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/*
* Copyright (c) 1998, 2023, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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*
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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#ifndef SHARE_OPTO_LOOPNODE_HPP
#define SHARE_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 BaseCountedLoopEndNode;
class CountedLoopNode;
class IdealLoopTree;
class LoopNode;
class Node;
class OuterStripMinedLoopEndNode;
class ParsePredicates;
class PathFrequency;
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:
uint _loop_flags;
// Names for flag bitfields
enum { Normal=0, Pre=1, Main=2, Post=3, PreMainPostFlagsMask=3,
MainHasNoPreLoop = 1<<2,
HasExactTripCount = 1<<3,
InnerLoop = 1<<4,
PartialPeelLoop = 1<<5,
PartialPeelFailed = 1<<6,
WasSlpAnalyzed = 1<<7,
PassedSlpAnalysis = 1<<8,
DoUnrollOnly = 1<<9,
VectorizedLoop = 1<<10,
HasAtomicPostLoop = 1<<11,
IsMultiversioned = 1<<12,
StripMined = 1<<13,
SubwordLoop = 1<<14,
ProfileTripFailed = 1<<15,
LoopNestInnerLoop = 1<<16,
LoopNestLongOuterLoop = 1<<17};
char _unswitch_count;
enum { _unswitch_max=3 };
char _postloop_flags;
enum { RCEPostLoop = 1 };
// Expected trip count from profile data
float _profile_trip_cnt;
public:
// Names for edge indices
enum { Self=0, EntryControl, LoopBackControl };
bool is_inner_loop() const { return _loop_flags & InnerLoop; }
void set_inner_loop() { _loop_flags |= InnerLoop; }
bool is_multiversioned() const { return _loop_flags & IsMultiversioned; }
bool is_vectorized_loop() const { return _loop_flags & VectorizedLoop; }
bool is_partial_peel_loop() const { return _loop_flags & PartialPeelLoop; }
void set_partial_peel_loop() { _loop_flags |= PartialPeelLoop; }
bool partial_peel_has_failed() const { return _loop_flags & PartialPeelFailed; }
bool is_strip_mined() const { return _loop_flags & StripMined; }
bool is_profile_trip_failed() const { return _loop_flags & ProfileTripFailed; }
bool is_subword_loop() const { return _loop_flags & SubwordLoop; }
bool is_loop_nest_inner_loop() const { return _loop_flags & LoopNestInnerLoop; }
bool is_loop_nest_outer_loop() const { return _loop_flags & LoopNestLongOuterLoop; }
void mark_partial_peel_failed() { _loop_flags |= PartialPeelFailed; }
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_is_multiversioned() { _loop_flags |= IsMultiversioned; }
void mark_strip_mined() { _loop_flags |= StripMined; }
void clear_strip_mined() { _loop_flags &= ~StripMined; }
void mark_profile_trip_failed() { _loop_flags |= ProfileTripFailed; }
void mark_subword_loop() { _loop_flags |= SubwordLoop; }
void mark_loop_nest_inner_loop() { _loop_flags |= LoopNestInnerLoop; }
void mark_loop_nest_outer_loop() { _loop_flags |= LoopNestLongOuterLoop; }
int unswitch_max() { return _unswitch_max; }
int unswitch_count() { return _unswitch_count; }
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;
}
void set_profile_trip_cnt(float ptc) { _profile_trip_cnt = ptc; }
float profile_trip_cnt() { return _profile_trip_cnt; }
LoopNode(Node *entry, Node *backedge)
: RegionNode(3), _loop_flags(0), _unswitch_count(0),
_postloop_flags(0), _profile_trip_cnt(COUNT_UNKNOWN) {
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(PhaseValues* phase) const {
return req() == 3 && in(0) != nullptr &&
in(1) != nullptr && phase->type(in(1)) != Type::TOP &&
in(2) != nullptr && phase->type(in(2)) != Type::TOP;
}
bool is_valid_counted_loop(BasicType bt) const;
#ifndef PRODUCT
virtual void dump_spec(outputStream *st) const;
#endif
void verify_strip_mined(int expect_skeleton) const NOT_DEBUG_RETURN;
virtual LoopNode* skip_strip_mined(int expect_skeleton = 1) { return this; }
virtual IfTrueNode* outer_loop_tail() const { ShouldNotReachHere(); return nullptr; }
virtual OuterStripMinedLoopEndNode* outer_loop_end() const { ShouldNotReachHere(); return nullptr; }
virtual IfFalseNode* outer_loop_exit() const { ShouldNotReachHere(); return nullptr; }
virtual SafePointNode* outer_safepoint() const { ShouldNotReachHere(); return nullptr; }
};
//------------------------------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 BaseCountedLoopNode : public LoopNode {
public:
BaseCountedLoopNode(Node *entry, Node *backedge)
: LoopNode(entry, backedge) {
}
Node *init_control() const { return in(EntryControl); }
Node *back_control() const { return in(LoopBackControl); }
Node* init_trip() const;
Node* stride() const;
bool stride_is_con() const;
Node* limit() const;
Node* incr() const;
Node* phi() const;
BaseCountedLoopEndNode* loopexit_or_null() const;
BaseCountedLoopEndNode* loopexit() const;
virtual BasicType bt() const = 0;
jlong stride_con() const;
static BaseCountedLoopNode* make(Node* entry, Node* backedge, BasicType bt);
};
class CountedLoopNode : public BaseCountedLoopNode {
// 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;
// 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;
// The eventual count of vectorizable packs in slp
int _slp_vector_pack_count;
public:
CountedLoopNode(Node *entry, Node *backedge)
: BaseCountedLoopNode(entry, backedge), _main_idx(0), _trip_count(max_juint),
_unrolled_count_log2(0), _node_count_before_unroll(0),
_slp_maximum_unroll_factor(0), _slp_vector_pack_count(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);
CountedLoopEndNode* loopexit_or_null() const { return (CountedLoopEndNode*) BaseCountedLoopNode::loopexit_or_null(); }
CountedLoopEndNode* loopexit() const { return (CountedLoopEndNode*) BaseCountedLoopNode::loopexit(); }
int stride_con() const;
// Match increment with optional truncation
static Node*
match_incr_with_optional_truncation(Node* expr, Node** trunc1, Node** trunc2, const TypeInteger** trunc_type,
BasicType bt);
// 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.
