // Point predecessor to me |
| *pp = loop; |
| // Point me to successor |
| IdealLoopTree *p = loop->_parent; |
| loop->_parent = l; // Point me to successor |
| if( p ) sort( p, innermost ); // Insert my parents into list as well |
| return innermost; |
| } |
| |
| //------------------------------build_loop_tree-------------------------------- |
| // I use a modified Vick/Tarjan algorithm. I need pre- and a post- visit |
| // bits. The _nodes[] array is mapped by Node index and holds a NULL for |
| // not-yet-pre-walked, pre-order # for pre-but-not-post-walked and holds the |
| // tightest enclosing IdealLoopTree for post-walked. |
| // |
| // During my forward walk I do a short 1-layer lookahead to see if I can find |
| // a loop backedge with that doesn't have any work on the backedge. This |
| // helps me construct nested loops with shared headers better. |
| // |
| // Once I've done the forward recursion, I do the post-work. For each child |
| // I check to see if there is a backedge. Backedges define a loop! I |
| // insert an IdealLoopTree at the target of the backedge. |
| // |
| // During the post-work I also check to see if I have several children |
| // belonging to different loops. If so, then this Node is a decision point |
| // where control flow can choose to change loop nests. It is at this |
| // decision point where I can figure out how loops are nested. At this |
| // time I can properly order the different loop nests from my children. |
| // Note that there may not be any backedges at the decision point! |
| // |
| // Since the decision point can be far removed from the backedges, I can't |
| // order my loops at the time I discover them. Thus at the decision point |
| // I need to inspect loop header pre-order numbers to properly nest my |
| // loops. This means I need to sort my childrens' loops by pre-order. |
| // The sort is of size number-of-control-children, which generally limits |
| // it to size 2 (i.e., I just choose between my 2 target loops). |
| void PhaseIdealLoop::build_loop_tree() { |
| // Allocate stack of size C->live_nodes()/2 to avoid frequent realloc |
| GrowableArray <Node *> bltstack(C->live_nodes() >> 1); |
| Node *n = C->root(); |
| bltstack.push(n); |
| int pre_order = 1; |
| int stack_size; |
| |
| while ( ( stack_size = bltstack.length() ) != 0 ) { |
| n = bltstack.top(); // Leave node on stack |
| if ( !is_visited(n) ) { |
| // ---- Pre-pass Work ---- |
| // Pre-walked but not post-walked nodes need a pre_order number. |
| |
| set_preorder_visited( n, pre_order ); // set as visited |
| |
| // ---- Scan over children ---- |
| // Scan first over control projections that lead to loop headers. |
| // This helps us find inner-to-outer loops with shared headers better. |
| |
| // Scan children's children for loop headers. |
| for ( int i = n->outcnt() - 1; i >= 0; --i ) { |
| Node* m = n->raw_out(i); // Child |
| if( m->is_CFG() && !is_visited(m) ) { // Only for CFG children |
| // Scan over children's children to find loop |
| for (DUIterator_Fast jmax, j = m->fast_outs(jmax); j < jmax; j++) { |
| Node* l = m->fast_out(j); |
| if( is_visited(l) && // Been visited? |
| !is_postvisited(l) && // But not post-visited |
| get_preorder(l) < pre_order ) { // And smaller pre-order |
| // Found! Scan the DFS down this path before doing other paths |
| bltstack.push(m); |
| break; |
| } |
| } |
| } |
| } |
| pre_order++; |
| } |
| else if ( !is_postvisited(n) ) { |
| // Note: build_loop_tree_impl() adds out edges on rare occasions, |
| // such as com.sun.rsasign.am::a. |
| // For non-recursive version, first, process current children. |
| // On next iteration, check if additional children were added. |
| for ( int k = n->outcnt() - 1; k >= 0; --k ) { |
| Node* u = n->raw_out(k); |
| if ( u->is_CFG() && !is_visited(u) ) { |
| bltstack.push(u); |
| } |
| } |
| if ( bltstack.length() == stack_size ) { |
| // There were no additional children, post visit node now |
| (void)bltstack.pop(); // Remove node from stack |
| pre_order = build_loop_tree_impl( n, pre_order ); |
| // Check for bailout |
| if (C->failing()) { |
| return; |
| } |
| // Check to grow _preorders[] array for the case when |
| // build_loop_tree_impl() adds new nodes. |
| check_grow_preorders(); |
| } |
| } |
| else { |
| (void)bltstack.pop(); // Remove post-visited node from stack |
| } |
| } |
| } |
| |
| //------------------------------build_loop_tree_impl--------------------------- |
| int PhaseIdealLoop::build_loop_tree_impl( Node *n, int pre_order ) { |
| // ---- Post-pass Work ---- |
| // Pre-walked but not post-walked nodes need a pre_order number. |
| |
| // Tightest enclosing loop for this Node |
| IdealLoopTree *innermost = NULL; |
| |
| // For all children, see if any edge is a backedge. If so, make a loop |
| // for it. Then find the tightest enclosing loop for the self Node. |
| for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { |
| Node* m = n->fast_out(i); // Child |
