[Mlir-commits] [mlir] [mlir][acc] Add LegalizeDataValues support for DeclareEnterOp (PR #138008)

[Razvan Lupusoru]

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@@ -71,7 +72,54 @@ static void replaceAllUsesInAccComputeRegionsWith(Value orig, Value replacement,
 }
 
 template <typename Op>
-static void collectAndReplaceInRegion(Op &op, bool hostToDevice) {
+static void replaceAllUsesInUnstructuredComputeRegionWith(
+    Op &op, llvm::SmallVector<std::pair<Value, Value>> &values,
+    DominanceInfo &domInfo, PostDominanceInfo &postDomInfo) {
+
+  Operation *exitOp = op.getOperation();
+  if constexpr (std::is_same_v<Op, acc::DeclareEnterOp>) {
+    // For declare enter/exit pairs, verify there is exactly one exit op using
+    // the token
+    if (!op.getToken().hasOneUse())
+      op.emitError("declare enter token must have exactly one use");
+    Operation *user = *op.getToken().getUsers().begin();
+    auto declareExit = dyn_cast<acc::DeclareExitOp>(user);
+    if (!declareExit)
+      op.emitError("declare enter token must be used by declare exit op");
+    exitOp = declareExit;
+  } else if constexpr (std::is_same_v<Op, acc::EnterDataOp>) {
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razvanlupusoru wrote:

I am excited about the potential to support acc.enter_data. As I looked at your algorithm here though I realized that maybe it should be left for another change. This is because enter_data and exit_data don't come in pairs - so a bit more analysis is needed to get this right. More specifically, finding an exit_data does not constitute the end of the lifetime for a particular variable.

https://github.com/llvm/llvm-project/pull/138008