[Mlir-commits] [mlir] e655c36 - [mlir][IR] Generalize `DenseElementsAttr` to custom element types (#183891)
llvmlistbot at llvm.org
llvmlistbot at llvm.org
Sat Feb 28 05:03:38 PST 2026
Author: Matthias Springer
Date: 2026-02-28T15:03:32+02:00
New Revision: e655c36c16c118e3f8ae0c95854f33119218a4bf
URL: https://github.com/llvm/llvm-project/commit/e655c36c16c118e3f8ae0c95854f33119218a4bf
DIFF: https://github.com/llvm/llvm-project/commit/e655c36c16c118e3f8ae0c95854f33119218a4bf.diff
LOG: [mlir][IR] Generalize `DenseElementsAttr` to custom element types (#183891)
`DenseElementsAttr` supports only a hard-coded list of element types:
`int`, `index`, `float`, `complex`. This commit generalizes the
`DenseElementsAttr` infrastructure: it now supports arbitrary element
types, as long as they implement the new `DenseElementTypeInterface`.
The `DenseElementTypeInterface` has the following helper functions:
- `getDenseElementBitSize`: Query the size of an element in bits. (When
storing an element in memory, each element is padded to a full byte.
This is an existing limitation of the `DenseElementsAttr`; with an
exception for `i1`.)
- `convertToAttribute`: Attribute factory / deserializer. Converts bytes
into an MLIR attribute. The attribute provides the assembly format /
printer for a single element.
- `convertFromAttribute`: Serializer. Converts an MLIR attribute into
bytes.
Note: `convertToAttribute` / `convertFromAttribute` are mainly for
writing test cases. For performance reasons, `DenseElementsAttr` users
should work with raw bytes / elements and avoid any API that
materializes MLIR attributes. However, MLIR attributes typically have
human-readable parsers/printers, making them suitable for lit tests and
debugging.
This PR introduces an additional assembly format for
`DenseElementsAttrs`. There are now two formats. (The existing one is
kept for compatibility reasons.)
- Literal-first (existing): `dense<[1, 2, 3]> : tensor<3xi32>`
- Type-first (new): `dense<tensor<3xi32> : [1 : i32, 2 : i32, 3 : i32]>`
The new syntax is needed to disambiguate between "literal" (e.g., `1`)
and attribute (e.g., `1 : i32`) when parsing the first token. In the
literal-first syntax, we only parse literals. In the type-first syntax,
we only parse attributes.
The existing `int`, `index`, `float`, `complex` types also implement the
`DenseElementTypeInterface`. This allows us to implement
`DenseElementsAttr::get` and `AttributeElementIterator::operator*` in a
generic way.
RFC:
https://discourse.llvm.org/t/rfc-allow-custom-element-types-in-denseelementattr/89656
This is a re-upload of #179122.
Added:
mlir/test/IR/dense-elements-type-interface.mlir
Modified:
mlir/include/mlir/IR/BuiltinAttributes.td
mlir/include/mlir/IR/BuiltinTypeInterfaces.h
mlir/include/mlir/IR/BuiltinTypeInterfaces.td
mlir/include/mlir/IR/BuiltinTypes.td
mlir/lib/AsmParser/AttributeParser.cpp
mlir/lib/IR/AsmPrinter.cpp
mlir/lib/IR/AttributeDetail.h
mlir/lib/IR/BuiltinAttributes.cpp
mlir/lib/IR/BuiltinTypeInterfaces.cpp
mlir/lib/IR/BuiltinTypes.cpp
mlir/test/lib/Dialect/Test/TestTypeDefs.td
mlir/test/lib/Dialect/Test/TestTypes.cpp
mlir/test/lib/Dialect/Test/TestTypes.h
Removed:
################################################################################
diff --git a/mlir/include/mlir/IR/BuiltinAttributes.td b/mlir/include/mlir/IR/BuiltinAttributes.td
index 798d3c84f9618..dced379d1f979 100644
--- a/mlir/include/mlir/IR/BuiltinAttributes.td
+++ b/mlir/include/mlir/IR/BuiltinAttributes.td
@@ -239,29 +239,48 @@ def Builtin_DenseIntOrFPElementsAttr : Builtin_Attr<
"DenseElementsAttr"
> {
let summary = "An Attribute containing a dense multi-dimensional array of "
- "integer or floating-point values";
+ "values";
let description = [{
- Syntax:
-
- ```
- tensor-literal ::= integer-literal | float-literal | bool-literal | [] | [tensor-literal (, tensor-literal)* ]
- dense-intorfloat-elements-attribute ::= `dense` `<` tensor-literal `>` `:`
- ( tensor-type | vector-type )
- ```
-
- A dense int-or-float elements attribute is an elements attribute containing
- a densely packed vector or tensor of integer or floating-point values. The
- element type of this attribute is required to be either an `IntegerType` or
- a `FloatType`.