| if( n == m ) continue; // Ignore control self-cycles |
| if( !m->is_CFG() ) continue;// Ignore non-CFG edges |
| |
| IdealLoopTree *l; // Child's loop |
| if( !is_postvisited(m) ) { // Child visited but not post-visited? |
| // Found a backedge |
| assert( get_preorder(m) < pre_order, "should be backedge" ); |
| // Check for the RootNode, which is already a LoopNode and is allowed |
| // to have multiple "backedges". |
| if( m == C->root()) { // Found the root? |
| l = _ltree_root; // Root is the outermost LoopNode |
| } else { // Else found a nested loop |
| // Insert a LoopNode to mark this loop. |
| l = new IdealLoopTree(this, m, n); |
| } // End of Else found a nested loop |
| if( !has_loop(m) ) // If 'm' does not already have a loop set |
| set_loop(m, l); // Set loop header to loop now |
| |
| } else { // Else not a nested loop |
| if( !_nodes[m->_idx] ) continue; // Dead code has no loop |
| l = get_loop(m); // Get previously determined loop |
| // If successor is header of a loop (nest), move up-loop till it |
| // is a member of some outer enclosing loop. Since there are no |
| // shared headers (I've split them already) I only need to go up |
| // at most 1 level. |
| while( l && l->_head == m ) // Successor heads loop? |
| l = l->_parent; // Move up 1 for me |
| // If this loop is not properly parented, then this loop |
| // has no exit path out, i.e. its an infinite loop. |
| if( !l ) { |
| // Make loop "reachable" from root so the CFG is reachable. Basically |
| // insert a bogus loop exit that is never taken. 'm', the loop head, |
| // points to 'n', one (of possibly many) fall-in paths. There may be |
| // many backedges as well. |
| |
| // Here I set the loop to be the root loop. I could have, after |
| // inserting a bogus loop exit, restarted the recursion and found my |
| // new loop exit. This would make the infinite loop a first-class |
| // loop and it would then get properly optimized. What's the use of |
| // optimizing an infinite loop? |
| l = _ltree_root; // Oops, found infinite loop |
| |
| if (!_verify_only) { |
| // Insert the NeverBranch between 'm' and it's control user. |
| NeverBranchNode *iff = new NeverBranchNode( m ); |
| _igvn.register_new_node_with_optimizer(iff); |
| set_loop(iff, l); |
| Node *if_t = new CProjNode( iff, 0 ); |
| _igvn.register_new_node_with_optimizer(if_t); |
| set_loop(if_t, l); |
| |
| Node* cfg = NULL; // Find the One True Control User of m |
| for (DUIterator_Fast jmax, j = m->fast_outs(jmax); j < jmax; j++) { |
| Node* x = m->fast_out(j); |
| if (x->is_CFG() && x != m && x != iff) |
| { cfg = x; break; } |
| } |
| assert(cfg != NULL, "must find the control user of m"); |
| uint k = 0; // Probably cfg->in(0) |
| while( cfg->in(k) != m ) k++; // But check incase cfg is a Region |
| cfg->set_req( k, if_t ); // Now point to NeverBranch |
| _igvn._worklist.push(cfg); |
| |
| // Now create the never-taken loop exit |
| Node *if_f = new CProjNode( iff, 1 ); |
| _igvn.register_new_node_with_optimizer(if_f); |
| set_loop(if_f, l); |
| // Find frame ptr for Halt. Relies on the optimizer |
| // V-N'ing. Easier and quicker than searching through |
| // the program structure. |
| Node *frame = new ParmNode( C->start(), TypeFunc::FramePtr ); |
| _igvn.register_new_node_with_optimizer(frame); |
| // Halt & Catch Fire |
| Node *halt = new HaltNode( if_f, frame ); |
| _igvn.register_new_node_with_optimizer(halt); |
| set_loop(halt, l); |
| C->root()->add_req(halt); |
| } |
| set_loop(C->root(), _ltree_root); |
| } |
| } |
| // Weeny check for irreducible. This child was already visited (this |
| // IS the post-work phase). Is this child's loop header post-visited |
| // as well? If so, then I found another entry into the loop. |
| if (!_verify_only) { |
| while( is_postvisited(l->_head) ) { |
| // found irreducible |
| l->_irreducible = 1; // = true |
| l = l->_parent; |
| _has_irreducible_loops = true; |
| // Check for bad CFG here to prevent crash, and bailout of compile |
| if (l == NULL) { |
| C->record_method_not_compilable("unhandled CFG detected during loop optimization"); |
| return pre_order; |
| } |
| } |
| C->set_has_irreducible_loop(_has_irreducible_loops); |
| } |
| |
| // This Node might be a decision point for loops. It is only if |
| // it's children belong to several different loops. The sort call |
| // does a trivial amount of work if there is only 1 child or all |
| // children belong to the same loop. If however, the children |
| // belong to different loops, the sort call will properly set the |
| // _parent pointers to show how the loops nest. |
| // |
| // In any case, it returns the tightest enclosing loop. |
| innermost = sort( l, innermost ); |
| } |
| |
| // Def-use info will have some dead stuff; dead stuff will have no |
| // loop decided on. |
| |
| // Am I a loop header? If so fix up my parent's child and next ptrs. |
| if( innermost && innermost->_head == n ) { |
| assert( get_loop(n) == innermost, "" ); |
