Jeff King [off-list ref] writes:
Git code was my introduction to it, too, and I was led to believe it was
idiomatic, so I can't speak further on that. I think it was Junio who
introduced me to it, so maybe he can shed more light on the history.
I think we picked the convention up from the kernel folks. At least
that is how I first met the construct. The uninitialized_var(x)
macro was (and still is) used to mark these "The compiler is too
dumb to realize, but we know what we are doing" cases:
$ git grep '#define uninitialized_var' include/
include/linux/compiler-gcc.h:#define uninitialized_var(x) x = x
include/linux/compiler-intel.h:#define uninitialized_var(x) x
but they recently had a discussion, e.g.
http://thread.gmane.org/gmane.linux.kernel.openipmi/1998/focus=1383705
so...