On Saturday, 27 October 2012 at 23:07:19 UTC, BLM768 wrote:
In any case, though, separately initializing every member of
an array is
silly. That's what a loop is for. That, or a memcpy from an
immutable
copy of .init.
I think that the reasoning behind DMD's implementation is that
for small structs, writing out the instructions is more
efficient than a loop or a memcpy(); it's essentially the
equivalent of loop unrolling and function inlining. However,
that reasoning breaks down as soon as the struct's size goes
beyond a certain value.
In my opinion, though, this behavior should be kept for small
structs. For example, if you have a struct that just wraps a
size_t, just generating a move instruction is _way_ faster than
a call to memcpy().
I just realized that this post is redundant; other posts have
also mentioned optimization for small structs. That makes two
relatively dumb posts from me in a day; maybe I should just stop
for now. :)
