If you're talking about the cast from an int literal to a char pointer, that's not what's happening. That's common C shorthand for incrementing a pointer to point to the next element.

For example, the char pointer increment compiles to:

  4004fb:	48 83 c0 01          	add    $0x1,%rax

While an int pointer increment compiles to:

  40050c:	48 83 c0 04          	add    $0x4,%rax

Because on my particular platform, an int is 4 bytes and a char is 1 byte and the memory is byte addressable.