Possible advantage

Possible advantage

I don't really see any advantage of making the code resemble the output of the compiler.

Hear, hear. There are two distinct ways to look at a program: 1) instructions to a computer; 2) description of the solution of a computational problem. The primary audience for (1) is a computer; for (2) it's a human. In view (2), a compiler's job is to produce a machine program that computes the solution described by the source code. A lot of programmers like to do that work themselves, but I think that is an inefficient use of brain power (for everyone who works on that code).

The closer the resemblance between source and executable, the more chance you have of understanding what you're seeing in the debugger.

That's definitely my experience. But there is a middle ground. I write human-oriented code and let the compiler do its job normally. But when I debug at the machine level I add -O0 to the compile options. That's usually described as "don't optimize", but as I consider optimization to be an integral part of the compiler's job, I view it as, "Make the machine program track the source code as closely as possible."