Re: [PATCH] add move CTOR to auto_vec, use auto_vec for get_loop_exit_edges

[Richard Biener <rguenther@suse.de>]

On Wed, 26 Aug 2020, Richard Biener wrote:

> On Thu, 6 Aug 2020, Richard Biener wrote:
> 
> > On Thu, 6 Aug 2020, Richard Biener wrote:
> > 
> > > This adds a move CTOR to auto_vec<T, 0> and makes use of a
> > > auto_vec<edge> return value for get_loop_exit_edges denoting
> > > that lifetime management of the vector is handed to the caller.
> > > 
> > > The move CTOR prompted the hash_table change because it appearantly
> > > makes the copy CTOR implicitely deleted (good) and hash-table
> > > expansion of the odr_enum_map which is
> > > hash_map <nofree_string_hash, odr_enum> where odr_enum has an
> > > auto_vec<odr_enum_val, 0> member triggers this.  Not sure if
> > > there's a latent bug there before this (I think we're not
> > > invoking DTORs, but we're invoking copy-CTORs).
> > > 
> > > Bootstrap / regtest running on x86_64-unknown-linux-gnu.
> > > 
> > > Does this all look sensible and is it a good change
> > > (the get_loop_exit_edges one)?
> > 
> > Regtest went OK, here's an update with a complete ChangeLog
> > (how useful..) plus the move assign operator deleted, copy
> > assign wouldn't work as auto-generated and at the moment
> > there's no use of assigning.  I guess if we'd have functions
> > that take an auto_vec<> argument meaning they will destroy
> > the vector that will become useful and we can implement it.
> > 
> > OK for trunk?
> 
> Ping.

Ping^2.

Thanks,
Richard.

> > Thanks,
> > Richard.
> > 
> > 
> > From d74c346e95ff967d930b7c83daabc26b0227aea3 Mon Sep 17 00:00:00 2001
> > From: Richard Biener <rguenther@suse.de>
> > Date: Thu, 6 Aug 2020 14:50:56 +0200
> > Subject: [PATCH] add move CTOR to auto_vec, use auto_vec for
> >  get_loop_exit_edges
> > 
> > This adds a move CTOR to auto_vec<T, 0> and makes use of a
> > auto_vec<edge> return value for get_loop_exit_edges denoting
> > that lifetime management of the vector is handed to the caller.
> > 
> > The move CTOR prompted the hash_table change because it appearantly
> > makes the copy CTOR implicitely deleted (good) and hash-table
> > expansion of the odr_enum_map which is
> > hash_map <nofree_string_hash, odr_enum> where odr_enum has an
> > auto_vec<odr_enum_val, 0> member triggers this.  Not sure if
> > there's a latent bug there before this (I think we're not
> > invoking DTORs, but we're invoking copy-CTORs).
> > 
> > 2020-08-06  Richard Biener  <rguenther@suse.de>
> > 
> > 	* vec.h (auto_vec<T, 0>::auto_vec (auto_vec &&)): New move CTOR.
> > 	(auto_vec<T, 0>::operator=(auto_vec &&)): Delete.
> > 	* hash-table.h (hash_table::expand): Use std::move when expanding.
> > 	* cfgloop.h (get_loop_exit_edges): Return auto_vec<edge>.
> > 	* cfgloop.c (get_loop_exit_edges): Adjust.
> > 	* cfgloopmanip.c (fix_loop_placement): Likewise.
> > 	* ipa-fnsummary.c (analyze_function_body): Likewise.
> > 	* ira-build.c (create_loop_tree_nodes): Likewise.
> > 	(create_loop_tree_node_allocnos): Likewise.
> > 	(loop_with_complex_edge_p): Likewise.
> > 	* ira-color.c (ira_loop_edge_freq): Likewise.
> > 	* loop-unroll.c (analyze_insns_in_loop): Likewise.
> > 	* predict.c (predict_loops): Likewise.
> > 	* tree-predcom.c (last_always_executed_block): Likewise.
