As far as I know at least some assemblers do this - certainly nasm, for example, makes all kinds of similar optimizations to the encoding, and I expect it to ge

As far as I know at least some assemblers do this - certainly nasm, for example, makes all kinds of similar optimizations to the encoding, and I expect it to get this one right. It's kind of too little, too late though: you want the higher level compiler to be avoiding rbp/r13 in scenarios where this could occur and the assembler couldn't fix it. I don't think compilers do this, though.