diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 820c45c55c3d3b48ff0d51b2b18570b7f2f22f7e..99c9b5744ce442be8257ca6e33f325f6d275151c 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2007-01-15 Jan Hubicka <jh@suse.cz>
+
+ * tree-ssa-dce.c (DCE_TODOs): New.
+ (propagate_necessity): Return if something changed.
+ (eliminate_unnecessary_stmts): Likewise.
+ (perform_tree_ssa_dce): Return TODO flags when needed.
+ (pass_dce, pass_dce_loop, pass_cd_dce): Remove TODO flags.
+
2007-01-15 Uros Bizjak <ubizjak@gmail.com>
* config/i386/i386.md (fyl2xxf3_i387): Rename from fyl2x_xf3.
diff --git a/gcc/tree-ssa-dce.c b/gcc/tree-ssa-dce.c
index a26b87f5d8ee57ba461cb9d2af81a8f62067974e..381d91016e05263a4848b49b16e05c1fdb7253ce 100644
--- a/gcc/tree-ssa-dce.c
+++ b/gcc/tree-ssa-dce.c
@@ -525,10 +525,11 @@ propagate_necessity (struct edge_list *el)
/* Remove dead PHI nodes from block BB. */
-static void
+static bool
remove_dead_phis (basic_block bb)
{
tree prev, phi;
+ bool something_changed = false;
prev = NULL_TREE;
phi = phi_nodes (bb);
@@ -540,6 +541,7 @@ remove_dead_phis (basic_block bb)
{
tree next = PHI_CHAIN (phi);
+ something_changed = true;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Deleting : ");
@@ -557,6 +559,7 @@ remove_dead_phis (basic_block bb)
phi = PHI_CHAIN (phi);
}
}
+ return something_changed;
}
@@ -649,9 +652,10 @@ remove_dead_stmt (block_stmt_iterator *i, basic_block bb)
/* Eliminate unnecessary statements. Any instruction not marked as necessary
contributes nothing to the program, and can be deleted. */
-static void
+static bool
eliminate_unnecessary_stmts (void)
{
+ bool something_changed = false;
basic_block bb;
block_stmt_iterator i;
@@ -662,7 +666,7 @@ eliminate_unnecessary_stmts (void)
FOR_EACH_BB (bb)
{
/* Remove dead PHI nodes. */
- remove_dead_phis (bb);
+ something_changed |= remove_dead_phis (bb);
}
FOR_EACH_BB (bb)
@@ -676,7 +680,10 @@ eliminate_unnecessary_stmts (void)
/* If `i' is not necessary then remove it. */
if (! NECESSARY (t))
- remove_dead_stmt (&i, bb);
+ {
+ remove_dead_stmt (&i, bb);
+ something_changed = true;
+ }
else
{
tree call = get_call_expr_in (t);
@@ -686,6 +693,7 @@ eliminate_unnecessary_stmts (void)
}
}
}
+ return something_changed;
}
@@ -774,10 +782,11 @@ tree_dce_done (bool aggressive)
as the last tree SSA pass, but keep this in mind when you
start experimenting with pass ordering. */
-static void
+static unsigned int
perform_tree_ssa_dce (bool aggressive)
{
struct edge_list *el = NULL;
+ bool something_changed = 0;
tree_dce_init (aggressive);
@@ -800,9 +809,10 @@ perform_tree_ssa_dce (bool aggressive)
propagate_necessity (el);
- eliminate_unnecessary_stmts ();
+ something_changed |= eliminate_unnecessary_stmts ();
+ something_changed |= cfg_altered;
- if (aggressive)
+ if (aggressive && something_changed)
free_dominance_info (CDI_POST_DOMINATORS);
/* If we removed paths in the CFG, then we need to update
@@ -818,30 +828,38 @@ perform_tree_ssa_dce (bool aggressive)
tree_dce_done (aggressive);
free_edge_list (el);
+
+ if (something_changed)
+ return (TODO_update_ssa | TODO_cleanup_cfg | TODO_ggc_collect
+ | TODO_remove_unused_locals);
+ else
+ return 0;
}
/* Pass entry points. */
static unsigned int
tree_ssa_dce (void)
{
- perform_tree_ssa_dce (/*aggressive=*/false);
- return 0;
+ return perform_tree_ssa_dce (/*aggressive=*/false);
}
static unsigned int
tree_ssa_dce_loop (void)
{
- perform_tree_ssa_dce (/*aggressive=*/false);
- free_numbers_of_iterations_estimates ();
- scev_reset ();
- return 0;
+ unsigned int todo;
+ todo = perform_tree_ssa_dce (/*aggressive=*/false);
+ if (todo)
+ {
+ free_numbers_of_iterations_estimates ();
+ scev_reset ();
+ }
+ return todo;
}
static unsigned int
tree_ssa_cd_dce (void)
{
- perform_tree_ssa_dce (/*aggressive=*/optimize >= 2);
- return 0;
+ return perform_tree_ssa_dce (/*aggressive=*/optimize >= 2);
}
static bool
@@ -863,12 +881,7 @@ struct tree_opt_pass pass_dce =
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_dump_func
- | TODO_update_ssa
- | TODO_cleanup_cfg
- | TODO_ggc_collect
- | TODO_verify_ssa
- | TODO_remove_unused_locals, /* todo_flags_finish */
+ TODO_dump_func | TODO_verify_ssa, /* todo_flags_finish */
0 /* letter */
};
@@ -885,10 +898,7 @@ struct tree_opt_pass pass_dce_loop =
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_dump_func
- | TODO_update_ssa
- | TODO_cleanup_cfg
- | TODO_verify_ssa, /* todo_flags_finish */
+ TODO_dump_func | TODO_verify_ssa, /* todo_flags_finish */
0 /* letter */
};
@@ -905,11 +915,7 @@ struct tree_opt_pass pass_cd_dce =
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_dump_func
- | TODO_update_ssa
- | TODO_cleanup_cfg
- | TODO_ggc_collect
- | TODO_verify_ssa
- | TODO_verify_flow, /* todo_flags_finish */
+ TODO_dump_func | TODO_verify_ssa
+ | TODO_verify_flow, /* todo_flags_finish */
0 /* letter */
};