> > 	* tree-ssa-loop-ch.c (ch_base::copy_headers): Likewise.
> > 	* tree-ssa-loop-im.c (store_motion_loop): Likewise.
> > 	* tree-ssa-loop-ivcanon.c (loop_edge_to_cancel): Likewise.
> > 	(canonicalize_loop_induction_variables): Likewise.
> > 	* tree-ssa-loop-manip.c (get_loops_exits): Likewise.
> > 	* tree-ssa-loop-niter.c (find_loop_niter): Likewise.
> > 	(finite_loop_p): Likewise.
> > 	(find_loop_niter_by_eval): Likewise.
> > 	(estimate_numbers_of_iterations): Likewise.
> > 	* tree-ssa-loop-prefetch.c (emit_mfence_after_loop): Likewise.
> > 	(may_use_storent_in_loop_p): Likewise.
> > ---
> >  gcc/cfgloop.c                |  4 ++--
> >  gcc/cfgloop.h                |  2 +-
> >  gcc/cfgloopmanip.c           |  3 +--
> >  gcc/hash-table.h             |  2 +-
> >  gcc/ipa-fnsummary.c          |  4 +---
> >  gcc/ira-build.c              | 12 +++---------
> >  gcc/ira-color.c              |  4 +---
> >  gcc/loop-unroll.c            |  3 +--
> >  gcc/predict.c                |  9 ++-------
> >  gcc/tree-predcom.c           |  3 +--
> >  gcc/tree-ssa-loop-ch.c       |  3 +--
> >  gcc/tree-ssa-loop-im.c       |  3 +--
> >  gcc/tree-ssa-loop-ivcanon.c  |  9 ++-------
> >  gcc/tree-ssa-loop-manip.c    |  3 +--
> >  gcc/tree-ssa-loop-niter.c    | 20 +++++---------------
> >  gcc/tree-ssa-loop-prefetch.c |  7 ++-----
> >  gcc/vec.h                    |  7 +++++++
> >  17 files changed, 33 insertions(+), 65 deletions(-)
> > 
> > diff --git a/gcc/cfgloop.c b/gcc/cfgloop.c
> > index 7720e6e5d2c..33a26cca6a4 100644
> > --- a/gcc/cfgloop.c
> > +++ b/gcc/cfgloop.c
> > @@ -1202,10 +1202,10 @@ release_recorded_exits (function *fn)
> >  
> >  /* Returns the list of the exit edges of a LOOP.  */
> >  
> > -vec<edge> 
> > +auto_vec<edge>
> >  get_loop_exit_edges (const class loop *loop, basic_block *body)
> >  {
> > -  vec<edge> edges = vNULL;
> > +  auto_vec<edge> edges;
> >    edge e;
> >    unsigned i;
> >    edge_iterator ei;
> > diff --git a/gcc/cfgloop.h b/gcc/cfgloop.h
> > index 18b404e292f..f1687f37401 100644
> > --- a/gcc/cfgloop.h
> > +++ b/gcc/cfgloop.h
> > @@ -383,7 +383,7 @@ extern basic_block *get_loop_body_in_custom_order (const class loop *,
> >  extern basic_block *get_loop_body_in_custom_order (const class loop *, void *,
> >  			       int (*) (const void *, const void *, void *));
> >  
> > -extern vec<edge> get_loop_exit_edges (const class loop *, basic_block * = NULL);
> > +extern auto_vec<edge> get_loop_exit_edges (const class loop *, basic_block * = NULL);
> >  extern edge single_exit (const class loop *);
> >  extern edge single_likely_exit (class loop *loop, vec<edge>);
> >  extern unsigned num_loop_branches (const class loop *);
> > diff --git a/gcc/cfgloopmanip.c b/gcc/cfgloopmanip.c
> > index 73134a20e33..3c9e2a0a99c 100644
> > --- a/gcc/cfgloopmanip.c
> > +++ b/gcc/cfgloopmanip.c
> > @@ -126,7 +126,7 @@ fix_loop_placement (class loop *loop, bool *irred_invalidated)