| IdealLoopTree *p = innermost->_parent; |
| IdealLoopTree *l = innermost; |
| while( p && l->_head == n ) { |
| l->_next = p->_child; // Put self on parents 'next child' |
| p->_child = l; // Make self as first child of parent |
| l = p; // Now walk up the parent chain |
| p = l->_parent; |
| } |
| } else { |
| // Note that it is possible for a LoopNode to reach here, if the |
| // backedge has been made unreachable (hence the LoopNode no longer |
| // denotes a Loop, and will eventually be removed). |
| |
| // Record tightest enclosing loop for self. Mark as post-visited. |
| set_loop(n, innermost); |
| // Also record has_call flag early on |
| if( innermost ) { |
| if( n->is_Call() && !n->is_CallLeaf() && !n->is_macro() ) { |
| // Do not count uncommon calls |
| if( !n->is_CallStaticJava() || !n->as_CallStaticJava()->_name ) { |
| Node *iff = n->in(0)->in(0); |
| // No any calls for vectorized loops. |
| if( UseSuperWord || !iff->is_If() || |
| (n->in(0)->Opcode() == Op_IfFalse && |
| (1.0 - iff->as_If()->_prob) >= 0.01) || |
| (iff->as_If()->_prob >= 0.01) ) |
| innermost->_has_call = 1; |
| } |
| } else if( n->is_Allocate() && n->as_Allocate()->_is_scalar_replaceable ) { |
| // Disable loop optimizations if the loop has a scalar replaceable |
| // allocation. This disabling may cause a potential performance lost |
| // if the allocation is not eliminated for some reason. |
| innermost->_allow_optimizations = false; |
| innermost->_has_call = 1; // = true |
| } else if (n->Opcode() == Op_SafePoint) { |
| // Record all safepoints in this loop. |
| if (innermost->_safepts == NULL) innermost->_safepts = new Node_List(); |
| innermost->_safepts->push(n); |
| } |
| } |
| } |
| |
| // Flag as post-visited now |
| set_postvisited(n); |
| return pre_order; |
| } |
| |
| |
| //------------------------------build_loop_early------------------------------- |
| // Put Data nodes into some loop nest, by setting the _nodes[]->loop mapping. |
| // First pass computes the earliest controlling node possible. This is the |
| // controlling input with the deepest dominating depth. |
| void PhaseIdealLoop::build_loop_early( VectorSet &visited, Node_List &worklist, Node_Stack &nstack ) { |
| while (worklist.size() != 0) { |
| // Use local variables nstack_top_n & nstack_top_i to cache values |
| // on nstack's top. |
| Node *nstack_top_n = worklist.pop(); |
| uint nstack_top_i = 0; |
| //while_nstack_nonempty: |
| while (true) { |
| // Get parent node and next input's index from stack's top. |
| Node *n = nstack_top_n; |
| uint i = nstack_top_i; |
| uint cnt = n->req(); // Count of inputs |
| if (i == 0) { // Pre-process the node. |
| if( has_node(n) && // Have either loop or control already? |
| !has_ctrl(n) ) { // Have loop picked out already? |
| // During "merge_many_backedges" we fold up several nested loops |
| // into a single loop. This makes the members of the original |
| // loop bodies pointing to dead loops; they need to move up |
| // to the new UNION'd larger loop. I set the _head field of these |
| // dead loops to NULL and the _parent field points to the owning |
| // loop. Shades of UNION-FIND algorithm. |
| IdealLoopTree *ilt; |
| while( !(ilt = get_loop(n))->_head ) { |
| // Normally I would use a set_loop here. But in this one special |
| // case, it is legal (and expected) to change what loop a Node |
| // belongs to. |
| _nodes.map(n->_idx, (Node*)(ilt->_parent) ); |
| } |
| // Remove safepoints ONLY if I've already seen I don't need one. |
| // (the old code here would yank a 2nd safepoint after seeing a |
| // first one, even though the 1st did not dominate in the loop body |
| // and thus could be avoided indefinitely) |
| if( !_verify_only && !_verify_me && ilt->_has_sfpt && n->Opcode() == Op_SafePoint && |
| is_deleteable_safept(n)) { |
| Node *in = n->in(TypeFunc::Control); |
| lazy_replace(n,in); // Pull safepoint now |
| if (ilt->_safepts != NULL) { |
| ilt->_safepts->yank(n); |
| } |
| // Carry on with the recursion "as if" we are walking |
| // only the control input |
| if( !visited.test_set( in->_idx ) ) { |
| worklist.push(in); // Visit this guy later, using worklist |
| } |
| // Get next node from nstack: |
| // - skip n's inputs processing by setting i > cnt; |
| // - we also will not call set_early_ctrl(n) since |
| // has_node(n) == true (see the condition above). |
| i = cnt + 1; |
| } |
| } |
| } // if (i == 0) |
| |
| // Visit all inputs |
| bool done = true; // Assume all n's inputs will be processed |
| while (i < cnt) { |
| Node *in = n->in(i); |
| ++i; |
| if (in == NULL) continue; |
| if (in->pinned() && !in->is_CFG()) |
| set_ctrl(in, in->in(0)); |
| int is_visited = visited.test_set( in->_idx ); |
| if (!has_node(in)) { // No controlling input yet? |
| assert( !in->is_CFG(), "CFG Node with no controlling input?" ); |
| assert( !is_visited, "visit only once" ); |
| nstack.push(n, i); // Save parent node and next input's index. |
| nstack_top_n = in; // Process current input now. |
