Are padding bits always zero?

[Adam D. Ruppe via Digitalmars-d-learn]

On Saturday, 24 June 2017 at 12:41:47 UTC, Steven Schveighoffer 
wrote:
> There is no spec for this, but I know that when the compiler 
> has to fill gaps with something it chooses 0.

I'm almost certain there at least used to be a spec for this, 
because I remember citing a link to someone who then complained 
that this zero requirement hurt optimization of void members. On 
the other hand though, the zero padding requirement does simplify 
equality to being memcmp.

I can't find the reference now. Perhaps I'm looking in the wrong 
place... or perhaps that optimization complaint actually got the 
requirement removed from the spec.

I don't know. (I find search of most D stuff to be fruitless and 
heavily rely on my old brain memory to index these things, but 
while my memory is pretty good, it isn't flawless.)