bool is_normal_loop () const { return (_loop_flags&PreMainPostFlagsMask) == Normal; }
bool is_pre_loop () const { return (_loop_flags&PreMainPostFlagsMask) == Pre; }
bool is_main_loop () const { return (_loop_flags&PreMainPostFlagsMask) == Main; }
bool is_post_loop () const { return (_loop_flags&PreMainPostFlagsMask) == Post; }
bool was_slp_analyzed () const { return (_loop_flags&WasSlpAnalyzed) == WasSlpAnalyzed; }
bool has_passed_slp () const { return (_loop_flags&PassedSlpAnalysis) == PassedSlpAnalysis; }
bool is_unroll_only () const { return (_loop_flags&DoUnrollOnly) == DoUnrollOnly; }
bool is_main_no_pre_loop() const { return _loop_flags & MainHasNoPreLoop; }
bool 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 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; }
void set_slp_pack_count(int pack_count) { _slp_vector_pack_count = pack_count; }
int slp_pack_count() const { return _slp_vector_pack_count; }
virtual LoopNode* skip_strip_mined(int expect_skeleton = 1);
OuterStripMinedLoopNode* outer_loop() const;
virtual IfTrueNode* outer_loop_tail() const;
virtual OuterStripMinedLoopEndNode* outer_loop_end() const;
virtual IfFalseNode* outer_loop_exit() const;
virtual SafePointNode* outer_safepoint() const;
// If this is a main loop in a pre/main/post loop nest, walk over
// the predicates that were inserted by
// duplicate_predicates()/add_range_check_predicate()
static Node* skip_predicates_from_entry(Node* ctrl);
Node* skip_predicates();
virtual BasicType bt() const {
return T_INT;
}
Node* is_canonical_loop_entry();
#ifndef PRODUCT
virtual void dump_spec(outputStream *st) const;
#endif
static bool is_zero_trip_guard_if(const IfNode* iff);
};
class LongCountedLoopNode : public BaseCountedLoopNode {
public:
LongCountedLoopNode(Node *entry, Node *backedge)
: BaseCountedLoopNode(entry, backedge) {
init_class_id(Class_LongCountedLoop);
}
virtual int Opcode() const;
virtual BasicType bt() const {
return T_LONG;
}
LongCountedLoopEndNode* loopexit_or_null() const { return (LongCountedLoopEndNode*) BaseCountedLoopNode::loopexit_or_null(); }
LongCountedLoopEndNode* loopexit() const { return (LongCountedLoopEndNode*) BaseCountedLoopNode::loopexit(); }
};
//------------------------------CountedLoopEndNode-----------------------------
// CountedLoopEndNodes end simple trip counted loops. They act much like
// IfNodes.
class BaseCountedLoopEndNode : public IfNode {
public:
enum { TestControl, TestValue };
BaseCountedLoopEndNode(Node *control, Node *test, float prob, float cnt)
: IfNode(control, test, prob, cnt) {
init_class_id(Class_BaseCountedLoopEnd);
}
Node *cmp_node() const { return (in(TestValue)->req() >=2) ? in(TestValue)->in(1) : nullptr; }
Node* incr() const { Node* tmp = cmp_node(); return (tmp && tmp->req() == 3) ? tmp->in(1) : nullptr; }
Node* limit() const { Node* tmp = cmp_node(); return (tmp && tmp->req() == 3) ? tmp->in(2) : nullptr; }
Node* stride() const { Node* tmp = incr(); return (tmp && tmp->req() == 3) ? tmp->in(2) : nullptr; }
Node* init_trip() const { Node* tmp = phi(); return (tmp && tmp->req() == 3) ? tmp->in(1) : nullptr; }
bool stride_is_con() const { Node *tmp = stride(); return (tmp != nullptr && tmp->is_Con()); }
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 nullptr;
}
BaseCountedLoopNode* 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 == nullptr) {
return nullptr;
}
Node* ln = iv_phi->in(0);
if (!ln->is_BaseCountedLoop() || ln->as_BaseCountedLoop()->loopexit_or_null() != this) {
return nullptr;
}
if (ln->as_BaseCountedLoop()->bt() != bt()) {
return nullptr;
}
return ln->as_BaseCountedLoop();
}
BoolTest::mask test_trip() const { return in(TestValue)->as_Bool()->_test._test; }
jlong stride_con() const;
virtual BasicType bt() const = 0;
static BaseCountedLoopEndNode* make(Node* control, Node* test, float prob, float cnt, BasicType bt);
};
class CountedLoopEndNode : public BaseCountedLoopEndNode {
public:
CountedLoopEndNode(Node *control, Node *test, float prob, float cnt)
: BaseCountedLoopEndNode(control, test, prob, cnt) {
init_class_id(Class_CountedLoopEnd);
}
virtual int Opcode() const;
CountedLoopNode* loopnode() const {
return (CountedLoopNode*) BaseCountedLoopEndNode::loopnode();
}
virtual BasicType bt() const {
return T_INT;
}
#ifndef PRODUCT
virtual void dump_spec(outputStream *st) const;
#endif
};
class LongCountedLoopEndNode : public BaseCountedLoopEndNode {
public:
LongCountedLoopEndNode(Node *control, Node *test, float prob, float cnt)
: BaseCountedLoopEndNode(control, test, prob, cnt) {
init_class_id(Class_LongCountedLoopEnd);
}
LongCountedLoopNode* loopnode() const {
return (LongCountedLoopNode*) BaseCountedLoopEndNode::loopnode();
}
virtual int Opcode() const;
virtual BasicType bt() const {
return T_LONG;
}
};
inline BaseCountedLoopEndNode* BaseCountedLoopNode::loopexit_or_null() const {
Node* bctrl = back_control();
if (bctrl == nullptr) return nullptr;
Node* lexit = bctrl->in(0);
if (!lexit->is_BaseCountedLoopEnd()) {
return nullptr;
}
BaseCountedLoopEndNode* result = lexit->as_BaseCountedLoopEnd();
if (result->bt() != bt()) {
return nullptr;
}
return result;
}
inline BaseCountedLoopEndNode* BaseCountedLoopNode::loopexit() const {
BaseCountedLoopEndNode* cle = loopexit_or_null();
assert(cle != nullptr, "loopexit is null");
return cle;
}
inline Node* BaseCountedLoopNode::init_trip() const {
