[cfe-dev] Signed overflow and vectors?

Eli Friedman eli.friedman at gmail.com
Fri May 6 11:48:53 PDT 2011

On Fri, May 6, 2011 at 11:45 AM, Chris Lattner <clattner at apple.com> wrote:
> 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?
> I think "no", we shouldn't be setting these on vector operations.

Done in r131000.


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