+ A dense elements attribute stores one or multiple elements of the same type.
+ The term "dense" refers to the fact that elements are not stored as
+ individual MLIR attributes, but in a raw buffer. The attribute provides a
+ covenience API to access elements in the form of MLIR attributes, but users
+ should avoid that API in performance-critical code and utilize APIs that
+ operate on raw bytes instead.
+
+ The number of elements is determined by the `type` shaped type. (Unranked
+ shaped types are not supported.) The element type of the shaped type must
+ implement the `DenseElementType` interface. This type interface defines the
+ bitwidth of an element and provides a serializer/deserializer to/from MLIR
+ attributes.
+
+ Storage format: Given an element bitwidth "w", element "i" starts at byte
+ offset "i * ceildiv(w, 8)". In other words, each element starts at a full
+ byte offset.
+
+ TODO: The name `DenseIntOrFPElements` is no longer accurate. The attribute
+ will be renamed in the future.
Examples:
```
- // A splat tensor of integer values.
+ // Literal-first syntax: A splat tensor of integer values.
dense<10> : tensor<2xi32>
- // A tensor of 2 float32 elements.
+
+ // Literal-first syntax: A tensor of 2 float32 elements.
dense<[10.0, 11.0]> : tensor<2xf32>
+
+ // Type-first syntax: A splat tensor of integer values.
+ dense<tensor<2xi32> : 10 : i32>
+
+ // Type-first syntax: A tensor of 2 float32 elements.
+ dense<tensor<2xf32> : [10.0, 11.0]>
```
+
+ Note: The literal-first syntax is supported only for complex, float, index,
+ int element types. The parser/print have special casing for these types.
+ Dense element attributes with other element types must use the type-first
+ syntax.
}];
let parameters = (ins AttributeSelfTypeParameter<"", "ShapedType">:$type,
"ArrayRef<char>":$rawData);
diff --git a/mlir/include/mlir/IR/BuiltinTypeInterfaces.h b/mlir/include/mlir/IR/BuiltinTypeInterfaces.h
index 5f14517d8dd71..9425d554b427c 100644
--- a/mlir/include/mlir/IR/BuiltinTypeInterfaces.h
+++ b/mlir/include/mlir/IR/BuiltinTypeInterfaces.h
@@ -19,6 +19,29 @@ struct fltSemantics;
namespace mlir {
class FloatType;
class MLIRContext;
+
+namespace detail {
+/// Float type implementation of
+/// DenseElementTypeInterface::getDenseElementBitSize.
+size_t getFloatTypeDenseElementBitSize(Type type);
+
+/// Float type implementation of DenseElementTypeInterface::convertToAttribute.
+Attribute convertFloatTypeToAttribute(Type type, llvm::ArrayRef<char> rawData);
+
+/// Float type implementation of
+/// DenseElementTypeInterface::convertFromAttribute.
+LogicalResult
+convertFloatTypeFromAttribute(Type type, Attribute attr,
+ llvm::SmallVectorImpl<char> &result);
+
+/// Read `bitWidth` bits from byte-aligned position in `rawData` and return as
+/// an APInt. Handles endianness correctly.
+llvm::APInt readBits(const char *rawData, size_t bitPos, size_t bitWidth);
+
+/// Write `value` to byte-aligned position `bitPos` in `rawData`. Handles
+/// endianness correctly.
