| /* |
| * 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. |
| * |
| */ |
| |
| #ifndef SHARE_VM_OPTO_LOOPNODE_HPP |
| #define SHARE_VM_OPTO_LOOPNODE_HPP |
| |
| #include "opto/cfgnode.hpp" |
| #include "opto/multnode.hpp" |
| #include "opto/phaseX.hpp" |
| #include "opto/subnode.hpp" |
| #include "opto/type.hpp" |
| |
| class CmpNode; |
| class CountedLoopEndNode; |
| class CountedLoopNode; |
| class IdealLoopTree; |
| class LoopNode; |
| class Node; |
| class PhaseIdealLoop; |
| class CountedLoopReserveKit; |
| class VectorSet; |
| class Invariance; |
| struct small_cache; |
| |
| // |
| // I D E A L I Z E D L O O P S |
| // |
| // Idealized loops are the set of loops I perform more interesting |
| // transformations on, beyond simple hoisting. |
| |
| //------------------------------LoopNode--------------------------------------- |
| // Simple loop header. Fall in path on left, loop-back path on right. |
| class LoopNode : public RegionNode { |
| // Size is bigger to hold the flags. However, the flags do not change |
| // the semantics so it does not appear in the hash & cmp functions. |
| virtual uint size_of() const { return sizeof(*this); } |
| protected: |
| short _loop_flags; |
| // Names for flag bitfields |
| enum { Normal=0, Pre=1, Main=2, Post=3, PreMainPostFlagsMask=3, |
| MainHasNoPreLoop=4, |
| HasExactTripCount=8, |
| InnerLoop=16, |
| PartialPeelLoop=32, |
| PartialPeelFailed=64, |
| HasReductions=128, |
| WasSlpAnalyzed=256, |
| PassedSlpAnalysis=512, |
| DoUnrollOnly=1024, |
| VectorizedLoop=2048, |
| HasAtomicPostLoop=4096, |
| HasRangeChecks=8192, |
| IsMultiversioned=16384}; |
| char _unswitch_count; |
| enum { _unswitch_max=3 }; |
| char _postloop_flags; |
| enum { LoopNotRCEChecked = 0, LoopRCEChecked = 1, RCEPostLoop = 2 }; |
| |
| public: |
| // Names for edge indices |
| enum { Self=0, EntryControl, LoopBackControl }; |
| |
| int is_inner_loop() const { return _loop_flags & InnerLoop; } |
| void set_inner_loop() { _loop_flags |= InnerLoop; } |
| |
| int range_checks_present() const { return _loop_flags & HasRangeChecks; } |
| int is_multiversioned() const { return _loop_flags & IsMultiversioned; } |
| int is_vectorized_loop() const { return _loop_flags & VectorizedLoop; } |
| int is_partial_peel_loop() const { return _loop_flags & PartialPeelLoop; } |
| void set_partial_peel_loop() { _loop_flags |= PartialPeelLoop; } |
| int partial_peel_has_failed() const { return _loop_flags & PartialPeelFailed; } |
| |
| void mark_partial_peel_failed() { _loop_flags |= PartialPeelFailed; } |
| void mark_has_reductions() { _loop_flags |= HasReductions; } |
| void mark_was_slp() { _loop_flags |= WasSlpAnalyzed; } |
| void mark_passed_slp() { _loop_flags |= PassedSlpAnalysis; } |
| void mark_do_unroll_only() { _loop_flags |= DoUnrollOnly; } |
| void mark_loop_vectorized() { _loop_flags |= VectorizedLoop; } |
| void mark_has_atomic_post_loop() { _loop_flags |= HasAtomicPostLoop; } |
| void mark_has_range_checks() { _loop_flags |= HasRangeChecks; } |
| void mark_is_multiversioned() { _loop_flags |= IsMultiversioned; } |
| |
| int unswitch_max() { return _unswitch_max; } |
| int unswitch_count() { return _unswitch_count; } |
| |
| int has_been_range_checked() const { return _postloop_flags & LoopRCEChecked; } |
| void set_has_been_range_checked() { _postloop_flags |= LoopRCEChecked; } |
| int is_rce_post_loop() const { return _postloop_flags & RCEPostLoop; } |
| void set_is_rce_post_loop() { _postloop_flags |= RCEPostLoop; } |
| |
| void set_unswitch_count(int val) { |
| assert (val <= unswitch_max(), "too many unswitches"); |
| _unswitch_count = val; |
| } |
| |
| LoopNode(Node *entry, Node *backedge) : RegionNode(3), _loop_flags(0), _unswitch_count(0), _postloop_flags(0) { |
| init_class_id(Class_Loop); |
| init_req(EntryControl, entry); |
| init_req(LoopBackControl, backedge); |
| } |
| |
| virtual Node *Ideal(PhaseGVN *phase, bool can_reshape); |
| virtual int Opcode() const; |
| bool can_be_counted_loop(PhaseTransform* phase) const { |
| return req() == 3 && in(0) != NULL && |
| in(1) != NULL && phase->type(in(1)) != Type::TOP && |
| in(2) != NULL && phase->type(in(2)) != Type::TOP; |
| } |
| bool is_valid_counted_loop() const; |
| #ifndef PRODUCT |
| virtual void dump_spec(outputStream *st) const; |
| #endif |
| }; |
| |
| //------------------------------Counted Loops---------------------------------- |
| // Counted loops are all trip-counted loops, with exactly 1 trip-counter exit |
| // path (and maybe some other exit paths). The trip-counter exit is always |
| // last in the loop. The trip-counter have to stride by a constant; |
| // the exit value is also loop invariant. |
| |
| // CountedLoopNodes and CountedLoopEndNodes come in matched pairs. The |
| // CountedLoopNode has the incoming loop control and the loop-back-control |
| // which is always the IfTrue before the matching CountedLoopEndNode. The |
| // CountedLoopEndNode has an incoming control (possibly not the |
| // CountedLoopNode if there is control flow in the loop), the post-increment |
| // trip-counter value, and the limit. The trip-counter value is always of |
| // the form (Op old-trip-counter stride). The old-trip-counter is produced |
| // by a Phi connected to the CountedLoopNode. The stride is constant. |
| // The Op is any commutable opcode, including Add, Mul, Xor. The |
| // CountedLoopEndNode also takes in the loop-invariant limit value. |
| |
| // From a CountedLoopNode I can reach the matching CountedLoopEndNode via the |
| // loop-back control. From CountedLoopEndNodes I can reach CountedLoopNodes |
| // via the old-trip-counter from the Op node. |
| |
| //------------------------------CountedLoopNode-------------------------------- |
| // CountedLoopNodes head simple counted loops. CountedLoopNodes have as |
| // inputs the incoming loop-start control and the loop-back control, so they |
| // act like RegionNodes. They also take in the initial trip counter, the |
| // loop-invariant stride and the loop-invariant limit value. CountedLoopNodes |
| // produce a loop-body control and the trip counter value. Since |
| // CountedLoopNodes behave like RegionNodes I still have a standard CFG model. |
| |
| class CountedLoopNode : public LoopNode { |
| // Size is bigger to hold _main_idx. However, _main_idx does not change |
| // the semantics so it does not appear in the hash & cmp functions. |
| virtual uint size_of() const { return sizeof(*this); } |
| |
| // For Pre- and Post-loops during debugging ONLY, this holds the index of |
| // the Main CountedLoop. Used to assert that we understand the graph shape. |
| node_idx_t _main_idx; |
| |
| // Known trip count calculated by compute_exact_trip_count() |
| uint _trip_count; |
| |
| // Expected trip count from profile data |
| float _profile_trip_cnt; |
| |
| // Log2 of original loop bodies in unrolled loop |
