Re: [PATCH] Remove SSA name value_handle field

[Daniel Berlin <dberlin at dberlin dot org>]

Please do.
Even in the new VN rewrite this field is still unused.


On Mon, Apr 27, 2009 at 11:51 AM, Richard Guenther <rguenther@suse.de> wrote:
>
> This removes the value_handle field from struct tree_ssa_name by
> using a VEC in DOM / jump threading.
>
> Bootstrapped and tested on x86_64-unknown-linux-gnu. ?I'll apply this
> tomorrow if there are no complaints.
>
> Richard.
>
> 2009-04-27 ?Richard Guenther ?<rguenther@suse.de>
>
> ? ? ? ?* tree.h (SSA_NAME_VALUE): Remove.
> ? ? ? ?(struct tree_ssa_name): Remove value_handle member.
> ? ? ? ?* tree-vrp.c (execute_vrp): Initialize/free the value-handle
> ? ? ? ?array for jump threading.
> ? ? ? ?* tree-ssa-propagate.c (ssa_prop_init): Do not initialize
> ? ? ? ?SSA_NAME_VALUEs.
> ? ? ? ?* print-tree.c (print_node): Do not dump SSA_NAME_VALUEs.
> ? ? ? ?* tree-flow.h (threadedge_initialize_values): Declare.
> ? ? ? ?(threadedge_finalize_values): Likewise.
> ? ? ? ?* tree-ssa-threadedge.c (ssa_name_values): New global variable.
> ? ? ? ?(SSA_NAME_VALUE): Define.
> ? ? ? ?(threadedge_initialize_values): New function.
> ? ? ? ?(threadedge_finalize_values): Likewise.
> ? ? ? ?* tree-ssa-dom.c (ssa_name_values): New global variable.
> ? ? ? ?(SSA_NAME_VALUE): Define.
> ? ? ? ?(tree_ssa_dominator_optimize): Initialize/free the value-handle
> ? ? ? ?array.
>
> Index: gcc/tree.h
> ===================================================================
> *** gcc/tree.h.orig ? ? 2009-04-27 13:13:57.000000000 +0200
> --- gcc/tree.h ?2009-04-27 13:33:51.000000000 +0200
> *************** struct GTY(()) tree_exp {
> *** 1854,1863 ****
> ?#define SSA_NAME_PTR_INFO(N) \
> ? ? ?SSA_NAME_CHECK (N)->ssa_name.ptr_info
>
> - /* Get the value of this SSA_NAME, if available. ?*/
> - #define SSA_NAME_VALUE(N) \
> - ? ?SSA_NAME_CHECK (N)->ssa_name.value_handle
> -
> ?#ifndef _TREE_FLOW_H
> ?struct ptr_info_def;
> ?#endif
> --- 1854,1859 ----
> *************** struct GTY(()) tree_ssa_name {
> *** 1896,1908 ****
> ? ?/* Pointer attributes used for alias analysis. ?*/
> ? ?struct ptr_info_def *ptr_info;
>
> - ? /* Value for SSA name used by various passes.
> -
> - ? ? ?Right now only invariants are allowed to persist beyond a pass in
> - ? ? ?this field; in the future we will allow VALUE_HANDLEs to persist
> - ? ? ?as well. ?*/
> - ? tree value_handle;
> -
> ? ?/* Immediate uses list for this SSA_NAME. ?*/
> ? ?struct ssa_use_operand_d imm_uses;
> ?};
> --- 1892,1897 ----
> Index: gcc/tree-vrp.c
> ===================================================================
> *** gcc/tree-vrp.c.orig 2009-04-27 13:13:57.000000000 +0200
> --- gcc/tree-vrp.c ? ? ?2009-04-27 13:33:51.000000000 +0200
> *************** execute_vrp (void)
> *** 7277,7282 ****
> --- 7277,7283 ----
>
> ? ?to_remove_edges = VEC_alloc (edge, heap, 10);
> ? ?to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
> + ? threadedge_initialize_values ();
>
> ? ?vrp_initialize ();
> ? ?ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
> *************** execute_vrp (void)
> *** 7322,7327 ****
> --- 7323,7329 ----
>
> ? ?VEC_free (edge, heap, to_remove_edges);
> ? ?VEC_free (switch_update, heap, to_update_switch_stmts);
> + ? threadedge_finalize_values ();
>
> ? ?scev_finalize ();
> ? ?loop_optimizer_finalize ();
> Index: gcc/tree-ssa-propagate.c
> ===================================================================
> *** gcc/tree-ssa-propagate.c.orig ? ? ? 2009-04-27 13:13:57.000000000 +0200
> --- gcc/tree-ssa-propagate.c ? ?2009-04-27 13:33:51.000000000 +0200
> *************** ssa_prop_init (void)
> *** 487,493 ****
> ? ?edge e;
> ? ?edge_iterator ei;
> ? ?basic_block bb;
> - ? size_t i;
>
> ? ?/* Worklists of SSA edges. ?*/
> ? ?interesting_ssa_edges = VEC_alloc (gimple, gc, 20);
> --- 487,492 ----
> *************** ssa_prop_init (void)
> *** 505,515 ****
> ? ?cfg_blocks = VEC_alloc (basic_block, heap, 20);
> ? ?VEC_safe_grow (basic_block, heap, cfg_blocks, 20);
>
> - ? /* Initialize the values for every SSA_NAME. ?*/
> - ? for (i = 1; i < num_ssa_names; i++)
> - ? ? if (ssa_name (i))
> - ? ? ? SSA_NAME_VALUE (ssa_name (i)) = NULL_TREE;
> -
> ? ?/* Initially assume that every edge in the CFG is not executable.
