[PATCH] D15730: [MachineLICM] Fix handling of memoperands

[Sanjoy Das via llvm-commits]

sanjoy added a subscriber: sanjoy.
sanjoy added a comment.

I think the right way to model "touches all memory" is with a bit on the machine instruction, not with an empty memoperand list.  Otherwise, for instance, every place that calls `MachineInstr::addMemOperand` has to be audited to ensure that it does not transition a machine instruction from 0 mem operands (allowed to clobber all memory) to non-zero mem operands (allowed to clobber only the specific named locations).  That or we need to change `MachineInstr::addMemOperand`.


http://reviews.llvm.org/D15730