| int _unrolled_count_log2; |
| |
| // Node count prior to last unrolling - used to decide if |
| // unroll,optimize,unroll,optimize,... is making progress |
| int _node_count_before_unroll; |
| |
| // If slp analysis is performed we record the maximum |
| // vector mapped unroll factor here |
| int _slp_maximum_unroll_factor; |
| |
| public: |
| CountedLoopNode( Node *entry, Node *backedge ) |
| : LoopNode(entry, backedge), _main_idx(0), _trip_count(max_juint), |
| _profile_trip_cnt(COUNT_UNKNOWN), _unrolled_count_log2(0), |
| _node_count_before_unroll(0), _slp_maximum_unroll_factor(0) { |
| init_class_id(Class_CountedLoop); |
| // Initialize _trip_count to the largest possible value. |
| // Will be reset (lower) if the loop's trip count is known. |
| } |
| |
| virtual int Opcode() const; |
| virtual Node *Ideal(PhaseGVN *phase, bool can_reshape); |
| |
| Node *init_control() const { return in(EntryControl); } |
| Node *back_control() const { return in(LoopBackControl); } |
| CountedLoopEndNode *loopexit() const; |
| Node *init_trip() const; |
| Node *stride() const; |
| int stride_con() const; |
| bool stride_is_con() const; |
| Node *limit() const; |
| Node *incr() const; |
| Node *phi() const; |
| |
| // Match increment with optional truncation |
| static Node* match_incr_with_optional_truncation(Node* expr, Node** trunc1, Node** trunc2, const TypeInt** trunc_type); |
| |
| // A 'main' loop has a pre-loop and a post-loop. The 'main' loop |
| // can run short a few iterations and may start a few iterations in. |
| // It will be RCE'd and unrolled and aligned. |
| |
| // A following 'post' loop will run any remaining iterations. Used |
| // during Range Check Elimination, the 'post' loop will do any final |
| // iterations with full checks. Also used by Loop Unrolling, where |
| // the 'post' loop will do any epilog iterations needed. Basically, |
| // a 'post' loop can not profitably be further unrolled or RCE'd. |
| |
| // A preceding 'pre' loop will run at least 1 iteration (to do peeling), |
| // it may do under-flow checks for RCE and may do alignment iterations |
| // so the following main loop 'knows' that it is striding down cache |
| // lines. |
| |
| // A 'main' loop that is ONLY unrolled or peeled, never RCE'd or |
| // Aligned, may be missing it's pre-loop. |
| int is_normal_loop () const { return (_loop_flags&PreMainPostFlagsMask) == Normal; } |
| int is_pre_loop () const { return (_loop_flags&PreMainPostFlagsMask) == Pre; } |
| int is_main_loop () const { return (_loop_flags&PreMainPostFlagsMask) == Main; } |
| int is_post_loop () const { return (_loop_flags&PreMainPostFlagsMask) == Post; } |
| int is_reduction_loop() const { return (_loop_flags&HasReductions) == HasReductions; } |
| int was_slp_analyzed () const { return (_loop_flags&WasSlpAnalyzed) == WasSlpAnalyzed; } |
| int has_passed_slp () const { return (_loop_flags&PassedSlpAnalysis) == PassedSlpAnalysis; } |
| int do_unroll_only () const { return (_loop_flags&DoUnrollOnly) == DoUnrollOnly; } |
| int is_main_no_pre_loop() const { return _loop_flags & MainHasNoPreLoop; } |
| int has_atomic_post_loop () const { return (_loop_flags & HasAtomicPostLoop) == HasAtomicPostLoop; } |
| void set_main_no_pre_loop() { _loop_flags |= MainHasNoPreLoop; } |
| |
| int main_idx() const { return _main_idx; } |
| |
| |
| void set_pre_loop (CountedLoopNode *main) { assert(is_normal_loop(),""); _loop_flags |= Pre ; _main_idx = main->_idx; } |
| void set_main_loop ( ) { assert(is_normal_loop(),""); _loop_flags |= Main; } |
| void set_post_loop (CountedLoopNode *main) { assert(is_normal_loop(),""); _loop_flags |= Post; _main_idx = main->_idx; } |
| void set_normal_loop( ) { _loop_flags &= ~PreMainPostFlagsMask; } |
| |
| void set_trip_count(uint tc) { _trip_count = tc; } |
| uint trip_count() { return _trip_count; } |
| |
| bool has_exact_trip_count() const { return (_loop_flags & HasExactTripCount) != 0; } |
| void set_exact_trip_count(uint tc) { |
| _trip_count = tc; |
| _loop_flags |= HasExactTripCount; |
| } |
| void set_nonexact_trip_count() { |
| _loop_flags &= ~HasExactTripCount; |
| } |
| void set_notpassed_slp() { |
| _loop_flags &= ~PassedSlpAnalysis; |
| } |
| |
| void set_profile_trip_cnt(float ptc) { _profile_trip_cnt = ptc; } |
| float profile_trip_cnt() { return _profile_trip_cnt; } |
| |
| void double_unrolled_count() { _unrolled_count_log2++; } |
| int unrolled_count() { return 1 << MIN2(_unrolled_count_log2, BitsPerInt-3); } |
| |
| void set_node_count_before_unroll(int ct) { _node_count_before_unroll = ct; } |
| int node_count_before_unroll() { return _node_count_before_unroll; } |
| void set_slp_max_unroll(int unroll_factor) { _slp_maximum_unroll_factor = unroll_factor; } |
| int slp_max_unroll() const { return _slp_maximum_unroll_factor; } |
| |
| #ifndef PRODUCT |
| virtual void dump_spec(outputStream *st) const; |
| #endif |
| }; |
| |
| //------------------------------CountedLoopEndNode----------------------------- |
| // CountedLoopEndNodes end simple trip counted loops. They act much like |
| // IfNodes. |
| class CountedLoopEndNode : public IfNode { |
| public: |
| enum { TestControl, TestValue }; |
| |
| CountedLoopEndNode( Node *control, Node *test, float prob, float cnt ) |
| : IfNode( control, test, prob, cnt) { |
| init_class_id(Class_CountedLoopEnd); |
| } |
| virtual int Opcode() const; |
| |
| Node *cmp_node() const { return (in(TestValue)->req() >=2) ? in(TestValue)->in(1) : NULL; } |
| Node *incr() const { Node *tmp = cmp_node(); return (tmp && tmp->req()==3) ? tmp->in(1) : NULL; } |
| Node *limit() const { Node *tmp = cmp_node(); return (tmp && tmp->req()==3) ? tmp->in(2) : NULL; } |
| Node *stride() const { Node *tmp = incr (); return (tmp && tmp->req()==3) ? tmp->in(2) : NULL; } |
| Node *init_trip() const { Node *tmp = phi (); return (tmp && tmp->req()==3) ? tmp->in(1) : NULL; } |
| int stride_con() const; |
| bool stride_is_con() const { Node *tmp = stride (); return (tmp != NULL && tmp->is_Con()); } |
| BoolTest::mask test_trip() const { return in(TestValue)->as_Bool()->_test._test; } |
| PhiNode *phi() const { |
| Node *tmp = incr(); |
| if (tmp && tmp->req() == 3) { |
| Node* phi = tmp->in(1); |
| if (phi->is_Phi()) { |
| return phi->as_Phi(); |
| } |
| } |
| return NULL; |
| } |
| CountedLoopNode *loopnode() const { |
| // The CountedLoopNode that goes with this CountedLoopEndNode may |
| // have been optimized out by the IGVN so be cautious with the |
| // pattern matching on the graph |
| PhiNode* iv_phi = phi(); |
| if (iv_phi == NULL) { |
| return NULL; |
| } |
| Node *ln = iv_phi->in(0); |
| if (ln->is_CountedLoop() && ln->as_CountedLoop()->loopexit() == this) { |
| return (CountedLoopNode*)ln; |
| } |
| return NULL; |
| } |
| |
| #ifndef PRODUCT |
| virtual void dump_spec(outputStream *st) const; |
| #endif |
| }; |
| |
| |
