diff options
Diffstat (limited to 'gcc/tree-ssa-dce.c')
| -rw-r--r-- | gcc/tree-ssa-dce.c | 66 |
1 files changed, 37 insertions, 29 deletions
diff --git a/gcc/tree-ssa-dce.c b/gcc/tree-ssa-dce.c index ae44ef189a6..edec49d374f 100644 --- a/gcc/tree-ssa-dce.c +++ b/gcc/tree-ssa-dce.c @@ -77,8 +77,8 @@ static VEC(gimple,heap) *worklist; as necessary. */ static sbitmap processed; -/* Vector indicating that last_stmt if a basic block has already been - marked as necessary. */ +/* Vector indicating that the last statement of a basic block has already + been marked as necessary. */ static sbitmap last_stmt_necessary; /* Vector indicating that BB contains statements that are live. */ @@ -197,6 +197,7 @@ find_all_control_dependences (struct edge_list *el) /* If STMT is not already marked necessary, mark it, and add it to the worklist if ADD_TO_WORKLIST is true. */ + static inline void mark_stmt_necessary (gimple stmt, bool add_to_worklist) { @@ -365,13 +366,30 @@ mark_stmt_if_obviously_necessary (gimple stmt, bool aggressive) } -/* Make corresponding control dependent edges necessary. We only - have to do this once for each basic block, so we clear the bitmap - after we're done. +/* Mark the last statement of BB as necessary. */ - When IGNORE_SELF it true, ignore BB from the list of control dependences. */ static void -mark_control_dependent_edges_necessary (basic_block bb, struct edge_list *el, bool ignore_self) +mark_last_stmt_necessary (basic_block bb) +{ + gimple stmt = last_stmt (bb); + + SET_BIT (last_stmt_necessary, bb->index); + SET_BIT (bb_contains_live_stmts, bb->index); + + /* We actually mark the statement only if it is a control statement. */ + if (stmt && is_ctrl_stmt (stmt)) + mark_stmt_necessary (stmt, true); +} + + +/* Mark control dependent edges of BB as necessary. We have to do this only + once for each basic block so we set the appropriate bit after we're done. + + When IGNORE_SELF is true, ignore BB in the list of control dependences. */ + +static void +mark_control_dependent_edges_necessary (basic_block bb, struct edge_list *el, + bool ignore_self) { bitmap_iterator bi; unsigned edge_number; @@ -384,7 +402,6 @@ mark_control_dependent_edges_necessary (basic_block bb, struct edge_list *el, bo EXECUTE_IF_CONTROL_DEPENDENT (bi, bb->index, edge_number) { - gimple stmt; basic_block cd_bb = INDEX_EDGE_PRED_BB (el, edge_number); if (ignore_self && cd_bb == bb) @@ -393,15 +410,10 @@ mark_control_dependent_edges_necessary (basic_block bb, struct edge_list *el, bo continue; } - if (TEST_BIT (last_stmt_necessary, cd_bb->index)) - continue; - SET_BIT (last_stmt_necessary, cd_bb->index); - SET_BIT (bb_contains_live_stmts, cd_bb->index); - - stmt = last_stmt (cd_bb); - if (stmt && is_ctrl_stmt (stmt)) - mark_stmt_necessary (stmt, true); + if (!TEST_BIT (last_stmt_necessary, cd_bb->index)) + mark_last_stmt_necessary (cd_bb); } + if (!skipped) SET_BIT (visited_control_parents, bb->index); } @@ -487,6 +499,9 @@ ref_may_be_aliased (tree ref) { while (handled_component_p (ref)) ref = TREE_OPERAND (ref, 0); + if (TREE_CODE (ref) == MEM_REF + && TREE_CODE (TREE_OPERAND (ref, 0)) == ADDR_EXPR) + ref = TREE_OPERAND (TREE_OPERAND (ref, 0), 0); return !(DECL_P (ref) && !may_be_aliased (ref)); } @@ -652,12 +667,12 @@ propagate_necessity (struct edge_list *el) if (aggressive) { - /* Mark the last statements of the basic blocks that the block - containing STMT is control dependent on, but only if we haven't + /* Mark the last statement of the basic blocks on which the block + containing STMT is control dependent, but only if we haven't already done so. */ basic_block bb = gimple_bb (stmt); if (bb != ENTRY_BLOCK_PTR - && ! TEST_BIT (visited_control_parents, bb->index)) + && !TEST_BIT (visited_control_parents, bb->index)) mark_control_dependent_edges_necessary (bb, el, false); } @@ -760,18 +775,11 @@ propagate_necessity (struct edge_list *el) != get_immediate_dominator (CDI_POST_DOMINATORS, arg_bb)) { if (!TEST_BIT (last_stmt_necessary, arg_bb->index)) - { - gimple stmt2; - SET_BIT (last_stmt_necessary, arg_bb->index); - SET_BIT (bb_contains_live_stmts, arg_bb->index); - - stmt2 = last_stmt (arg_bb); - if (stmt2 && is_ctrl_stmt (stmt2)) - mark_stmt_necessary (stmt2, true); - } + mark_last_stmt_necessary (arg_bb); } else if (arg_bb != ENTRY_BLOCK_PTR - && ! TEST_BIT (visited_control_parents, arg_bb->index)) + && !TEST_BIT (visited_control_parents, + arg_bb->index)) mark_control_dependent_edges_necessary (arg_bb, el, true); } } |