[llvm] r196508 - SLPVectorizer: An in-tree vectorized entry cannot also be a scalar external use

[Joerg Sonnenberger]

On Thu, Dec 05, 2013 at 03:14:40PM -0000, Arnold Schwaighofer wrote:
> Author: arnolds
> Date: Thu Dec  5 09:14:40 2013
> New Revision: 196508
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=196508&view=rev
> Log:
> SLPVectorizer: An in-tree vectorized entry cannot also be a scalar external use
> 
> We were creating external uses for scalar values in MustGather entries that also
> had a ScalarToTreeEntry (they also are present in a vectorized tuple). This
> meant we would keep a value 'alive' as a scalar and vectorized causing havoc.
> This is not necessary because when we create a MustGather vector we explicitly
> create external uses entries for the insertelement instructions of the
> MustGather vector elements.
> 
> Fixes PR18129.
> 
> radar://15582184

Bill, initial testing shows that this fixes the issue successfully. I am
preparing more a more thorough test now. I'd suggest pulling this into
3.4 and doing another RC ASAP?

Joerg