| inline CountedLoopEndNode *CountedLoopNode::loopexit() const { |
| Node *bc = back_control(); |
| if( bc == NULL ) return NULL; |
| Node *le = bc->in(0); |
| if( le->Opcode() != Op_CountedLoopEnd ) |
| return NULL; |
| return (CountedLoopEndNode*)le; |
| } |
| inline Node *CountedLoopNode::init_trip() const { return loopexit() ? loopexit()->init_trip() : NULL; } |
| inline Node *CountedLoopNode::stride() const { return loopexit() ? loopexit()->stride() : NULL; } |
| inline int CountedLoopNode::stride_con() const { return loopexit() ? loopexit()->stride_con() : 0; } |
| inline bool CountedLoopNode::stride_is_con() const { return loopexit() && loopexit()->stride_is_con(); } |
| inline Node *CountedLoopNode::limit() const { return loopexit() ? loopexit()->limit() : NULL; } |
| inline Node *CountedLoopNode::incr() const { return loopexit() ? loopexit()->incr() : NULL; } |
| inline Node *CountedLoopNode::phi() const { return loopexit() ? loopexit()->phi() : NULL; } |
| |
| //------------------------------LoopLimitNode----------------------------- |
| // Counted Loop limit node which represents exact final iterator value: |
| // trip_count = (limit - init_trip + stride - 1)/stride |
| // final_value= trip_count * stride + init_trip. |
| // Use HW instructions to calculate it when it can overflow in integer. |
| // Note, final_value should fit into integer since counted loop has |
| // limit check: limit <= max_int-stride. |
| class LoopLimitNode : public Node { |
| enum { Init=1, Limit=2, Stride=3 }; |
| public: |
| LoopLimitNode( Compile* C, Node *init, Node *limit, Node *stride ) : Node(0,init,limit,stride) { |
| // Put it on the Macro nodes list to optimize during macro nodes expansion. |
| init_flags(Flag_is_macro); |
| C->add_macro_node(this); |
| } |
| virtual int Opcode() const; |
| virtual const Type *bottom_type() const { return TypeInt::INT; } |
| virtual uint ideal_reg() const { return Op_RegI; } |
| virtual const Type* Value(PhaseGVN* phase) const; |
| virtual Node *Ideal(PhaseGVN *phase, bool can_reshape); |
| virtual Node* Identity(PhaseGVN* phase); |
| }; |
| |
| // -----------------------------IdealLoopTree---------------------------------- |
| class IdealLoopTree : public ResourceObj { |
| public: |
| IdealLoopTree *_parent; // Parent in loop tree |
| IdealLoopTree *_next; // Next sibling in loop tree |
| IdealLoopTree *_child; // First child in loop tree |
| |
| // The head-tail backedge defines the loop. |
| // If tail is NULL then this loop has multiple backedges as part of the |
| // same loop. During cleanup I'll peel off the multiple backedges; merge |
| // them at the loop bottom and flow 1 real backedge into the loop. |
| Node *_head; // Head of loop |
| Node *_tail; // Tail of loop |
| inline Node *tail(); // Handle lazy update of _tail field |
| PhaseIdealLoop* _phase; |
| int _local_loop_unroll_limit; |
| int _local_loop_unroll_factor; |
| |
| Node_List _body; // Loop body for inner loops |
| |
| uint8_t _nest; // Nesting depth |
| uint8_t _irreducible:1, // True if irreducible |
| _has_call:1, // True if has call safepoint |
| _has_sfpt:1, // True if has non-call safepoint |
| _rce_candidate:1; // True if candidate for range check elimination |
| |
| Node_List* _safepts; // List of safepoints in this loop |
| Node_List* _required_safept; // A inner loop cannot delete these safepts; |
| bool _allow_optimizations; // Allow loop optimizations |
| |
| IdealLoopTree( PhaseIdealLoop* phase, Node *head, Node *tail ) |
| : _parent(0), _next(0), _child(0), |
| _head(head), _tail(tail), |
| _phase(phase), |
| _safepts(NULL), |
| _required_safept(NULL), |
| _allow_optimizations(true), |
| _nest(0), _irreducible(0), _has_call(0), _has_sfpt(0), _rce_candidate(0), |
| _local_loop_unroll_limit(0), _local_loop_unroll_factor(0) |
| { } |
| |
| // Is 'l' a member of 'this'? |
| bool is_member(const IdealLoopTree *l) const; // Test for nested membership |
| |
| // Set loop nesting depth. Accumulate has_call bits. |
| int set_nest( uint depth ); |
| |
| // 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 split_fall_in( PhaseIdealLoop *phase, int fall_in_cnt ); |
| |
| // Split out the outermost loop from this shared header. |
| void split_outer_loop( PhaseIdealLoop *phase ); |
| |
| // Merge all the backedges from the shared header into a private Region. |
| // Feed that region as the one backedge to this loop. |
| void merge_many_backedges( PhaseIdealLoop *phase ); |
| |
| // Split shared headers and insert loop landing pads. |
| // Insert a LoopNode to replace the RegionNode. |
| // Returns TRUE if loop tree is structurally changed. |
| bool beautify_loops( PhaseIdealLoop *phase ); |
| |
| // Perform optimization to use the loop predicates for null checks and range checks. |
| // Applies to any loop level (not just the innermost one) |
| bool loop_predication( PhaseIdealLoop *phase); |
| |
| // Perform iteration-splitting on inner loops. Split iterations to |
| // avoid range checks or one-shot null checks. Returns false if the |
| // current round of loop opts should stop. |
| bool iteration_split( PhaseIdealLoop *phase, Node_List &old_new ); |
| |
| // Driver for various flavors of iteration splitting. Returns false |
| // if the current round of loop opts should stop. |
| bool iteration_split_impl( PhaseIdealLoop *phase, Node_List &old_new ); |
| |
| // 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). |
| void check_safepts(VectorSet &visited, Node_List &stack); |
| |
| // Allpaths backwards scan from loop tail, terminating each path at first safepoint |
| // encountered. |
| void allpaths_check_safepts(VectorSet &visited, Node_List &stack); |
| |
| // Remove safepoints from loop. Optionally keeping one. |
| void remove_safepoints(PhaseIdealLoop* phase, bool keep_one); |
| |
| // Convert to counted loops where possible |
| void counted_loop( PhaseIdealLoop *phase ); |
| |
| // Check for Node being a loop-breaking test |
| Node *is_loop_exit(Node *iff) const; |
| |
| // Remove simplistic dead code from loop body |
| void DCE_loop_body(); |
| |
| // Look for loop-exit tests with my 50/50 guesses from the Parsing stage. |
| // Replace with a 1-in-10 exit guess. |
| void adjust_loop_exit_prob( PhaseIdealLoop *phase ); |
| |
| // Return TRUE or FALSE if the loop should never be RCE'd or aligned. |
| // Useful for unrolling loops with NO array accesses. |
| bool policy_peel_only( PhaseIdealLoop *phase ) const; |
| |
| // Return TRUE or FALSE if the loop should be unswitched -- clone |
| // loop with an invariant test |
| bool policy_unswitching( PhaseIdealLoop *phase ) const; |
| |
| // Micro-benchmark spamming. Remove empty loops. |
| bool policy_do_remove_empty_loop( PhaseIdealLoop *phase ); |
| |
| // Convert one iteration loop into normal code. |
| bool policy_do_one_iteration_loop( PhaseIdealLoop *phase ); |
| |
