On 11/17/2016 01:48 AM, Richard Biener wrote:
On Wed, 16 Nov 2016, Jeff Law wrote:
On 11/16/2016 05:17 PM, Martin Sebor wrote:
(I've heard some noise in C++-land about making memcpy(0,0,0) valid, but
that may have just been noise)
We may have read the same discussion. It would make some things
a little easier in C++ (and remove what most people view as yet
another unnecessary gotcha in the language).
And that may be a reasonable thing to do.
While GCC does take advantage of the non-null attribute when trying to prove
certain pointers must be non-null, it only does so when the magic flag is
turned on. There was a sense that it was too aggressive and that time may be
necessary for folks to come to terms with what GCC was doing, particularly in
the the memcpy (*, *, 0) case -- but I've never gotten the sense that happened
and we've never turned that flag on by default.
We only have -f[no-]delete-null-pointer-checks and that's on by default.
So we _do_ take advantage of those.
Hmm, maybe it's the path isolation I'm thinking about where we have the
additional flag to control whether or not we use the attributes to help
identify erroneous paths.
jeff