BaseCountedLoopEndNode* cle = loopexit_or_null();
return cle != nullptr ? cle->init_trip() : nullptr;
}
inline Node* BaseCountedLoopNode::stride() const {
BaseCountedLoopEndNode* cle = loopexit_or_null();
return cle != nullptr ? cle->stride() : nullptr;
}
inline bool BaseCountedLoopNode::stride_is_con() const {
BaseCountedLoopEndNode* cle = loopexit_or_null();
return cle != nullptr && cle->stride_is_con();
}
inline Node* BaseCountedLoopNode::limit() const {
BaseCountedLoopEndNode* cle = loopexit_or_null();
return cle != nullptr ? cle->limit() : nullptr;
}
inline Node* BaseCountedLoopNode::incr() const {
BaseCountedLoopEndNode* cle = loopexit_or_null();
return cle != nullptr ? cle->incr() : nullptr;
}
inline Node* BaseCountedLoopNode::phi() const {
BaseCountedLoopEndNode* cle = loopexit_or_null();
return cle != nullptr ? cle->phi() : nullptr;
}
inline jlong BaseCountedLoopNode::stride_con() const {
BaseCountedLoopEndNode* cle = loopexit_or_null();
return cle != nullptr ? cle->stride_con() : 0;
}
//------------------------------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);
};
// Support for strip mining
class OuterStripMinedLoopNode : public LoopNode {
private:
static void fix_sunk_stores(CountedLoopEndNode* inner_cle, LoopNode* inner_cl, PhaseIterGVN* igvn, PhaseIdealLoop* iloop);
public:
OuterStripMinedLoopNode(Compile* C, Node *entry, Node *backedge)
: LoopNode(entry, backedge) {
init_class_id(Class_OuterStripMinedLoop);
init_flags(Flag_is_macro);
C->add_macro_node(this);
}
virtual int Opcode() const;
virtual IfTrueNode* outer_loop_tail() const;
virtual OuterStripMinedLoopEndNode* outer_loop_end() const;
virtual IfFalseNode* outer_loop_exit() const;
virtual SafePointNode* outer_safepoint() const;
void adjust_strip_mined_loop(PhaseIterGVN* igvn);
void remove_outer_loop_and_safepoint(PhaseIterGVN* igvn) const;
void transform_to_counted_loop(PhaseIterGVN* igvn, PhaseIdealLoop* iloop);
static Node* register_new_node(Node* node, LoopNode* ctrl, PhaseIterGVN* igvn, PhaseIdealLoop* iloop);
Node* register_control(Node* node, Node* loop, Node* idom, PhaseIterGVN* igvn,
PhaseIdealLoop* iloop);
};
class OuterStripMinedLoopEndNode : public IfNode {
public:
OuterStripMinedLoopEndNode(Node *control, Node *test, float prob, float cnt)
: IfNode(control, test, prob, cnt) {
init_class_id(Class_OuterStripMinedLoopEnd);
}
virtual int Opcode() const;
virtual const Type* Value(PhaseGVN* phase) const;
virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
bool is_expanded(PhaseGVN *phase) const;
};
// -----------------------------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 a loop has multiple backedges, this is addressed during cleanup where
// we peel off the multiple backedges, merging all edges at the bottom and
// ensuring that one proper backedge flow into the loop.
Node *_head; // Head of loop
Node *_tail; // Tail of loop
inline Node *tail(); // Handle lazy update of _tail field
inline Node *head(); // Handle lazy update of _head field
PhaseIdealLoop* _phase;
int _local_loop_unroll_limit;
int _local_loop_unroll_factor;
Node_List _body; // Loop body for inner loops
uint16_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
_has_range_checks:1,
_has_range_checks_computed:1;
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),
_local_loop_unroll_limit(0), _local_loop_unroll_factor(0),
_nest(0), _irreducible(0), _has_call(0), _has_sfpt(0), _rce_candidate(0),
_has_range_checks(0), _has_range_checks_computed(0),
_safepts(nullptr),
_required_safept(nullptr),
_allow_optimizations(true)
{
precond(_head != nullptr);
precond(_tail != nullptr);
}
// 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 do_remove_empty_loop( PhaseIdealLoop *phase );
// Convert one iteration loop into normal code.
bool do_one_iteration_loop( PhaseIdealLoop *phase );
// Return TRUE or FALSE if the loop should be peeled or not. Peel if we can
// move some loop-invariant test (usually a null-check) before the loop.
bool policy_peeling(PhaseIdealLoop *phase);
uint estimate_peeling(PhaseIdealLoop *phase);
// 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. Apply unroll
// if the loop is a counted loop and the loop 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, bool provisional, BasicType bt) const;
// Return TRUE if "iff" is a range check.
bool is_range_check_if(IfProjNode* if_success_proj, PhaseIdealLoop* phase, Invariance& invar DEBUG_ONLY(COMMA ProjNode* predicate_proj)) const;
bool is_range_check_if(IfProjNode* if_success_proj, PhaseIdealLoop* phase, BasicType bt, Node* iv, Node*& range, Node*& offset,
jlong& scale) const;
// Estimate the number of nodes required when cloning a loop (body).
uint est_loop_clone_sz(uint factor) const;
// Estimate the number of nodes required when unrolling a loop (body).
uint est_loop_unroll_sz(uint factor) const;
// Compute loop trip count if possible
void compute_trip_count(PhaseIdealLoop* phase);
// Compute loop trip count from profile data
float compute_profile_trip_cnt_helper(Node* n);
void compute_profile_trip_cnt( PhaseIdealLoop *phase );
// Reassociate invariant expressions.
void reassociate_invariants(PhaseIdealLoop *phase);
// Reassociate invariant binary expressions.
Node* reassociate(Node* n1, PhaseIdealLoop *phase);
// Reassociate invariant add and subtract expressions.
