Note that the non-splat lshr+lshr test folded, but that does not
work in general. Something is missing or wrong in computeKnownBits
as the non-splat shl+shl test still shows.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@288005 91177308-0d34-0410-b5e6-96231b3b80d8
If the shifter operand is a constant, and all of the bits shifted out
are known to be zero, then if X is known non-zero at least one
non-zero bit must remain.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248508 91177308-0d34-0410-b5e6-96231b3b80d8
