src/share/vm/opto/phaseX.cpp

@@ -755,25 +755,28 @@
 
 //=============================================================================
 //------------------------------PhaseIterGVN-----------------------------------
 // Initialize hash table to fresh and clean for +VerifyOpto
 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn, const char *dummy ) : PhaseGVN(igvn,dummy), _worklist( ),
+                                                                      _stack(C->unique() >> 1),
                                                                       _delay_transform(false) {
 }
 
 //------------------------------PhaseIterGVN-----------------------------------
 // Initialize with previous PhaseIterGVN info; used by PhaseCCP
 PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn ) : PhaseGVN(igvn),
                                                    _worklist( igvn->_worklist ),
+                                                   _stack( igvn->_stack ),
                                                    _delay_transform(igvn->_delay_transform)
 {
 }
 
 //------------------------------PhaseIterGVN-----------------------------------
 // Initialize with previous PhaseGVN info from Parser
 PhaseIterGVN::PhaseIterGVN( PhaseGVN *gvn ) : PhaseGVN(gvn),
                                               _worklist(*C->for_igvn()),
+                                              _stack(C->unique() >> 1),
                                               _delay_transform(false)
 {
   uint max;
 
   // Dead nodes in the hash table inherited from GVN were not treated as

@@ -1136,25 +1139,40 @@
 
 //------------------------------remove_globally_dead_node----------------------
 // Kill a globally dead Node.  All uses are also globally dead and are
 // aggressively trimmed.
 void PhaseIterGVN::remove_globally_dead_node( Node *dead ) {
+  enum DeleteProgress {
+    PROCESS_INPUTS,
+    PROCESS_OUTPUTS
+  };
+  assert(_stack.is_empty(), "not empty");
+  _stack.push(dead, PROCESS_INPUTS);
+
+  while (_stack.is_nonempty()) {
+    dead = _stack.node();
+    uint progress_state = _stack.index();
   assert(dead != C->root(), "killing root, eh?");
-  if (dead->is_top())  return;
+    assert(!dead->is_top(), "add check for top when pushing");
   NOT_PRODUCT( set_progress(); )
+    if (progress_state == PROCESS_INPUTS) {
+      // After following inputs, continue to outputs
+      _stack.set_index(PROCESS_OUTPUTS);
   // Remove from iterative worklist
   _worklist.remove(dead);
   if (!dead->is_Con()) { // Don't kill cons but uses
+        bool recurse = false;
     // Remove from hash table
     _table.hash_delete( dead );
     // Smash all inputs to 'dead', isolating him completely
     for( uint i = 0; i < dead->req(); i++ ) {
       Node *in = dead->in(i);
       if( in ) {                 // Points to something?
         dead->set_req(i,NULL);  // Kill the edge
         if (in->outcnt() == 0 && in != C->top()) {// Made input go dead?
-          remove_dead_node(in); // Recursively remove
+              _stack.push(in, PROCESS_INPUTS); // Recursively remove
+              recurse = true;
         } else if (in->outcnt() == 1 &&
                    in->has_special_unique_user()) {
           _worklist.push(in->unique_out());
         } else if (in->outcnt() <= 2 && dead->is_Phi()) {
           if( in->Opcode() == Op_Region )

@@ -1174,16 +1192,27 @@
     }
 
     if (dead->is_macro()) {
       C->remove_macro_node(dead);
     }
+
+        if (recurse) {
+          continue;
+        }
+      }
   }
+
   // Aggressively kill globally dead uses
-  // (Cannot use DUIterator_Last because of the indefinite number
+    // (Rather than pushing all the outs at once, we push one at a time,
+    // plus the parent to resume later, because of the indefinite number
   // of edge deletions per loop trip.)
-  while (dead->outcnt() > 0) {
-    remove_globally_dead_node(dead->raw_out(0));
+    if (dead->outcnt() > 0) {
+      // Recursively remove
+      _stack.push(dead->raw_out(0), PROCESS_INPUTS);
+    } else {
+      _stack.pop();
+    }
   }
 }
 
 //------------------------------subsume_node-----------------------------------
 // Remove users from node 'old' and add them to node 'nn'.