+void writeBits(char *rawData, size_t bitPos, llvm::APInt value);
+} // namespace detail
} // namespace mlir
#include "mlir/IR/BuiltinTypeInterfaces.h.inc"
diff --git a/mlir/include/mlir/IR/BuiltinTypeInterfaces.td b/mlir/include/mlir/IR/BuiltinTypeInterfaces.td
index 9ef08b7020b99..93c8c0694b467 100644
--- a/mlir/include/mlir/IR/BuiltinTypeInterfaces.td
+++ b/mlir/include/mlir/IR/BuiltinTypeInterfaces.td
@@ -41,12 +41,70 @@ def VectorElementTypeInterface : TypeInterface<"VectorElementTypeInterface"> {
}];
}
+//===----------------------------------------------------------------------===//
+// DenseElementTypeInterface
+//===----------------------------------------------------------------------===//
+
+def DenseElementTypeInterface : TypeInterface<"DenseElementType"> {
+ let cppNamespace = "::mlir";
+ let description = [{
+ This interface allows custom types to be used as element types in
+ DenseElementsAttr. Types implementing this interface define:
+
+ 1. The bit size for element storage.
+ 2. Helper methods for converting from/to Attribute. This assumes that there
+ is a corresponding attribute for each type that implements this
+ interface.
+
+ The helper methods for converting from/to Attribute are utilized when
+ parsing/printing IR or iterating over the elements via Attribute.
+ }];
+
+ let methods = [
+ InterfaceMethod<
+ /*desc=*/[{
+ Return the number of bits required to store one element in dense
+ storage.
+
+ Note: The DenseElementsAttr infrastructure will automatically align
+ every element to a full byte in storage. This limitation could be lifted
+ in the future to support dense packing of non-byte-sized elements.
+ }],
+ /*retTy=*/"size_t",
+ /*methodName=*/"getDenseElementBitSize",
+ /*args=*/(ins)
+ >,
+ InterfaceMethod<
+ /*desc=*/[{
+ Attribute deserialization / attribute factory: Convert raw storage bytes
+ into an MLIR attribute. The size of `rawData` is
+ "ceilDiv(getDenseElementBitSize(), 8)".
+ }],
+ /*retTy=*/"::mlir::Attribute",
+ /*methodName=*/"convertToAttribute",
+ /*args=*/(ins "::llvm::ArrayRef<char>":$rawData)
+ >,
+ InterfaceMethod<
+ /*desc=*/[{
+ Attribute serialization: Convert an MLIR attribute into raw bytes.
+ Implementations must append "getDenseElementBitSize() / 8" values to
+ `result`. Return "failure" if the attribute is incompatible with this
+ element type.
+ }],
+ /*retTy=*/"::llvm::LogicalResult",
+ /*methodName=*/"convertFromAttribute",
+ /*args=*/(ins "::mlir::Attribute":$attr,
+ "::llvm::SmallVectorImpl<char>&":$result)
+ >,
+ ];
+}
+
//===----------------------------------------------------------------------===//
// FloatTypeInterface
//===----------------------------------------------------------------------===//
def FloatTypeInterface : TypeInterface<"FloatType",
- [VectorElementTypeInterface]> {
+ [DenseElementTypeInterface, VectorElementTypeInterface]> {
let cppNamespace = "::mlir";
let description = [{
This type interface should be implemented by all floating-point types. It
@@ -83,6 +141,21 @@ def FloatTypeInterface : TypeInterface<"FloatType",
/// The width includes the integer bit.
unsigned getFPMantissaWidth();
}];
+
+ let extraTraitClassDeclaration = [{
+ /// DenseElementTypeInterface implementations for float types.
