[llvm] [StackSlotColoring] Ignore non-spill objects in RemoveDeadStores. (PR #80242)

[Eli Friedman via llvm-commits]

efriedma-quic wrote:

Shouldn't isLoadFromStackSlot fail if the target register is the zero register?  I mean, it's technically a load, and the source is a stack slot, but saying it loads a value into x0 is nonsense.

More generally, looking at the documentation for isLoadFromStackSlot and isStoreToStackSlot, I think they should perform all the checks necessary to make this transform legal.

https://github.com/llvm/llvm-project/pull/80242