[llvm] [AMDGPU] Relax lds dma waitcnt with no aliasing pair (PR #131842)

[Pierre van Houtryve via llvm-commits]

================
@@ -1748,7 +1753,7 @@ bool SIInsertWaitcnts::generateWaitcntInstBefore(MachineInstr &MI,
             }
           }
         }
-        if (!FoundAliasingStore)
+        if (!FoundAliasingStore && !RelaxLDSDMA)
----------------
Pierre-vh wrote:

Is this still correct w.r.t. the check above?
```
if (Ptr && Memop->getAAInfo() && Memop->getAAInfo().Scope)
```
If that is false, I assume we want the wait anyway because we couldn't do alias analysis. Should we still add the conservative wait in that case?

https://github.com/llvm/llvm-project/pull/131842