+ size_t getDenseElementBitSize() const {
+ return ::mlir::detail::getFloatTypeDenseElementBitSize($_type);
+ }
+ ::mlir::Attribute convertToAttribute(::llvm::ArrayRef<char> rawData) const {
+ return ::mlir::detail::convertFloatTypeToAttribute($_type, rawData);
+ }
+ ::llvm::LogicalResult
+ convertFromAttribute(::mlir::Attribute attr,
+ ::llvm::SmallVectorImpl<char> &result) const {
+ return ::mlir::detail::convertFloatTypeFromAttribute($_type, attr, result);
+ }
+ }];
}
//===----------------------------------------------------------------------===//
diff --git a/mlir/include/mlir/IR/BuiltinTypes.td b/mlir/include/mlir/IR/BuiltinTypes.td
index 806064faeda00..e7d0a03a85e7d 100644
--- a/mlir/include/mlir/IR/BuiltinTypes.td
+++ b/mlir/include/mlir/IR/BuiltinTypes.td
@@ -45,7 +45,10 @@ def ValueSemantics : NativeTypeTrait<"ValueSemantics"> {
// ComplexType
//===----------------------------------------------------------------------===//
-def Builtin_Complex : Builtin_Type<"Complex", "complex"> {
+def Builtin_Complex : Builtin_Type<"Complex", "complex",
+ [DeclareTypeInterfaceMethods<DenseElementTypeInterface,
+ ["getDenseElementBitSize", "convertToAttribute", "convertFromAttribute"]>
+ ]> {
let summary = "Complex number with a parameterized element type";
let description = [{
Syntax:
@@ -560,7 +563,9 @@ def Builtin_Graph : Builtin_FunctionLike<"Graph", "graph">;
//===----------------------------------------------------------------------===//
def Builtin_Index : Builtin_Type<"Index", "index",
- [VectorElementTypeInterface]> {
+ [DeclareTypeInterfaceMethods<DenseElementTypeInterface,
+ ["getDenseElementBitSize", "convertToAttribute", "convertFromAttribute"]>,
+ VectorElementTypeInterface]> {
let summary = "Integer-like type with unknown platform-dependent bit width";
let description = [{
Syntax:
@@ -591,7 +596,10 @@ def Builtin_Index : Builtin_Type<"Index", "index",
//===----------------------------------------------------------------------===//
def Builtin_Integer : Builtin_Type<"Integer", "integer",
- [VectorElementTypeInterface, QuantStorageTypeInterface]> {
+ [VectorElementTypeInterface, QuantStorageTypeInterface,
+ DeclareTypeInterfaceMethods<DenseElementTypeInterface, [
+ "getDenseElementBitSize", "convertToAttribute",
+ "convertFromAttribute"]>]> {
let summary = "Integer type with arbitrary precision up to a fixed limit";
let description = [{
Syntax:
diff --git a/mlir/lib/AsmParser/AttributeParser.cpp b/mlir/lib/AsmParser/AttributeParser.cpp
index 5978a11d06bc9..dc9744a42b730 100644
--- a/mlir/lib/AsmParser/AttributeParser.cpp
+++ b/mlir/lib/AsmParser/AttributeParser.cpp
@@ -16,6 +16,7 @@
#include "mlir/IR/AffineMap.h"
#include "mlir/IR/BuiltinAttributes.h"
#include "mlir/IR/BuiltinDialect.h"
+#include "mlir/IR/BuiltinTypeInterfaces.h"
#include "mlir/IR/BuiltinTypes.h"
#include "mlir/IR/DialectResourceBlobManager.h"
#include "mlir/IR/IntegerSet.h"
@@ -953,6 +954,119 @@ Attribute Parser::parseDenseArrayAttr(Type attrType) {
return eltParser.getAttr();
}
+/// Try to parse a dense elements attribute with the type-first syntax.
+/// Syntax: dense<TYPE : [ATTR, ATTR, ...]>
+/// This syntax is used for types other than int, float, index and complex.
+///
+/// Returns:
+/// - "null" attribute if this is not the type-first syntax.
+/// - "failure" in case of a parse error.
+/// - A valid Attribute otherwise.
+static FailureOr<Attribute> parseDenseElementsAttrTyped(Parser &p, SMLoc loc) {
+ // Skip l_paren because "parseType" would try to parse it as a tuple/function
+ // type, but '(' starts a complex literal like in the literal-first syntax.
+ if (p.getToken().is(Token::l_paren))
+ return Attribute();
+
+ // Parse type and valdiate that it's a shaped type.