| // Return TRUE or FALSE if the loop should be peeled or not. Peel if we can |
| // make some loop-invariant test (usually a null-check) happen before the |
| // loop. |
| bool policy_peeling( PhaseIdealLoop *phase ) const; |
| |
| // Return TRUE or FALSE if the loop should be maximally unrolled. Stash any |
| // known trip count in the counted loop node. |
| bool policy_maximally_unroll( PhaseIdealLoop *phase ) const; |
| |
| // Return TRUE or FALSE if the loop should be unrolled or not. Unroll if |
| // the loop is a CountedLoop and the body is small enough. |
| bool policy_unroll(PhaseIdealLoop *phase); |
| |
| // Loop analyses to map to a maximal superword unrolling for vectorization. |
| void policy_unroll_slp_analysis(CountedLoopNode *cl, PhaseIdealLoop *phase, int future_unroll_ct); |
| |
| // Return TRUE or FALSE if the loop should be range-check-eliminated. |
| // Gather a list of IF tests that are dominated by iteration splitting; |
| // also gather the end of the first split and the start of the 2nd split. |
| bool policy_range_check( PhaseIdealLoop *phase ) const; |
| |
| // Return TRUE or FALSE if the loop should be cache-line aligned. |
| // Gather the expression that does the alignment. Note that only |
| // one array base can be aligned in a loop (unless the VM guarantees |
| // mutual alignment). Note that if we vectorize short memory ops |
| // into longer memory ops, we may want to increase alignment. |
| bool policy_align( PhaseIdealLoop *phase ) const; |
| |
| // Return TRUE if "iff" is a range check. |
| bool is_range_check_if(IfNode *iff, PhaseIdealLoop *phase, Invariance& invar) const; |
| |
| // Compute loop trip count if possible |
| void compute_trip_count(PhaseIdealLoop* phase); |
| |
| // Compute loop trip count from profile data |
| void compute_profile_trip_cnt( PhaseIdealLoop *phase ); |
| |
| // Reassociate invariant expressions. |
| void reassociate_invariants(PhaseIdealLoop *phase); |
| // Reassociate invariant add and subtract expressions. |
| Node* reassociate_add_sub(Node* n1, PhaseIdealLoop *phase); |
| // Return nonzero index of invariant operand if invariant and variant |
| // are combined with an Add or Sub. Helper for reassociate_invariants. |
| int is_invariant_addition(Node* n, PhaseIdealLoop *phase); |
| |
| // Return true if n is invariant |
| bool is_invariant(Node* n) const; |
| |
| // Put loop body on igvn work list |
| void record_for_igvn(); |
| |
| bool is_loop() { return !_irreducible && _tail && !_tail->is_top(); } |
| bool is_inner() { return is_loop() && _child == NULL; } |
| bool is_counted() { return is_loop() && _head != NULL && _head->is_CountedLoop(); } |
| |
| void remove_main_post_loops(CountedLoopNode *cl, PhaseIdealLoop *phase); |
| |
| #ifndef PRODUCT |
| void dump_head( ) const; // Dump loop head only |
| void dump() const; // Dump this loop recursively |
| void verify_tree(IdealLoopTree *loop, const IdealLoopTree *parent) const; |
| #endif |
| |
| }; |
| |
| // -----------------------------PhaseIdealLoop--------------------------------- |
| // Computes the mapping from Nodes to IdealLoopTrees. Organizes IdealLoopTrees into a |
| // loop tree. Drives the loop-based transformations on the ideal graph. |
| class PhaseIdealLoop : public PhaseTransform { |
| friend class IdealLoopTree; |
| friend class SuperWord; |
| friend class CountedLoopReserveKit; |
| |
| // Pre-computed def-use info |
| PhaseIterGVN &_igvn; |
| |
| // Head of loop tree |
| IdealLoopTree *_ltree_root; |
| |
| // Array of pre-order numbers, plus post-visited bit. |
| // ZERO for not pre-visited. EVEN for pre-visited but not post-visited. |
| // ODD for post-visited. Other bits are the pre-order number. |
| uint *_preorders; |
| uint _max_preorder; |
| |
| const PhaseIdealLoop* _verify_me; |
| bool _verify_only; |
| |
| // Allocate _preorders[] array |
| void allocate_preorders() { |
| _max_preorder = C->unique()+8; |
| _preorders = NEW_RESOURCE_ARRAY(uint, _max_preorder); |
| memset(_preorders, 0, sizeof(uint) * _max_preorder); |
| } |
| |
| // Allocate _preorders[] array |
| void reallocate_preorders() { |
| if ( _max_preorder < C->unique() ) { |
| _preorders = REALLOC_RESOURCE_ARRAY(uint, _preorders, _max_preorder, C->unique()); |
| _max_preorder = C->unique(); |
| } |
| memset(_preorders, 0, sizeof(uint) * _max_preorder); |
| } |
| |
| // Check to grow _preorders[] array for the case when build_loop_tree_impl() |
| // adds new nodes. |
| void check_grow_preorders( ) { |
| if ( _max_preorder < C->unique() ) { |
| uint newsize = _max_preorder<<1; // double size of array |
| _preorders = REALLOC_RESOURCE_ARRAY(uint, _preorders, _max_preorder, newsize); |
| memset(&_preorders[_max_preorder],0,sizeof(uint)*(newsize-_max_preorder)); |
| _max_preorder = newsize; |
| } |
| } |
| // Check for pre-visited. Zero for NOT visited; non-zero for visited. |
| int is_visited( Node *n ) const { return _preorders[n->_idx]; } |
| // Pre-order numbers are written to the Nodes array as low-bit-set values. |
| void set_preorder_visited( Node *n, int pre_order ) { |
| assert( !is_visited( n ), "already set" ); |
| _preorders[n->_idx] = (pre_order<<1); |
| }; |
| // Return pre-order number. |
| int get_preorder( Node *n ) const { assert( is_visited(n), "" ); return _preorders[n->_idx]>>1; } |
| |
| // Check for being post-visited. |
| // Should be previsited already (checked with assert(is_visited(n))). |
| int is_postvisited( Node *n ) const { assert( is_visited(n), "" ); return _preorders[n->_idx]&1; } |
| |
| // Mark as post visited |
| void set_postvisited( Node *n ) { assert( !is_postvisited( n ), "" ); _preorders[n->_idx] |= 1; } |
| |
| // Set/get control node out. Set lower bit to distinguish from IdealLoopTree |
| // Returns true if "n" is a data node, false if it's a control node. |
| bool has_ctrl( Node *n ) const { return ((intptr_t)_nodes[n->_idx]) & 1; } |
| |
| // clear out dead code after build_loop_late |
| Node_List _deadlist; |
| |
| // Support for faster execution of get_late_ctrl()/dom_lca() |
| // when a node has many uses and dominator depth is deep. |
| Node_Array _dom_lca_tags; |
| void init_dom_lca_tags(); |
| void clear_dom_lca_tags(); |
| |
| // Helper for debugging bad dominance relationships |
| bool verify_dominance(Node* n, Node* use, Node* LCA, Node* early); |
| |
| Node* compute_lca_of_uses(Node* n, Node* early, bool verify = false); |
| |
| // Inline wrapper for frequent cases: |
| // 1) only one use |
| // 2) a use is the same as the current LCA passed as 'n1' |
| Node *dom_lca_for_get_late_ctrl( Node *lca, Node *n, Node *tag ) { |
| assert( n->is_CFG(), "" ); |
| // Fast-path NULL lca |
| if( lca != NULL && lca != n ) { |
| assert( lca->is_CFG(), "" ); |
| // find LCA of all uses |
| n = dom_lca_for_get_late_ctrl_internal( lca, n, tag ); |
| } |
| return find_non_split_ctrl(n); |
| } |