> ? ? ? (including the edges coming out of ENTRY_BLOCK_PTR). ?*/
> ? ?FOR_ALL_BB (bb)
> --- 504,509 ----
> Index: gcc/print-tree.c
> ===================================================================
> *** gcc/print-tree.c.orig ? ? ? 2009-04-27 13:13:57.000000000 +0200
> --- gcc/print-tree.c ? ?2009-04-27 13:33:51.000000000 +0200
> *************** print_node (FILE *file, const char *pref
> *** 896,909 ****
> ? ? ? ? ?if (SSA_NAME_IN_FREE_LIST (node))
> ? ? ? ? ? ?fprintf (file, " in-free-list");
>
> ! ? ? ? ? if (SSA_NAME_PTR_INFO (node)
> ! ? ? ? ? ? ? || SSA_NAME_VALUE (node))
> ? ? ? ? ? ?{
> ? ? ? ? ? ? ?indent_to (file, indent + 3);
> ? ? ? ? ? ? ?if (SSA_NAME_PTR_INFO (node))
> ? ? ? ? ? ? ? ?dump_addr (file, " ptr-info ", SSA_NAME_PTR_INFO (node));
> - ? ? ? ? ? ? if (SSA_NAME_VALUE (node))
> - ? ? ? ? ? ? ? dump_addr (file, " value ", SSA_NAME_VALUE (node));
> ? ? ? ? ? ?}
> ? ? ? ? ?break;
>
> --- 896,906 ----
> ? ? ? ? ?if (SSA_NAME_IN_FREE_LIST (node))
> ? ? ? ? ? ?fprintf (file, " in-free-list");
>
> ! ? ? ? ? if (SSA_NAME_PTR_INFO (node))
> ? ? ? ? ? ?{
> ? ? ? ? ? ? ?indent_to (file, indent + 3);
> ? ? ? ? ? ? ?if (SSA_NAME_PTR_INFO (node))
> ? ? ? ? ? ? ? ?dump_addr (file, " ptr-info ", SSA_NAME_PTR_INFO (node));
> ? ? ? ? ? ?}
> ? ? ? ? ?break;
>
> Index: gcc/tree-flow.h
> ===================================================================
> *** gcc/tree-flow.h.orig ? ? ? ?2009-04-27 13:13:57.000000000 +0200
> --- gcc/tree-flow.h ? ? 2009-04-27 15:52:52.000000000 +0200
> *************** bool stmt_dominates_stmt_p (gimple, gimp
> *** 803,808 ****
> --- 803,816 ----
> ?void mark_virtual_ops_for_renaming (gimple);
>
> ?/* In tree-ssa-threadedge.c */
> + extern void threadedge_initialize_values (void);
> + extern void threadedge_finalize_values (void);
> + extern VEC(tree,heap) *ssa_name_values;
> + #define SSA_NAME_VALUE(x) \
> + ? ? (SSA_NAME_VERSION(x) < VEC_length(tree, ssa_name_values) \
> + ? ? ?? VEC_index(tree, ssa_name_values, SSA_NAME_VERSION(x)) \
> + ? ? ?: NULL_TREE)
> + extern void set_ssa_name_value (tree, tree);
> ?extern bool potentially_threadable_block (basic_block);
> ?extern void thread_across_edge (gimple, edge, bool,
> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?VEC(tree, heap) **, tree (*) (gimple, gimple));
> Index: gcc/tree-ssa-threadedge.c
> ===================================================================
> *** gcc/tree-ssa-threadedge.c.orig ? ? ?2009-04-27 13:13:57.000000000 +0200
> --- gcc/tree-ssa-threadedge.c ? 2009-04-27 15:55:10.000000000 +0200
> *************** along with GCC; see the file COPYING3.