+ auto typeLoc = p.getToken().getLoc();
+ Type type;
+ OptionalParseResult typeResult = p.parseOptionalType(type);
+ if (!typeResult.has_value())
+ return Attribute(); // Not type-first syntax.
+ if (failed(*typeResult))
+ return failure(); // Type parse error.
+
+ auto shapedType = dyn_cast<ShapedType>(type);
+ if (!shapedType) {
+ p.emitError(typeLoc, "expected a shaped type for dense elements");
+ return failure();
+ }
+ if (!shapedType.hasStaticShape()) {
+ p.emitError(typeLoc, "dense elements type must have static shape");
+ return failure();
+ }
+
+ // Check that the element type implements DenseElementTypeInterface.
+ auto denseEltType = dyn_cast<DenseElementType>(shapedType.getElementType());
+ if (!denseEltType) {
+ p.emitError(typeLoc,
+ "element type must implement DenseElementTypeInterface "
+ "for type-first dense syntax");
+ return failure();
+ }
+
+ // Parse colon.
+ if (p.parseToken(Token::colon, "expected ':' after type in dense attribute"))
+ return failure();
+
+ // Parse the element attributes and convert to raw bytes.
+ SmallVector<char> rawData;
+
+ // Helper to parse a single element.
+ auto parseSingleElement = [&]() -> ParseResult {
+ Attribute elemAttr = p.parseAttribute();
+ if (!elemAttr)
+ return failure();
+ if (failed(denseEltType.convertFromAttribute(elemAttr, rawData))) {
+ p.emitError("incompatible attribute for element type");
+ return failure();
+ }
+ return success();
+ };
+
+ // Recursively parse elements matching the expected shape.
+ std::function<ParseResult(ArrayRef<int64_t>)> parseElements;
+ parseElements = [&](ArrayRef<int64_t> remainingShape) -> ParseResult {
+ // Leaf: parse a single element.
+ if (remainingShape.empty())
+ return parseSingleElement();
+
+ // Non-leaf: expect a list with the correct number of elements.
+ int64_t expectedCount = remainingShape.front();
+ ArrayRef<int64_t> innerShape = remainingShape.drop_front();
+ int64_t actualCount = 0;
+
+ auto parseOne = [&]() -> ParseResult {
+ if (parseElements(innerShape))
+ return failure();
+ ++actualCount;
+ return success();
+ };
+
+ if (p.parseCommaSeparatedList(Parser::Delimiter::Square, parseOne))
+ return failure();
+
+ if (actualCount != expectedCount) {
+ p.emitError() << "expected " << expectedCount
+ << " elements in dimension, got " << actualCount;
+ return failure();
+ }
+ return success();
+ };
+
+ // Parse elements.
+ if (!p.getToken().is(Token::l_square)) {
+ // Single element - parse as splat.
+ if (parseSingleElement())
+ return failure();
+ } else if (shapedType.getShape().empty()) {
+ // Scalar type shouldn't have a list.
+ p.emitError(loc, "expected single element for scalar type, got list");
+ return failure();
+ } else {
+ // Parse structured literal matching the shape.
+ if (parseElements(shapedType.getShape()))
+ return failure();
+ }
+
+ if (p.parseToken(Token::greater, "expected '>' to close dense attribute"))
+ return failure();
+
+ // Create the attribute from raw buffer.
+ return DenseElementsAttr::getFromRawBuffer(shapedType, rawData);
+}
+
/// Parse a dense elements attribute.
Attribute Parser::parseDenseElementsAttr(Type attrType) {
auto attribLoc = getToken().getLoc();
@@ -960,7 +1074,16 @@ Attribute Parser::parseDenseElementsAttr(Type attrType) {
if (parseToken(Token::less, "expected '<' after 'dense'"))
return nullptr;
- // Parse the literal data if necessary.
+ // Try to parse the type-first syntax: dense<TYPE : [ATTR, ...]>
+ FailureOr<Attribute> typedResult =
+ parseDenseElementsAttrTyped(*this, attribLoc);
+ if (failed(typedResult))
+ return nullptr;
+ if (*typedResult)
+ return *typedResult;
+
+ // Try to parse the literal-first syntax, which is the default format for
+ // int, float, index and complex element types.
