8350485: C2: factor out common code in Node::grow() and Node::out_grow()

src/hotspot/share/opto/node.cpp

@@ -664,55 +664,45 @@ void Node::destruct(PhaseValues* phase) {
   }
 }
 
-//------------------------------grow-------------------------------------------
-// Grow the input array, making space for more edges
-void Node::grow(uint len) {
+// Resize input or output array to grow it to the next larger power-of-2 bigger
+// than len.
+void Node::resize_array(Node**& array, node_idx_t& max_size, uint len, bool needs_clearing) {
   Arena* arena = Compile::current()->node_arena();
-  uint new_max = _max;
-  if( new_max == 0 ) {
-    _max = 4;
-    _in = (Node**)arena->Amalloc(4*sizeof(Node*));
-    Node** to = _in;
-    to[0] = nullptr;
-    to[1] = nullptr;
-    to[2] = nullptr;
-    to[3] = nullptr;
+  uint new_max = max_size;
+  if (new_max == 0) {
+    max_size = 4;
+    array = (Node**)arena->Amalloc(4 * sizeof(Node*));
+    if (needs_clearing) {
+      array[0] = nullptr;
+      array[1] = nullptr;
+      array[2] = nullptr;
+      array[3] = nullptr;
+    }
     return;
   }
   new_max = next_power_of_2(len);
-  // Trimming to limit allows a uint8 to handle up to 255 edges.
-  // Previously I was using only powers-of-2 which peaked at 128 edges.
-  //if( new_max >= limit ) new_max = limit-1;
-  _in = (Node**)arena->Arealloc(_in, _max*sizeof(Node*), new_max*sizeof(Node*));
-  Copy::zero_to_bytes(&_in[_max], (new_max-_max)*sizeof(Node*)); // null all new space
-  _max = new_max;               // Record new max length
+  assert(needs_clearing || (array != nullptr && array != NO_OUT_ARRAY), "out must have sensible value");
+  array = (Node**)arena->Arealloc(array, max_size * sizeof(Node*), new_max * sizeof(Node*));
+  if (needs_clearing) {
+    Copy::zero_to_bytes(&array[max_size], (new_max - max_size) * sizeof(Node*)); // null all new space
+  }
+  max_size = new_max;               // Record new max length
   // This assertion makes sure that Node::_max is wide enough to
   // represent the numerical value of new_max.
-  assert(_max == new_max && _max > len, "int width of _max is too small");
+  assert(max_size > len, "int width of _max or _outmax is too small");
+}
+
+//------------------------------grow-------------------------------------------
+// Grow the input array, making space for more edges
+void Node::grow(uint len) {
+  resize_array(_in, _max, len, true);
 }
 
 //-----------------------------out_grow----------------------------------------
 // Grow the input array, making space for more edges
-void Node::out_grow( uint len ) {
+void Node::out_grow(uint len) {
   assert(!is_top(), "cannot grow a top node's out array");
-  Arena* arena = Compile::current()->node_arena();
-  uint new_max = _outmax;
-  if( new_max == 0 ) {
-    _outmax = 4;
-    _out = (Node **)arena->Amalloc(4*sizeof(Node*));
-    return;
-  }
-  new_max = next_power_of_2(len);
-  // Trimming to limit allows a uint8 to handle up to 255 edges.
-  // Previously I was using only powers-of-2 which peaked at 128 edges.
-  //if( new_max >= limit ) new_max = limit-1;
-  assert(_out != nullptr && _out != NO_OUT_ARRAY, "out must have sensible value");
-  _out = (Node**)arena->Arealloc(_out,_outmax*sizeof(Node*),new_max*sizeof(Node*));
-  //Copy::zero_to_bytes(&_out[_outmax], (new_max-_outmax)*sizeof(Node*)); // null all new space
-  _outmax = new_max;               // Record new max length
-  // This assertion makes sure that Node::_max is wide enough to
-  // represent the numerical value of new_max.
-  assert(_outmax == new_max && _outmax > len, "int width of _outmax is too small");
+  resize_array(_out, _outmax, len, false);
 }
 
 #ifdef ASSERT

src/hotspot/share/opto/node.hpp

@@ -335,8 +335,11 @@ class Node {
   void grow( uint len );
   // Grow the output array to the next larger power-of-2 bigger than len.
   void out_grow( uint len );
+  // Resize input or output array to grow it to the next larger power-of-2
+  // bigger than len.
+  void resize_array(Node**& array, node_idx_t& max_size, uint len, bool needs_clearing);
 
- public:
+public:
   // Each Node is assigned a unique small/dense number. This number is used
   // to index into auxiliary arrays of data and bit vectors.
   // The value of _idx can be changed using the set_idx() method.