What if you made BINARY_OP a __forceinline (http://msdn.microsoft.com/en-us/library/z8y1yy88.aspx) function instead of a macro?

Things that the function contains that might disable optimization: a lot of gotos, inline assembly in GO_NEXT (this does affect optimization: http://msdn.microsoft.com/en-us/library/5hd5ywk0.aspx)...

It's also not immediately obvious to me that pCurEvalStack is initialized.

Having a look at the architecture optimization manual re: the redundant loads; it's not immediately obvious to me that modern processors won't handle this fine (http://www.intel.com/Assets/PDF/manual/248966.pdf).