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src/hotspot/share/opto/loopnode.hpp

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*** 588,607 **** // 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 ! // 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); --- 588,608 ---- // 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);
*** 618,627 **** --- 619,631 ---- 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; + // Estimate the number of nodes required when cloning a loop (body). + uint est_loop_clone_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);
*** 1354,1407 **** // A simplistic node request tracking mechanism, where // = UINT_MAX Request not valid or made final. // < UINT_MAX Nodes currently requested (estimate). uint _nodes_required; 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; } ! uint require_nodes(uint require) { precond(require > 0); ! _nodes_required += MAX2(100u, require); // Keep requests at minimum 100. return _nodes_required; } ! bool may_require_nodes(uint require) { ! return !exceeding_node_budget(require) && require_nodes(require) > 0; } ! void require_nodes_begin() { assert(_nodes_required == UINT_MAX, "Bad state (begin)."); _nodes_required = 0; } ! // Final check that the requested nodes did not exceed the limit and that ! // the request was reasonably correct with respect to the number of new ! // nodes introduced by any transform since the last 'begin'. ! void require_nodes_final_check(uint live_at_begin) { ! uint required = _nodes_required; ! require_nodes_final(); ! uint delta = C->live_nodes() - live_at_begin; ! // Assert is disabled, see JDK-8223911 and related issues. ! assert(true || delta <= 2 * required, "Bad node estimate (actual: %d, request: %d)", ! delta, required); ! } ! ! void require_nodes_final() { assert(_nodes_required < UINT_MAX, "Bad state (final)."); ! assert(!exceeding_node_budget(), "Too many NODES required!"); _nodes_required = UINT_MAX; } bool _created_loop_node; public: - uint nodes_required() const { return _nodes_required; } - 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 --- 1358,1427 ---- // 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; } ! 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)."); ! ! if (check_estimate) { ! // Assert 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. ! assert(C->live_nodes() - live_at_begin <= 2 * _nodes_required, ! "Bad node estimate: actual = %d >> request = %d", ! C->live_nodes() - live_at_begin, _nodes_required); ! } ! // 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; } 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
*** 1436,1487 **** _check_at_final(chk == BUDGET_CHECK), _nodes_at_begin(0) { precond(_phase != NULL); ! _nodes_at_begin = _phase->C->live_nodes(); ! _phase->require_nodes_begin(); } ~AutoNodeBudget() { - if (_check_at_final) { #ifndef PRODUCT if (TraceLoopOpts) { uint request = _phase->nodes_required(); - - if (request > 0) { uint delta = _phase->C->live_nodes() - _nodes_at_begin; if (request < delta) { tty->print_cr("Exceeding node budget: %d < %d", request, delta); } } } - #endif - _phase->require_nodes_final_check(_nodes_at_begin); - } else { - _phase->require_nodes_final(); } } private: PhaseIdealLoop* _phase; bool _check_at_final; uint _nodes_at_begin; }; - // The Estimated Loop Clone Size: CloneFactor * (BodySize + BC) + CC, where BC - // and CC are totally ad-hoc/magic "body" and "clone" constants, respectively, - // used to ensure that node usage estimates made are on the safe side, for the - // most part. - static inline uint est_loop_clone_sz(uint fact, uint size) { - uint const bc = 31; - uint const cc = 41; - uint estimate = fact * (size + bc) + cc; - return (estimate - cc) / fact == size + bc ? estimate : UINT_MAX; - } - // 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. --- 1456,1497 ---- _check_at_final(chk == BUDGET_CHECK), _nodes_at_begin(0) { precond(_phase != NULL); ! _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.
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