A method includes, in a processor, processing program code that includes memory-access instructions, wherein at least some of the memory-access instructions include symbolic expressions that specify memory addresses in an external memory in terms of one or more register names. At least first and second load instructions that access a same memory address in the external memory are identified in the program code, based on respective formats of the memory addresses specified in the symbolic expressions of the load instructions. An outcome of at least one of the load instructions is assigned to be served from an internal memory in the processor.