[mlir][OpenMP] Extend omp.private with a dealloc region

mlir/include/mlir/Dialect/OpenMP/OpenMPOps.td

@@ -158,8 +158,9 @@ def PrivateClauseOp : OpenMP_Op<"private", [IsolatedFromAbove]> {
   let description = [{
     This operation provides a declaration of how to implement the
     [first]privatization of a variable. The dialect users should provide
-    information about how to create an instance of the type in the alloc region
-    and how to initialize the copy from the original item in the copy region.
+    information about how to create an instance of the type in the alloc region,
+    how to initialize the copy from the original item in the copy region, and if
+    needed, how to deallocate allocated memory in the dealloc region.
 
     Examples:
 
@@ -187,10 +188,23 @@ def PrivateClauseOp : OpenMP_Op<"private", [IsolatedFromAbove]> {
     }
     ```
 
+    * `private(x)` for "allocatables" would be emitted as:
+    ```mlir
+    omp.private {type = private} @x.privatizer : !some.type alloc {
+    ^bb0(%arg0: !some.type):
+    %0 = ... allocate proper memory for the private clone ...
+    omp.yield(%0 : !fir.ref<i32>)
+    } deaclloc {
+    ^bb0(%arg0: !some.type):
+    ... deallocate allocated memory ...
+    omp.yield
+    }
+    ```
+
     There are no restrictions on the body except for:
-    - The `alloc` region has a single argument.
+    - The `alloc` & `dealloc` regions have a single argument.
     - The `copy` region has 2 arguments.
-    - Both regions are terminated by `omp.yield` ops.
+    - All 3 regions are terminated by `omp.yield` ops.
     The above restrictions and other obvious restrictions (e.g. verifying the
     type of yielded values) are verified by the custom op verifier. The actual
     contents of the blocks inside both regions are not verified.
@@ -212,12 +226,14 @@ def PrivateClauseOp : OpenMP_Op<"private", [IsolatedFromAbove]> {
                        DataSharingClauseTypeAttr:$data_sharing_type);
 
   let regions = (region MinSizedRegion<1>:$alloc_region,
-                        AnyRegion:$copy_region);
+                        AnyRegion:$copy_region,
+                        AnyRegion:$dealloc_region);
 
   let assemblyFormat = [{
     $data_sharing_type $sym_name `:` $type
       `alloc` $alloc_region
       (`copy` $copy_region^)?
+      (`dealloc` $dealloc_region^)?
       attr-dict
   }];
 

mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp

@@ -2258,17 +2258,28 @@ void PrivateClauseOp::build(OpBuilder &odsBuilder, OperationState &odsState,
 LogicalResult PrivateClauseOp::verify() {
   Type symType = getType();
 
-  auto verifyTerminator = [&](Operation *terminator) -> LogicalResult {
+  auto verifyTerminator = [&](Operation *terminator,
+                              bool yieldsValue) -> LogicalResult {
     if (!terminator->getBlock()->getSuccessors().empty())
       return success();
 
     if (!llvm::isa<YieldOp>(terminator))
       return mlir::emitError(terminator->getLoc())
              << "expected exit block terminator to be an `omp.yield` op.";
 
+
+
     YieldOp yieldOp = llvm::cast<YieldOp>(terminator);
     TypeRange yieldedTypes = yieldOp.getResults().getTypes();
 
+    if (!yieldsValue) {
+      if (yieldedTypes.empty())
+        return success();
+
+      return mlir::emitError(terminator->getLoc())
+             << "Did not expect any values to be yielded.";
+    }
+
     if (yieldedTypes.size() == 1 && yieldedTypes.front() == symType)
       return success();
 
@@ -2285,7 +2296,8 @@ LogicalResult PrivateClauseOp::verify() {
   };
 
   auto verifyRegion = [&](Region &region, unsigned expectedNumArgs,
-                          StringRef regionName) -> LogicalResult {
+                          StringRef regionName,
+                          bool yieldsValue) -> LogicalResult {
     assert(!region.empty());
 
     if (region.getNumArguments() != expectedNumArgs)
@@ -2299,14 +2311,15 @@ LogicalResult PrivateClauseOp::verify() {
       if (!block.mightHaveTerminator())
         continue;
 
-      if (failed(verifyTerminator(block.getTerminator())))
+      if (failed(verifyTerminator(block.getTerminator(), yieldsValue)))
         return failure();
     }
 
     return success();
   };
 
