Yes, same source code; different program. The point of compilers is to output a different program that (hopefully) has similar enough I/O but it better suited to the hardware. The program that runs when a human has to adds 1+1 is still largely unknown to us but the source '1+1' isn't.

Why use a new compiler if your program isn't meaningfully changed by it? I'd consider running on two completely different machines to already constitute "meaningfully different"