clarify some node comments

[libfirm] / ir / opt / jumpthreading.c

diff --git a/ir/opt/jumpthreading.c b/ir/opt/jumpthreading.c
index 39de745..3a18401 100644 (file)
--- a/ir/opt/jumpthreading.c
+++ b/ir/opt/jumpthreading.c
@@ -22,7 +22,6 @@
  * @brief   Path-Sensitive Jump Threading
  * @date    10. Sep. 2006
  * @author  Christoph Mallon, Matthias Braun
- * @version $Id$
  */
 #include "config.h"
 
@@ -46,10 +45,11 @@
 #include "iropt_dbg.h"
 #include "irpass.h"
 #include "vrp.h"
+#include "opt_manage.h"
 
 #undef AVOID_PHIB
 
-DEBUG_ONLY(static firm_dbg_module_t *dbg);
+DEBUG_ONLY(static firm_dbg_module_t *dbg;)
 
 /**
  * Add the new predecessor x to node node, which is either a Block or a Phi
@@ -294,7 +294,7 @@ static void copy_and_fix(const jumpthreading_env_t *env, ir_node *block,
                }
                /* ignore control flow */
                mode = get_irn_mode(node);
-               if (mode == mode_X || is_Cond(node))
+               if (mode == mode_X || is_Cond(node) || is_Switch(node))
                        continue;
 #ifdef AVOID_PHIB
                /* we may not copy mode_b nodes, because this could produce Phi with
@@ -347,7 +347,7 @@ static void copy_and_fix(const jumpthreading_env_t *env, ir_node *block,
                ir_mode *mode;
 
                mode = get_irn_mode(node);
-               if (mode == mode_X || is_Cond(node))
+               if (mode == mode_X || is_Cond(node) || is_Switch(node))
                        continue;
 #ifdef AVOID_PHIB
                if (mode == mode_b)
@@ -654,15 +654,12 @@ static void thread_jumps(ir_node* block, void* data)
        assert(get_irn_mode(projx) == mode_X);
 
        cond = get_Proj_pred(projx);
-       if (!is_Cond(cond))
-               return;
-
-       selector = get_Cond_selector(cond);
        /* TODO handle switch Conds */
-       if (get_irn_mode(selector) != mode_b)
+       if (!is_Cond(cond))
                return;
 
        /* handle cases that can be immediately evaluated */
+       selector = get_Cond_selector(cond);
        selector_evaluated = -1;
        if (is_Cmp(selector)) {
                ir_node *left  = get_Cmp_left(selector);
@@ -753,21 +750,15 @@ static void thread_jumps(ir_node* block, void* data)
        *changed = 1;
 }
 
-void opt_jumpthreading(ir_graph* irg)
+static ir_graph_state_t do_jumpthread(ir_graph* irg)
 {
        int changed, rerun;
+       ir_graph_state_t res = 0;
 
        FIRM_DBG_REGISTER(dbg, "firm.opt.jumpthreading");
 
        DB((dbg, LEVEL_1, "===> Performing jumpthreading on %+F\n", irg));
 
-       remove_critical_cf_edges(irg);
-
-       /* ugly: jump threading might get confused by garbage nodes
-        * of mode_X in copy_and_fix_node(), so remove all garbage edges. */
-       edges_deactivate(irg);
-
-       edges_assure(irg);
        ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK | IR_RESOURCE_IRN_VISITED);
 
        changed = 0;
@@ -779,12 +770,22 @@ void opt_jumpthreading(ir_graph* irg)
 
        ir_free_resources(irg, IR_RESOURCE_IRN_LINK | IR_RESOURCE_IRN_VISITED);
 
-       if (changed) {
-               /* control flow changed, some blocks may become dead */
-               set_irg_doms_inconsistent(irg);
-               set_irg_extblk_inconsistent(irg);
-               set_irg_entity_usage_state(irg, ir_entity_usage_not_computed);
+       if (!changed) {
+               res |= IR_GRAPH_STATE_CONSISTENT_DOMINANCE | IR_GRAPH_STATE_CONSISTENT_ENTITY_USAGE;
        }
+
+       return res;
+}
+
+static optdesc_t opt_jumpthread = {
+       "jumpthreading",
+       IR_GRAPH_STATE_NO_UNREACHABLE_CODE | IR_GRAPH_STATE_CONSISTENT_OUT_EDGES | IR_GRAPH_STATE_NO_CRITICAL_EDGES,
+       do_jumpthread,
+};
+
+void opt_jumpthreading(ir_graph* irg)
+{
+       perform_irg_optimization(irg, &opt_jumpthread);
 }
 
 /* Creates an ir_graph pass for opt_jumpthreading. */