[MLIR][OpenMP] Split region-associated op verification

This patch moves the part of operation verifiers dependent on the contents of
their regions to the corresponding `verifyRegions` method. This ensures these
are only triggered after the operations in the region have themselved already
been verified in advance, avoiding checks based on invalid nested operations.

The `LoopWrapperInterface` is also updated so that its verifier runs after
operations in the region of ops with this interface have already been verified.

Author: skatrak

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

@@ -137,7 +137,7 @@ def PrivateClauseOp : OpenMP_Op<"private", [IsolatedFromAbove, RecipeInterface]>
     }
   }];
 
-  let hasVerifier = 1;
+  let hasRegionVerifier = 1;
 }
 
 //===----------------------------------------------------------------------===//
@@ -175,6 +175,7 @@ def ParallelOp : OpenMP_Op<"parallel", traits = [
   }];
 
   let hasVerifier = 1;
+  let hasRegionVerifier = 1;
 }
 
 def TerminatorOp : OpenMP_Op<"terminator", [Terminator, Pure]> {
@@ -426,6 +427,7 @@ def WsloopOp : OpenMP_Op<"wsloop", traits = [
   }];
 
   let hasVerifier = 1;
+  let hasRegionVerifier = 1;
 }
 
 //===----------------------------------------------------------------------===//
@@ -479,6 +481,7 @@ def SimdOp : OpenMP_Op<"simd", traits = [
   }];
 
   let hasVerifier = 1;
+  let hasRegionVerifier = 1;
 }
 
 
@@ -556,6 +559,7 @@ def DistributeOp : OpenMP_Op<"distribute", traits = [
   }];
 
   let hasVerifier = 1;
+  let hasRegionVerifier = 1;
 }
 
 //===----------------------------------------------------------------------===//
@@ -693,6 +697,7 @@ def TaskloopOp : OpenMP_Op<"taskloop", traits = [
   }] # clausesExtraClassDeclaration;
 
   let hasVerifier = 1;
+  let hasRegionVerifier = 1;
 }
 
 def TaskgroupOp : OpenMP_Op<"taskgroup", traits = [

mlir/include/mlir/Dialect/OpenMP/OpenMPOpsInterfaces.td

@@ -258,6 +258,7 @@ def LoopWrapperInterface : OpInterface<"LoopWrapperInterface"> {
   let verify = [{
     return ::llvm::cast<::mlir::omp::LoopWrapperInterface>($_op).verifyImpl();
   }];
+  let verifyWithRegions = 1;
 }
 
 def ComposableOpInterface : OpInterface<"ComposableOpInterface"> {

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

@@ -1760,6 +1760,18 @@ static LogicalResult verifyPrivateVarList(OpType &op) {
 }
 
 LogicalResult ParallelOp::verify() {
+  if (getAllocateVars().size() != getAllocatorVars().size())
+    return emitError(
+        "expected equal sizes for allocate and allocator variables");
+
+  if (failed(verifyPrivateVarList(*this)))
+    return failure();
+
+  return verifyReductionVarList(*this, getReductionSyms(), getReductionVars(),
+                                getReductionByref());
+}
+
+LogicalResult ParallelOp::verifyRegions() {
   auto distributeChildOps = getOps<DistributeOp>();
   if (!distributeChildOps.empty()) {
     if (!isComposite())
@@ -1780,16 +1792,7 @@ LogicalResult ParallelOp::verify() {
     return emitError()
            << "'omp.composite' attribute present in non-composite operation";
   }
-
-  if (getAllocateVars().size() != getAllocatorVars().size())
-    return emitError(
-        "expected equal sizes for allocate and allocator variables");
-
-  if (failed(verifyPrivateVarList(*this)))
-    return failure();
-
-  return verifyReductionVarList(*this, getReductionSyms(), getReductionVars(),
-                                getReductionByref());
+  return success();
 }
 
 //===----------------------------------------------------------------------===//
@@ -1979,6 +1982,11 @@ void WsloopOp::build(OpBuilder &builder, OperationState &state,
 }
 
