diff options
Diffstat (limited to 'gcc/tree-ssa-loop-manip.c')
| -rw-r--r-- | gcc/tree-ssa-loop-manip.c | 39 |
1 files changed, 24 insertions, 15 deletions
diff --git a/gcc/tree-ssa-loop-manip.c b/gcc/tree-ssa-loop-manip.c index 5aa8c7d3c3f..98846138e7c 100644 --- a/gcc/tree-ssa-loop-manip.c +++ b/gcc/tree-ssa-loop-manip.c @@ -34,6 +34,10 @@ along with GCC; see the file COPYING3. If not see #include "tree-inline.h" #include "langhooks.h" +/* All bitmaps for rewriting into loop-closed SSA go on this obstack, + so that we can free them all at once. */ +static bitmap_obstack loop_renamer_obstack; + /* Creates an induction variable with value BASE + STEP * iteration in LOOP. It is expected that neither BASE nor STEP are shared with other expressions (unless the sharing rules allow this). Use VAR as a base var_decl for it @@ -168,7 +172,7 @@ add_exit_phis_var (tree var, bitmap livein, bitmap exits) gcc_checking_assert (is_gimple_reg (var)); bitmap_clear_bit (livein, def_bb->index); - def = BITMAP_ALLOC (NULL); + def = BITMAP_ALLOC (&loop_renamer_obstack); bitmap_set_bit (def, def_bb->index); compute_global_livein (livein, def); BITMAP_FREE (def); @@ -177,6 +181,10 @@ add_exit_phis_var (tree var, bitmap livein, bitmap exits) { add_exit_phis_edge (BASIC_BLOCK (index), var); } + + /* Free the livein bitmap. We'll not be needing it anymore, and + it may have grown quite large. No reason to hold on to it. */ + bitmap_clear (livein); } /* Add exit phis for the names marked in NAMES_TO_RENAME. @@ -200,7 +208,7 @@ add_exit_phis (bitmap names_to_rename, bitmap *use_blocks, bitmap loop_exits) static bitmap get_loops_exits (void) { - bitmap exits = BITMAP_ALLOC (NULL); + bitmap exits = BITMAP_ALLOC (&loop_renamer_obstack); basic_block bb; edge e; edge_iterator ei; @@ -253,11 +261,11 @@ find_uses_to_rename_use (basic_block bb, tree use, bitmap *use_blocks, if (flow_bb_inside_loop_p (def_loop, bb)) return; - if (!use_blocks[ver]) - use_blocks[ver] = BITMAP_ALLOC (NULL); + /* If we're seeing VER for the first time, we still have to allocate + a bitmap for its uses. */ + if (bitmap_set_bit (need_phis, ver)) + use_blocks[ver] = BITMAP_ALLOC (&loop_renamer_obstack); bitmap_set_bit (use_blocks[ver], bb->index); - - bitmap_set_bit (need_phis, ver); } /* For uses in STMT, mark names that are used outside of the loop they are @@ -312,6 +320,7 @@ find_uses_to_rename (bitmap changed_bbs, bitmap *use_blocks, bitmap need_phis) unsigned index; bitmap_iterator bi; + /* ??? If CHANGED_BBS is empty we rewrite the whole function -- why? */ if (changed_bbs && !bitmap_empty_p (changed_bbs)) { EXECUTE_IF_SET_IN_BITMAP (changed_bbs, 0, index, bi) @@ -365,22 +374,25 @@ rewrite_into_loop_closed_ssa (bitmap changed_bbs, unsigned update_flag) { bitmap loop_exits; bitmap *use_blocks; - unsigned i, old_num_ssa_names; bitmap names_to_rename; loops_state_set (LOOP_CLOSED_SSA); if (number_of_loops () <= 1) return; + bitmap_obstack_initialize (&loop_renamer_obstack); + loop_exits = get_loops_exits (); - names_to_rename = BITMAP_ALLOC (NULL); + names_to_rename = BITMAP_ALLOC (&loop_renamer_obstack); /* If the pass has caused the SSA form to be out-of-date, update it now. */ update_ssa (update_flag); - old_num_ssa_names = num_ssa_names; - use_blocks = XCNEWVEC (bitmap, old_num_ssa_names); + /* Uses of names to rename. We don't have to initialize this array, + because we know that we will only have entries for the SSA names + in NAMES_TO_RENAME. */ + use_blocks = XCNEWVEC (bitmap, num_ssa_names); /* Find the uses outside loops. */ find_uses_to_rename (changed_bbs, use_blocks, names_to_rename); @@ -389,11 +401,8 @@ rewrite_into_loop_closed_ssa (bitmap changed_bbs, unsigned update_flag) rewrite. */ add_exit_phis (names_to_rename, use_blocks, loop_exits); - for (i = 0; i < old_num_ssa_names; i++) - BITMAP_FREE (use_blocks[i]); + bitmap_obstack_release (&loop_renamer_obstack); free (use_blocks); - BITMAP_FREE (loop_exits); - BITMAP_FREE (names_to_rename); /* Fix up all the names found to be used outside their original loops. */ @@ -428,7 +437,7 @@ check_loop_closed_ssa_stmt (basic_block bb, gimple stmt) if (is_gimple_debug (stmt)) return; - FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_ALL_USES) + FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_USE) check_loop_closed_ssa_use (bb, var); } |