Node* reassociate_add_sub(Node* n1, int inv1_idx, int inv2_idx, PhaseIdealLoop *phase);
// Return nonzero index of invariant operand if invariant and variant
// are combined with an associative binary. Helper for reassociate_invariants.
int find_invariant(Node* n, PhaseIdealLoop *phase);
// Return TRUE if "n" is associative.
bool is_associative(Node* n, Node* base=nullptr);
// 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_root() { return _parent == nullptr; }
// A proper/reducible loop w/o any (occasional) dead back-edge.
bool is_loop() { return !_irreducible && !tail()->is_top(); }
bool is_counted() { return is_loop() && _head->is_CountedLoop(); }
bool is_innermost() { return is_loop() && _child == nullptr; }
void remove_main_post_loops(CountedLoopNode *cl, PhaseIdealLoop *phase);
bool compute_has_range_checks() const;
bool range_checks_present() {
if (!_has_range_checks_computed) {
if (compute_has_range_checks()) {
_has_range_checks = 1;
}
_has_range_checks_computed = 1;
}
return _has_range_checks;
}
#ifndef PRODUCT
void dump_head(); // Dump loop head only
void dump(); // Dump this loop recursively
#endif
#ifdef ASSERT
GrowableArray<IdealLoopTree*> collect_sorted_children() const;
bool verify_tree(IdealLoopTree* loop_verify) const;
#endif
private:
enum { EMPTY_LOOP_SIZE = 7 }; // Number of nodes in an empty loop.
// Estimate the number of nodes resulting from control and data flow merge.
uint est_loop_flow_merge_sz() const;
// Check if the number of residual iterations is large with unroll_cnt.
// Return true if the residual iterations are more than 10% of the trip count.
bool is_residual_iters_large(int unroll_cnt, CountedLoopNode *cl) const {
return (unroll_cnt - 1) * (100.0 / LoopPercentProfileLimit) > cl->profile_trip_cnt();
}
void collect_loop_core_nodes(PhaseIdealLoop* phase, Unique_Node_List& wq) const;
bool empty_loop_with_data_nodes(PhaseIdealLoop* phase) const;
void enqueue_data_nodes(PhaseIdealLoop* phase, Unique_Node_List& empty_loop_nodes, Unique_Node_List& wq) const;
bool process_safepoint(PhaseIdealLoop* phase, Unique_Node_List& empty_loop_nodes, Unique_Node_List& wq,
Node* sfpt) const;
bool empty_loop_candidate(PhaseIdealLoop* phase) const;
bool empty_loop_with_extra_nodes_candidate(PhaseIdealLoop* phase) const;
};
// -----------------------------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;
friend class ShenandoahBarrierC2Support;
friend class AutoNodeBudget;
// Map loop membership for CFG nodes, and ctrl for non-CFG nodes.
Node_List _loop_or_ctrl;
// 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; }
public:
// 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(const Node* n) const { return ((intptr_t)_loop_or_ctrl[n->_idx]) & 1; }
private:
// clear out dead code after build_loop_late
Node_List _deadlist;
Node_List _zero_trip_guard_opaque_nodes;
// Support for faster execution of get_late_ctrl()/dom_lca()
// when a node has many uses and dominator depth is deep.
GrowableArray<jlong> _dom_lca_tags;
uint _dom_lca_tags_round;
void init_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 != nullptr && 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 != nullptr) {
if (ctrl->is_MultiBranch()) {
ctrl = ctrl->in(0);
}
assert(ctrl->is_CFG(), "CFG");
}
return ctrl;
}
Node* cast_incr_before_loop(Node* incr, Node* ctrl, Node* loop);
#ifdef ASSERT
void ensure_zero_trip_guard_proj(Node* node, bool is_main_loop);
#endif
void copy_assertion_predicates_to_main_loop_helper(Node* predicate, Node* init, Node* stride, IdealLoopTree* outer_loop,
LoopNode* outer_main_head, uint dd_main_head,
uint idx_before_pre_post, uint idx_after_post_before_pre,
Node* zero_trip_guard_proj_main, Node* zero_trip_guard_proj_post,
const Node_List &old_new);
void copy_assertion_predicates_to_main_loop(CountedLoopNode* pre_head, Node* init, Node* stride, IdealLoopTree* outer_loop,
LoopNode* outer_main_head, uint dd_main_head, uint idx_before_pre_post,
uint idx_after_post_before_pre, Node* zero_trip_guard_proj_main,
Node* zero_trip_guard_proj_post, const Node_List& old_new);
Node* clone_assertion_predicate_and_initialize(Node* iff, Node* new_init, Node* new_stride, Node* predicate,
Node* uncommon_proj, Node* control, IdealLoopTree* outer_loop,
Node* input_proj);
static void count_opaque_loop_nodes(Node* n, uint& init, uint& stride);
static bool subgraph_has_opaque(Node* n);
Node* create_bool_from_template_assertion_predicate(Node* template_assertion_predicate, Node* new_init, Node* new_stride,
Node* control);
static bool assertion_predicate_has_loop_opaque_node(IfNode* iff);
static void get_assertion_predicates(Node* predicate, Unique_Node_List& list, bool get_opaque = false);
void update_main_loop_assertion_predicates(Node* ctrl, CountedLoopNode* loop_head, Node* init, int stride_con);
void copy_assertion_predicates_to_post_loop(LoopNode* main_loop_head, CountedLoopNode* post_loop_head, Node* init,
Node* stride);
void initialize_assertion_predicates_for_peeled_loop(IfProjNode* predicate_proj, LoopNode* outer_loop_head,
const int dd_outer_loop_head, Node* init, Node* stride,
IdealLoopTree* outer_loop, const uint idx_before_clone,
const Node_List& old_new);
void insert_loop_limit_check_predicate(ParsePredicateSuccessProj* loop_limit_check_parse_proj, Node* cmp_limit,
Node* bol);
#ifdef ASSERT
bool only_has_infinite_loops();
#endif
void log_loop_tree();
public:
PhaseIterGVN &igvn() const { return _igvn; }
bool has_node(const Node* n) const {
guarantee(n != nullptr, "No Node.");
return _loop_or_ctrl[n->_idx] != nullptr;
}
// 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, bool update_body);
void set_subtree_ctrl(Node* n, bool update_body);
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" );
_loop_or_ctrl.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 == nullptr) old_loop->_body.yank(n);
if (new_loop->_child == nullptr) 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(const Node* i) {
assert(has_node(i), "");
Node *n = get_ctrl_no_update(i);
_loop_or_ctrl.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;
}
}
Node* get_ctrl_no_update_helper(const Node* i) const {
assert(has_ctrl(i), "should be control, not loop");
return (Node*)(((intptr_t)_loop_or_ctrl[i->_idx]) & ~1);
}
Node* get_ctrl_no_update(const 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 ) {
_loop_or_ctrl.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.
