Revert "[ValueTracking] Pass only a single lambda to computeKnownBitsFromShiftOperator by using KnownBits struct instead of separate APInts. NFCI"

This reverts commit r319624, which seems to cause a miscompile (breaks the
multistage PPC buildbots)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319652 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed