[Mlir-commits] [flang] [mlir] [acc][flang] Define hasUnknownDimensions in MappableType (PR #165794)
llvmlistbot at llvm.org
llvmlistbot at llvm.org
Thu Oct 30 15:47:15 PDT 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-mlir
Author: Razvan Lupusoru (razvanlupusoru)
<details>
<summary>Changes</summary>
The MappableType interface currently defines a `generateAccBounds` method which examines a variable and generates `acc.bounds` operations that encode its dimensions. The implementation can extract bounds information in various ways: either from the MLIR type itself or by analyzing the IR to find dimension information from defining operations.
However, we need to distinguish between cases where dimensional information is not directly available from the type itself. This new `hasUnknownDimensions` API returns true when the MLIR type does not encode dimensional information and there is no associated descriptor or metadata that would make this information extractable from the visible ssa value the represents the variable. The expected use case is calling `generateAccBounds` only when this returns true, as it indicates that bounds must be extracted from the IR (by walking back from current variable to its defining spots or its descriptor).
This supports cases such as raw references to arrays with non-constant bounds (e.g., explicit-shape arrays in Fortran where bounds are passed as arguments). This functionality could also be leveraged for CIR VLA support in the future.
For FIR types:
- Box types return false (descriptor encodes dimensions)
- Reference types check if the pointee has dynamic size using fir::hasDynamicSize()
---
Full diff: https://github.com/llvm/llvm-project/pull/165794.diff
6 Files Affected:
- (modified) flang/include/flang/Optimizer/OpenACC/Support/FIROpenACCTypeInterfaces.h (+2)
- (modified) flang/lib/Optimizer/OpenACC/Support/FIROpenACCTypeInterfaces.cpp (+22)
- (modified) flang/test/Fir/OpenACC/openacc-mappable.fir (+5)
- (modified) flang/test/lib/OpenACC/TestOpenACCInterfaces.cpp (+4)
- (modified) mlir/include/mlir/Dialect/OpenACC/OpenACCTypeInterfaces.td (+12)
- (modified) mlir/unittests/Dialect/OpenACC/OpenACCOpsTest.cpp (+3-1)
``````````diff
diff --git a/flang/include/flang/Optimizer/OpenACC/Support/FIROpenACCTypeInterfaces.h b/flang/include/flang/Optimizer/OpenACC/Support/FIROpenACCTypeInterfaces.h
index 4817ed933ba06..3167c554abbdd 100644
--- a/flang/include/flang/Optimizer/OpenACC/Support/FIROpenACCTypeInterfaces.h
+++ b/flang/include/flang/Optimizer/OpenACC/Support/FIROpenACCTypeInterfaces.h
@@ -60,6 +60,8 @@ struct OpenACCMappableModel
getOffsetInBytes(mlir::Type type, mlir::Value var, mlir::ValueRange accBounds,
const mlir::DataLayout &dataLayout) const;
+ bool hasUnknownDimensions(mlir::Type type) const;
+
llvm::SmallVector<mlir::Value>
generateAccBounds(mlir::Type type, mlir::Value var,
mlir::OpBuilder &builder) const;
diff --git a/flang/lib/Optimizer/OpenACC/Support/FIROpenACCTypeInterfaces.cpp b/flang/lib/Optimizer/OpenACC/Support/FIROpenACCTypeInterfaces.cpp
index ed9e41c743754..ae0f5fb8197fa 100644
--- a/flang/lib/Optimizer/OpenACC/Support/FIROpenACCTypeInterfaces.cpp
+++ b/flang/lib/Optimizer/OpenACC/Support/FIROpenACCTypeInterfaces.cpp
@@ -193,6 +193,28 @@ OpenACCMappableModel<fir::PointerType>::getOffsetInBytes(
mlir::Type type, mlir::Value var, mlir::ValueRange accBounds,
const mlir::DataLayout &dataLayout) const;
+template <typename Ty>
+bool OpenACCMappableModel<Ty>::hasUnknownDimensions(mlir::Type type) const {
+ assert(fir::isa_ref_type(type) && "expected FIR reference type");
+ return fir::hasDynamicSize(fir::unwrapRefType(type));
+}
+
+template bool OpenACCMappableModel<fir::ReferenceType>::hasUnknownDimensions(
+ mlir::Type type) const;
+
+template bool OpenACCMappableModel<fir::HeapType>::hasUnknownDimensions(
+ mlir::Type type) const;
+
+template bool OpenACCMappableModel<fir::PointerType>::hasUnknownDimensions(
+ mlir::Type type) const;
+
+template <>
+bool OpenACCMappableModel<fir::BaseBoxType>::hasUnknownDimensions(
+ mlir::Type type) const {
+ // Descriptor-based entities have dimensions encoded.
+ return false;
+}
+
static llvm::SmallVector<mlir::Value>
generateSeqTyAccBounds(fir::SequenceType seqType, mlir::Value var,
mlir::OpBuilder &builder) {
diff --git a/flang/test/Fir/OpenACC/openacc-mappable.fir b/flang/test/Fir/OpenACC/openacc-mappable.fir
index 05df35a482907..00fe2574da62a 100644
--- a/flang/test/Fir/OpenACC/openacc-mappable.fir
+++ b/flang/test/Fir/OpenACC/openacc-mappable.fir
@@ -21,11 +21,13 @@ module attributes {dlti.dl_spec = #dlti.dl_spec<f16 = dense<16> : vector<2xi64>,
// CHECK: Mappable: !fir.box<!fir.array<10xf32>>
// CHECK: Type category: array
// CHECK: Size: 40
+ // CHECK: Has unknown dimensions: false
// CHECK: Visiting: %{{.*}} = acc.copyin varPtr(%{{.*}} : !fir.ref<!fir.array<10xf32>>) -> !fir.ref<!fir.array<10xf32>> {name = "arr", structured = false}
// CHECK: Pointer-like and Mappable: !fir.ref<!fir.array<10xf32>>
// CHECK: Type category: array
// CHECK: Size: 40
+ // CHECK: Has unknown dimensions: false
// This second test exercises argument of explicit-shape arrays in following forms:
// `real :: arr1(nn), arr2(2:nn), arr3(10)`
@@ -62,6 +64,7 @@ module attributes {dlti.dl_spec = #dlti.dl_spec<f16 = dense<16> : vector<2xi64>,
// CHECK: Visiting: %{{.*}} = acc.copyin varPtr(%{{.*}} : !fir.ref<!fir.array<?xf32>>) -> !fir.ref<!fir.array<?xf32>> {name = "arr1", structured = false}
// CHECK: Pointer-like and Mappable: !fir.ref<!fir.array<?xf32>>
// CHECK: Type category: array
+ // CHECK: Has unknown dimensions: true
// CHECK: Shape: %{{.*}} = fir.shape %[[EXTENT1:.*]] : (index) -> !fir.shape<1>
// CHECK: Bound[0]: %{{.*}} = acc.bounds lowerbound(%[[LB1:.*]] : index) upperbound(%[[UB1:.*]] : index) extent(%{{.*}} : index) stride(%c1{{.*}} : index) startIdx(%c1{{.*}} : index)
// CHECK: Lower bound: %[[LB1]] = arith.constant 0 : index
@@ -70,6 +73,7 @@ module attributes {dlti.dl_spec = #dlti.dl_spec<f16 = dense<16> : vector<2xi64>,
// CHECK: Visiting: %{{.*}} = acc.copyin varPtr(%{{.*}} : !fir.ref<!fir.array<?xf32>>) -> !fir.ref<!fir.array<?xf32>> {name = "arr2", structured = false}
// CHECK: Pointer-like and Mappable: !fir.ref<!fir.array<?xf32>>
// CHECK: Type category: array
+ // CHECK: Has unknown dimensions: true
// CHECK: Shape: %{{.*}} = fir.shape_shift %c2{{.*}}, %[[EXTENT2:.*]] : (index, index) -> !fir.shapeshift<1>
// CHECK: Bound[0]: %{{.*}} = acc.bounds lowerbound(%[[LB2:.*]] : index) upperbound(%[[UB2:.*]] : index) extent(%{{.*}} : index) stride(%c1{{.*}} : index) startIdx(%c2{{.*}} : index)
// CHECK: Lower bound: %[[LB2]] = arith.constant 0 : index
@@ -80,6 +84,7 @@ module attributes {dlti.dl_spec = #dlti.dl_spec<f16 = dense<16> : vector<2xi64>,
// CHECK: Type category: array
// CHECK: Size: 40
// CHECK: Offset: 0
+ // CHECK: Has unknown dimensions: false