| nstack_top_i = 0; |
| done = false; // Not all n's inputs processed. |
| break; // continue while_nstack_nonempty; |
| } else if (!is_visited) { |
| // This guy has a location picked out for him, but has not yet |
| // been visited. Happens to all CFG nodes, for instance. |
| // Visit him using the worklist instead of recursion, to break |
| // cycles. Since he has a location already we do not need to |
| // find his location before proceeding with the current Node. |
| worklist.push(in); // Visit this guy later, using worklist |
| } |
| } |
| if (done) { |
| // All of n's inputs have been processed, complete post-processing. |
| |
| // Compute earliest point this Node can go. |
| // CFG, Phi, pinned nodes already know their controlling input. |
| if (!has_node(n)) { |
| // Record earliest legal location |
| set_early_ctrl( n ); |
| } |
| if (nstack.is_empty()) { |
| // Finished all nodes on stack. |
| // Process next node on the worklist. |
| break; |
| } |
| // Get saved parent node and next input's index. |
| nstack_top_n = nstack.node(); |
| nstack_top_i = nstack.index(); |
| nstack.pop(); |
| } |
| } // while (true) |
| } |
| } |
| |
| //------------------------------dom_lca_internal-------------------------------- |
| // Pair-wise LCA |
| Node *PhaseIdealLoop::dom_lca_internal( Node *n1, Node *n2 ) const { |
| if( !n1 ) return n2; // Handle NULL original LCA |
| assert( n1->is_CFG(), "" ); |
| assert( n2->is_CFG(), "" ); |
| // find LCA of all uses |
| uint d1 = dom_depth(n1); |
| uint d2 = dom_depth(n2); |
| while (n1 != n2) { |
| if (d1 > d2) { |
| n1 = idom(n1); |
| d1 = dom_depth(n1); |
| } else if (d1 < d2) { |
| n2 = idom(n2); |
| d2 = dom_depth(n2); |
| } else { |
| // Here d1 == d2. Due to edits of the dominator-tree, sections |
| // of the tree might have the same depth. These sections have |
| // to be searched more carefully. |
| |
| // Scan up all the n1's with equal depth, looking for n2. |
| Node *t1 = idom(n1); |
| while (dom_depth(t1) == d1) { |
| if (t1 == n2) return n2; |
| t1 = idom(t1); |
| } |
| // Scan up all the n2's with equal depth, looking for n1. |
| Node *t2 = idom(n2); |
| while (dom_depth(t2) == d2) { |
| if (t2 == n1) return n1; |
| t2 = idom(t2); |
| } |
| // Move up to a new dominator-depth value as well as up the dom-tree. |
| n1 = t1; |
| n2 = t2; |
| d1 = dom_depth(n1); |
| d2 = dom_depth(n2); |
| } |
| } |
| return n1; |
| } |
| |
| //------------------------------compute_idom----------------------------------- |
| // Locally compute IDOM using dom_lca call. Correct only if the incoming |
| // IDOMs are correct. |
| Node *PhaseIdealLoop::compute_idom( Node *region ) const { |
| assert( region->is_Region(), "" ); |
| Node *LCA = NULL; |
| for( uint i = 1; i < region->req(); i++ ) { |
| if( region->in(i) != C->top() ) |
| LCA = dom_lca( LCA, region->in(i) ); |
| } |
| return LCA; |
| } |
| |
| bool PhaseIdealLoop::verify_dominance(Node* n, Node* use, Node* LCA, Node* early) { |
| bool had_error = false; |
| #ifdef ASSERT |
| if (early != C->root()) { |
| // Make sure that there's a dominance path from LCA to early |
| Node* d = LCA; |
| while (d != early) { |
| if (d == C->root()) { |
| dump_bad_graph("Bad graph detected in compute_lca_of_uses", n, early, LCA); |
| tty->print_cr("*** Use %d isn't dominated by def %d ***", use->_idx, n->_idx); |
| had_error = true; |
| break; |
| } |
| d = idom(d); |
| } |
| } |
| #endif |
| return had_error; |
| } |
| |
| |
| Node* PhaseIdealLoop::compute_lca_of_uses(Node* n, Node* early, bool verify) { |
| // Compute LCA over list of uses |
| bool had_error = false; |
| Node *LCA = NULL; |
| for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax && LCA != early; i++) { |
| Node* c = n->fast_out(i); |
| if (_nodes[c->_idx] == NULL) |
| continue; // Skip the occasional dead node |
| if( c->is_Phi() ) { // For Phis, we must land above on the path |
| for( uint j=1; j<c->req(); j++ ) {// For all inputs |
| if( c->in(j) == n ) { // Found matching input? |
| Node *use = c->in(0)->in(j); |
| if (_verify_only && use->is_top()) continue; |
| LCA = dom_lca_for_get_late_ctrl( LCA, use, n ); |
| if (verify) had_error = verify_dominance(n, use, LCA, early) || had_error; |
| } |
| } |
| } else { |
| // For CFG data-users, use is in the block just prior |
| Node *use = has_ctrl(c) ? get_ctrl(c) : c->in(0); |
| LCA = dom_lca_for_get_late_ctrl( LCA, use, n ); |
| if (verify) had_error = verify_dominance(n, use, LCA, early) || had_error; |
| } |
| } |
| assert(!had_error, "bad dominance"); |
| return LCA; |
| } |
| |
| // Check the shape of the graph at the loop entry. In some cases, |
| // the shape of the graph does not match the shape outlined below. |
| // That is caused by the Opaque1 node "protecting" the shape of |
| // the graph being removed by, for example, the IGVN performed |
| // in PhaseIdealLoop::build_and_optimize(). |
| // |
| // After the Opaque1 node has been removed, optimizations (e.g., split-if, |
