[cfe-dev] Signed overflow and vectors?

[Eric Christopher]

On May 5, 2011, at 12:00 PM, Eli Friedman wrote:

> Looking at http://llvm.org/bugs/show_bug.cgi?id=9850 , I realized that
> we are setting nsw flags on vector instructions.  To fix that bug, at
> the very least, we need to fix *mmintrin.h to not use instructions
> with undefined overflow behavior.  But generally, do we want to be
> setting nsw on vector addition/subtraction/etc. generated by clang?

My thought would be "No?", but I may be suffering from a lack of
imagination where it would be helpful to do that.

-eric