bug_20170921.txt

(1) for performance
see https://gitee.com/weimingtom/lua-5.1.4_profile/blob/master/Lua/src/lcode.cs


		public static InstructionPtr Assign(InstructionPtr ptr)
		{
			if (ptr == null) return null;
			return new InstructionPtr(ptr.codes, ptr.pc);
		}
-->
		public static void Assign(InstructionPtr ptr, ref InstructionPtr target)
		{
			if (ptr == null) {target = null; return;}
			if (target == null) {target = new InstructionPtr(ptr.codes, ptr.pc); return;}
			target.codes = ptr.codes; target.pc = ptr.pc;
		}

----------------------
(y) lua-5.1.4  
(y) lua-5.1.5  
(y) lua-5.2.0-2007  <---------------only 5 changes (from here below)
(y) lua-5.2.0-20071029  
(y) lua-5.2.0-2008  
(y) lua-5.2.0-2009  
(y) lua-5.2.0-20090702 <---------------no changes (???no use InstructionPtr.Assign())
(y) lua-5.2.0-20100206  
(y) lua-5.2.0-alpha  
(y) lua-5.2.0-beta
(y) lua-5.2.0
----------------------

L.savedpc = InstructionPtr.Assign(pc);
->
InstructionPtr.Assign(pc, ref L.savedpc);


-------------
hidden bug:(maybe not fixed)

from lua-5.2.0-20090702, not used InstructionPtr.Assign()
for example:
oci.u.l.savedpc = nci.u.l.savedpc;