[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [csmith-dev] Floating-point support in csmith

Thank you All very much for responses! To summarize, csmith with --float can be used to detect crash bugs for the moment, and should NOT be used for wrong code bugs. Please correct me if I got it wrong.



On Wed, Nov 4, 2015 at 3:23 PM, John Regehr <regehr@cs.utah.edu> wrote:
  - Floating-point support was introduced in version 2.2.0 according to
the release note [1]. Floating point support must be turned on passing
--float command-line option. This note acknowledges work of Dr. Alastair
Donaldson for the initial implementation.

Yes, please check with Ally, he and his people have been doing this.  I think basically all of us are interested but it's been a matter of making time to work on it.

  - I conducted a run of csmith 2.2.0 with --float argument on Ubuntu
10.04 (gcc 4.4.3). Number of crash-programs is significantly more now.
Running csmith without --float found 3 crash-bugs, while running with
--float found more than 300 crash-bugs within the (almost) same runtime.

Nice.  There are a few things going on here.  As Yang observes, there's some number <300 of bugs that are getting triggered multiple times.  To find the true set of bugs you can start to report them, one at a time.

Another thing that is going on is that GCC has built up a huge resistance to Csmith.   We've beaten it up for years now.  We have not beaten on its FP code so of course there's more low-hanging fruit.

I am interested to know current support-level for floating points, any
limitations and any future works you plan regarding float-point support.

I'll also appreciate any source which explains current support level of
floating-point in csmith.

Hopefully Ally will chime in.  You should the source code too, there's not that much that deals with FP, as far as I know.