TensorLiteralParser literalParser(*this);
if (!consumeIf(Token::greater)) {
if (literalParser.parse(/*allowHex=*/true) ||
diff --git a/mlir/lib/IR/AsmPrinter.cpp b/mlir/lib/IR/AsmPrinter.cpp
index 81455699421cc..b3242f838fc1d 100644
--- a/mlir/lib/IR/AsmPrinter.cpp
+++ b/mlir/lib/IR/AsmPrinter.cpp
@@ -507,11 +507,18 @@ class AsmPrinter::Impl {
/// Print a dense string elements attribute.
void printDenseStringElementsAttr(DenseStringElementsAttr attr);
- /// Print a dense elements attribute. If 'allowHex' is true, a hex string is
- /// used instead of individual elements when the elements attr is large.
+ /// Print a dense elements attribute in the literal-first syntax. If
+ /// 'allowHex' is true, a hex string is used instead of individual elements
+ /// when the elements attr is large.
void printDenseIntOrFPElementsAttr(DenseIntOrFPElementsAttr attr,
bool allowHex);
+ /// Print a dense elements attribute using the type-first syntax and the
+ /// DenseElementTypeInterface, which provides the attribute printer for each
+ /// element.
+ void printTypeFirstDenseElementsAttr(DenseElementsAttr attr,
+ DenseElementType denseEltType);
+
/// Print a dense array attribute.
void printDenseArrayAttr(DenseArrayAttr attr);
@@ -2507,7 +2514,17 @@ void AsmPrinter::Impl::printAttributeImpl(Attribute attr,
printElidedElementsAttr(os);
} else {
os << "dense<";
- printDenseIntOrFPElementsAttr(intOrFpEltAttr, /*allowHex=*/true);
+ // Check if the element type implements DenseElementTypeInterface and is
+ // not a built-in type. Built-in types (int, float, index, complex) use
+ // the existing printing format for backwards compatibility.
+ Type eltType = intOrFpEltAttr.getElementType();
+ if (isa<FloatType, IntegerType, IndexType, ComplexType>(eltType)) {
+ printDenseIntOrFPElementsAttr(intOrFpEltAttr, /*allowHex=*/true);
+ } else {
+ printTypeFirstDenseElementsAttr(intOrFpEltAttr,
+ cast<DenseElementType>(eltType));
+ typeElision = AttrTypeElision::Must;
+ }
os << '>';
}
@@ -2705,6 +2722,27 @@ void AsmPrinter::Impl::printDenseStringElementsAttr(
printDenseElementsAttrImpl(attr.isSplat(), attr.getType(), os, printFn);
}
+void AsmPrinter::Impl::printTypeFirstDenseElementsAttr(
+ DenseElementsAttr attr, DenseElementType denseEltType) {
+ // Print the type first: dense<TYPE : [ELEMENTS]>
+ printType(attr.getType());
+ os << " : ";
+
+ ArrayRef<char> rawData = attr.getRawData();
+ // Storage is byte-aligned: align bit size up to next byte boundary.
+ size_t bitSize = denseEltType.getDenseElementBitSize();
+ size_t byteSize = llvm::divideCeil(bitSize, static_cast<size_t>(CHAR_BIT));
+
+ // Print elements: convert raw bytes to attribute, then print attribute.
+ printDenseElementsAttrImpl(
+ attr.isSplat(), attr.getType(), os, [&](unsigned index) {
+ size_t offset = attr.isSplat() ? 0 : index * byteSize;
+ ArrayRef<char> elemData = rawData.slice(offset, byteSize);
+ Attribute elemAttr = denseEltType.convertToAttribute(elemData);
+ printAttributeImpl(elemAttr);
+ });
+}
+
void AsmPrinter::Impl::printDenseArrayAttr(DenseArrayAttr attr) {
Type type = attr.getElementType();
unsigned bitwidth = type.isInteger(1) ? 8 : type.getIntOrFloatBitWidth();
diff --git a/mlir/lib/IR/AttributeDetail.h b/mlir/lib/IR/AttributeDetail.h
index 1f268603cf37f..8505149afdd9c 100644
--- a/mlir/lib/IR/AttributeDetail.h
+++ b/mlir/lib/IR/AttributeDetail.h
@@ -16,6 +16,7 @@
#include "mlir/IR/AffineMap.h"
#include "mlir/IR/AttributeSupport.h"
#include "mlir/IR/BuiltinAttributes.h"
+#include "mlir/IR/BuiltinTypeInterfaces.h"
#include "mlir/IR/BuiltinTypes.h"
#include "mlir/IR/IntegerSet.h"
#include "mlir/IR/MLIRContext.h"
@@ -32,12 +33,9 @@ namespace detail {
/// Return the bit width which DenseElementsAttr should use for this type.
