We are allowed to remove any values from the `memref` list for which there is no
memref in the `retained` list with a may-alias relation. Before removing, we
just have to make sure that the corresponding op results for all retained
memrefs with must-alias relation are updated accordingly. This means, the the
condition operand has to become part of the disjunction the result value is
computed with.
Reviewed By: springerm
Differential Revision: https://reviews.llvm.org/D158395
765e82eeb6