Summary:
This will be used for 64-bit MULHU, which is in turn used for the 64-bit
divide-by-constant optimization (see D24822).
Reviewers: arsenm, tstellarAMD
Subscribers: kzhuravl, wdng, yaxunl, llvm-commits, tony-tye
Differential Revision: https://reviews.llvm.org/D25289
llvm-svn: 284224