[llvm] [NVPTX] Load/Store/Fence syncscope support (PR #106101)

[Artem Belevich via llvm-commits]

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@@ -915,6 +920,42 @@ getOperationOrderings(MemSDNode *N, const NVPTXSubtarget *Subtarget) {
 
 } // namespace
 
+NVPTX::Scope NVPTXDAGToDAGISel::getOperationScope(MemSDNode *N,
+                                                  NVPTX::Ordering Ord) const {
+  switch (Ord) {
+  case NVPTX::Ordering::NotAtomic:
+  case NVPTX::Ordering::Volatile: // Non-atomic volatile operations
+    // NVPTX uses Thread scope as the scope of non-atomic operations.
+    return NVPTX::Scope::Thread;
+  case NVPTX::Ordering::RelaxedMMIO:
+    // RelaxedMMIO operations are always system scope.
+    // If a RelaxedMMIO order was generated from an atomic volatile operation
+    // with a smaller thread scope, we bump it here to system scope.
+    return NVPTX::Scope::System;
+  case NVPTX::Ordering::Relaxed:
+  case NVPTX::Ordering::Acquire:
+  case NVPTX::Ordering::Release:
+  case NVPTX::Ordering::AcquireRelease:
+  case NVPTX::Ordering::SequentiallyConsistent:
+    auto S = Scopes[N->getSyncScopeID()];
+
+    // Atomic operations must have a scope greater than thread.
+    if (S == NVPTX::Scope::Thread)
+      report_fatal_error(
+          formatv("Atomics need scope > \"{}\".", ScopeToString(S)));
+
+    // If scope is cluster, clusters must be supported.
+    if (S == NVPTX::Scope::Cluster)
+      Subtarget->requireClusters("cluster scope");
+
+    // If operation is volatile, then its scope is system.
+    if (N->isVolatile())
+      S = NVPTX::Scope::System;
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Artem-B wrote:

Prefer early return, as that's the final decision, and we're not planning to change `S` later on.

https://github.com/llvm/llvm-project/pull/106101