[llvm] [AMDGPU] Enable volatile and non-temporal for loads to LDS (PR #153244)

[Matt Arsenault via llvm-commits]

================
@@ -937,6 +951,43 @@ std::optional<SIMemOpInfo> SIMemOpAccess::getAtomicCmpxchgOrRmwInfo(
   return constructFromMIWithMMO(MI);
 }
 
+std::optional<std::tuple<SIMemOpInfo, SIMemOp>>
+SIMemOpAccess::getLdsLoadStoreInfo(
+    const MachineBasicBlock::iterator &MI) const {
+  assert(MI->getDesc().TSFlags & SIInstrFlags::maybeAtomic);
+
+  if (!MI->mayLoad() || !MI->mayStore())
+    return std::nullopt;
+
+  // An LDS DMA will have exactly two memory operands.
+  if (MI->getNumMemOperands() != 2)
+    return std::nullopt;
+
+  bool HasLDS = false;
+  bool HasNonLDS = false;
+  SIMemOp OpKind = SIMemOp::LOAD;
+  for (const auto &MMO : MI->memoperands()) {
+    unsigned AS = MMO->getAddrSpace();
+    HasLDS |= AS == AMDGPUAS::LOCAL_ADDRESS;
+    if (AS != AMDGPUAS::LOCAL_ADDRESS) {
+      HasNonLDS |= true;
+      if (!HasLDS) {
+        // If the pointer to LDS was in the first memop, this is a store
+        // from that pointer.
+        OpKind = SIMemOp::STORE;
+      }
+    }
+  }
+  if (!HasLDS || !HasNonLDS) {
+    return std::nullopt;
+  }
+
+  if (auto MOI = constructFromMIWithMMO(MI)) {
+    return std::make_tuple(*MOI, OpKind);
----------------
arsenm wrote:

```suggestion
    return {*MOI, OpKind};
```

https://github.com/llvm/llvm-project/pull/153244