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.

1 files changed, 2 insertions, 7 deletions

diff --git a/gcc/tree-ssa-loop-ivcanon.c b/gcc/tree-ssa-loop-ivcanon.c
index 298ab21..5bb781d 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.  */