> >  {
> >    unsigned i;
> >    edge e;
> > -  vec<edge> exits = get_loop_exit_edges (loop);
> > +  auto_vec<edge> exits = get_loop_exit_edges (loop);
> >    class loop *father = current_loops->tree_root, *act;
> >    bool ret = false;
> >  
> > @@ -157,7 +157,6 @@ fix_loop_placement (class loop *loop, bool *irred_invalidated)
> >        ret = true;
> >      }
> >  
> > -  exits.release ();
> >    return ret;
> >  }
> >  
> > diff --git a/gcc/hash-table.h b/gcc/hash-table.h
> > index 32f3a634e1e..487003c3acf 100644
> > --- a/gcc/hash-table.h
> > +++ b/gcc/hash-table.h
> > @@ -819,7 +819,7 @@ hash_table<Descriptor, Lazy, Allocator>::expand ()
> >        if (!is_empty (x) && !is_deleted (x))
> >          {
> >            value_type *q = find_empty_slot_for_expand (Descriptor::hash (x));
> > -	  new ((void*) q) value_type (x);
> > +	  new ((void*) q) value_type (std::move (x));
> >          }
> >  
> >        p++;
> > diff --git a/gcc/ipa-fnsummary.c b/gcc/ipa-fnsummary.c
> > index 59e52927151..f750ec1725c 100644
> > --- a/gcc/ipa-fnsummary.c
> > +++ b/gcc/ipa-fnsummary.c
> > @@ -2767,7 +2767,6 @@ analyze_function_body (struct cgraph_node *node, bool early)
> >        scev_initialize ();
> >        FOR_EACH_LOOP (loop, 0)
> >  	{
> > -	  vec<edge> exits;
> >  	  edge ex;
> >  	  unsigned int j;
> >  	  class tree_niter_desc niter_desc;
> > @@ -2776,7 +2775,7 @@ analyze_function_body (struct cgraph_node *node, bool early)
> >  	  else
> >  	    bb_predicate = false;
> >  
> > -	  exits = get_loop_exit_edges (loop);
> > +	  auto_vec<edge> exits = get_loop_exit_edges (loop);
> >  	  FOR_EACH_VEC_ELT (exits, j, ex)
> >  	    if (number_of_iterations_exit (loop, ex, &niter_desc, false)
> >  		&& !is_gimple_min_invariant (niter_desc.niter))
> > @@ -2794,7 +2793,6 @@ analyze_function_body (struct cgraph_node *node, bool early)
> >  		   loop with independent predicate.  */
> >  		loop_iterations &= will_be_nonconstant;
> >  	    }
> > -	  exits.release ();
> >  	}
> >  
> >        /* To avoid quadratic behavior we analyze stride predicates only
> > diff --git a/gcc/ira-build.c b/gcc/ira-build.c
> > index 0bbdb4d0c4b..9b35d0e83a9 100644
> > --- a/gcc/ira-build.c
> > +++ b/gcc/ira-build.c
> > @@ -128,7 +128,6 @@ create_loop_tree_nodes (void)
> >    bool skip_p;
> >    edge_iterator ei;
> >    edge e;
> > -  vec<edge> edges;
> >    loop_p loop;
> >  
> >    ira_bb_nodes
> > @@ -173,14 +172,13 @@ create_loop_tree_nodes (void)
> >  	      }
> >  	  if (skip_p)
> >  	    continue;
> > -	  edges = get_loop_exit_edges (loop);
> > +	  auto_vec<edge> edges = get_loop_exit_edges (loop);
> >  	  FOR_EACH_VEC_ELT (edges, j, e)
> >  	    if ((e->flags & EDGE_ABNORMAL) && EDGE_CRITICAL_P (e))
> >  	      {
> >  		skip_p = true;
> >  		break;
> >  	      }
> > -	  edges.release ();
> >  	  if (skip_p)
> >  	    continue;
> >  	}