 LogicalResult WsloopOp::verify() {
+  return verifyReductionVarList(*this, getReductionSyms(), getReductionVars(),
+                                getReductionByref());
+}
+
+LogicalResult WsloopOp::verifyRegions() {
   bool isCompositeChildLeaf =
       llvm::dyn_cast_if_present<LoopWrapperInterface>((*this)->getParentOp());
 
@@ -2000,8 +2008,7 @@ LogicalResult WsloopOp::verify() {
            << "'omp.composite' attribute missing from composite wrapper";
   }
 
-  return verifyReductionVarList(*this, getReductionSyms(), getReductionVars(),
-                                getReductionByref());
+  return success();
 }
 
 //===----------------------------------------------------------------------===//
@@ -2037,9 +2044,6 @@ LogicalResult SimdOp::verify() {
   if (verifyNontemporalClause(*this, getNontemporalVars()).failed())
     return failure();
 
-  if (getNestedWrapper())
-    return emitOpError() << "must wrap an 'omp.loop_nest' directly";
-
   bool isCompositeChildLeaf =
       llvm::dyn_cast_if_present<LoopWrapperInterface>((*this)->getParentOp());
 
@@ -2054,6 +2058,13 @@ LogicalResult SimdOp::verify() {
   return success();
 }
 
+LogicalResult SimdOp::verifyRegions() {
+  if (getNestedWrapper())
+    return emitOpError() << "must wrap an 'omp.loop_nest' directly";
+
+  return success();
+}
+
 //===----------------------------------------------------------------------===//
 // Distribute construct [2.9.4.1]
 //===----------------------------------------------------------------------===//
@@ -2076,6 +2087,10 @@ LogicalResult DistributeOp::verify() {
     return emitError(
         "expected equal sizes for allocate and allocator variables");
 
+  return success();
+}
+
+LogicalResult DistributeOp::verifyRegions() {
   if (LoopWrapperInterface nested = getNestedWrapper()) {
     if (!isComposite())
       return emitError()
@@ -2281,6 +2296,10 @@ LogicalResult TaskloopOp::verify() {
         "may not appear on the same taskloop directive");
   }
 
+  return success();
+}
+
+LogicalResult TaskloopOp::verifyRegions() {
   if (LoopWrapperInterface nested = getNestedWrapper()) {
     if (!isComposite())
       return emitError()
@@ -2725,7 +2744,7 @@ void PrivateClauseOp::build(OpBuilder &odsBuilder, OperationState &odsState,
                                      DataSharingClauseType::Private));
 }
 
-LogicalResult PrivateClauseOp::verify() {
+LogicalResult PrivateClauseOp::verifyRegions() {
   Type symType = getType();
 
   auto verifyTerminator = [&](Operation *terminator,

mlir/test/Dialect/OpenMP/invalid.mlir

@@ -136,9 +136,11 @@ func.func @invalid_nested_wrapper(%lb : index, %ub : index, %step : index) {
   // expected-error @below {{only supported nested wrapper is 'omp.simd'}}
   omp.wsloop {
     omp.distribute {
-      omp.loop_nest (%iv) : index = (%lb) to (%ub) step (%step) {
-        omp.yield
-      }
+      omp.simd {
+        omp.loop_nest (%iv) : index = (%lb) to (%ub) step (%step) {
+          omp.yield
+        }
+      } {omp.composite}
     } {omp.composite}
   } {omp.composite}
 }
@@ -1975,7 +1977,7 @@ func.func @taskloop(%lb: i32, %ub: i32, %step: i32) {
       omp.loop_nest (%iv) : i32 = (%lb) to (%ub) step (%step) {
         omp.yield
       }
-    } {omp.composite}
+    }
   } {omp.composite}
   return
 }
@@ -2188,7 +2190,7 @@ func.func @omp_distribute_nested_wrapper2(%lb: index, %ub: index, %step: index)
       omp.loop_nest (%iv) : index = (%lb) to (%ub) step (%step) {
         "omp.yield"() : () -> ()
       }
-    }) {omp.composite} : () -> ()
+    }) : () -> ()
   } {omp.composite}
 }