| // loop unswitching, and IGVN, or a combination of them) can freely change |
| // the graph's shape. As a result, the graph shape outlined below cannot |
| // be guaranteed anymore. |
| bool PhaseIdealLoop::is_canonical_loop_entry(CountedLoopNode* cl) { |
| if (!cl->is_main_loop() && !cl->is_post_loop()) { |
| return false; |
| } |
| Node* ctrl = cl->in(LoopNode::EntryControl); |
| if (ctrl == NULL || (!ctrl->is_IfTrue() && !ctrl->is_IfFalse())) { |
| return false; |
| } |
| Node* iffm = ctrl->in(0); |
| if (iffm == NULL || !iffm->is_If()) { |
| return false; |
| } |
| Node* bolzm = iffm->in(1); |
| if (bolzm == NULL || !bolzm->is_Bool()) { |
| return false; |
| } |
| Node* cmpzm = bolzm->in(1); |
| if (cmpzm == NULL || !cmpzm->is_Cmp()) { |
| return false; |
| } |
| // compares can get conditionally flipped |
| bool found_opaque = false; |
| for (uint i = 1; i < cmpzm->req(); i++) { |
| Node* opnd = cmpzm->in(i); |
| if (opnd && opnd->Opcode() == Op_Opaque1) { |
| found_opaque = true; |
| break; |
| } |
| } |
| if (!found_opaque) { |
| return false; |
| } |
| return true; |
| } |
| |
| //------------------------------get_late_ctrl---------------------------------- |
| // Compute latest legal control. |
| Node *PhaseIdealLoop::get_late_ctrl( Node *n, Node *early ) { |
| assert(early != NULL, "early control should not be NULL"); |
| |
| Node* LCA = compute_lca_of_uses(n, early); |
| #ifdef ASSERT |
| if (LCA == C->root() && LCA != early) { |
| // def doesn't dominate uses so print some useful debugging output |
| compute_lca_of_uses(n, early, true); |
| } |
| #endif |
| |
| // if this is a load, check for anti-dependent stores |
| // We use a conservative algorithm to identify potential interfering |
| // instructions and for rescheduling the load. The users of the memory |
| // input of this load are examined. Any use which is not a load and is |
| // dominated by early is considered a potentially interfering store. |
| // This can produce false positives. |
| if (n->is_Load() && LCA != early) { |
| Node_List worklist; |
| |
| Node *mem = n->in(MemNode::Memory); |
| for (DUIterator_Fast imax, i = mem->fast_outs(imax); i < imax; i++) { |
| Node* s = mem->fast_out(i); |
| worklist.push(s); |
| } |
| while(worklist.size() != 0 && LCA != early) { |
| Node* s = worklist.pop(); |
| if (s->is_Load()) { |
| continue; |
| } else if (s->is_MergeMem()) { |
| for (DUIterator_Fast imax, i = s->fast_outs(imax); i < imax; i++) { |
| Node* s1 = s->fast_out(i); |
| worklist.push(s1); |
| } |
| } else { |
| Node *sctrl = has_ctrl(s) ? get_ctrl(s) : s->in(0); |
| assert(sctrl != NULL || s->outcnt() == 0, "must have control"); |
| if (sctrl != NULL && !sctrl->is_top() && is_dominator(early, sctrl)) { |
| LCA = dom_lca_for_get_late_ctrl(LCA, sctrl, n); |
| } |
| } |
| } |
| } |
| |
| assert(LCA == find_non_split_ctrl(LCA), "unexpected late control"); |
| return LCA; |
| } |
| |
| // true if CFG node d dominates CFG node n |
| bool PhaseIdealLoop::is_dominator(Node *d, Node *n) { |
| if (d == n) |
| return true; |
| assert(d->is_CFG() && n->is_CFG(), "must have CFG nodes"); |
| uint dd = dom_depth(d); |
| while (dom_depth(n) >= dd) { |
| if (n == d) |
| return true; |
| n = idom(n); |
| } |
| return false; |
| } |
| |
| //------------------------------dom_lca_for_get_late_ctrl_internal------------- |
| // Pair-wise LCA with tags. |
| // Tag each index with the node 'tag' currently being processed |
| // before advancing up the dominator chain using idom(). |
| // Later calls that find a match to 'tag' know that this path has already |
| // been considered in the current LCA (which is input 'n1' by convention). |
| // Since get_late_ctrl() is only called once for each node, the tag array |
| // does not need to be cleared between calls to get_late_ctrl(). |
| // Algorithm trades a larger constant factor for better asymptotic behavior |
| // |
| Node *PhaseIdealLoop::dom_lca_for_get_late_ctrl_internal( Node *n1, Node *n2, Node *tag ) { |
| uint d1 = dom_depth(n1); |
| uint d2 = dom_depth(n2); |
| |
| do { |
| if (d1 > d2) { |
| // current lca is deeper than n2 |
| _dom_lca_tags.map(n1->_idx, tag); |
| n1 = idom(n1); |
| d1 = dom_depth(n1); |
| } else if (d1 < d2) { |
| // n2 is deeper than current lca |
| Node *memo = _dom_lca_tags[n2->_idx]; |
| if( memo == tag ) { |
| return n1; // Return the current LCA |
| } |
| _dom_lca_tags.map(n2->_idx, tag); |
| n2 = idom(n2); |
| d2 = dom_depth(n2); |
| } else { |
| // Here d1 == d2. Due to edits of the dominator-tree, sections |
| // of the tree might have the same depth. These sections have |
| // to be searched more carefully. |
| |
| // Scan up all the n1's with equal depth, looking for n2. |
| _dom_lca_tags.map(n1->_idx, tag); |
| Node *t1 = idom(n1); |
| while (dom_depth(t1) == d1) { |
| if (t1 == n2) return n2; |
| _dom_lca_tags.map(t1->_idx, tag); |
| t1 = idom(t1); |
| } |
| // Scan up all the n2's with equal depth, looking for n1. |
| _dom_lca_tags.map(n2->_idx, tag); |
| Node *t2 = idom(n2); |
