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

[via llvm-commits]

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@@ -4064,3 +4158,43 @@ unsigned NVPTXDAGToDAGISel::GetConvertOpcode(MVT DestTy, MVT SrcTy,
     }
   }
 }
+
+bool NVPTXDAGToDAGISel::tryFence(SDNode *N) {
+  SDLoc DL(N);
+  assert(N->getOpcode() == ISD::ATOMIC_FENCE);
+  unsigned int FenceOp =
+      getFenceOp(NVPTX::Ordering(N->getConstantOperandVal(1)),
+                 Scopes[N->getConstantOperandVal(2)], Subtarget);
+  SDValue Chain = N->getOperand(0);
+  SDNode *FenceNode = CurDAG->getMachineNode(FenceOp, DL, MVT::Other, Chain);
+  ReplaceNode(N, FenceNode);
+  return true;
+}
+
+NVPTXScopes::NVPTXScopes(LLVMContext &C) : CTX(&C) {
+  Scopes[C.getOrInsertSyncScopeID("singlethread")] = NVPTX::Scope::Thread;
+  Scopes[C.getOrInsertSyncScopeID("")] = NVPTX::Scope::System;
+  Scopes[C.getOrInsertSyncScopeID("block")] = NVPTX::Scope::Block;
+  Scopes[C.getOrInsertSyncScopeID("cluster")] = NVPTX::Scope::Cluster;
+  Scopes[C.getOrInsertSyncScopeID("device")] = NVPTX::Scope::Device;
+}
+
+NVPTX::Scope NVPTXScopes::operator[](SyncScope::ID ID) const {
+  if (Scopes.empty())
+    report_fatal_error("NVPTX Scopes must be initialized before calling "
+                       "NVPTXScopes::operator[]");
+
+  auto S = Scopes.find(ID);
+  if (S == Scopes.end()) {
+    SmallVector<StringRef, 8> ScopeNames;
+    assert(CTX != nullptr && "CTX is nullptr");
+    CTX->getSyncScopeNames(ScopeNames);
+    StringRef Unknown{"unknown"};
+    auto Name = ID < ScopeNames.size() ? ScopeNames[ID] : Unknown;
+    report_fatal_error(
+        formatv("Could not find scope ID={} with name \"{}\".", int(ID), Name));
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gonzalobg wrote:

We already have a way to get the name: call this API `operator[]` which gives you a `NVPTX::Scope`, and then do `<<` on that, or `ScopeToString`. 

Within the error path of `operator[]`, we don't have a valid `NVPTX::Scope` yet, so have to do a bit more work here to get the name, and since we are in the error path, it may be that the ID isn't even in the map, so need to handle that case as well.

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