[llvm] [AMDGPU] Add target hook to isGlobalMemoryObject (PR #112781)

[Matt Arsenault via llvm-commits]

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@@ -549,7 +549,7 @@ void ScheduleDAGInstrs::addVRegUseDeps(SUnit *SU, unsigned OperIdx) {
 
 /// Returns true if MI is an instruction we are unable to reason about
 /// (like a call or something with unmodeled side effects).
-static inline bool isGlobalMemoryObject(MachineInstr *MI) {
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arsenm wrote:

What's the difference between this and TII::isSchedulingBoundary? 

Also wondering if we could treat these like isPosition 

https://github.com/llvm/llvm-project/pull/112781