[llvm][CodeGen] Check for memory instructions when querying for alias status
Add a check to make sure that MachineInstr::mayAlias returns prematurely if at least one of its instruction parameters does not access memory. This prevents calls to TargetInstrInfo::areMemAccessesTriviallyDisjoint with incompatible instructions.
A side effect of this change is to render the mayAlias helper in the AArch64 load/store optimizer obsolete. We can now directly call the MachineInstr::mayAlias member function.
Reviewers: hfinkel, t.p.northover, mcrosier, eli.friedman, efriedma
Reviewed By: efriedma
Subscribers: efriedma, kristof.beyls, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D78823