// CHECK: Shape: %{{.*}} = fir.shape %[[EXTENT3:.*]] : (index) -> !fir.shape<1>
// CHECK: Bound[0]: %{{.*}} = acc.bounds lowerbound(%[[LB3:.*]] : index) upperbound(%[[UB3:.*]] : index) extent(%c10{{.*}} : index) stride(%c1{{.*}} : index) startIdx(%c1{{.*}} : index)
// CHECK: Lower bound: %[[LB3]] = arith.constant 0 : index
diff --git a/flang/test/lib/OpenACC/TestOpenACCInterfaces.cpp b/flang/test/lib/OpenACC/TestOpenACCInterfaces.cpp
index 9a80e3b1a9aee..072aee5ba269f 100644
--- a/flang/test/lib/OpenACC/TestOpenACCInterfaces.cpp
+++ b/flang/test/lib/OpenACC/TestOpenACCInterfaces.cpp
@@ -100,6 +100,10 @@ struct TestFIROpenACCInterfaces
}
}
+ llvm::errs() << "\t\tHas unknown dimensions: "
+ << (mappableTy.hasUnknownDimensions() ? "true" : "false")
+ << "\n";
+
if (auto declareOp =
dyn_cast_if_present<hlfir::DeclareOp>(var.getDefiningOp())) {
llvm::errs() << "\t\tShape: " << declareOp.getShape() << "\n";
diff --git a/mlir/include/mlir/Dialect/OpenACC/OpenACCTypeInterfaces.td b/mlir/include/mlir/Dialect/OpenACC/OpenACCTypeInterfaces.td
index 93e9e3d0689f7..d1bbc7f206ce6 100644
--- a/mlir/include/mlir/Dialect/OpenACC/OpenACCTypeInterfaces.td
+++ b/mlir/include/mlir/Dialect/OpenACC/OpenACCTypeInterfaces.td
@@ -259,6 +259,18 @@ def OpenACC_MappableTypeInterface : TypeInterface<"MappableType"> {
return {};
}]
>,
+ InterfaceMethod<
+ /*description=*/[{
+ Returns true if the dimensions of this type are not known. This occurs
+ when the MLIR type does not encode dimensional information and there is
+ no associated descriptor or metadata in the current entity that would
+ make this information extractable. For example, an opaque pointer type
+ pointing to an array without dimension information would have unknown
+ dimensions.
+ }],
+ /*retTy=*/"bool",
+ /*methodName=*/"hasUnknownDimensions"
+ >,
InterfaceMethod<
/*description=*/[{
Returns explicit `acc.bounds` operations that envelop the whole
diff --git a/mlir/unittests/Dialect/OpenACC/OpenACCOpsTest.cpp b/mlir/unittests/Dialect/OpenACC/OpenACCOpsTest.cpp
index 6ac9a873e6154..d6203b97e00d7 100644
--- a/mlir/unittests/Dialect/OpenACC/OpenACCOpsTest.cpp
+++ b/mlir/unittests/Dialect/OpenACC/OpenACCOpsTest.cpp
@@ -766,7 +766,9 @@ void testShortDataEntryOpBuildersMappableVar(OpBuilder &b, MLIRContext &context,
struct IntegerOpenACCMappableModel
: public mlir::acc::MappableType::ExternalModel<IntegerOpenACCMappableModel,
- IntegerType> {};
+ IntegerType> {
+ bool hasUnknownDimensions(mlir::Type type) const { return false; }
+};
TEST_F(OpenACCOpsTest, mappableTypeBuilderDataEntry) {
// First, set up the test by attaching MappableInterface to IntegerType.
``````````
</details>
https://github.com/llvm/llvm-project/pull/165794
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