> > @@ -1964,17 +1962,15 @@ create_loop_tree_node_allocnos (ira_loop_tree_node_t loop_node)
> >        int i;
> >        edge_iterator ei;
> >        edge e;
> > -      vec<edge> edges;
> >  
> >        ira_assert (current_loops != NULL);
> >        FOR_EACH_EDGE (e, ei, loop_node->loop->header->preds)
> >  	if (e->src != loop_node->loop->latch)
> >  	  create_loop_allocnos (e);
> >  
> > -      edges = get_loop_exit_edges (loop_node->loop);
> > +      auto_vec<edge> edges = get_loop_exit_edges (loop_node->loop);
> >        FOR_EACH_VEC_ELT (edges, i, e)
> >  	create_loop_allocnos (e);
> > -      edges.release ();
> >      }
> >  }
> >  
> > @@ -2167,13 +2163,12 @@ loop_with_complex_edge_p (class loop *loop)
> >    int i;
> >    edge_iterator ei;
> >    edge e;
> > -  vec<edge> edges;
> >    bool res;
> >  
> >    FOR_EACH_EDGE (e, ei, loop->header->preds)
> >      if (e->flags & EDGE_EH)
> >        return true;
> > -  edges = get_loop_exit_edges (loop);
> > +  auto_vec<edge> edges = get_loop_exit_edges (loop);
> >    res = false;
> >    FOR_EACH_VEC_ELT (edges, i, e)
> >      if (e->flags & EDGE_COMPLEX)
> > @@ -2181,7 +2176,6 @@ loop_with_complex_edge_p (class loop *loop)
> >  	res = true;
> >  	break;
> >        }
> > -  edges.release ();
> >    return res;
> >  }
> >  #endif
> > diff --git a/gcc/ira-color.c b/gcc/ira-color.c
> > index dbb3b7a2a51..d3f8e23faff 100644
> > --- a/gcc/ira-color.c
> > +++ b/gcc/ira-color.c
> > @@ -2539,7 +2539,6 @@ ira_loop_edge_freq (ira_loop_tree_node_t loop_node, int regno, bool exit_p)
> >    int freq, i;
> >    edge_iterator ei;
> >    edge e;
> > -  vec<edge> edges;
> >  
> >    ira_assert (current_loops != NULL && loop_node->loop != NULL
> >  	      && (regno < 0 || regno >= FIRST_PSEUDO_REGISTER));
> > @@ -2555,13 +2554,12 @@ ira_loop_edge_freq (ira_loop_tree_node_t loop_node, int regno, bool exit_p)
> >      }
> >    else
> >      {
> > -      edges = get_loop_exit_edges (loop_node->loop);
> > +      auto_vec<edge> edges = get_loop_exit_edges (loop_node->loop);
> >        FOR_EACH_VEC_ELT (edges, i, e)
> >  	if (regno < 0
> >  	    || (bitmap_bit_p (df_get_live_out (e->src), regno)
> >  		&& bitmap_bit_p (df_get_live_in (e->dest), regno)))
> >  	  freq += EDGE_FREQUENCY (e);
> > -      edges.release ();
> >      }
> >  
> >    return REG_FREQ_FROM_EDGE_FREQ (freq);
> > diff --git a/gcc/loop-unroll.c b/gcc/loop-unroll.c
> > index 693c7768868..e1efe624361 100644
> > --- a/gcc/loop-unroll.c
> > +++ b/gcc/loop-unroll.c
> > @@ -1580,7 +1580,7 @@ analyze_insns_in_loop (class loop *loop)
> >    struct var_to_expand *ves = NULL;
> >    iv_to_split **slot1;
> >    var_to_expand **slot2;
> > -  vec<edge> edges = get_loop_exit_edges (loop);
> > +  auto_vec<edge> edges = get_loop_exit_edges (loop);
> >    edge exit;
> >    bool can_apply = false;
> >  
> > @@ -1656,7 +1656,6 @@ analyze_insns_in_loop (class loop *loop)
> >        }
> >      }
> >  
> > -  edges.release ();
