7087453: PhaseChaitin::yank_if_dead() should handle MachTemp inputs

Summary: PhaseChaitin::yank_if_dead() should be able to handle MachTemp inputs as a special case and yank them.
Reviewed-by: never, kvn

src/share/vm/opto/chaitin.hpp

@@ -482,6 +482,7 @@ private:
   }
 
   int yank_if_dead( Node *old, Block *current_block, Node_List *value, Node_List *regnd );
+  int yank( Node *old, Block *current_block, Node_List *value, Node_List *regnd );
   int elide_copy( Node *n, int k, Block *current_block, Node_List &value, Node_List &regnd, bool can_change_regs );
   int use_prior_register( Node *copy, uint idx, Node *def, Block *current_block, Node_List &value, Node_List &regnd );
   bool may_be_copy_of_callee( Node *def ) const;

src/share/vm/opto/postaloc.cpp

@@ -72,14 +72,10 @@ bool PhaseChaitin::may_be_copy_of_callee( Node *def ) const {
   return i == limit;
 }
 
-
-
-//------------------------------yank_if_dead-----------------------------------
-// Removed an edge from 'old'.  Yank if dead.  Return adjustment counts to
-// iterators in the current block.
-int PhaseChaitin::yank_if_dead( Node *old, Block *current_block, Node_List *value, Node_List *regnd ) {
+//------------------------------yank-----------------------------------
+// Helper function for yank_if_dead
+int PhaseChaitin::yank( Node *old, Block *current_block, Node_List *value, Node_List *regnd ) {
   int blk_adjust=0;
-  while (old->outcnt() == 0 && old != C->top()) {
   Block *oldb = _cfg._bbs[old->_idx];
   oldb->find_remove(old);
   // Count 1 if deleting an instruction from the current block
@@ -90,8 +86,29 @@ int PhaseChaitin::yank_if_dead( Node *old, Block *current_block, Node_List *valu
     value->map(old_reg,NULL);  // Yank from value/regnd maps
     regnd->map(old_reg,NULL);  // This register's value is now unknown
   }
-    assert(old->req() <= 2, "can't handle more inputs");
-    Node *tmp = old->req() > 1 ? old->in(1) : NULL;
+  return blk_adjust;
+}
+
+//------------------------------yank_if_dead-----------------------------------
+// Removed an edge from 'old'.  Yank if dead.  Return adjustment counts to
+// iterators in the current block.
+int PhaseChaitin::yank_if_dead( Node *old, Block *current_block, Node_List *value, Node_List *regnd ) {
+  int blk_adjust=0;
+  while (old->outcnt() == 0 && old != C->top()) {
+    blk_adjust += yank(old, current_block, value, regnd);
+
+    Node *tmp = NULL;
+    for (uint i = 1; i < old->req(); i++) {
+      if (old->in(i)->is_MachTemp()) {
+        Node* machtmp = old->in(i);
+        assert(machtmp->outcnt() == 1, "expected for a MachTemp");
+        blk_adjust += yank(machtmp, current_block, value, regnd);
+        machtmp->disconnect_inputs(NULL);
+      } else {
+        assert(tmp == NULL, "can't handle more non MachTemp inputs");
+        tmp = old->in(i);
+      }
+    }
     old->disconnect_inputs(NULL);
     if( !tmp ) break;
     old = tmp;