Move SLP nodes to an alloc-pool

This introduces a global alloc-pool for SLP nodes to reduce overhead
on SLP allocation churn which will get worse and to eventually release
SLP cycles which will retain a refcount of one and thus are never
freed at the moment.

2020-10-26  Richard Biener  <rguenther@suse.de>

	* tree-vectorizer.h (slp_tree_pool): Declare.
	(_slp_tree::operator new): Likewise.
	(_slp_tree::operator delete): Likewise.
	* tree-vectorizer.c (vectorize_loops): Allocate and free the
	slp_tree_pool.
	(pass_slp_vectorize::execute): Likewise.
	* tree-vect-slp.c (slp_tree_pool): Define.
	(_slp_tree::operator new): Likewise.
	(_slp_tree::operator delete): Likewise.

1 files changed, 9 insertions, 0 deletions

diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
index b56073c..9c55383 100644
--- a/gcc/tree-vectorizer.h
+++ b/gcc/tree-vectorizer.h
@@ -26,6 +26,7 @@ typedef class _stmt_vec_info *stmt_vec_info;
 #include "tree-data-ref.h"
 #include "tree-hash-traits.h"
 #include "target.h"
+#include "alloc-pool.h"
 
 
 /* Used for naming of new temporaries.  */
@@ -115,6 +116,8 @@ typedef hash_map<tree_operand_hash,
  ************************************************************************/
 typedef struct _slp_tree *slp_tree;
 
+extern object_allocator<_slp_tree> *slp_tree_pool;
+
 /* A computation tree of an SLP instance.  Each node corresponds to a group of
    stmts to be packed in a SIMD stmt.  */
 struct _slp_tree {
@@ -163,6 +166,12 @@ struct _slp_tree {
   enum tree_code code;
 
   int vertex;
+
+  /* Allocate from slp_tree_pool.  */
+  static void *operator new (size_t);
+
+  /* Return memory to slp_tree_pool.  */
+  static void operator delete (void *, size_t);
 };