> >    free (body);
> >    return opt_info;
> >  }
> > diff --git a/gcc/predict.c b/gcc/predict.c
> > index 0a317a7a4ac..a847b9b4045 100644
> > --- a/gcc/predict.c
> > +++ b/gcc/predict.c
> > @@ -1915,7 +1915,6 @@ predict_loops (void)
> >      {
> >        basic_block bb, *bbs;
> >        unsigned j, n_exits = 0;
> > -      vec<edge> exits;
> >        class tree_niter_desc niter_desc;
> >        edge ex;
> >        class nb_iter_bound *nb_iter;
> > @@ -1926,15 +1925,12 @@ predict_loops (void)
> >        gcond *stmt = NULL;
> >        bool recursion = with_recursion.contains (loop);
> >  
> > -      exits = get_loop_exit_edges (loop);
> > +      auto_vec<edge> exits = get_loop_exit_edges (loop);
> >        FOR_EACH_VEC_ELT (exits, j, ex)
> >  	if (!unlikely_executed_edge_p (ex) && !(ex->flags & EDGE_ABNORMAL_CALL))
> >  	  n_exits ++;
> >        if (!n_exits)
> > -	{
> > -          exits.release ();
> > -	  continue;
> > -	}
> > +	continue;
> >  
> >        if (dump_file && (dump_flags & TDF_DETAILS))
> >  	fprintf (dump_file, "Predicting loop %i%s with %i exits.\n",
> > @@ -2048,7 +2044,6 @@ predict_loops (void)
> >  	  probability = RDIV (REG_BR_PROB_BASE, nitercst);
> >  	  predict_edge (ex, predictor, probability);
> >  	}
> > -      exits.release ();
> >  
> >        /* Find information about loop bound variables.  */
> >        for (nb_iter = loop->bounds; nb_iter;
> > diff --git a/gcc/tree-predcom.c b/gcc/tree-predcom.c
> > index d2dcfe7f42d..93e6da1e2ab 100644
> > --- a/gcc/tree-predcom.c
> > +++ b/gcc/tree-predcom.c
> > @@ -737,13 +737,12 @@ static basic_block
> >  last_always_executed_block (class loop *loop)
> >  {
> >    unsigned i;
> > -  vec<edge> exits = get_loop_exit_edges (loop);
> > +  auto_vec<edge> exits = get_loop_exit_edges (loop);
> >    edge ex;
> >    basic_block last = loop->latch;
> >  
> >    FOR_EACH_VEC_ELT (exits, i, ex)
> >      last = nearest_common_dominator (CDI_DOMINATORS, last, ex->src);
> > -  exits.release ();
> >  
> >    return last;
> >  }
> > diff --git a/gcc/tree-ssa-loop-ch.c b/gcc/tree-ssa-loop-ch.c
> > index b9002d8e294..b86acf7c39d 100644
> > --- a/gcc/tree-ssa-loop-ch.c
> > +++ b/gcc/tree-ssa-loop-ch.c
> > @@ -504,14 +504,13 @@ ch_base::copy_headers (function *fun)
> >  	{
> >  	  edge entry = copied[i].first;
> >  	  loop_p loop = copied[i].second;
> > -	  vec<edge> exit_edges = get_loop_exit_edges (loop);
> > +	  auto_vec<edge> exit_edges = get_loop_exit_edges (loop);
> >  	  bitmap exit_bbs = BITMAP_ALLOC (NULL);
> >  	  for (unsigned j = 0; j < exit_edges.length (); ++j)
> >  	    bitmap_set_bit (exit_bbs, exit_edges[j]->dest->index);
> >  	  bitmap_set_bit (exit_bbs, loop->header->index);
> >  	  do_rpo_vn (cfun, entry, exit_bbs);
> >  	  BITMAP_FREE (exit_bbs);
> > -	  exit_edges.release ();
> >  	}
> >      }
> >    free (bbs);
> > diff --git a/gcc/tree-ssa-loop-im.c b/gcc/tree-ssa-loop-im.c
