[mlir][acc] Add ACCImplicitData pass for implicit data attributes

mlir/include/mlir/Dialect/OpenACC/Transforms/Passes.h

@@ -9,6 +9,9 @@
 #ifndef MLIR_DIALECT_OPENACC_TRANSFORMS_PASSES_H
 #define MLIR_DIALECT_OPENACC_TRANSFORMS_PASSES_H
 
+#include "mlir/Dialect/Arith/IR/Arith.h"
+#include "mlir/Dialect/MemRef/IR/MemRef.h"
+#include "mlir/Dialect/OpenACC/OpenACC.h"
 #include "mlir/Pass/Pass.h"
 
 namespace mlir {

mlir/include/mlir/Dialect/OpenACC/Transforms/Passes.td

@@ -27,4 +27,40 @@ def LegalizeDataValuesInRegion : Pass<"openacc-legalize-data-values", "mlir::fun
   ];
 }
 
+def ACCImplicitData : Pass<"acc-implicit-data", "mlir::ModuleOp"> {
+  let summary = "Generate implicit data attributes for OpenACC compute constructs";
+  let description = [{
+    This pass implements the OpenACC specification for "Variables with
+    Implicitly Determined Data Attributes" (OpenACC 3.4 spec, section 2.6.2).
+
+    The pass automatically generates data clause operations for variables used
+    within OpenACC compute constructs (parallel, kernels, serial) that do not
+    already have explicit data clauses. The semantics follow these rules:
+
+    1. If there is a default(none) clause visible, no implicit data actions
+       apply.
+
+    2. An aggregate variable (arrays, derived types, etc.) will be treated as:
+       - In a present clause when default(present) is visible.
+       - In a copy clause otherwise.
+
+    3. A scalar variable will be treated as if it appears in:
+       - A copy clause if the compute construct is a kernels construct.
+       - A firstprivate clause otherwise (parallel, serial).
+  }];
+  let dependentDialects = ["mlir::acc::OpenACCDialect",
+      "mlir::memref::MemRefDialect",
+      "mlir::arith::ArithDialect"];
+  let options = [
+    Option<"enableImplicitReductionCopy", "enable-implicit-reduction-copy",
+           "bool", "true",
+           "Enable applying implicit copy in lieu of implicit firstprivate for "
+           "reduction variables. This allows uniform treatment of reduction "
+           "variables between combined constructs (e.g., 'parallel loop') and "
+           "separate constructs (e.g., 'parallel' followed by 'loop'), where "
+           "the OpenACC spec requires copy semantics for the former but "
+           "firstprivate would normally apply for the latter.">
+  ];
+}
+
 #endif // MLIR_DIALECT_OPENACC_TRANSFORMS_PASSES