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.
_loop_or_ctrl.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 );
#ifdef ASSERT
// verify that regions in irreducible loops are marked is_in_irreducible_loop
void verify_regions_in_irreducible_loops();
bool is_in_irreducible_loop(RegionNode* region);
#endif
// 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_work(Node* n, bool pinned);
void build_loop_late_post(Node* n);
void verify_strip_mined_scheduling(Node *n, Node* least);
// 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
LoopOptsMode _mode;
// build the loop tree and perform any requested optimizations
void build_and_optimize();
// Dominators for the sea of nodes
void Dominators();
// Compute the Ideal Node to Loop mapping
PhaseIdealLoop(PhaseIterGVN& igvn, LoopOptsMode mode) :
PhaseTransform(Ideal_Loop),
_loop_or_ctrl(igvn.C->comp_arena()),
_igvn(igvn),
_verify_me(nullptr),
_verify_only(false),
_mode(mode),
_nodes_required(UINT_MAX) {
assert(mode != LoopOptsVerify, "wrong constructor to verify IdealLoop");
build_and_optimize();
}
#ifndef PRODUCT
// Verify that verify_me made the same decisions as a fresh run
// or only verify that the graph is valid if verify_me is null.
PhaseIdealLoop(PhaseIterGVN& igvn, const PhaseIdealLoop* verify_me = nullptr) :
PhaseTransform(Ideal_Loop),
_loop_or_ctrl(igvn.C->comp_arena()),
_igvn(igvn),
_verify_me(verify_me),
_verify_only(verify_me == nullptr),
_mode(LoopOptsVerify),
_nodes_required(UINT_MAX) {
build_and_optimize();
}
#endif
public:
Node* idom_no_update(Node* d) const {
return idom_no_update(d->_idx);
}
Node* idom_no_update(uint didx) const {
assert(didx < _idom_size, "oob");
Node* n = _idom[didx];
assert(n != nullptr,"Bad immediate dominator info.");
while (n->in(0) == nullptr) { // Skip dead CFG nodes
n = (Node*)(((intptr_t)_loop_or_ctrl[n->_idx]) & ~1);
assert(n != nullptr,"Bad immediate dominator info.");
}
return n;
}
Node *idom(Node* d) const {
return idom(d->_idx);
}
Node *idom(uint didx) const {
Node *n = idom_no_update(didx);
_idom[didx] = n; // Lazily remove dead CFG nodes from table.
return n;
}
uint dom_depth(Node* d) const {
guarantee(d != nullptr, "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);
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;
// 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
ResourceMark rm;
Compile::TracePhase tp("idealLoopVerify", &timers[_t_idealLoopVerify]);
PhaseIdealLoop v(igvn);
#endif
}
// Recommended way to use PhaseIdealLoop.
// Run PhaseIdealLoop in some mode and allocates a local scope for memory allocations.
static void optimize(PhaseIterGVN &igvn, LoopOptsMode mode) {
ResourceMark rm;
PhaseIdealLoop v(igvn, mode);
Compile* C = Compile::current();
if (!C->failing()) {
// Cleanup any modified bits
igvn.optimize();
if (C->failing()) { return; }
v.log_loop_tree();
}
}
// True if the method has at least 1 irreducible loop
bool _has_irreducible_loops;
// Per-Node transform
virtual Node* transform(Node* n) { return nullptr; }
Node* loop_exit_control(Node* x, IdealLoopTree* loop);
Node* loop_exit_test(Node* back_control, IdealLoopTree* loop, Node*& incr, Node*& limit, BoolTest::mask& bt, float& cl_prob);
Node* loop_iv_incr(Node* incr, Node* x, IdealLoopTree* loop, Node*& phi_incr);
Node* loop_iv_stride(Node* incr, IdealLoopTree* loop, Node*& xphi);
PhiNode* loop_iv_phi(Node* xphi, Node* phi_incr, Node* x, IdealLoopTree* loop);
bool is_counted_loop(Node* x, IdealLoopTree*&loop, BasicType iv_bt);
Node* loop_nest_replace_iv(Node* iv_to_replace, Node* inner_iv, Node* outer_phi, Node* inner_head, BasicType bt);
bool create_loop_nest(IdealLoopTree* loop, Node_List &old_new);
#ifdef ASSERT
bool convert_to_long_loop(Node* cmp, Node* phi, IdealLoopTree* loop);
#endif
void add_parse_predicate(Deoptimization::DeoptReason reason, Node* inner_head, IdealLoopTree* loop, SafePointNode* sfpt);
SafePointNode* find_safepoint(Node* back_control, Node* x, IdealLoopTree* loop);
IdealLoopTree* insert_outer_loop(IdealLoopTree* loop, LoopNode* outer_l, Node* outer_ift);
IdealLoopTree* create_outer_strip_mined_loop(BoolNode *test, Node *cmp, Node *init_control,
IdealLoopTree* loop, float cl_prob, float le_fcnt,
Node*& entry_control, Node*& iffalse);
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*)_loop_or_ctrl[n->_idx];
}
IdealLoopTree* ltree_root() const { return _ltree_root; }
// 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.
enum CloneLoopMode {
IgnoreStripMined = 0, // Only clone inner strip mined loop
CloneIncludesStripMined = 1, // clone both inner and outer strip mined loops
ControlAroundStripMined = 2 // Only clone inner strip mined loop,
// result control flow branches
// either to inner clone or outer
// strip mined loop.