| while (dom_depth(t2) == d2) { |
| if (t2 == n1) return n1; |
| _dom_lca_tags.map(t2->_idx, tag); |
| t2 = idom(t2); |
| } |
| // Move up to a new dominator-depth value as well as up the dom-tree. |
| n1 = t1; |
| n2 = t2; |
| d1 = dom_depth(n1); |
| d2 = dom_depth(n2); |
| } |
| } while (n1 != n2); |
| return n1; |
| } |
| |
| //------------------------------init_dom_lca_tags------------------------------ |
| // Tag could be a node's integer index, 32bits instead of 64bits in some cases |
| // Intended use does not involve any growth for the array, so it could |
| // be of fixed size. |
| void PhaseIdealLoop::init_dom_lca_tags() { |
| uint limit = C->unique() + 1; |
| _dom_lca_tags.map( limit, NULL ); |
| #ifdef ASSERT |
| for( uint i = 0; i < limit; ++i ) { |
| assert(_dom_lca_tags[i] == NULL, "Must be distinct from each node pointer"); |
| } |
| #endif // ASSERT |
| } |
| |
| //------------------------------clear_dom_lca_tags------------------------------ |
| // Tag could be a node's integer index, 32bits instead of 64bits in some cases |
| // Intended use does not involve any growth for the array, so it could |
| // be of fixed size. |
| void PhaseIdealLoop::clear_dom_lca_tags() { |
| uint limit = C->unique() + 1; |
| _dom_lca_tags.map( limit, NULL ); |
| _dom_lca_tags.clear(); |
| #ifdef ASSERT |
| for( uint i = 0; i < limit; ++i ) { |
| assert(_dom_lca_tags[i] == NULL, "Must be distinct from each node pointer"); |
| } |
| #endif // ASSERT |
| } |
| |
| //------------------------------build_loop_late-------------------------------- |
| // Put Data nodes into some loop nest, by setting the _nodes[]->loop mapping. |
| // Second pass finds latest legal placement, and ideal loop placement. |
| void PhaseIdealLoop::build_loop_late( VectorSet &visited, Node_List &worklist, Node_Stack &nstack ) { |
| while (worklist.size() != 0) { |
| Node *n = worklist.pop(); |
| // Only visit once |
| if (visited.test_set(n->_idx)) continue; |
| uint cnt = n->outcnt(); |
| uint i = 0; |
| while (true) { |
| assert( _nodes[n->_idx], "no dead nodes" ); |
| // Visit all children |
| if (i < cnt) { |
| Node* use = n->raw_out(i); |
| ++i; |
| // Check for dead uses. Aggressively prune such junk. It might be |
| // dead in the global sense, but still have local uses so I cannot |
| // easily call 'remove_dead_node'. |
| if( _nodes[use->_idx] != NULL || use->is_top() ) { // Not dead? |
| // Due to cycles, we might not hit the same fixed point in the verify |
| // pass as we do in the regular pass. Instead, visit such phis as |
| // simple uses of the loop head. |
| if( use->in(0) && (use->is_CFG() || use->is_Phi()) ) { |
| if( !visited.test(use->_idx) ) |
| worklist.push(use); |
| } else if( !visited.test_set(use->_idx) ) { |
| nstack.push(n, i); // Save parent and next use's index. |
| n = use; // Process all children of current use. |
| cnt = use->outcnt(); |
| i = 0; |
| } |
| } else { |
| // Do not visit around the backedge of loops via data edges. |
| // push dead code onto a worklist |
| _deadlist.push(use); |
| } |
| } else { |
| // All of n's children have been processed, complete post-processing. |
| build_loop_late_post(n); |
| if (nstack.is_empty()) { |
| // Finished all nodes on stack. |
| // Process next node on the worklist. |
| break; |
| } |
| // Get saved parent node and next use's index. Visit the rest of uses. |
| n = nstack.node(); |
| cnt = n->outcnt(); |
| i = nstack.index(); |
| nstack.pop(); |
| } |
| } |
| } |
| } |
| |
| //------------------------------build_loop_late_post--------------------------- |
| // Put Data nodes into some loop nest, by setting the _nodes[]->loop mapping. |
| // Second pass finds latest legal placement, and ideal loop placement. |
| void PhaseIdealLoop::build_loop_late_post( Node *n ) { |
| |
| if (n->req() == 2 && (n->Opcode() == Op_ConvI2L || n->Opcode() == Op_CastII) && !C->major_progress() && !_verify_only) { |
| _igvn._worklist.push(n); // Maybe we'll normalize it, if no more loops. |
| } |
| |
| #ifdef ASSERT |
| if (_verify_only && !n->is_CFG()) { |
| // Check def-use domination. |
| compute_lca_of_uses(n, get_ctrl(n), true /* verify */); |
| } |
| #endif |
| |
| // CFG and pinned nodes already handled |
| if( n->in(0) ) { |
| if( n->in(0)->is_top() ) return; // Dead? |
| |
| // We'd like +VerifyLoopOptimizations to not believe that Mod's/Loads |
| // _must_ be pinned (they have to observe their control edge of course). |
| // Unlike Stores (which modify an unallocable resource, the memory |
| // state), Mods/Loads can float around. So free them up. |
| bool pinned = true; |
| switch( n->Opcode() ) { |
| case Op_DivI: |
| case Op_DivF: |
| case Op_DivD: |
| case Op_ModI: |
| case Op_ModF: |
| case Op_ModD: |
| case Op_LoadB: // Same with Loads; they can sink |
| case Op_LoadUB: // during loop optimizations. |
| case Op_LoadUS: |
| case Op_LoadD: |
| case Op_LoadF: |
| case Op_LoadI: |
| case Op_LoadKlass: |
| case Op_LoadNKlass: |
| case Op_LoadL: |
