[InstCombine] Fold (!iszero(A & K1) & !iszero(A & K2)) -> (A & (K1 | K2)) ==...

[InstCombine] Fold (!iszero(A & K1) & !iszero(A & K2)) ->  (A & (K1 | K2)) == (K1 | K2) if K1 and K2 are a 1-bit mask

Summary: This is the demorganed version of the case we already handle for the OR of iszero.

Reviewers: spatel

Reviewed By: spatel

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D34244

llvm-svn: 305548