Staring at more x86_64 assembly today. There's one section which is generated from C code similar to this:
/* initialise 'ptr' in some manner */
*(*ptr)++ = 'z';
If the mess of asterisks and post-increments doesn't hurt your head enough already (especially if you don't have all of C's precedence rules perfectly memorised), it turns out that the way clang compiles this (with all optimisations turned off, at least) is to copy the address pointed to by 'ptr' into multiple registers so it can perform the post-increment *before* it performs the assignment.