Re: [RFC] overflow checks optimized away

On Fri, Oct 9, 2015 at 2:52 PM, Bruce Momjian <bruce(at)momjian(dot)us> wrote:

> Any news on this item from 2013, worked on again 2014?
>

Sorry, I didn't look at it since. At the time I was using Xi Wang's
software to find the overflow checks that need to be redone. He published a
paper on it and it's actually pretty impressive. It constructs a constraint
problem and then throws a kSAT solver at it to find out if there's any code
that a compiler could optimize away regardless of whether any existant
compiler is actually capable of detecting the case and optimizing it away.
https://pdos.csail.mit.edu/papers/stack:sosp13.pdf

Xi Wang actually went on to pursue the same issues in the Linux kernel,
Clang, and elsewhere:

https://css.csail.mit.edu/stack/
http://kqueue.org/blog/2012/03/16/fast-integer-overflow-detection/
http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20130617/082221.html

I'm up for trying again but it's a long slong to replace all the overflow
checks and the patch will be big....

--
greg