| Node *dom_lca_for_get_late_ctrl_internal( Node *lca, Node *n, Node *tag ); |
| |
| // Helper function for directing control inputs away from CFG split |
| // points. |
| Node *find_non_split_ctrl( Node *ctrl ) const { |
| if (ctrl != NULL) { |
| if (ctrl->is_MultiBranch()) { |
| ctrl = ctrl->in(0); |
| } |
| assert(ctrl->is_CFG(), "CFG"); |
| } |
| return ctrl; |
| } |
| |
| bool cast_incr_before_loop(Node* incr, Node* ctrl, Node* loop); |
| |
| public: |
| |
| static bool is_canonical_loop_entry(CountedLoopNode* cl); |
| |
| bool has_node( Node* n ) const { |
| guarantee(n != NULL, "No Node."); |
| return _nodes[n->_idx] != NULL; |
| } |
| // check if transform created new nodes that need _ctrl recorded |
| Node *get_late_ctrl( Node *n, Node *early ); |
| Node *get_early_ctrl( Node *n ); |
| Node *get_early_ctrl_for_expensive(Node *n, Node* earliest); |
| void set_early_ctrl( Node *n ); |
| void set_subtree_ctrl( Node *root ); |
| void set_ctrl( Node *n, Node *ctrl ) { |
| assert( !has_node(n) || has_ctrl(n), "" ); |
| assert( ctrl->in(0), "cannot set dead control node" ); |
| assert( ctrl == find_non_split_ctrl(ctrl), "must set legal crtl" ); |
| _nodes.map( n->_idx, (Node*)((intptr_t)ctrl + 1) ); |
| } |
| // Set control and update loop membership |
| void set_ctrl_and_loop(Node* n, Node* ctrl) { |
| IdealLoopTree* old_loop = get_loop(get_ctrl(n)); |
| IdealLoopTree* new_loop = get_loop(ctrl); |
| if (old_loop != new_loop) { |
| if (old_loop->_child == NULL) old_loop->_body.yank(n); |
| if (new_loop->_child == NULL) new_loop->_body.push(n); |
| } |
| set_ctrl(n, ctrl); |
| } |
| // Control nodes can be replaced or subsumed. During this pass they |
| // get their replacement Node in slot 1. Instead of updating the block |
| // location of all Nodes in the subsumed block, we lazily do it. As we |
| // pull such a subsumed block out of the array, we write back the final |
| // correct block. |
| Node *get_ctrl( Node *i ) { |
| assert(has_node(i), ""); |
| Node *n = get_ctrl_no_update(i); |
| _nodes.map( i->_idx, (Node*)((intptr_t)n + 1) ); |
| assert(has_node(i) && has_ctrl(i), ""); |
| assert(n == find_non_split_ctrl(n), "must return legal ctrl" ); |
| return n; |
| } |
| // true if CFG node d dominates CFG node n |
| bool is_dominator(Node *d, Node *n); |
| // return get_ctrl for a data node and self(n) for a CFG node |
| Node* ctrl_or_self(Node* n) { |
| if (has_ctrl(n)) |
| return get_ctrl(n); |
| else { |
| assert (n->is_CFG(), "must be a CFG node"); |
| return n; |
| } |
| } |
| |
| private: |
| Node *get_ctrl_no_update_helper(Node *i) const { |
| assert(has_ctrl(i), "should be control, not loop"); |
| return (Node*)(((intptr_t)_nodes[i->_idx]) & ~1); |
| } |
| |
| Node *get_ctrl_no_update(Node *i) const { |
| assert( has_ctrl(i), "" ); |
| Node *n = get_ctrl_no_update_helper(i); |
| if (!n->in(0)) { |
| // Skip dead CFG nodes |
| do { |
| n = get_ctrl_no_update_helper(n); |
| } while (!n->in(0)); |
| n = find_non_split_ctrl(n); |
| } |
| return n; |
| } |
| |
| // Check for loop being set |
| // "n" must be a control node. Returns true if "n" is known to be in a loop. |
| bool has_loop( Node *n ) const { |
| assert(!has_node(n) || !has_ctrl(n), ""); |
| return has_node(n); |
| } |
| // Set loop |
| void set_loop( Node *n, IdealLoopTree *loop ) { |
| _nodes.map(n->_idx, (Node*)loop); |
| } |
| // Lazy-dazy update of 'get_ctrl' and 'idom_at' mechanisms. Replace |
| // the 'old_node' with 'new_node'. Kill old-node. Add a reference |
| // from old_node to new_node to support the lazy update. Reference |
| // replaces loop reference, since that is not needed for dead node. |
| public: |
| void lazy_update(Node *old_node, Node *new_node) { |
| assert(old_node != new_node, "no cycles please"); |
| // Re-use the side array slot for this node to provide the |
| // forwarding pointer. |
| _nodes.map(old_node->_idx, (Node*)((intptr_t)new_node + 1)); |
| } |
| void lazy_replace(Node *old_node, Node *new_node) { |
| _igvn.replace_node(old_node, new_node); |
| lazy_update(old_node, new_node); |
| } |
| |
| private: |
| |
| // Place 'n' in some loop nest, where 'n' is a CFG node |
| void build_loop_tree(); |
| int build_loop_tree_impl( Node *n, int pre_order ); |
| // Insert loop into the existing loop tree. 'innermost' is a leaf of the |
| // loop tree, not the root. |
| IdealLoopTree *sort( IdealLoopTree *loop, IdealLoopTree *innermost ); |
| |
| // Place Data nodes in some loop nest |
| void build_loop_early( VectorSet &visited, Node_List &worklist, Node_Stack &nstack ); |
| void build_loop_late ( VectorSet &visited, Node_List &worklist, Node_Stack &nstack ); |
| void build_loop_late_post ( Node* n ); |
| |
| // Array of immediate dominance info for each CFG node indexed by node idx |
| private: |
| uint _idom_size; |
| Node **_idom; // Array of immediate dominators |
| uint *_dom_depth; // Used for fast LCA test |
| GrowableArray<uint>* _dom_stk; // For recomputation of dom depth |
| |
| Node* idom_no_update(Node* d) const { |
| assert(d->_idx < _idom_size, "oob"); |
| Node* n = _idom[d->_idx]; |
| assert(n != NULL,"Bad immediate dominator info."); |
| while (n->in(0) == NULL) { // Skip dead CFG nodes |
| //n = n->in(1); |
| n = (Node*)(((intptr_t)_nodes[n->_idx]) & ~1); |
| assert(n != NULL,"Bad immediate dominator info."); |
| } |
| return n; |
| } |
| Node *idom(Node* d) const { |
| uint didx = d->_idx; |
| Node *n = idom_no_update(d); |
| _idom[didx] = n; // Lazily remove dead CFG nodes from table. |
| return n; |
| } |
| uint dom_depth(Node* d) const { |
| guarantee(d != NULL, "Null dominator info."); |
| guarantee(d->_idx < _idom_size, ""); |
| return _dom_depth[d->_idx]; |
| } |
| void set_idom(Node* d, Node* n, uint dom_depth); |
| // Locally compute IDOM using dom_lca call |
| Node *compute_idom( Node *region ) const; |
| // Recompute dom_depth |
| void recompute_dom_depth(); |
| |
| // Is safept not required by an outer loop? |
| bool is_deleteable_safept(Node* sfpt); |
| |
| // Replace parallel induction variable (parallel to trip counter) |
| void replace_parallel_iv(IdealLoopTree *loop); |
| |
| // Perform verification that the graph is valid. |
| PhaseIdealLoop( PhaseIterGVN &igvn) : |
| PhaseTransform(Ideal_Loop), |
| _igvn(igvn), |
| _dom_lca_tags(arena()), // Thread::resource_area |
| _verify_me(NULL), |
| _verify_only(true) { |
| build_and_optimize(false, false); |
| } |
| |
| // build the loop tree and perform any requested optimizations |
| void build_and_optimize(bool do_split_if, bool skip_loop_opts); |
| |
| public: |
| // Dominators for the sea of nodes |
| void Dominators(); |
| Node *dom_lca( Node *n1, Node *n2 ) const { |
| return find_non_split_ctrl(dom_lca_internal(n1, n2)); |
| } |
| Node *dom_lca_internal( Node *n1, Node *n2 ) const; |
| |
| // Compute the Ideal Node to Loop mapping |
| PhaseIdealLoop( PhaseIterGVN &igvn, bool do_split_ifs, bool skip_loop_opts = false) : |