};
void clone_loop( IdealLoopTree *loop, Node_List &old_new, int dom_depth,
CloneLoopMode mode, Node* side_by_side_idom = nullptr);
void clone_loop_handle_data_uses(Node* old, Node_List &old_new,
IdealLoopTree* loop, IdealLoopTree* companion_loop,
Node_List*& split_if_set, Node_List*& split_bool_set,
Node_List*& split_cex_set, Node_List& worklist,
uint new_counter, CloneLoopMode mode);
void clone_outer_loop(LoopNode* head, CloneLoopMode mode, IdealLoopTree *loop,
IdealLoopTree* outer_loop, int dd, Node_List &old_new,
Node_List& extra_data_nodes);
// 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 );
// Return true if exp is a constant times an induction var
bool is_scaled_iv(Node* exp, Node* iv, BasicType bt, jlong* p_scale, bool* p_short_scale, int depth = 0);
bool is_iv(Node* exp, Node* iv, BasicType bt);
// Return true if exp is a scaled induction var plus (or minus) constant
bool is_scaled_iv_plus_offset(Node* exp, Node* iv, BasicType bt, jlong* p_scale, Node** p_offset, bool* p_short_scale = nullptr, int depth = 0);
bool is_scaled_iv_plus_offset(Node* exp, Node* iv, int* p_scale, Node** p_offset) {
jlong long_scale;
if (is_scaled_iv_plus_offset(exp, iv, T_INT, &long_scale, p_offset)) {
int int_scale = checked_cast<int>(long_scale);
if (p_scale != nullptr) {
*p_scale = int_scale;
}
return true;
}
return false;
}
// Helper for finding more complex matches to is_scaled_iv_plus_offset.
bool is_scaled_iv_plus_extra_offset(Node* exp1, Node* offset2, Node* iv,
BasicType bt,
jlong* p_scale, Node** p_offset,
bool* p_short_scale, int depth);
// Create a new if above the uncommon_trap_if_pattern for the predicate to be promoted
IfProjNode* create_new_if_for_predicate(IfProjNode* cont_proj, Node* new_entry, Deoptimization::DeoptReason reason,
int opcode, bool rewire_uncommon_proj_phi_inputs = false,
bool if_cont_is_true_proj = true);
private:
// Helper functions for create_new_if_for_predicate()
void set_ctrl_of_nodes_with_same_ctrl(Node* node, ProjNode* old_ctrl, Node* new_ctrl);
Unique_Node_List find_nodes_with_same_ctrl(Node* node, const ProjNode* ctrl);
Node* clone_nodes_with_same_ctrl(Node* node, ProjNode* old_ctrl, Node* new_ctrl);
Dict clone_nodes(const Node_List& list_to_clone);
void rewire_cloned_nodes_to_ctrl(const ProjNode* old_ctrl, Node* new_ctrl, const Node_List& nodes_with_same_ctrl,
const Dict& old_new_mapping);
void rewire_inputs_of_clones_to_clones(Node* new_ctrl, Node* clone, const Dict& old_new_mapping, const Node* next);
bool has_dominating_loop_limit_check(Node* init_trip, Node* limit, jlong stride_con, BasicType iv_bt,
Node* loop_entry);
public:
void register_control(Node* n, IdealLoopTree *loop, Node* pred, bool update_body = true);
// 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);
bool loop_predication_impl_helper(IdealLoopTree* loop, IfProjNode* if_success_proj,
ParsePredicateSuccessProj* parse_predicate_proj, CountedLoopNode* cl, ConNode* zero,
Invariance& invar, Deoptimization::DeoptReason reason);
bool loop_predication_should_follow_branches(IdealLoopTree* loop, IfProjNode* predicate_proj, float& loop_trip_cnt);
void loop_predication_follow_branches(Node *c, IdealLoopTree *loop, float loop_trip_cnt,
PathFrequency& pf, Node_Stack& stack, VectorSet& seen,
Node_List& if_proj_list);
IfProjNode* add_template_assertion_predicate(IfNode* iff, IdealLoopTree* loop, IfProjNode* if_proj, IfProjNode* predicate_proj,
IfProjNode* upper_bound_proj, int scale, Node* offset, Node* init, Node* limit,
jint stride, Node* rng, bool& overflow, Deoptimization::DeoptReason reason);
Node* add_range_check_elimination_assertion_predicate(IdealLoopTree* loop, Node* predicate_proj, int scale_con,
Node* offset, Node* limit, jint stride_con, Node* value);
// 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();
void eliminate_useless_zero_trip_guard();
// 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.
void do_range_check(IdealLoopTree *loop, Node_List &old_new);
// 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.
// Return the inserted if.
IfNode* create_slow_version_of_loop(IdealLoopTree *loop,
Node_List &old_new,
IfNode* unswitch_iff,
CloneLoopMode mode);
// 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(jlong stride_con, jlong 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(bool reduce, Node* scale, Node* offset, Node* rc_limit, Node* old_limit, Node* pre_ctrl, bool round);
// Partially peel loop up through last_peel node.
bool partial_peel( IdealLoopTree *loop, Node_List &old_new );
bool duplicate_loop_backedge(IdealLoopTree *loop, Node_List &old_new);
// Move UnorderedReduction out of loop if possible
void move_unordered_reduction_out_of_loop(IdealLoopTree* loop);
// 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, uint 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.
Node* clone_iff(PhiNode* phi);
CmpNode* clone_bool(PhiNode* phi);
// 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);
Node* remix_address_expressions_add_left_shift(Node* n, IdealLoopTree* n_loop, Node* n_ctrl, BasicType bt);
// Convert add to muladd to generate MuladdS2I under certain criteria
Node * convert_add_to_muladd(Node * n);
// Attempt to use a conditional move instead of a phi/branch
Node *conditional_move( Node *n );
// 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(IfProjNode* prevdom, IfNode* iff, bool flip = false, bool exclude_loop_predicate = false);
// Split Node 'n' through merge point
RegionNode* split_thru_region(Node* n, RegionNode* 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, RegionNode** new_false_region = nullptr, RegionNode** new_true_region = nullptr);
// Conversion of fill/copy patterns into intrinsic 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, nullptr); }
// 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 );
Node* place_outside_loop(Node* useblock, IdealLoopTree* loop) 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 cannot_split_division(const Node* n, const Node* region) const;
static bool is_divisor_counted_loop_phi(const Node* divisor, const Node* loop);
bool loop_phi_backedge_type_contains_zero(const Node* phi_divisor, const Type* zero) const;
// Determine if a method is too big for a/another round of split-if, based on
// a magic (approximate) ratio derived from the equally magic constant 35000,
// previously used for this purpose (but without relating to the node limit).
bool must_throttle_split_if() {
uint threshold = C->max_node_limit() * 2 / 5;
return C->live_nodes() > threshold;
}
// A simplistic node request tracking mechanism, where
// = UINT_MAX Request not valid or made final.
