[InstCombine] Simplify icmp ult/uge (shl %x, C2), C1 iff C1 is power of two -> icmp eq/ne (and %x, (lshr -C1, C2)), 0.
Simplify 'shl' inequality test into 'and' equality test.
This pattern happens in the middle-end while simplifying bitfield access,
Exposed in https://reviews.llvm.org/D63505
Reviewers: lebedev.ri, efriedma
Reviewed By: lebedev.ri
Subscribers: spatel, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D63675