| PhaseTransform(Ideal_Loop), |
| _igvn(igvn), |
| _dom_lca_tags(arena()), // Thread::resource_area |
| _verify_me(NULL), |
| _verify_only(false) { |
| build_and_optimize(do_split_ifs, skip_loop_opts); |
| } |
| |
| // Verify that verify_me made the same decisions as a fresh run. |
| PhaseIdealLoop( PhaseIterGVN &igvn, const PhaseIdealLoop *verify_me) : |
| PhaseTransform(Ideal_Loop), |
| _igvn(igvn), |
| _dom_lca_tags(arena()), // Thread::resource_area |
| _verify_me(verify_me), |
| _verify_only(false) { |
| build_and_optimize(false, false); |
| } |
| |
| // Build and verify the loop tree without modifying the graph. This |
| // is useful to verify that all inputs properly dominate their uses. |
| static void verify(PhaseIterGVN& igvn) { |
| #ifdef ASSERT |
| PhaseIdealLoop v(igvn); |
| #endif |
| } |
| |
| // True if the method has at least 1 irreducible loop |
| bool _has_irreducible_loops; |
| |
| // Per-Node transform |
| virtual Node *transform( Node *a_node ) { return 0; } |
| |
| bool is_counted_loop( Node *x, IdealLoopTree *loop ); |
| |
| Node* exact_limit( IdealLoopTree *loop ); |
| |
| // Return a post-walked LoopNode |
| IdealLoopTree *get_loop( Node *n ) const { |
| // Dead nodes have no loop, so return the top level loop instead |
| if (!has_node(n)) return _ltree_root; |
| assert(!has_ctrl(n), ""); |
| return (IdealLoopTree*)_nodes[n->_idx]; |
| } |
| |
| // Is 'n' a (nested) member of 'loop'? |
| int is_member( const IdealLoopTree *loop, Node *n ) const { |
| return loop->is_member(get_loop(n)); } |
| |
| // This is the basic building block of the loop optimizations. It clones an |
| // entire loop body. It makes an old_new loop body mapping; with this |
| // mapping you can find the new-loop equivalent to an old-loop node. All |
| // new-loop nodes are exactly equal to their old-loop counterparts, all |
| // edges are the same. All exits from the old-loop now have a RegionNode |
| // that merges the equivalent new-loop path. This is true even for the |
| // normal "loop-exit" condition. All uses of loop-invariant old-loop values |
| // now come from (one or more) Phis that merge their new-loop equivalents. |
| // Parameter side_by_side_idom: |
| // When side_by_size_idom is NULL, the dominator tree is constructed for |
| // the clone loop to dominate the original. Used in construction of |
| // pre-main-post loop sequence. |
| // When nonnull, the clone and original are side-by-side, both are |
| // dominated by the passed in side_by_side_idom node. Used in |
| // construction of unswitched loops. |
| void clone_loop( IdealLoopTree *loop, Node_List &old_new, int dom_depth, |
| Node* side_by_side_idom = NULL); |
| |
| // If we got the effect of peeling, either by actually peeling or by |
| // making a pre-loop which must execute at least once, we can remove |
| // all loop-invariant dominated tests in the main body. |
| void peeled_dom_test_elim( IdealLoopTree *loop, Node_List &old_new ); |
| |
| // Generate code to do a loop peel for the given loop (and body). |
| // old_new is a temp array. |
| void do_peeling( IdealLoopTree *loop, Node_List &old_new ); |
| |
| // Add pre and post loops around the given loop. These loops are used |
| // during RCE, unrolling and aligning loops. |
| void insert_pre_post_loops( IdealLoopTree *loop, Node_List &old_new, bool peel_only ); |
| |
| // Add post loop after the given loop. |
| Node *insert_post_loop(IdealLoopTree *loop, Node_List &old_new, |
| CountedLoopNode *main_head, CountedLoopEndNode *main_end, |
| Node *incr, Node *limit, CountedLoopNode *&post_head); |
| |
| // Add an RCE'd post loop which we will multi-version adapt for run time test path usage |
| void insert_scalar_rced_post_loop( IdealLoopTree *loop, Node_List &old_new ); |
| |
| // Add a vector post loop between a vector main loop and the current post loop |
| void insert_vector_post_loop(IdealLoopTree *loop, Node_List &old_new); |
| // If Node n lives in the back_ctrl block, we clone a private version of n |
| // in preheader_ctrl block and return that, otherwise return n. |
| Node *clone_up_backedge_goo( Node *back_ctrl, Node *preheader_ctrl, Node *n, VectorSet &visited, Node_Stack &clones ); |
| |
| // Take steps to maximally unroll the loop. Peel any odd iterations, then |
| // unroll to do double iterations. The next round of major loop transforms |
| // will repeat till the doubled loop body does all remaining iterations in 1 |
| // pass. |
| void do_maximally_unroll( IdealLoopTree *loop, Node_List &old_new ); |
| |
| // Unroll the loop body one step - make each trip do 2 iterations. |
| void do_unroll( IdealLoopTree *loop, Node_List &old_new, bool adjust_min_trip ); |
| |
| // Mark vector reduction candidates before loop unrolling |
| void mark_reductions( IdealLoopTree *loop ); |
| |
| // Return true if exp is a constant times an induction var |
| bool is_scaled_iv(Node* exp, Node* iv, int* p_scale); |
| |
| // Return true if exp is a scaled induction var plus (or minus) constant |
| bool is_scaled_iv_plus_offset(Node* exp, Node* iv, int* p_scale, Node** p_offset, int depth = 0); |
| |
| // Create a new if above the uncommon_trap_if_pattern for the predicate to be promoted |
| ProjNode* create_new_if_for_predicate(ProjNode* cont_proj, Node* new_entry, |
| Deoptimization::DeoptReason reason, |
| int opcode); |
| void register_control(Node* n, IdealLoopTree *loop, Node* pred); |
| |
| // Clone loop predicates to cloned loops (peeled, unswitched) |
| static ProjNode* clone_predicate(ProjNode* predicate_proj, Node* new_entry, |
| Deoptimization::DeoptReason reason, |
| PhaseIdealLoop* loop_phase, |
| PhaseIterGVN* igvn); |
| |
| static Node* clone_loop_predicates(Node* old_entry, Node* new_entry, |
| bool clone_limit_check, |
| PhaseIdealLoop* loop_phase, |
| PhaseIterGVN* igvn); |
| Node* clone_loop_predicates(Node* old_entry, Node* new_entry, bool clone_limit_check); |
| |
| static Node* skip_loop_predicates(Node* entry); |
| |
| // Find a good location to insert a predicate |
| static ProjNode* find_predicate_insertion_point(Node* start_c, Deoptimization::DeoptReason reason); |
| // Find a predicate |
| static Node* find_predicate(Node* entry); |
| // Construct a range check for a predicate if |
| BoolNode* rc_predicate(IdealLoopTree *loop, Node* ctrl, |
| int scale, Node* offset, |
| Node* init, Node* limit, jint stride, |
| Node* range, bool upper, bool &overflow); |
| |
| // Implementation of the loop predication to promote checks outside the loop |
| bool loop_predication_impl(IdealLoopTree *loop); |
| |
| // Helper function to collect predicate for eliminating the useless ones |
| void collect_potentially_useful_predicates(IdealLoopTree *loop, Unique_Node_List &predicate_opaque1); |
| void eliminate_useless_predicates(); |
| |
| // Change the control input of expensive nodes to allow commoning by |
