src/share/vm/opto/memnode.cpp

@@ -2730,10 +2730,13 @@
 }
 
 //------------------------------Idealize---------------------------------------
 // Clearing a short array is faster with stores
 Node *ClearArrayNode::Ideal(PhaseGVN *phase, bool can_reshape){
+  // Already know this is a large node, do not try to ideal it
+  if (_is_large) return NULL;
+
   const int unit = BytesPerLong;
   const TypeX* t = phase->type(in(2))->isa_intptr_t();
   if (!t)  return NULL;
   if (!t->is_con())  return NULL;
   intptr_t raw_count = t->get_con();

@@ -2742,12 +2745,15 @@
   // Clearing nothing uses the Identity call.
   // Negative clears are possible on dead ClearArrays
   // (see jck test stmt114.stmt11402.val).
   if (size <= 0 || size % unit != 0)  return NULL;
   intptr_t count = size / unit;
-  // Length too long; use fast hardware clear
-  if (size > Matcher::init_array_short_size)  return NULL;
+  // Length too long; communicate this to matchers and assemblers.
+  // Assemblers are responsible to produce fast hardware clears for it.
+  if (size > InitArrayShortSize) {
+    return new ClearArrayNode(in(0), in(1), in(2), in(3), true);
+  }
   Node *mem = in(1);
   if( phase->type(mem)==Type::TOP ) return NULL;
   Node *adr = in(3);
   const Type* at = phase->type(adr);
   if( at==Type::TOP ) return NULL;

@@ -3890,11 +3896,11 @@
         zeroes_done = align_size_down(zeroes_done, BytesPerInt);
         rawmem = ClearArrayNode::clear_memory(rawctl, rawmem, rawptr,
                                               zeroes_done, zeroes_needed,
                                               phase);
         zeroes_done = zeroes_needed;
-        if (zsize > Matcher::init_array_short_size && ++big_init_gaps > 2)
+        if (zsize > InitArrayShortSize && ++big_init_gaps > 2)
           do_zeroing = false;   // leave the hole, next time
       }
     }
 
     // Collect the store and move on: