Re: [PATCH 04/18] remove TREE_CHAIN from SSA_NAME nodes

[Richard Guenther <richard dot guenther at gmail dot com>]

On Fri, Mar 11, 2011 at 5:23 AM, Nathan Froyd <froydnj@codesourcery.com> wrote:
> This conversion is straightforward. ?The tricky part is converting
> FREE_SSANAMES into a VEC to eliminate the only use of TREE_CHAIN on
> SSA_NAMEs.

Ok for 4.7.

Thanks,
Richard.

> -Nathan
>
> gcc/
> ? ? ? ?* tree-flow.h (struct gimple_df): Make free_ssanames a VEC.
> ? ? ? ?* tree-ssanames.c (fini_ssanames): VEC_free it.
> ? ? ? ?(make_ssa_name_fn): Update for VECness of free_ssanames.
> ? ? ? ?(release_ssa_name, release_dead_ssa_names): Likewise.
> ? ? ? ?* tree.h (struct tree_ssa_name): Include typed_tree instead of
> ? ? ? ?tree_common.
> ? ? ? ?* tree.c (initialize_tree_contains_struct): Mark TS_SSA_NAME as
> ? ? ? ?TS_TYPED instead of TS_COMMON.
>
> diff --git a/gcc/tree-flow.h b/gcc/tree-flow.h
> index 14c8827..6b48697 100644
> --- a/gcc/tree-flow.h
> +++ b/gcc/tree-flow.h
> @@ -61,7 +61,7 @@ struct GTY(()) gimple_df {
> ? struct pointer_map_t * GTY((skip(""))) decls_to_pointers;
>
> ? /* Free list of SSA_NAMEs. ?*/
> - ?tree free_ssanames;
> + ?VEC(tree,gc) *free_ssanames;
>
> ? /* Hashtable holding definition for symbol. ?If this field is not NULL, it
> ? ? ?means that the first reference to this variable in the function is a
> diff --git a/gcc/tree-ssanames.c b/gcc/tree-ssanames.c
> index c76dba5..06cdbee 100644
> --- a/gcc/tree-ssanames.c
> +++ b/gcc/tree-ssanames.c
> @@ -96,7 +96,7 @@ void
> ?fini_ssanames (void)
> ?{
> ? VEC_free (tree, gc, SSANAMES (cfun));
> - ?FREE_SSANAMES (cfun) = NULL;
> + ?VEC_free (tree, gc, FREE_SSANAMES (cfun));
> ?}
>
> ?/* Dump some simple statistics regarding the re-use of SSA_NAME nodes. ?*/
> @@ -124,10 +124,9 @@ make_ssa_name_fn (struct function *fn, tree var, gimple stmt)
> ? gcc_assert (DECL_P (var));
>
> ? /* If our free list has an element, then use it. ?*/
> - ?if (FREE_SSANAMES (fn))
> + ?if (!VEC_empty (tree, FREE_SSANAMES (fn)))
> ? ? {
> - ? ? ?t = FREE_SSANAMES (fn);
> - ? ? ?FREE_SSANAMES (fn) = TREE_CHAIN (FREE_SSANAMES (fn));
> + ? ? ?t = VEC_pop (tree, FREE_SSANAMES (fn));
> ?#ifdef GATHER_STATISTICS
> ? ? ? ssa_name_nodes_reused++;
> ?#endif
> @@ -234,9 +233,8 @@ release_ssa_name (tree var)
> ? ? ? /* Note this SSA_NAME is now in the first list. ?*/
> ? ? ? SSA_NAME_IN_FREE_LIST (var) = 1;
>
> - ? ? ?/* And finally link it into the free list. ?*/
> - ? ? ?TREE_CHAIN (var) = FREE_SSANAMES (cfun);
> - ? ? ?FREE_SSANAMES (cfun) = var;
> + ? ? ?/* And finally put it on the free list. ?*/
> + ? ? ?VEC_safe_push (tree, gc, FREE_SSANAMES (cfun), var);
> ? ? }
> ?}
>
> @@ -334,8 +332,8 @@ replace_ssa_name_symbol (tree ssa_name, tree sym)
> ?static unsigned int
> ?release_dead_ssa_names (void)
> ?{
> - ?tree t, next;
> - ?int n = 0;
> + ?tree t;
> + ?int n = VEC_length (tree, FREE_SSANAMES (cfun));
> ? referenced_var_iterator rvi;
>
> ? /* Current defs point to various dead SSA names that in turn point to
> @@ -343,17 +341,7 @@ release_dead_ssa_names (void)
> ? FOR_EACH_REFERENCED_VAR (cfun, t, rvi)
> ? ? set_current_def (t, NULL);
> ? /* Now release the freelist. ?*/
> - ?for (t = FREE_SSANAMES (cfun); t; t = next)
> - ? ?{
> - ? ? ?next = TREE_CHAIN (t);
> - ? ? ?/* Dangling pointers might make GGC to still see dead SSA names, so it is
> - ? ? ? ?important to unlink the list and avoid GGC from seeing all subsequent
> - ? ? ? ?SSA names. ?In longer run we want to have all dangling pointers here
> - ? ? ? ?removed (since they usually go through dead statements that consume
> - ? ? ? ?considerable amounts of memory). ?*/
> - ? ? ?TREE_CHAIN (t) = NULL_TREE;
> - ? ? ?n++;
> - ? ?}
> + ?VEC_free (tree, gc, FREE_SSANAMES (cfun));
> ? FREE_SSANAMES (cfun) = NULL;
>
> ? statistics_counter_event (cfun, "SSA names released", n);
> diff --git a/gcc/tree.c b/gcc/tree.c
> index 7d73c74..072ff19 100644
> --- a/gcc/tree.c
> +++ b/gcc/tree.c
> @@ -376,6 +376,7 @@ initialize_tree_contains_struct (void)
> ? ? ? ?case TS_VECTOR:
> ? ? ? ?case TS_STRING:
> ? ? ? ?case TS_COMPLEX:
> + ? ? ? case TS_SSA_NAME:
> ? ? ? ? ?MARK_TS_TYPED (code);
> ? ? ? ? ?break;
>
> @@ -385,7 +386,6 @@ initialize_tree_contains_struct (void)
> ? ? ? ?case TS_LIST:
> ? ? ? ?case TS_VEC:
> ? ? ? ?case TS_EXP:
> - ? ? ? case TS_SSA_NAME:
> ? ? ? ?case TS_BLOCK:
> ? ? ? ?case TS_BINFO:
> ? ? ? ?case TS_STATEMENT_LIST:
> diff --git a/gcc/tree.h b/gcc/tree.h
> index 11c2f83..80888bc 100644
> --- a/gcc/tree.h
> +++ b/gcc/tree.h
> @@ -1970,7 +1970,7 @@ typedef struct GTY(()) ssa_use_operand_d {
> ?#define SSA_NAME_IMM_USE_NODE(NODE) SSA_NAME_CHECK (NODE)->ssa_name.imm_uses
>
> ?struct GTY(()) tree_ssa_name {
> - ?struct tree_common common;
> + ?struct typed_tree typed;
>
> ? /* _DECL wrapped by this SSA name. ?*/
> ? tree var;
> --
> 1.7.0.4
>
>