| // IGVN when it is guaranteed to not result in a more frequent |
| // execution of the expensive node. Return true if progress. |
| bool process_expensive_nodes(); |
| |
| // Check whether node has become unreachable |
| bool is_node_unreachable(Node *n) const { |
| return !has_node(n) || n->is_unreachable(_igvn); |
| } |
| |
| // Eliminate range-checks and other trip-counter vs loop-invariant tests. |
| int do_range_check( IdealLoopTree *loop, Node_List &old_new ); |
| |
| // Check to see if do_range_check(...) cleaned the main loop of range-checks |
| void has_range_checks(IdealLoopTree *loop); |
| |
| // Process post loops which have range checks and try to build a multi-version |
| // guard to safely determine if we can execute the post loop which was RCE'd. |
| bool multi_version_post_loops(IdealLoopTree *rce_loop, IdealLoopTree *legacy_loop); |
| |
| // Cause the rce'd post loop to optimized away, this happens if we cannot complete multiverioning |
| void poison_rce_post_loop(IdealLoopTree *rce_loop); |
| |
| // Create a slow version of the loop by cloning the loop |
| // and inserting an if to select fast-slow versions. |
| ProjNode* create_slow_version_of_loop(IdealLoopTree *loop, |
| Node_List &old_new, |
| int opcode); |
| |
| // Clone a loop and return the clone head (clone_loop_head). |
| // Added nodes include int(1), int(0) - disconnected, If, IfTrue, IfFalse, |
| // This routine was created for usage in CountedLoopReserveKit. |
| // |
| // int(1) -> If -> IfTrue -> original_loop_head |
| // | |
| // V |
| // IfFalse -> clone_loop_head (returned by function pointer) |
| // |
| LoopNode* create_reserve_version_of_loop(IdealLoopTree *loop, CountedLoopReserveKit* lk); |
| // Clone loop with an invariant test (that does not exit) and |
| // insert a clone of the test that selects which version to |
| // execute. |
| void do_unswitching (IdealLoopTree *loop, Node_List &old_new); |
| |
| // Find candidate "if" for unswitching |
| IfNode* find_unswitching_candidate(const IdealLoopTree *loop) const; |
| |
| // Range Check Elimination uses this function! |
| // Constrain the main loop iterations so the affine function: |
| // low_limit <= scale_con * I + offset < upper_limit |
| // always holds true. That is, either increase the number of iterations in |
| // the pre-loop or the post-loop until the condition holds true in the main |
| // loop. Scale_con, offset and limit are all loop invariant. |
| void add_constraint( int stride_con, int scale_con, Node *offset, Node *low_limit, Node *upper_limit, Node *pre_ctrl, Node **pre_limit, Node **main_limit ); |
| // Helper function for add_constraint(). |
| Node* adjust_limit( int stride_con, Node * scale, Node *offset, Node *rc_limit, Node *loop_limit, Node *pre_ctrl ); |
| |
| // Partially peel loop up through last_peel node. |
| bool partial_peel( IdealLoopTree *loop, Node_List &old_new ); |
| |
| // Create a scheduled list of nodes control dependent on ctrl set. |
| void scheduled_nodelist( IdealLoopTree *loop, VectorSet& ctrl, Node_List &sched ); |
| // Has a use in the vector set |
| bool has_use_in_set( Node* n, VectorSet& vset ); |
| // Has use internal to the vector set (ie. not in a phi at the loop head) |
| bool has_use_internal_to_set( Node* n, VectorSet& vset, IdealLoopTree *loop ); |
| // clone "n" for uses that are outside of loop |
| int clone_for_use_outside_loop( IdealLoopTree *loop, Node* n, Node_List& worklist ); |
| // clone "n" for special uses that are in the not_peeled region |
| void clone_for_special_use_inside_loop( IdealLoopTree *loop, Node* n, |
| VectorSet& not_peel, Node_List& sink_list, Node_List& worklist ); |
| // Insert phi(lp_entry_val, back_edge_val) at use->in(idx) for loop lp if phi does not already exist |
| void insert_phi_for_loop( Node* use, uint idx, Node* lp_entry_val, Node* back_edge_val, LoopNode* lp ); |
| #ifdef ASSERT |
| // Validate the loop partition sets: peel and not_peel |
| bool is_valid_loop_partition( IdealLoopTree *loop, VectorSet& peel, Node_List& peel_list, VectorSet& not_peel ); |
| // Ensure that uses outside of loop are of the right form |
| bool is_valid_clone_loop_form( IdealLoopTree *loop, Node_List& peel_list, |
| uint orig_exit_idx, uint clone_exit_idx); |
| bool is_valid_clone_loop_exit_use( IdealLoopTree *loop, Node* use, uint exit_idx); |
| #endif |
| |
| // Returns nonzero constant stride if-node is a possible iv test (otherwise returns zero.) |
| int stride_of_possible_iv( Node* iff ); |
| bool is_possible_iv_test( Node* iff ) { return stride_of_possible_iv(iff) != 0; } |
| // Return the (unique) control output node that's in the loop (if it exists.) |
| Node* stay_in_loop( Node* n, IdealLoopTree *loop); |
| // Insert a signed compare loop exit cloned from an unsigned compare. |
| IfNode* insert_cmpi_loop_exit(IfNode* if_cmpu, IdealLoopTree *loop); |
| void remove_cmpi_loop_exit(IfNode* if_cmp, IdealLoopTree *loop); |
| // Utility to register node "n" with PhaseIdealLoop |
| void register_node(Node* n, IdealLoopTree *loop, Node* pred, int ddepth); |
| // Utility to create an if-projection |
| ProjNode* proj_clone(ProjNode* p, IfNode* iff); |
| // Force the iff control output to be the live_proj |
| Node* short_circuit_if(IfNode* iff, ProjNode* live_proj); |
| // Insert a region before an if projection |
| RegionNode* insert_region_before_proj(ProjNode* proj); |
| // Insert a new if before an if projection |
| ProjNode* insert_if_before_proj(Node* left, bool Signed, BoolTest::mask relop, Node* right, ProjNode* proj); |
| |
| // Passed in a Phi merging (recursively) some nearly equivalent Bool/Cmps. |
| // "Nearly" because all Nodes have been cloned from the original in the loop, |
| // but the fall-in edges to the Cmp are different. Clone bool/Cmp pairs |
| // through the Phi recursively, and return a Bool. |
| BoolNode *clone_iff( PhiNode *phi, IdealLoopTree *loop ); |
| CmpNode *clone_bool( PhiNode *phi, IdealLoopTree *loop ); |
| |
| |
| // Rework addressing expressions to get the most loop-invariant stuff |
| // moved out. We'd like to do all associative operators, but it's especially |
| // important (common) to do address expressions. |
| Node *remix_address_expressions( Node *n ); |
| |
| // Attempt to use a conditional move instead of a phi/branch |
| Node *conditional_move( Node *n ); |
| |
| // Reorganize offset computations to lower register pressure. |
| // Mostly prevent loop-fallout uses of the pre-incremented trip counter |
| // (which are then alive with the post-incremented trip counter |
| // forcing an extra register move) |
| void reorg_offsets( IdealLoopTree *loop ); |
| |
| // Check for aggressive application of 'split-if' optimization, |
| // using basic block level info. |
| void split_if_with_blocks ( VectorSet &visited, Node_Stack &nstack ); |
| Node *split_if_with_blocks_pre ( Node *n ); |