| case Op_LoadS: |
| case Op_LoadP: |
| case Op_LoadN: |
| case Op_LoadRange: |
| case Op_LoadD_unaligned: |
| case Op_LoadL_unaligned: |
| case Op_StrComp: // Does a bunch of load-like effects |
| case Op_StrEquals: |
| case Op_StrIndexOf: |
| case Op_StrIndexOfChar: |
| case Op_AryEq: |
| case Op_HasNegatives: |
| pinned = false; |
| } |
| if( pinned ) { |
| IdealLoopTree *chosen_loop = get_loop(n->is_CFG() ? n : get_ctrl(n)); |
| if( !chosen_loop->_child ) // Inner loop? |
| chosen_loop->_body.push(n); // Collect inner loops |
| return; |
| } |
| } else { // No slot zero |
| if( n->is_CFG() ) { // CFG with no slot 0 is dead |
| _nodes.map(n->_idx,0); // No block setting, it's globally dead |
| return; |
| } |
| assert(!n->is_CFG() || n->outcnt() == 0, ""); |
| } |
| |
| // Do I have a "safe range" I can select over? |
| Node *early = get_ctrl(n);// Early location already computed |
| |
| // Compute latest point this Node can go |
| Node *LCA = get_late_ctrl( n, early ); |
| // LCA is NULL due to uses being dead |
| if( LCA == NULL ) { |
| #ifdef ASSERT |
| for (DUIterator i1 = n->outs(); n->has_out(i1); i1++) { |
| assert( _nodes[n->out(i1)->_idx] == NULL, "all uses must also be dead"); |
| } |
| #endif |
| _nodes.map(n->_idx, 0); // This node is useless |
| _deadlist.push(n); |
| return; |
| } |
| assert(LCA != NULL && !LCA->is_top(), "no dead nodes"); |
| |
| Node *legal = LCA; // Walk 'legal' up the IDOM chain |
| Node *least = legal; // Best legal position so far |
| while( early != legal ) { // While not at earliest legal |
| #ifdef ASSERT |
| if (legal->is_Start() && !early->is_Root()) { |
| // Bad graph. Print idom path and fail. |
| dump_bad_graph("Bad graph detected in build_loop_late", n, early, LCA); |
| assert(false, "Bad graph detected in build_loop_late"); |
| } |
| #endif |
| // Find least loop nesting depth |
| legal = idom(legal); // Bump up the IDOM tree |
| // Check for lower nesting depth |
| if( get_loop(legal)->_nest < get_loop(least)->_nest ) |
| least = legal; |
| } |
| assert(early == legal || legal != C->root(), "bad dominance of inputs"); |
| |
| // Try not to place code on a loop entry projection |
| // which can inhibit range check elimination. |
| if (least != early) { |
| Node* ctrl_out = least->unique_ctrl_out(); |
| if (ctrl_out && ctrl_out->is_CountedLoop() && |
| least == ctrl_out->in(LoopNode::EntryControl)) { |
| Node* least_dom = idom(least); |
| if (get_loop(least_dom)->is_member(get_loop(least))) { |
| least = least_dom; |
| } |
| } |
| } |
| |
| #ifdef ASSERT |
| // If verifying, verify that 'verify_me' has a legal location |
| // and choose it as our location. |
| if( _verify_me ) { |
| Node *v_ctrl = _verify_me->get_ctrl_no_update(n); |
| Node *legal = LCA; |
| while( early != legal ) { // While not at earliest legal |
| if( legal == v_ctrl ) break; // Check for prior good location |
| legal = idom(legal) ;// Bump up the IDOM tree |
| } |
| // Check for prior good location |
| if( legal == v_ctrl ) least = legal; // Keep prior if found |
| } |
| #endif |
| |
| // Assign discovered "here or above" point |
| least = find_non_split_ctrl(least); |
| set_ctrl(n, least); |
| |
| // Collect inner loop bodies |
| IdealLoopTree *chosen_loop = get_loop(least); |
| if( !chosen_loop->_child ) // Inner loop? |
| chosen_loop->_body.push(n);// Collect inner loops |
| } |
| |
| #ifdef ASSERT |
| void PhaseIdealLoop::dump_bad_graph(const char* msg, Node* n, Node* early, Node* LCA) { |
| tty->print_cr("%s", msg); |
| tty->print("n: "); n->dump(); |
| tty->print("early(n): "); early->dump(); |
| if (n->in(0) != NULL && !n->in(0)->is_top() && |
| n->in(0) != early && !n->in(0)->is_Root()) { |
| tty->print("n->in(0): "); n->in(0)->dump(); |
| } |
| for (uint i = 1; i < n->req(); i++) { |
| Node* in1 = n->in(i); |
| if (in1 != NULL && in1 != n && !in1->is_top()) { |
| tty->print("n->in(%d): ", i); in1->dump(); |
| Node* in1_early = get_ctrl(in1); |
| tty->print("early(n->in(%d)): ", i); in1_early->dump(); |
| if (in1->in(0) != NULL && !in1->in(0)->is_top() && |
| in1->in(0) != in1_early && !in1->in(0)->is_Root()) { |
| tty->print("n->in(%d)->in(0): ", i); in1->in(0)->dump(); |
| } |
| for (uint j = 1; j < in1->req(); j++) { |
| Node* in2 = in1->in(j); |
| if (in2 != NULL && in2 != n && in2 != in1 && !in2->is_top()) { |
| tty->print("n->in(%d)->in(%d): ", i, j); in2->dump(); |
| Node* in2_early = get_ctrl(in2); |
| tty->print("early(n->in(%d)->in(%d)): ", i, j); in2_early->dump(); |
| if (in2->in(0) != NULL && !in2->in(0)->is_top() && |
| in2->in(0) != in2_early && !in2->in(0)->is_Root()) { |
| tty->print("n->in(%d)->in(%d)->in(0): ", i, j); in2->in(0)->dump(); |
| } |
| } |
| } |
| } |
| } |
| tty->cr(); |
| tty->print("LCA(n): "); LCA->dump(); |
| for (uint i = 0; i < n->outcnt(); i++) { |
| Node* u1 = n->raw_out(i); |
| if (u1 == n) |
| continue; |
| tty->print("n->out(%d): ", i); u1->dump(); |
| if (u1->is_CFG()) { |
| for (uint j = 0; j < u1->outcnt(); j++) { |