> *** 49,54 ****
> --- 49,83 ----
> ? ? to copy as part of the jump threading process. ?*/
> ?static int stmt_count;
>
> + /* Array to record value-handles per SSA_NAME. ?*/
> + VEC(tree,heap) *ssa_name_values;
> +
> + /* Set the value for the SSA name NAME to VALUE. ?*/
> +
> + void
> + set_ssa_name_value (tree name, tree value)
> + {
> + ? if (SSA_NAME_VERSION (name) >= VEC_length (tree, ssa_name_values))
> + ? ? VEC_safe_grow_cleared (tree, heap, ssa_name_values,
> + ? ? ? ? ? ? ? ? ? ? ? ? ?SSA_NAME_VERSION (name) + 1);
> + ? VEC_replace (tree, ssa_name_values, SSA_NAME_VERSION (name), value);
> + }
> +
> + /* Initialize the per SSA_NAME value-handles array. ?Returns it. ?*/
> + void
> + threadedge_initialize_values (void)
> + {
> + ? gcc_assert (ssa_name_values == NULL);
> + ? ssa_name_values = VEC_alloc(tree, heap, num_ssa_names);
> + }
> +
> + /* Free the per SSA_NAME value-handle array. ?*/
> + void
> + threadedge_finalize_values (void)
> + {
> + ? VEC_free(tree, heap, ssa_name_values);
> + }
> +
> ?/* Return TRUE if we may be able to thread an incoming edge into
> ? ? BB to an outgoing edge from BB. ?Return FALSE otherwise. ?*/
>
> *************** remove_temporary_equivalences (VEC(tree,
> *** 126,132 ****
> ? ? ? ?break;
>
> ? ? ? ?prev_value = VEC_pop (tree, *stack);
> ! ? ? ? SSA_NAME_VALUE (dest) = prev_value;
> ? ? ?}
> ?}
>
> --- 155,161 ----
> ? ? ? ?break;
>
> ? ? ? ?prev_value = VEC_pop (tree, *stack);
> ! ? ? ? set_ssa_name_value (dest, prev_value);
> ? ? ?}
> ?}
>
> *************** record_temporary_equivalence (tree x, tr
> *** 145,151 ****
> ? ? ? ?y = tmp ? tmp : y;
> ? ? ?}
>
> ! ? SSA_NAME_VALUE (x) = y;
> ? ?VEC_reserve (tree, heap, *stack, 2);
> ? ?VEC_quick_push (tree, *stack, prev_x);
> ? ?VEC_quick_push (tree, *stack, x);
> --- 174,180 ----
> ? ? ? ?y = tmp ? tmp : y;
> ? ? ?}
>
> ! ? set_ssa_name_value (x, y);
> ? ?VEC_reserve (tree, heap, *stack, 2);
> ? ?VEC_quick_push (tree, *stack, prev_x);
> ? ?VEC_quick_push (tree, *stack, x);
> Index: gcc/tree-ssa-dom.c
> ===================================================================
> *** gcc/tree-ssa-dom.c.orig ? ? 2009-04-27 13:13:57.000000000 +0200
> --- gcc/tree-ssa-dom.c ?2009-04-27 15:55:25.000000000 +0200
> *************** static unsigned int
> *** 619,625 ****
> ?tree_ssa_dominator_optimize (void)
> ?{
> ? ?struct dom_walk_data walk_data;
> - ? unsigned int i;
>
> ? ?memset (&opt_stats, 0, sizeof (opt_stats));
>
> --- 619,624 ----
> *************** tree_ssa_dominator_optimize (void)
> *** 659,664 ****
> --- 658,666 ----
> ? ? ? that we update the loop info. ?*/
> ? ?loop_optimizer_init (LOOPS_HAVE_SIMPLE_LATCHES);
>
> + ? /* Initialize the value-handle array. ?*/
> + ? threadedge_initialize_values ();
> +
> ? ?/* We need accurate information regarding back edges in the CFG
> ? ? ? for jump threading; this may include back edges that are not part of
> ? ? ? a single loop. ?*/
> *************** tree_ssa_dominator_optimize (void)
> *** 716,738 ****
> ? ? ? ?bitmap_zero (need_eh_cleanup);
> ? ? ?}
>
> - ? /* Finally, remove everything except invariants in SSA_NAME_VALUE.
