From d904350bc3a4b3b9c77a71d683be6c44b041a33d Mon Sep 17 00:00:00 2001
From: Michael Beck <beck@ipd.info.uni-karlsruhe.de>
Date: Tue, 9 May 2006 12:39:35 +0000
Subject: [PATCH] optimize_graph_df():  - sets the current_ir_graph  - pushes
 the uses to the wait queue BEFORE the node is exchanged,    otherwise old
 users of the optimized node are evaluated again

more doxygen docu
removed identities declarations, added right header

[r7703]
---
 ir/ir/irgopt.c | 50 ++++++++++++++++++++++++++++++--------------------
 1 file changed, 30 insertions(+), 20 deletions(-)

diff --git a/ir/ir/irgopt.c b/ir/ir/irgopt.c
index 543483c70..e2d633289 100644
--- a/ir/ir/irgopt.c
+++ b/ir/ir/irgopt.c
@@ -46,11 +46,6 @@
 #include "iredges_t.h"
 #include "irtools.h"
 
-/* Defined in iropt.c */
-pset *new_identities (void);
-void  del_identities (pset *value_table);
-void  add_identities (pset *value_table, ir_node *node);
-
 /*------------------------------------------------------------------*/
 /* apply optimizations of iropt to all nodes.                       */
 /*------------------------------------------------------------------*/
@@ -63,6 +58,14 @@ static void optimize_in_place_wrapper (ir_node *n, void *env) {
   if (optimized != n) exchange (n, optimized);
 }
 
+/**
+ * Do local optimizations for a node.
+ *
+ * @param n  the IR-node where to start. Typically the End node
+ *           of a graph
+ *
+ * @note current_ir_graph must be set
+ */
 static INLINE void do_local_optimize(ir_node *n) {
   /* Handle graph state */
   assert(get_irg_phase_state(current_ir_graph) != phase_building);
@@ -81,6 +84,7 @@ static INLINE void do_local_optimize(ir_node *n) {
   irg_walk(n, firm_clear_link, optimize_in_place_wrapper, NULL);
 }
 
+/* Applies local optimizations (see iropt.h) to all nodes reachable from node n */
 void local_optimize_node(ir_node *n) {
   ir_graph *rem = current_ir_graph;
   current_ir_graph = get_irn_irg(n);
@@ -95,12 +99,13 @@ void local_optimize_node(ir_node *n) {
  */
 static void kill_dead_blocks(ir_node *block, void *env)
 {
-  if (get_Block_dom_depth(block) < 0)
-    if (block != get_irg_end_block(current_ir_graph)) {
-      /* we don't want that the end block of graphs with
-         endless loops is marked bad (although it is of course */
-      set_Block_dead(block);
-    }
+  if (get_Block_dom_depth(block) < 0) {
+    /*
+     * Note that the new dominance code correctly handles
+     * the End block, i.e. it is always reachable from Start
+     */
+    set_Block_dead(block);
+  }
 }
 
 void
@@ -108,7 +113,7 @@ local_optimize_graph (ir_graph *irg) {
   ir_graph *rem = current_ir_graph;
   current_ir_graph = irg;
 
-  if (get_irg_dom_state(current_ir_graph) == dom_consistent)
+  if (get_irg_dom_state(irg) == dom_consistent)
     irg_block_walk_graph(irg, NULL, kill_dead_blocks, NULL);
 
   do_local_optimize(get_irg_end(irg));
@@ -129,8 +134,7 @@ static void opt_walker(ir_node *n, void *env) {
   if (optimized != n) {
     const ir_edge_t *edge;
 
-    exchange(n, optimized);
-    foreach_out_edge(optimized, edge) {
+    foreach_out_edge(n, edge) {
       ir_node *succ = get_edge_src_irn(edge);
 
       if (get_irn_link(succ) != waitq) {
@@ -138,12 +142,16 @@ static void opt_walker(ir_node *n, void *env) {
         set_irn_link(succ, waitq);
       }
     }
+    exchange(n, optimized);
   }
 }
 
 void optimize_graph_df(ir_graph *irg) {
-  pdeq *waitq = new_pdeq();
-  int  state = edges_activated(irg);
+  pdeq     *waitq = new_pdeq();
+  int      state = edges_activated(irg);
+  ir_graph *rem = current_ir_graph;
+
+  current_ir_graph = irg;
 
   if (! state)
     edges_activate(irg);
@@ -176,6 +184,8 @@ void optimize_graph_df(ir_graph *irg) {
 
   if (! state)
     edges_deactivate(irg);
+
+  current_ir_graph = rem;
 }
 
 
@@ -562,14 +572,14 @@ dead_node_elimination(ir_graph *irg) {
     graveyard_obst = irg->obst;
 
     /* A new obstack, where the reachable nodes will be copied to. */
-    rebirth_obst = xmalloc (sizeof(*rebirth_obst));
+    rebirth_obst = xmalloc(sizeof(*rebirth_obst));
     current_ir_graph->obst = rebirth_obst;
     obstack_init (current_ir_graph->obst);
     current_ir_graph->last_node_idx = 0;
 
-    /* We also need a new hash table for cse */
-    del_identities (irg->value_table);
-    irg->value_table = new_identities ();
+    /* We also need a new value table for CSE */
+    del_identities(irg->value_table);
+    irg->value_table = new_identities();
 
     /* Copy the graph from the old to the new obstack */
     copy_graph_env(1);
-- 
2.20.1