[Bug c/15685] printf("%s\n") optimized to puts also when parameter might be null

["mathias dot hasselmann at gmx dot de" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #4 from mathias dot hasselmann at gmx dot de  2007-10-01 06:45 -------
(In reply to comment #1)
> Not a bug as printf can segfault if it is supplied a NULL pointer for the
> string formatter.
> If glibc does something different than that, glibc is does not have a bug
> either as it is undefined really 
> so converting the call to a puts is a vaild transformation.
> 
Even if its a valid transformation, there is the question if this is a
reasonable transformation. Obviously that optimization was introduced because
quite alot of people do not know about the puts function and use printf to
output static lines of text. On the other hand there are people who rely on
glibc's handling of the undefined NULL pointer situation.

Question is: Which group is bigger. The missuse printf as puts group or the
rely on glibc's relaxed NULL handling group. My guess would be that people who
do not even know puts care even less about the fact that ANSI and ISO didn't
care about NULL handling in format strings. If that would true, this
optimization would be valid, but unreasonable as it breaks the expections of
your clients.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15685