| void split_if_with_blocks_post( Node *n ); |
| Node *has_local_phi_input( Node *n ); |
| // Mark an IfNode as being dominated by a prior test, |
| // without actually altering the CFG (and hence IDOM info). |
| void dominated_by( Node *prevdom, Node *iff, bool flip = false, bool exclude_loop_predicate = false ); |
| |
| // Split Node 'n' through merge point |
| Node *split_thru_region( Node *n, Node *region ); |
| // Split Node 'n' through merge point if there is enough win. |
| Node *split_thru_phi( Node *n, Node *region, int policy ); |
| // Found an If getting its condition-code input from a Phi in the |
| // same block. Split thru the Region. |
| void do_split_if( Node *iff ); |
| |
| // Conversion of fill/copy patterns into intrisic versions |
| bool do_intrinsify_fill(); |
| bool intrinsify_fill(IdealLoopTree* lpt); |
| bool match_fill_loop(IdealLoopTree* lpt, Node*& store, Node*& store_value, |
| Node*& shift, Node*& offset); |
| |
| private: |
| // Return a type based on condition control flow |
| const TypeInt* filtered_type( Node *n, Node* n_ctrl); |
| const TypeInt* filtered_type( Node *n ) { return filtered_type(n, NULL); } |
| // Helpers for filtered type |
| const TypeInt* filtered_type_from_dominators( Node* val, Node *val_ctrl); |
| |
| // Helper functions |
| Node *spinup( Node *iff, Node *new_false, Node *new_true, Node *region, Node *phi, small_cache *cache ); |
| Node *find_use_block( Node *use, Node *def, Node *old_false, Node *new_false, Node *old_true, Node *new_true ); |
| void handle_use( Node *use, Node *def, small_cache *cache, Node *region_dom, Node *new_false, Node *new_true, Node *old_false, Node *old_true ); |
| bool split_up( Node *n, Node *blk1, Node *blk2 ); |
| void sink_use( Node *use, Node *post_loop ); |
| Node *place_near_use( Node *useblock ) const; |
| Node* try_move_store_before_loop(Node* n, Node *n_ctrl); |
| void try_move_store_after_loop(Node* n); |
| bool identical_backtoback_ifs(Node *n); |
| bool can_split_if(Node *n_ctrl); |
| |
| bool _created_loop_node; |
| public: |
| void set_created_loop_node() { _created_loop_node = true; } |
| bool created_loop_node() { return _created_loop_node; } |
| void register_new_node( Node *n, Node *blk ); |
| |
| #ifdef ASSERT |
| void dump_bad_graph(const char* msg, Node* n, Node* early, Node* LCA); |
| #endif |
| |
| #ifndef PRODUCT |
| void dump( ) const; |
| void dump( IdealLoopTree *loop, uint rpo_idx, Node_List &rpo_list ) const; |
| void rpo( Node *start, Node_Stack &stk, VectorSet &visited, Node_List &rpo_list ) const; |
| void verify() const; // Major slow :-) |
| void verify_compare( Node *n, const PhaseIdealLoop *loop_verify, VectorSet &visited ) const; |
| IdealLoopTree *get_loop_idx(Node* n) const { |
| // Dead nodes have no loop, so return the top level loop instead |
| return _nodes[n->_idx] ? (IdealLoopTree*)_nodes[n->_idx] : _ltree_root; |
| } |
| // Print some stats |
| static void print_statistics(); |
| static int _loop_invokes; // Count of PhaseIdealLoop invokes |
| static int _loop_work; // Sum of PhaseIdealLoop x _unique |
| #endif |
| }; |
| |
| // This kit may be used for making of a reserved copy of a loop before this loop |
| // goes under non-reversible changes. |
| // |
| // Function create_reserve() creates a reserved copy (clone) of the loop. |
| // The reserved copy is created by calling |
| // PhaseIdealLoop::create_reserve_version_of_loop - see there how |
| // the original and reserved loops are connected in the outer graph. |
| // If create_reserve succeeded, it returns 'true' and _has_reserved is set to 'true'. |
| // |
| // By default the reserved copy (clone) of the loop is created as dead code - it is |
| // dominated in the outer loop by this node chain: |
| // intcon(1)->If->IfFalse->reserved_copy. |
| // The original loop is dominated by the the same node chain but IfTrue projection: |
| // intcon(0)->If->IfTrue->original_loop. |
| // |
| // In this implementation of CountedLoopReserveKit the ctor includes create_reserve() |
| // and the dtor, checks _use_new value. |
| // If _use_new == false, it "switches" control to reserved copy of the loop |
| // by simple replacing of node intcon(1) with node intcon(0). |
| // |
| // Here is a proposed example of usage (see also SuperWord::output in superword.cpp). |
| // |
| // void CountedLoopReserveKit_example() |
| // { |
| // CountedLoopReserveKit lrk((phase, lpt, DoReserveCopy = true); // create local object |
| // if (DoReserveCopy && !lrk.has_reserved()) { |
| // return; //failed to create reserved loop copy |
| // } |
| // ... |
| // //something is wrong, switch to original loop |
| /// if(something_is_wrong) return; // ~CountedLoopReserveKit makes the switch |
| // ... |
| // //everything worked ok, return with the newly modified loop |
| // lrk.use_new(); |
| // return; // ~CountedLoopReserveKit does nothing once use_new() was called |
| // } |
| // |
| // Keep in mind, that by default if create_reserve() is not followed by use_new() |
| // the dtor will "switch to the original" loop. |
| // NOTE. You you modify outside of the original loop this class is no help. |
| // |
| class CountedLoopReserveKit { |
| private: |
| PhaseIdealLoop* _phase; |
| IdealLoopTree* _lpt; |
| LoopNode* _lp; |
| IfNode* _iff; |
| LoopNode* _lp_reserved; |
| bool _has_reserved; |
| bool _use_new; |
| const bool _active; //may be set to false in ctor, then the object is dummy |
| |
| public: |
| CountedLoopReserveKit(PhaseIdealLoop* phase, IdealLoopTree *loop, bool active); |
| ~CountedLoopReserveKit(); |
| void use_new() {_use_new = true;} |
| void set_iff(IfNode* x) {_iff = x;} |
| bool has_reserved() const { return _active && _has_reserved;} |
| private: |
| bool create_reserve(); |
| };// class CountedLoopReserveKit |
| |
| inline Node* IdealLoopTree::tail() { |
| // Handle lazy update of _tail field |
| Node *n = _tail; |
| //while( !n->in(0) ) // Skip dead CFG nodes |
| //n = n->in(1); |
| if (n->in(0) == NULL) |
| n = _phase->get_ctrl(n); |
| _tail = n; |
| return n; |
| } |
| |
| |
| // Iterate over the loop tree using a preorder, left-to-right traversal. |
| // |
| // Example that visits all counted loops from within PhaseIdealLoop |
| // |
| // for (LoopTreeIterator iter(_ltree_root); !iter.done(); iter.next()) { |
| // IdealLoopTree* lpt = iter.current(); |
| // if (!lpt->is_counted()) continue; |
| // ... |
| class LoopTreeIterator : public StackObj { |
| private: |
| IdealLoopTree* _root; |
| IdealLoopTree* _curnt; |
| |
| public: |
| LoopTreeIterator(IdealLoopTree* root) : _root(root), _curnt(root) {} |
| |
| bool done() { return _curnt == NULL; } // Finished iterating? |
| |
| void next(); // Advance to next loop tree |
| |
| IdealLoopTree* current() { return _curnt; } // Return current value of iterator. |
| }; |
| |
| #endif // SHARE_VM_OPTO_LOOPNODE_HPP |