> > index 35da1fb26a6..8b7eb57514f 100644
> > --- a/gcc/tree-ssa-loop-im.c
> > +++ b/gcc/tree-ssa-loop-im.c
> > @@ -2866,7 +2866,7 @@ loop_suitable_for_sm (class loop *loop ATTRIBUTE_UNUSED,
> >  static void
> >  store_motion_loop (class loop *loop, bitmap sm_executed)
> >  {
> > -  vec<edge> exits = get_loop_exit_edges (loop);
> > +  auto_vec<edge> exits = get_loop_exit_edges (loop);
> >    class loop *subloop;
> >    bitmap sm_in_loop = BITMAP_ALLOC (&lim_bitmap_obstack);
> >  
> > @@ -2876,7 +2876,6 @@ store_motion_loop (class loop *loop, bitmap sm_executed)
> >        if (!bitmap_empty_p (sm_in_loop))
> >  	hoist_memory_references (loop, sm_in_loop, exits);
> >      }
> > -  exits.release ();
> >  
> >    bitmap_ior_into (sm_executed, sm_in_loop);
> >    for (subloop = loop->inner; subloop != NULL; subloop = subloop->next)
> > diff --git a/gcc/tree-ssa-loop-ivcanon.c b/gcc/tree-ssa-loop-ivcanon.c
> > index 298ab215530..5bb781dc7fa 100644
> > --- a/gcc/tree-ssa-loop-ivcanon.c
> > +++ b/gcc/tree-ssa-loop-ivcanon.c
> > @@ -444,7 +444,6 @@ estimated_unrolled_size (struct loop_size *size,
> >  static edge
> >  loop_edge_to_cancel (class loop *loop)
> >  {
> > -  vec<edge> exits;
> >    unsigned i;
> >    edge edge_to_cancel;
> >    gimple_stmt_iterator gsi;
> > @@ -453,7 +452,7 @@ loop_edge_to_cancel (class loop *loop)
> >    if (EDGE_COUNT (loop->latch->preds) > 1)
> >      return NULL;
> >  
> > -  exits = get_loop_exit_edges (loop);
> > +  auto_vec<edge> exits = get_loop_exit_edges (loop);
> >  
> >    FOR_EACH_VEC_ELT (exits, i, edge_to_cancel)
> >      {
> > @@ -477,8 +476,6 @@ loop_edge_to_cancel (class loop *loop)
> >        if (edge_to_cancel->dest != loop->latch)
> >          continue;
> >  
> > -      exits.release ();
> > -
> >        /* Verify that the code in loop latch does nothing that may end program
> >           execution without really reaching the exit.  This may include
> >  	 non-pure/const function calls, EH statements, volatile ASMs etc.  */
> > @@ -487,7 +484,6 @@ loop_edge_to_cancel (class loop *loop)
> >  	   return NULL;
> >        return edge_to_cancel;
> >      }
> > -  exits.release ();
> >    return NULL;
> >  }
> >  
> > @@ -1222,10 +1218,9 @@ canonicalize_loop_induction_variables (class loop *loop,
> >       by find_loop_niter_by_eval.  Be sure to keep it for future.  */
> >    if (niter && TREE_CODE (niter) == INTEGER_CST)
> >      {
> > -      vec<edge> exits = get_loop_exit_edges  (loop);
> > +      auto_vec<edge> exits = get_loop_exit_edges  (loop);
> >        record_niter_bound (loop, wi::to_widest (niter),
> >  			  exit == single_likely_exit (loop, exits), true);
> > -      exits.release ();
> >      }
> >  
> >    /* Force re-computation of loop bounds so we can remove redundant exits.  */
> > diff --git a/gcc/tree-ssa-loop-manip.c b/gcc/tree-ssa-loop-manip.c
> > index a2717a411a3..cdd1ac76833 100644
> > --- a/gcc/tree-ssa-loop-manip.c