// < UINT_MAX Nodes currently requested (estimate).
uint _nodes_required;
enum { REQUIRE_MIN = 70 };
uint nodes_required() const { return _nodes_required; }
// Given the _currently_ available number of nodes, check whether there is
// "room" for an additional request or not, considering the already required
// number of nodes. Return TRUE if the new request is exceeding the node
// budget limit, otherwise return FALSE. Note that this interpretation will
// act pessimistic on additional requests when new nodes have already been
// generated since the 'begin'. This behaviour fits with the intention that
// node estimates/requests should be made upfront.
bool exceeding_node_budget(uint required = 0) {
assert(C->live_nodes() < C->max_node_limit(), "sanity");
uint available = C->max_node_limit() - C->live_nodes();
return available < required + _nodes_required + REQUIRE_MIN;
}
uint require_nodes(uint require, uint minreq = REQUIRE_MIN) {
precond(require > 0);
_nodes_required += MAX2(require, minreq);
return _nodes_required;
}
bool may_require_nodes(uint require, uint minreq = REQUIRE_MIN) {
return !exceeding_node_budget(require) && require_nodes(require, minreq) > 0;
}
uint require_nodes_begin() {
assert(_nodes_required == UINT_MAX, "Bad state (begin).");
_nodes_required = 0;
return C->live_nodes();
}
// When a node request is final, optionally check that the requested number
// of nodes was reasonably correct with respect to the number of new nodes
// introduced since the last 'begin'. Always check that we have not exceeded
// the maximum node limit.
void require_nodes_final(uint live_at_begin, bool check_estimate) {
assert(_nodes_required < UINT_MAX, "Bad state (final).");
#ifdef ASSERT
if (check_estimate) {
// Check that the node budget request was not off by too much (x2).
// Should this be the case we _surely_ need to improve the estimates
// used in our budget calculations.
if (C->live_nodes() - live_at_begin > 2 * _nodes_required) {
log_info(compilation)("Bad node estimate: actual = %d >> request = %d",
C->live_nodes() - live_at_begin, _nodes_required);
}
}
#endif
// Assert that we have stayed within the node budget limit.
assert(C->live_nodes() < C->max_node_limit(),
"Exceeding node budget limit: %d + %d > %d (request = %d)",
C->live_nodes() - live_at_begin, live_at_begin,
C->max_node_limit(), _nodes_required);
_nodes_required = UINT_MAX;
}
// Clone Parse Predicates to slow and fast loop when unswitching a loop
void clone_parse_and_assertion_predicates_to_unswitched_loop(IdealLoopTree* loop, Node_List& old_new,
IfProjNode*& iffast_pred, IfProjNode*& ifslow_pred);
IfProjNode* clone_parse_predicate_to_unswitched_loop(ParsePredicateSuccessProj* predicate_proj, Node* new_entry,
Deoptimization::DeoptReason reason, bool slow_loop);
void clone_assertion_predicates_to_unswitched_loop(IdealLoopTree* loop, const Node_List& old_new,
Deoptimization::DeoptReason reason, IfProjNode* old_predicate_proj,
IfProjNode* iffast_pred, IfProjNode* ifslow_pred);
IfProjNode* clone_assertion_predicate_for_unswitched_loops(Node* iff, IfProjNode* predicate,
Deoptimization::DeoptReason reason,
IfProjNode* output_proj);
static void check_cloned_parse_predicate_for_unswitching(const Node* new_entry, bool is_fast_loop) PRODUCT_RETURN;
bool _created_loop_node;
DEBUG_ONLY(void dump_idoms(Node* early, Node* wrong_lca);)
NOT_PRODUCT(void dump_idoms_in_reverse(const Node* n, const Node_List& idom_list) const;)
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_idom(Node* n) const { dump_idom(n, 1000); } // For debugging
void dump_idom(Node* n, uint count) const;
void get_idoms(Node* n, uint count, Unique_Node_List& idoms) const;
void dump(IdealLoopTree* loop, uint rpo_idx, Node_List &rpo_list) const;
IdealLoopTree* get_loop_idx(Node* n) const {
// Dead nodes have no loop, so return the top level loop instead
return _loop_or_ctrl[n->_idx] ? (IdealLoopTree*)_loop_or_ctrl[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
static volatile int _long_loop_candidates;
static volatile int _long_loop_nests;
static volatile int _long_loop_counted_loops;
#endif
#ifdef ASSERT
void verify() const;
bool verify_idom_and_nodes(Node* root, const PhaseIdealLoop* phase_verify) const;
bool verify_idom(Node* n, const PhaseIdealLoop* phase_verify) const;
bool verify_loop_ctrl(Node* n, const PhaseIdealLoop* phase_verify) const;
#endif
void rpo(Node* start, Node_Stack &stk, VectorSet &visited, Node_List &rpo_list) const;
void check_counted_loop_shape(IdealLoopTree* loop, Node* x, BasicType bt) NOT_DEBUG_RETURN;
LoopNode* create_inner_head(IdealLoopTree* loop, BaseCountedLoopNode* head, IfNode* exit_test);
int extract_long_range_checks(const IdealLoopTree* loop, jint stride_con, int iters_limit, PhiNode* phi,
Node_List &range_checks);
void transform_long_range_checks(int stride_con, const Node_List &range_checks, Node* outer_phi,
Node* inner_iters_actual_int, Node* inner_phi,
Node* iv_add, LoopNode* inner_head);
Node* get_late_ctrl_with_anti_dep(LoadNode* n, Node* early, Node* LCA);
bool ctrl_of_use_out_of_loop(const Node* n, Node* n_ctrl, IdealLoopTree* n_loop, Node* ctrl);
bool ctrl_of_all_uses_out_of_loop(const Node* n, Node* n_ctrl, IdealLoopTree* n_loop);
Node* compute_early_ctrl(Node* n, Node* n_ctrl);
void try_sink_out_of_loop(Node* n);
Node* clamp(Node* R, Node* L, Node* H);
bool safe_for_if_replacement(const Node* dom) const;
void push_pinned_nodes_thru_region(IfNode* dom_if, Node* region);
bool try_merge_identical_ifs(Node* n);
void clone_loop_body(const Node_List& body, Node_List &old_new, CloneMap* cm);
void fix_body_edges(const Node_List &body, IdealLoopTree* loop, const Node_List &old_new, int dd,
IdealLoopTree* parent, bool partial);
void fix_ctrl_uses(const Node_List& body, const IdealLoopTree* loop, Node_List &old_new, CloneLoopMode mode,
Node* side_by_side_idom, CloneMap* cm, Node_List &worklist);
void fix_data_uses(Node_List& body, IdealLoopTree* loop, CloneLoopMode mode, IdealLoopTree* outer_loop,
uint new_counter, Node_List& old_new, Node_List& worklist, Node_List*& split_if_set,
Node_List*& split_bool_set, Node_List*& split_cex_set);
void finish_clone_loop(Node_List* split_if_set, Node_List* split_bool_set, Node_List* split_cex_set);
bool clone_cmp_down(Node* n, const Node* blk1, const Node* blk2);
void clone_loadklass_nodes_at_cmp_index(const Node* n, Node* cmp, int i);
bool clone_cmp_loadklass_down(Node* n, const Node* blk1, const Node* blk2);
bool at_relevant_ctrl(Node* n, const Node* blk1, const Node* blk2);
void update_addp_chain_base(Node* x, Node* old_base, Node* new_base);
};
class AutoNodeBudget : public StackObj
{
public:
enum budget_check_t { BUDGET_CHECK, NO_BUDGET_CHECK };
AutoNodeBudget(PhaseIdealLoop* phase, budget_check_t chk = BUDGET_CHECK)
: _phase(phase),
_check_at_final(chk == BUDGET_CHECK),
_nodes_at_begin(0)
{
precond(_phase != nullptr);
_nodes_at_begin = _phase->require_nodes_begin();
}
~AutoNodeBudget() {
#ifndef PRODUCT
if (TraceLoopOpts) {
uint request = _phase->nodes_required();
uint delta = _phase->C->live_nodes() - _nodes_at_begin;
if (request < delta) {
tty->print_cr("Exceeding node budget: %d < %d", request, delta);
} else {
uint const REQUIRE_MIN = PhaseIdealLoop::REQUIRE_MIN;
// Identify the worst estimates as "poor" ones.