| Node* u2 = u1->raw_out(j); |
| if (u2 != u1 && u2 != n && u2->is_CFG()) { |
| tty->print("n->out(%d)->out(%d): ", i, j); u2->dump(); |
| } |
| } |
| } else { |
| Node* u1_later = get_ctrl(u1); |
| tty->print("later(n->out(%d)): ", i); u1_later->dump(); |
| if (u1->in(0) != NULL && !u1->in(0)->is_top() && |
| u1->in(0) != u1_later && !u1->in(0)->is_Root()) { |
| tty->print("n->out(%d)->in(0): ", i); u1->in(0)->dump(); |
| } |
| for (uint j = 0; j < u1->outcnt(); j++) { |
| Node* u2 = u1->raw_out(j); |
| if (u2 == n || u2 == u1) |
| continue; |
| tty->print("n->out(%d)->out(%d): ", i, j); u2->dump(); |
| if (!u2->is_CFG()) { |
| Node* u2_later = get_ctrl(u2); |
| tty->print("later(n->out(%d)->out(%d)): ", i, j); u2_later->dump(); |
| if (u2->in(0) != NULL && !u2->in(0)->is_top() && |
| u2->in(0) != u2_later && !u2->in(0)->is_Root()) { |
| tty->print("n->out(%d)->in(0): ", i); u2->in(0)->dump(); |
| } |
| } |
| } |
| } |
| } |
| tty->cr(); |
| int ct = 0; |
| Node *dbg_legal = LCA; |
| while(!dbg_legal->is_Start() && ct < 100) { |
| tty->print("idom[%d] ",ct); dbg_legal->dump(); |
| ct++; |
| dbg_legal = idom(dbg_legal); |
| } |
| tty->cr(); |
| } |
| #endif |
| |
| #ifndef PRODUCT |
| //------------------------------dump------------------------------------------- |
| void PhaseIdealLoop::dump( ) const { |
| ResourceMark rm; |
| Arena* arena = Thread::current()->resource_area(); |
| Node_Stack stack(arena, C->live_nodes() >> 2); |
| Node_List rpo_list; |
| VectorSet visited(arena); |
| visited.set(C->top()->_idx); |
| rpo( C->root(), stack, visited, rpo_list ); |
| // Dump root loop indexed by last element in PO order |
| dump( _ltree_root, rpo_list.size(), rpo_list ); |
| } |
| |
| void PhaseIdealLoop::dump( IdealLoopTree *loop, uint idx, Node_List &rpo_list ) const { |
| loop->dump_head(); |
| |
| // Now scan for CFG nodes in the same loop |
| for( uint j=idx; j > 0; j-- ) { |
| Node *n = rpo_list[j-1]; |
| if( !_nodes[n->_idx] ) // Skip dead nodes |
| continue; |
| if( get_loop(n) != loop ) { // Wrong loop nest |
| if( get_loop(n)->_head == n && // Found nested loop? |
| get_loop(n)->_parent == loop ) |
| dump(get_loop(n),rpo_list.size(),rpo_list); // Print it nested-ly |
| continue; |
| } |
| |
| // Dump controlling node |
| for( uint x = 0; x < loop->_nest; x++ ) |
| tty->print(" "); |
| tty->print("C"); |
| if( n == C->root() ) { |
| n->dump(); |
| } else { |
| Node* cached_idom = idom_no_update(n); |
| Node *computed_idom = n->in(0); |
| if( n->is_Region() ) { |
| computed_idom = compute_idom(n); |
| // computed_idom() will return n->in(0) when idom(n) is an IfNode (or |
| // any MultiBranch ctrl node), so apply a similar transform to |
| // the cached idom returned from idom_no_update. |
| cached_idom = find_non_split_ctrl(cached_idom); |
| } |
| tty->print(" ID:%d",computed_idom->_idx); |
| n->dump(); |
| if( cached_idom != computed_idom ) { |
| tty->print_cr("*** BROKEN IDOM! Computed as: %d, cached as: %d", |
| computed_idom->_idx, cached_idom->_idx); |
| } |
| } |
| // Dump nodes it controls |
| for( uint k = 0; k < _nodes.Size(); k++ ) { |
| // (k < C->unique() && get_ctrl(find(k)) == n) |
| if (k < C->unique() && _nodes[k] == (Node*)((intptr_t)n + 1)) { |
| Node *m = C->root()->find(k); |
| if( m && m->outcnt() > 0 ) { |
| if (!(has_ctrl(m) && get_ctrl_no_update(m) == n)) { |
| tty->print_cr("*** BROKEN CTRL ACCESSOR! _nodes[k] is %p, ctrl is %p", |
| _nodes[k], has_ctrl(m) ? get_ctrl_no_update(m) : NULL); |
| } |
| for( uint j = 0; j < loop->_nest; j++ ) |
| tty->print(" "); |
| tty->print(" "); |
| m->dump(); |
| } |
| } |
| } |
| } |
| } |
| |
| // Collect a R-P-O for the whole CFG. |
| // Result list is in post-order (scan backwards for RPO) |
| void PhaseIdealLoop::rpo( Node *start, Node_Stack &stk, VectorSet &visited, Node_List &rpo_list ) const { |
| stk.push(start, 0); |
| visited.set(start->_idx); |
| |
| while (stk.is_nonempty()) { |
| Node* m = stk.node(); |
| uint idx = stk.index(); |
| if (idx < m->outcnt()) { |
| stk.set_index(idx + 1); |
| Node* n = m->raw_out(idx); |
| if (n->is_CFG() && !visited.test_set(n->_idx)) { |
| stk.push(n, 0); |
| } |
| } else { |
| rpo_list.push(m); |
| stk.pop(); |
| } |
| } |
| } |
| #endif |
| |
| |
| //============================================================================= |
| //------------------------------LoopTreeIterator----------------------------------- |
| |
| // Advance to next loop tree using a preorder, left-to-right traversal. |
| void LoopTreeIterator::next() { |
| assert(!done(), "must not be done."); |
| if (_curnt->_child != NULL) { |
| _curnt = _curnt->_child; |
| } else if (_curnt->_next != NULL) { |
| _curnt = _curnt->_next; |
| } else { |
| while (_curnt != _root && _curnt->_next == NULL) { |
| _curnt = _curnt->_parent; |
| } |
| if (_curnt == _root) { |
| _curnt = NULL; |
| assert(done(), "must be done."); |
| } else { |
| assert(_curnt->_next != NULL, "must be more to do"); |
| _curnt = _curnt->_next; |
| } |
| } |
| } |