diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 10 | ||||
| -rw-r--r-- | gcc/tree-cfgcleanup.c | 89 |
2 files changed, 65 insertions, 34 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index af60aed..e9bb5ae 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,13 @@ +2017-11-14 Richard Biener <rguenther@suse.de> + + * tree-cfgcleanup.c (cleanup_control_expr_graph): Remove first_p + paramter and handling. + (cleanup_control_flow_bb): Likewise. + (cleanup_control_flow_pre): New helper performing a DFS walk + to call cleanup_control_flow_bb in PRE order. + (cleanup_tree_cfg_1): Do the first phase of cleanup_control_flow_bb + via cleanup_control_flow_pre. + 2017-11-14 James Greenhalgh <james.greenhalgh@arm.com> * config/aarch64/aarch64-simd.md diff --git a/gcc/tree-cfgcleanup.c b/gcc/tree-cfgcleanup.c index 9b7f08c..5267937 100644 --- a/gcc/tree-cfgcleanup.c +++ b/gcc/tree-cfgcleanup.c @@ -122,8 +122,7 @@ convert_single_case_switch (gswitch *swtch, gimple_stmt_iterator &gsi) at block BB. */ static bool -cleanup_control_expr_graph (basic_block bb, gimple_stmt_iterator gsi, - bool first_p) +cleanup_control_expr_graph (basic_block bb, gimple_stmt_iterator gsi) { edge taken_edge; bool retval = false; @@ -146,25 +145,14 @@ cleanup_control_expr_graph (basic_block bb, gimple_stmt_iterator gsi, switch (gimple_code (stmt)) { case GIMPLE_COND: - /* During a first iteration on the CFG only remove trivially - dead edges but mark other conditions for re-evaluation. */ - if (first_p) - { - val = const_binop (gimple_cond_code (stmt), boolean_type_node, - gimple_cond_lhs (stmt), - gimple_cond_rhs (stmt)); - if (! val) - bitmap_set_bit (cfgcleanup_altered_bbs, bb->index); - } - else - { - code_helper rcode; - tree ops[3] = {}; - if (gimple_simplify (stmt, &rcode, ops, NULL, no_follow_ssa_edges, - no_follow_ssa_edges) - && rcode == INTEGER_CST) - val = ops[0]; - } + { + code_helper rcode; + tree ops[3] = {}; + if (gimple_simplify (stmt, &rcode, ops, NULL, no_follow_ssa_edges, + no_follow_ssa_edges) + && rcode == INTEGER_CST) + val = ops[0]; + } break; case GIMPLE_SWITCH: @@ -235,7 +223,7 @@ cleanup_call_ctrl_altering_flag (gimple *bb_end) true if anything changes. */ static bool -cleanup_control_flow_bb (basic_block bb, bool first_p) +cleanup_control_flow_bb (basic_block bb) { gimple_stmt_iterator gsi; bool retval = false; @@ -258,7 +246,7 @@ cleanup_control_flow_bb (basic_block bb, bool first_p) || gimple_code (stmt) == GIMPLE_SWITCH) { gcc_checking_assert (gsi_stmt (gsi_last_bb (bb)) == stmt); - retval |= cleanup_control_expr_graph (bb, gsi, first_p); + retval |= cleanup_control_expr_graph (bb, gsi); } else if (gimple_code (stmt) == GIMPLE_GOTO && TREE_CODE (gimple_goto_dest (stmt)) == ADDR_EXPR @@ -732,6 +720,45 @@ cleanup_tree_cfg_bb (basic_block bb) return false; } +/* Do cleanup_control_flow_bb in PRE order. */ + +static bool +cleanup_control_flow_pre () +{ + bool retval = false; + + auto_vec<edge_iterator, 20> stack (n_basic_blocks_for_fn (cfun) + 1); + auto_sbitmap visited (last_basic_block_for_fn (cfun)); + bitmap_clear (visited); + + stack.quick_push (ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs)); + + while (! stack.is_empty ()) + { + /* Look at the edge on the top of the stack. */ + edge_iterator ei = stack.last (); + basic_block dest = ei_edge (ei)->dest; + + if (dest != EXIT_BLOCK_PTR_FOR_FN (cfun) + && ! bitmap_bit_p (visited, dest->index)) + { + bitmap_set_bit (visited, dest->index); + retval |= cleanup_control_flow_bb (dest); + if (EDGE_COUNT (dest->succs) > 0) + stack.quick_push (ei_start (dest->succs)); + } + else + { + if (!ei_one_before_end_p (ei)) + ei_next (&stack.last ()); + else + stack.pop (); + } + } + + return retval; +} + /* Iterate the cfg cleanups, while anything changes. */ static bool @@ -752,17 +779,11 @@ cleanup_tree_cfg_1 (void) /* We cannot use FOR_EACH_BB_FN for the BB iterations below since the basic blocks may get removed. */ - /* Start by iterating over all basic blocks looking for edge removal - opportunities. Do this first because incoming SSA form may be - invalid and we want to avoid performing SSA related tasks such + /* Start by iterating over all basic blocks in PRE order looking for + edge removal opportunities. Do this first because incoming SSA form + may be invalid and we want to avoid performing SSA related tasks such as propgating out a PHI node during BB merging in that state. */ - n = last_basic_block_for_fn (cfun); - for (i = NUM_FIXED_BLOCKS; i < n; i++) - { - bb = BASIC_BLOCK_FOR_FN (cfun, i); - if (bb) - retval |= cleanup_control_flow_bb (bb, true); - } + retval |= cleanup_control_flow_pre (); /* After doing the above SSA form should be valid (or an update SSA should be required). */ @@ -789,7 +810,7 @@ cleanup_tree_cfg_1 (void) if (!bb) continue; - retval |= cleanup_control_flow_bb (bb, false); + retval |= cleanup_control_flow_bb (bb); retval |= cleanup_tree_cfg_bb (bb); } |