[]PATCH A bug in DAG Combiner caused by undef mask

Fri May 10 02:33:42 PDT 2013

On 10.05.2013, at 04:27, Hao Liu <Hao.Liu at arm.com> wrote:

> Hi,
>  
> Please consider a patch to fix PR15950: http://llvm.org/bugs/show_bug.cgi?id=15950.
> A function partitionShuffleOfConats tries to turn a shuffle with undef mask of two concats into a single concat, but it doesn’t consider undef a masks, whose value is -1 and will cause an overflow in an unsigned type variable.
>  
> To fix this bug, we just need to consider two more situations for a concatenated vector: all masks are undef, mixed undef and general masks. The former situation is resolved by adding an undef vector. The latter situation is resolved by directly bailing out.
>  
> Thanks,
> -Hao
> <DAGComb-overflow-5-10.patch>

LGTM!

- Ben