> > +++ b/gcc/tree-ssa-loop-manip.c
> > @@ -368,11 +368,10 @@ get_loops_exits (bitmap *loop_exits)
> >  
> >    FOR_EACH_LOOP (loop, 0)
> >      {
> > -      vec<edge> exit_edges = get_loop_exit_edges (loop);
> > +      auto_vec<edge> exit_edges = get_loop_exit_edges (loop);
> >        loop_exits[loop->num] = BITMAP_ALLOC (&loop_renamer_obstack);
> >        FOR_EACH_VEC_ELT (exit_edges, j, e)
> >          bitmap_set_bit (loop_exits[loop->num], e->dest->index);
> > -      exit_edges.release ();
> >      }
> >  }
> >  
> > diff --git a/gcc/tree-ssa-loop-niter.c b/gcc/tree-ssa-loop-niter.c
> > index 7d61ef080eb..8bb29c2470f 100644
> > --- a/gcc/tree-ssa-loop-niter.c
> > +++ b/gcc/tree-ssa-loop-niter.c
> > @@ -2752,7 +2752,7 @@ tree
> >  find_loop_niter (class loop *loop, edge *exit)
> >  {
> >    unsigned i;
> > -  vec<edge> exits = get_loop_exit_edges (loop);
> > +  auto_vec<edge> exits = get_loop_exit_edges (loop);
> >    edge ex;
> >    tree niter = NULL_TREE, aniter;
> >    class tree_niter_desc desc;
> > @@ -2803,7 +2803,6 @@ find_loop_niter (class loop *loop, edge *exit)
> >  	  continue;
> >  	}
> >      }
> > -  exits.release ();
> >  
> >    return niter ? niter : chrec_dont_know;
> >  }
> > @@ -2837,21 +2836,18 @@ finite_loop_p (class loop *loop)
> >    if (loop->finite_p)
> >      {
> >        unsigned i;
> > -      vec<edge> exits = get_loop_exit_edges (loop);
> > +      auto_vec<edge> exits = get_loop_exit_edges (loop);
> >        edge ex;
> >  
> >        /* If the loop has a normal exit, we can assume it will terminate.  */
> >        FOR_EACH_VEC_ELT (exits, i, ex)
> >  	if (!(ex->flags & (EDGE_EH | EDGE_ABNORMAL | EDGE_FAKE)))
> >  	  {
> > -	    exits.release ();
> >  	    if (dump_file)
> >  	      fprintf (dump_file, "Assume loop %i to be finite: it has an exit "
> >  		       "and -ffinite-loops is on.\n", loop->num);
> >  	    return true;
> >  	  }
> > -
> > -      exits.release ();
> >      }
> >  
> >    return false;
> > @@ -3114,7 +3110,7 @@ tree
> >  find_loop_niter_by_eval (class loop *loop, edge *exit)
> >  {
> >    unsigned i;
> > -  vec<edge> exits = get_loop_exit_edges (loop);
> > +  auto_vec<edge> exits = get_loop_exit_edges (loop);
> >    edge ex;
> >    tree niter = NULL_TREE, aniter;
> >  
> > @@ -3123,10 +3119,7 @@ find_loop_niter_by_eval (class loop *loop, edge *exit)
> >    /* Loops with multiple exits are expensive to handle and less important.  */
> >    if (!flag_expensive_optimizations
> >        && exits.length () > 1)
> > -    {
> > -      exits.release ();
> > -      return chrec_dont_know;
> > -    }
> > +    return chrec_dont_know;
> >  
> >    FOR_EACH_VEC_ELT (exits, i, ex)
> >      {
> > @@ -3144,7 +3137,6 @@ find_loop_niter_by_eval (class loop *loop, edge *exit)
> >        niter = aniter;
> >        *exit = ex;
> >      }
> > -  exits.release ();
> >  
> >    return niter ? niter : chrec_dont_know;
