[AMDGPU] Recognize x & ~(-1 << y) pattern.

Summary: The same pattern as D48010, but this one is IR-canonical as of D47428.

Reviewers: nhaehnle, bogner, tstellar, arsenm

Reviewed By: arsenm

Subscribers: arsenm, kzhuravl, wdng, yaxunl, dstuttard, tpr, t-tye, llvm-commits

Tags: #amdgpu

Differential Revision: https://reviews.llvm.org/D48012

llvm-svn: 334817