Re: [PATCH] befs/btree: remove unneeded initializations

From: Andrew Morton
Date: Wed Jun 01 2016 - 18:42:46 EST

On Mon, 30 May 2016 01:39:59 +0100 Luis de Bethencourt <luisbg@xxxxxxxxxxxxxxx> wrote:

> off in befs_bt_read_node() will be written by befs_read_datastream(), with
> the value that node->od_node needs.
> node_off in befs_btree_read() isn't read before set to root_node_ptr.
> Removing these two unneeded initializations.
> ...
> --- a/fs/befs/btree.c
> +++ b/fs/befs/btree.c
> @@ -196,7 +196,7 @@ static int
> befs_bt_read_node(struct super_block *sb, const befs_data_stream *ds,
> struct befs_btree_node *node, befs_off_t node_off)
> {
> - uint off = 0;
> + uint off;
> befs_debug(sb, "---> %s", __func__);

With this code:

int foo;


whatever = foo;

some versions of gcc will warn that foo might be used uninitialized.
Other versions of gcc don't do this. That's why the seemingly-unneeded
initializations are there.

Neither of the versions of gcc which I tested with actually do warn,
but I'm inclined to leave things as-is: some people will get warnings
and that's probably worse than a couple of bytes bloat in befs.

It shouldn't cause any bloat, really. We have the "uninitialized_var"
macro which avoids any bloat and is self-documenting. And the nice
thing about self-documenting code is that it prevents Andrew from
having to explain strange code to Luis ;) But unintialized_var in
unpopular for reasons which I personally find unpersuasive, given
the advantages...