if (request > REQUIRE_MIN && delta > 0) {
if ((delta > REQUIRE_MIN && request > 3 * delta) ||
(delta <= REQUIRE_MIN && request > 10 * delta)) {
tty->print_cr("Poor node estimate: %d >> %d", request, delta);
}
}
}
}
#endif // PRODUCT
_phase->require_nodes_final(_nodes_at_begin, _check_at_final);
}
private:
PhaseIdealLoop* _phase;
bool _check_at_final;
uint _nodes_at_begin;
};
// 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 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.
if (_tail->in(0) == nullptr) {
_tail = _phase->get_ctrl(_tail);
}
return _tail;
}
inline Node* IdealLoopTree::head() {
// Handle lazy update of _head field.
if (_head->in(0) == nullptr) {
_head = _phase->get_ctrl(_head);
}
return _head;
}
// 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 == nullptr; } // Finished iterating?
void next(); // Advance to next loop tree
IdealLoopTree* current() { return _curnt; } // Return current value of iterator.
};
// Compute probability of reaching some CFG node from a fixed
// dominating CFG node
class PathFrequency {
private:
Node* _dom; // frequencies are computed relative to this node
Node_Stack _stack;
GrowableArray<float> _freqs_stack; // keep track of intermediate result at regions
GrowableArray<float> _freqs; // cache frequencies
PhaseIdealLoop* _phase;
float check_and_truncate_frequency(float f) {
assert(f >= 0, "Incorrect frequency");
// We do not perform an exact (f <= 1) check
// this would be error prone with rounding of floats.
// Performing a check like (f <= 1+eps) would be of benefit,
// however, it is not evident how to determine such an eps,
// given that an arbitrary number of add/mul operations
// are performed on these frequencies.
return (f > 1) ? 1 : f;
}
public:
PathFrequency(Node* dom, PhaseIdealLoop* phase)
: _dom(dom), _stack(0), _phase(phase) {
}
float to(Node* n);
};
// Utility class to work on predicates.
class Predicates {
public:
static Node* skip_all_predicates(Node* node);
static Node* skip_all_predicates(ParsePredicates& parse_predicates);
static Node* skip_predicates_in_block(ParsePredicateSuccessProj* parse_predicate_success_proj);
static IfProjNode* next_predicate_proj_in_block(IfProjNode* proj);
static bool has_profiled_loop_predicates(ParsePredicates& parse_predicates);
};
// Class representing the Parse Predicates that are added during parsing with ParsePredicateNodes.
class ParsePredicates {
private:
ParsePredicateSuccessProj* _loop_predicate_proj = nullptr;
ParsePredicateSuccessProj* _profiled_loop_predicate_proj = nullptr;
ParsePredicateSuccessProj* _loop_limit_check_predicate_proj = nullptr;
// The success projection of the Parse Predicate that comes first when starting from root.
ParsePredicateSuccessProj* _top_predicate_proj;
ParsePredicateSuccessProj* _starting_proj;
void find_parse_predicate_projections();
static bool is_uct_proj(Node* node, Deoptimization::DeoptReason deopt_reason);
static ParsePredicateNode* get_parse_predicate_or_null(Node* proj);
bool assign_predicate_proj(ParsePredicateSuccessProj* parse_predicate_proj);
public:
ParsePredicates(Node* starting_proj);
// Success projection of Loop Parse Predicate.
ParsePredicateSuccessProj* loop_predicate_proj() {
return _loop_predicate_proj;
}
// Success proj of Profiled Loop Parse Predicate.
ParsePredicateSuccessProj* profiled_loop_predicate_proj() {
return _profiled_loop_predicate_proj;
}
// Success proj of Loop Limit Check Parse Predicate.
ParsePredicateSuccessProj* loop_limit_check_predicate_proj() {
return _loop_limit_check_predicate_proj;
}
// Return the success projection of the Parse Predicate that comes first when starting from root.
ParsePredicateSuccessProj* get_top_predicate_proj() {
return _top_predicate_proj;
}
static bool is_success_proj(Node* node);
// Are there any Parse Predicates?
bool has_any() const {
return _top_predicate_proj != nullptr;
}
static bool is_loop_limit_check_predicate_proj(Node* node) {
ParsePredicateNode* parse_predicate = get_parse_predicate_or_null(node);
return parse_predicate != nullptr && parse_predicate->deopt_reason() == Deoptimization::DeoptReason::Reason_loop_limit_check;
}
};
#endif // SHARE_OPTO_LOOPNODE_HPP