> -
> - ? ? ?Long term we will be able to let everything in SSA_NAME_VALUE
> - ? ? ?persist. ?However, for now, we know this is the safe thing to do. ?*/
> - ? for (i = 0; i < num_ssa_names; i++)
> - ? ?{
> - ? ? ? tree name = ssa_name (i);
> - ? ? ? tree value;
> -
> - ? ? ? if (!name)
> - ? ? ? ? continue;
> -
> - ? ? ? value = SSA_NAME_VALUE (name);
> - ? ? ? if (value && !is_gimple_min_invariant (value))
> - ? ? ? SSA_NAME_VALUE (name) = NULL;
> - ? ? }
> -
> ? ?statistics_counter_event (cfun, "Redundant expressions eliminated",
> ? ? ? ? ? ? ? ? ? ? ? ? ? ?opt_stats.num_re);
> ? ?statistics_counter_event (cfun, "Constants propagated",
> --- 718,723 ----
> *************** tree_ssa_dominator_optimize (void)
> *** 759,764 ****
> --- 744,753 ----
> ? ?VEC_free (tree, heap, const_and_copies_stack);
> ? ?VEC_free (gimple_p, heap, stmts_to_rescan);
>
> + ? /* Free the value-handle array. ?*/
> + ? threadedge_finalize_values ();
> + ? ssa_name_values = NULL;
> +
> ? ?return 0;
> ?}
>
> *************** restore_vars_to_original_value (void)
> *** 912,918 ****
> ? ? ? ?}
>
> ? ? ? ?prev_value = VEC_pop (tree, const_and_copies_stack);
> ! ? ? ? SSA_NAME_VALUE (dest) = ?prev_value;
> ? ? ?}
> ?}
>
> --- 901,907 ----
> ? ? ? ?}
>
> ? ? ? ?prev_value = VEC_pop (tree, const_and_copies_stack);
> ! ? ? ? set_ssa_name_value (dest, prev_value);
> ? ? ?}
> ?}
>
> *************** record_equivalences_from_phis (basic_blo
> *** 1124,1130 ****
> ? ? ? ? inferred from a comparison. ?All uses of this ssa name are dominated
> ? ? ? ? by this assignment, so unwinding just costs time and space. ?*/
> ? ? ? ?if (i == gimple_phi_num_args (phi) && may_propagate_copy (lhs, rhs))
> ! ? ? ? SSA_NAME_VALUE (lhs) = rhs;
> ? ? ?}
> ?}
>
> --- 1113,1119 ----
> ? ? ? ? inferred from a comparison. ?All uses of this ssa name are dominated
> ? ? ? ? by this assignment, so unwinding just costs time and space. ?*/
> ? ? ? ?if (i == gimple_phi_num_args (phi) && may_propagate_copy (lhs, rhs))
> ! ? ? ? set_ssa_name_value (lhs, rhs);
> ? ? ?}
> ?}
>
> *************** record_conditions (struct edge_info *edg
> *** 1437,1443 ****
> ?static void
> ?record_const_or_copy_1 (tree x, tree y, tree prev_x)
> ?{
> ! ? SSA_NAME_VALUE (x) = y;
>
> ? ?if (dump_file && (dump_flags & TDF_DETAILS))
> ? ? ?{
> --- 1426,1432 ----
> ?static void
> ?record_const_or_copy_1 (tree x, tree y, tree prev_x)
> ?{
> ! ? set_ssa_name_value (x, y);
>
> ? ?if (dump_file && (dump_flags & TDF_DETAILS))
> ? ? ?{
> *************** record_equivalences_from_stmt (gimple st
> *** 1956,1962 ****
> ? ? ? ? ? ?fprintf (dump_file, "\n");
> ? ? ? ? ?}
>
> ! ? ? ? SSA_NAME_VALUE (lhs) = rhs;
> ? ? ? ?}
> ? ? ?}
>
> --- 1945,1951 ----
> ? ? ? ? ? ?fprintf (dump_file, "\n");
> ? ? ? ? ?}
>
> ! ? ? ? set_ssa_name_value (lhs, rhs);
> ? ? ? ?}
> ? ? ?}
>
>