> >  }
> > @@ -4236,7 +4228,6 @@ get_upper_bound_based_on_builtin_expr_with_prob (gcond *cond)
> >  void
> >  estimate_numbers_of_iterations (class loop *loop)
> >  {
> > -  vec<edge> exits;
> >    tree niter, type;
> >    unsigned i;
> >    class tree_niter_desc niter_desc;
> > @@ -4275,7 +4266,7 @@ estimate_numbers_of_iterations (class loop *loop)
> >    number_of_latch_executions (loop);
> >  
> >    basic_block *body = get_loop_body (loop);
> > -  exits = get_loop_exit_edges (loop, body);
> > +  auto_vec<edge> exits = get_loop_exit_edges (loop, body);
> >    likely_exit = single_likely_exit (loop, exits);
> >    FOR_EACH_VEC_ELT (exits, i, ex)
> >      {
> > @@ -4311,7 +4302,6 @@ estimate_numbers_of_iterations (class loop *loop)
> >  		       true, ex == likely_exit, true);
> >        record_control_iv (loop, &niter_desc);
> >      }
> > -  exits.release ();
> >  
> >    if (flag_aggressive_loop_optimizations)
> >      infer_loop_bounds_from_undefined (loop, body);
> > diff --git a/gcc/tree-ssa-loop-prefetch.c b/gcc/tree-ssa-loop-prefetch.c
> > index d19ece6410d..5e94a19c964 100644
> > --- a/gcc/tree-ssa-loop-prefetch.c
> > +++ b/gcc/tree-ssa-loop-prefetch.c
> > @@ -1289,7 +1289,7 @@ mark_nontemporal_store (struct mem_ref *ref)
> >  static void
> >  emit_mfence_after_loop (class loop *loop)
> >  {
> > -  vec<edge> exits = get_loop_exit_edges (loop);
> > +  auto_vec<edge> exits = get_loop_exit_edges (loop);
> >    edge exit;
> >    gcall *call;
> >    gimple_stmt_iterator bsi;
> > @@ -1309,7 +1309,6 @@ emit_mfence_after_loop (class loop *loop)
> >        gsi_insert_before (&bsi, call, GSI_NEW_STMT);
> >      }
> >  
> > -  exits.release ();
> >    update_ssa (TODO_update_ssa_only_virtuals);
> >  }
> >  
> > @@ -1327,7 +1326,7 @@ may_use_storent_in_loop_p (class loop *loop)
> >       is a suitable place for it at each of the loop exits.  */
> >    if (FENCE_FOLLOWING_MOVNT != NULL_TREE)
> >      {
> > -      vec<edge> exits = get_loop_exit_edges (loop);
> > +      auto_vec<edge> exits = get_loop_exit_edges (loop);
> >        unsigned i;
> >        edge exit;
> >  
> > @@ -1335,8 +1334,6 @@ may_use_storent_in_loop_p (class loop *loop)
> >  	if ((exit->flags & EDGE_ABNORMAL)
> >  	    && exit->dest == EXIT_BLOCK_PTR_FOR_FN (cfun))
> >  	  ret = false;
> > -
> > -      exits.release ();
> >      }
> >  
> >    return ret;
> > diff --git a/gcc/vec.h b/gcc/vec.h
> > index 3ad99b83690..4f18116e1b8 100644
> > --- a/gcc/vec.h
> > +++ b/gcc/vec.h
> > @@ -1533,6 +1533,13 @@ public:
> >    auto_vec () { this->m_vec = NULL; }
> >    auto_vec (size_t n) { this->create (n); }
> >    ~auto_vec () { this->release (); }
> > +
> > +  auto_vec (auto_vec&& r)
> > +    {
> > +      this->m_vec = r.m_vec;
> > +      r.m_vec = NULL;
> > +    }
> > +  void operator= (auto_vec&&) = delete;
> >  };
> >  
> >  
> > 
> 
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imend