-  if (failed(verifyRegion(getAllocRegion(), /*expectedNumArgs=*/1, "alloc")))
+  if (failed(verifyRegion(getAllocRegion(), /*expectedNumArgs=*/1, "alloc",
+                          /*yieldsValue=*/true)))
     return failure();
 
   DataSharingClauseType dsType = getDataSharingType();
@@ -2319,7 +2332,13 @@ LogicalResult PrivateClauseOp::verify() {
         "`firstprivate` clauses require both `alloc` and `copy` regions.");
 
   if (dsType == DataSharingClauseType::FirstPrivate &&
-      failed(verifyRegion(getCopyRegion(), /*expectedNumArgs=*/2, "copy")))
+      failed(verifyRegion(getCopyRegion(), /*expectedNumArgs=*/2, "copy",
+                          /*yieldsValue=*/true)))
+    return failure();
+
+  if (!getDeallocRegion().empty() &&
+      failed(verifyRegion(getDeallocRegion(), /*expectedNumArgs=*/1, "dealloc",
+                          /*yieldsValue=*/false)))
     return failure();
 
   return success();

mlir/test/Dialect/OpenMP/invalid.mlir

@@ -2151,6 +2151,17 @@ omp.private {type = private} @x.privatizer : i32 alloc {
 
 // -----
 
+omp.private {type = private} @x.privatizer : f32 alloc {
+^bb0(%arg0: f32):
+  omp.yield(%arg0 : f32)
+} dealloc {
+^bb0(%arg0: f32):
+  // expected-error @below {{Did not expect any values to be yielded.}}
+  omp.yield(%arg0 : f32)
+}
+
+// -----
+
 omp.private {type = private} @x.privatizer : i32 alloc {
 ^bb0(%arg0: i32):
   // expected-error @below {{expected exit block terminator to be an `omp.yield` op.}}
@@ -2178,6 +2189,17 @@ omp.private {type = firstprivate} @x.privatizer : f32 alloc {
 
 // -----
 
+// expected-error @below {{`dealloc`: expected 1 region arguments, got: 2}}
+omp.private {type = private} @x.privatizer : f32 alloc {
+^bb0(%arg0: f32):
+  omp.yield(%arg0 : f32)
+} dealloc {
+^bb0(%arg0: f32, %arg1: f32):
+  omp.yield
+}
+
+// -----
+
 // expected-error @below {{`private` clauses require only an `alloc` region.}}
 omp.private {type = private} @x.privatizer : f32 alloc {
 ^bb0(%arg0: f32):
@@ -2249,4 +2271,4 @@ func.func @undefined_privatizer(%arg0: !llvm.ptr) {
       omp.terminator
     }) : (!llvm.ptr) -> ()
   return
-}
+}

mlir/test/Dialect/OpenMP/ops.mlir

@@ -2492,11 +2492,22 @@ func.func @parallel_op_privatizers(%arg0: !llvm.ptr, %arg1: !llvm.ptr) {
   return
 }
 
+// CHECK-LABEL: omp.private {type = private} @a.privatizer : !llvm.ptr alloc {
+omp.private {type = private} @a.privatizer : !llvm.ptr alloc {
+// CHECK: ^bb0(%{{.*}}: {{.*}}):
+^bb0(%arg0: !llvm.ptr):
+  omp.yield(%arg0 : !llvm.ptr)
+}
+
 // CHECK-LABEL: omp.private {type = private} @x.privatizer : !llvm.ptr alloc {
 omp.private {type = private} @x.privatizer : !llvm.ptr alloc {
 // CHECK: ^bb0(%{{.*}}: {{.*}}):
 ^bb0(%arg0: !llvm.ptr):
   omp.yield(%arg0 : !llvm.ptr)
+} dealloc {
+// CHECK: ^bb0(%{{.*}}: {{.*}}):
+^bb0(%arg0: !llvm.ptr):
+  omp.yield
 }
 
 // CHECK-LABEL: omp.private {type = firstprivate} @y.privatizer : !llvm.ptr alloc {
@@ -2509,6 +2520,10 @@ omp.private {type = firstprivate} @y.privatizer : !llvm.ptr alloc {
 // CHECK: ^bb0(%{{.*}}: {{.*}}, %{{.*}}: {{.*}}):
 ^bb0(%arg0: !llvm.ptr, %arg1: !llvm.ptr):
   omp.yield(%arg0 : !llvm.ptr)
+} dealloc {
+// CHECK: ^bb0(%{{.*}}: {{.*}}):
+^bb0(%arg0: !llvm.ptr):
+  omp.yield
 }
 
 // CHECK-LABEL: parallel_op_reduction_and_private