From: Richard Biener Date: Mon, 29 Jul 2019 14:19:07 +0000 (+0000) Subject: re PR tree-optimization/91257 (Compile-time and memory-hog hog) X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=390c0dd61dc36a6eca8262b9814aa00e1bba5483;p=gcc.git re PR tree-optimization/91257 (Compile-time and memory-hog hog) 2019-07-29 Richard Biener PR tree-optimization/91257 * tree-ssa-sccvn.h (struct vn_avail): New. (struct vn_ssa_aux): Add avail member. * tree-ssa-sccvn.c (class rpo_elim): Remove m_rpo_avail member, add m_avail_freelist one. (rpo_elim::~rpo_elim): Remove. (rpo_elim::eliminate_avail): Adjust to new avail tracking data structure. (rpo_elim::eliminate_push_avail): Likewise. (do_unwind): Likewise. (do_rpo_vn): Likewise. From-SVN: r273877 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index d3089062e36..7bdb466e097 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,17 @@ +2019-07-29 Richard Biener + + PR tree-optimization/91257 + * tree-ssa-sccvn.h (struct vn_avail): New. + (struct vn_ssa_aux): Add avail member. + * tree-ssa-sccvn.c (class rpo_elim): Remove m_rpo_avail + member, add m_avail_freelist one. + (rpo_elim::~rpo_elim): Remove. + (rpo_elim::eliminate_avail): Adjust to new avail tracking + data structure. + (rpo_elim::eliminate_push_avail): Likewise. + (do_unwind): Likewise. + (do_rpo_vn): Likewise. + 2019-07-29 Richard Biener PR tree-optimization/91257 diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c index bafbea27241..a2cb237293e 100644 --- a/gcc/tree-ssa-sccvn.c +++ b/gcc/tree-ssa-sccvn.c @@ -2126,36 +2126,17 @@ class rpo_elim : public eliminate_dom_walker { public: rpo_elim(basic_block entry_) - : eliminate_dom_walker (CDI_DOMINATORS, NULL), entry (entry_) {} - ~rpo_elim(); + : eliminate_dom_walker (CDI_DOMINATORS, NULL), entry (entry_), + m_avail_freelist (NULL) {} virtual tree eliminate_avail (basic_block, tree op); virtual void eliminate_push_avail (basic_block, tree); basic_block entry; - /* Instead of having a local availability lattice for each - basic-block and availability at X defined as union of - the local availabilities at X and its dominators we're - turning this upside down and track availability per - value given values are usually made available at very - few points (at least one). - So we have a value -> vec map where - LOCATION is specifying the basic-block LEADER is made - available for VALUE. We push to this vector in RPO - order thus for iteration we can simply pop the last - entries. - LOCATION is the basic-block index and LEADER is its - SSA name version. */ - /* ??? We'd like to use auto_vec here with embedded storage - but that doesn't play well until we can provide move - constructors and use std::move on hash-table expansion. - So for now this is a bit more expensive than necessary. - We eventually want to switch to a chaining scheme like - for hashtable entries for unwinding which would make - making the vector part of the vn_ssa_aux structure possible. */ - typedef hash_map > > rpo_avail_t; - rpo_avail_t m_rpo_avail; + /* Freelist of avail entries which are allocated from the vn_ssa_aux + obstack. */ + vn_avail *m_avail_freelist; }; /* Global RPO state for access from hooks. */ @@ -6197,14 +6178,6 @@ vn_lookup_simplify_result (gimple_match_op *res_op) return res; } -rpo_elim::~rpo_elim () -{ - /* Release the avail vectors. */ - for (rpo_avail_t::iterator i = m_rpo_avail.begin (); - i != m_rpo_avail.end (); ++i) - (*i).second.release (); -} - /* Return a leader for OPs value that is valid at BB. */ tree @@ -6220,16 +6193,15 @@ rpo_elim::eliminate_avail (basic_block bb, tree op) { if (SSA_NAME_IS_DEFAULT_DEF (valnum)) return valnum; - vec > *av = m_rpo_avail.get (valnum); - if (!av || av->is_empty ()) + vn_avail *av = VN_INFO (valnum)->avail; + if (!av) return NULL_TREE; - int i = av->length () - 1; - if ((*av)[i].first == bb->index) + if (av->location == bb->index) /* On tramp3d 90% of the cases are here. */ - return ssa_name ((*av)[i].second); + return ssa_name (av->leader); do { - basic_block abb = BASIC_BLOCK_FOR_FN (cfun, (*av)[i].first); + basic_block abb = BASIC_BLOCK_FOR_FN (cfun, av->location); /* ??? During elimination we have to use availability at the definition site of a use we try to replace. This is required to not run into inconsistencies because @@ -6243,7 +6215,7 @@ rpo_elim::eliminate_avail (basic_block bb, tree op) executable. */ if (dominated_by_p_w_unex (bb, abb)) { - tree leader = ssa_name ((*av)[i].second); + tree leader = ssa_name (av->leader); /* Prevent eliminations that break loop-closed SSA. */ if (loops_state_satisfies_p (LOOP_CLOSED_SSA) && ! SSA_NAME_IS_DEFAULT_DEF (leader) @@ -6265,8 +6237,9 @@ rpo_elim::eliminate_avail (basic_block bb, tree op) /* ??? Can we somehow skip to the immediate dominator RPO index (bb_to_rpo)? Again, maybe not worth, on tramp3d the worst number of elements in the vector is 9. */ + av = av->next; } - while (--i >= 0); + while (av); } else if (valnum != VN_TOP) /* valnum is is_gimple_min_invariant. */ @@ -6290,15 +6263,19 @@ rpo_elim::eliminate_push_avail (basic_block bb, tree leader) print_generic_expr (dump_file, valnum); fprintf (dump_file, "\n"); } - bool existed; - vec > &av = m_rpo_avail.get_or_insert (valnum, &existed); - if (!existed) + vn_ssa_aux_t value = VN_INFO (valnum); + vn_avail *av; + if (m_avail_freelist) { - new (&av) vec >; - av = vNULL; - av.reserve_exact (2); + av = m_avail_freelist; + m_avail_freelist = m_avail_freelist->next; } - av.safe_push (std::make_pair (bb->index, SSA_NAME_VERSION (leader))); + else + av = XOBNEW (&vn_ssa_aux_obstack, vn_avail); + av->location = bb->index; + av->leader = SSA_NAME_VERSION (leader); + av->next = value->avail; + value->avail = av; } /* Valueization hook for RPO VN plus required state. */ @@ -6780,15 +6757,17 @@ do_unwind (unwind_state *to, int rpo_idx, rpo_elim &avail, int *bb_to_rpo) /* Prune [rpo_idx, ] from avail. */ /* ??? This is O(number-of-values-in-region) which is O(region-size) rather than O(iteration-piece). */ - for (rpo_elim::rpo_avail_t::iterator i - = avail.m_rpo_avail.begin (); - i != avail.m_rpo_avail.end (); ++i) + for (hash_table::iterator i = vn_ssa_aux_hash->begin (); + i != vn_ssa_aux_hash->end (); ++i) { - while (! (*i).second.is_empty ()) + while ((*i)->avail) { - if (bb_to_rpo[(*i).second.last ().first] < rpo_idx) + if (bb_to_rpo[(*i)->avail->location] < rpo_idx) break; - (*i).second.pop (); + vn_avail *av = (*i)->avail; + (*i)->avail = (*i)->avail->next; + av->next = avail.m_avail_freelist; + avail.m_avail_freelist = av; } } } @@ -7184,11 +7163,16 @@ do_rpo_vn (function *fn, edge entry, bitmap exit_bbs, max_visited = rpo_state[i].visited; } unsigned nvalues = 0, navail = 0; - for (rpo_elim::rpo_avail_t::iterator i = avail.m_rpo_avail.begin (); - i != avail.m_rpo_avail.end (); ++i) + for (hash_table::iterator i = vn_ssa_aux_hash->begin (); + i != vn_ssa_aux_hash->end (); ++i) { nvalues++; - navail += (*i).second.length (); + vn_avail *av = (*i)->avail; + while (av) + { + navail++; + av = av->next; + } } statistics_counter_event (cfun, "RPO blocks", n); statistics_counter_event (cfun, "RPO blocks visited", nblk); diff --git a/gcc/tree-ssa-sccvn.h b/gcc/tree-ssa-sccvn.h index 93718b2848f..1a5f2389586 100644 --- a/gcc/tree-ssa-sccvn.h +++ b/gcc/tree-ssa-sccvn.h @@ -193,6 +193,25 @@ vn_constant_eq_with_type (tree c1, tree c2) && types_compatible_p (TREE_TYPE (c1), TREE_TYPE (c2))); } +/* Instead of having a local availability lattice for each basic-block + and availability at X defined as union of the local availabilities + at X and its dominators we're turning this upside down and track + availability per value given values are usually made available at very + few points. + So we have a chain of LOCATION, LEADER entries where LOCATION is + specifying the basic-block LEADER is made available for VALUE. + We prepend to this chain in RPO order thus for iteration we can simply + remove the last entries. + LOCATION is the basic-block index and LEADER is its SSA name version. */ +struct vn_avail +{ + vn_avail *next; + /* The basic-block LEADER is made available. */ + int location; + /* The LEADER for the value we are chained on. */ + int leader; +}; + typedef struct vn_ssa_aux { /* SSA name this vn_ssa_aux is associated with in the lattice. */ @@ -202,6 +221,10 @@ typedef struct vn_ssa_aux /* Statements to insert if needs_insertion is true. */ gimple_seq expr; + /* AVAIL entries, last in RPO order is first. This is only tracked + for SSA names also serving as values (NAME == VALNUM). */ + vn_avail *avail; + /* Unique identifier that all expressions with the same value have. */ unsigned int value_id;