inline size_t getDenseElementBitWidth(Type eltType) {
- // Align the width for complex to 8 to make storage and interpretation easier.
- if (ComplexType comp = llvm::dyn_cast<ComplexType>(eltType))
- return llvm::alignTo<8>(getDenseElementBitWidth(comp.getElementType())) * 2;
- if (eltType.isIndex())
- return IndexType::kInternalStorageBitWidth;
- return eltType.getIntOrFloatBitWidth();
+ if (auto denseEltType = llvm::dyn_cast<DenseElementType>(eltType))
+ return denseEltType.getDenseElementBitSize();
+ llvm_unreachable("unsupported element type");
}
/// An attribute representing a reference to a dense vector or tensor object.
diff --git a/mlir/lib/IR/BuiltinAttributes.cpp b/mlir/lib/IR/BuiltinAttributes.cpp
index 1a29fc534b40f..bbbc9198a68ab 100644
--- a/mlir/lib/IR/BuiltinAttributes.cpp
+++ b/mlir/lib/IR/BuiltinAttributes.cpp
@@ -10,6 +10,7 @@
#include "AttributeDetail.h"
#include "mlir/IR/AffineMap.h"
#include "mlir/IR/BuiltinDialect.h"
+#include "mlir/IR/BuiltinTypeInterfaces.h"
#include "mlir/IR/Dialect.h"
#include "mlir/IR/DialectResourceBlobManager.h"
#include "mlir/IR/IntegerSet.h"
@@ -527,7 +528,7 @@ static void copyArrayToAPIntForBEmachine(const char *inArray, size_t numBytes,
}
/// Writes value to the bit position `bitPos` in array `rawData`.
-static void writeBits(char *rawData, size_t bitPos, APInt value) {
+void mlir::detail::writeBits(char *rawData, size_t bitPos, APInt value) {
size_t bitWidth = value.getBitWidth();
// The bit position is guaranteed to be byte aligned.
@@ -549,7 +550,8 @@ static void writeBits(char *rawData, size_t bitPos, APInt value) {
/// Reads the next `bitWidth` bits from the bit position `bitPos` in array
/// `rawData`.
-static APInt readBits(const char *rawData, size_t bitPos, size_t bitWidth) {
+APInt mlir::detail::readBits(const char *rawData, size_t bitPos,
+ size_t bitWidth) {
// The bit position is guaranteed to be byte aligned.
assert((bitPos % CHAR_BIT) == 0 && "expected bitPos to be 8-bit aligned");
APInt result(bitWidth, 0);
@@ -595,39 +597,21 @@ DenseElementsAttr::AttributeElementIterator::AttributeElementIterator(
Attribute DenseElementsAttr::AttributeElementIterator::operator*() const {
auto owner = llvm::cast<DenseElementsAttr>(getFromOpaquePointer(base));
Type eltTy = owner.getElementType();
- if (llvm::dyn_cast<IntegerType>(eltTy))
- return IntegerAttr::get(eltTy, *IntElementIterator(owner, index));
- if (llvm::isa<IndexType>(eltTy))
- return IntegerAttr::get(eltTy, *IntElementIterator(owner, index));
- if (auto floatEltTy = llvm::dyn_cast<FloatType>(eltTy)) {
- IntElementIterator intIt(owner, index);
- FloatElementIterator floatIt(floatEltTy.getFloatSemantics(), intIt);
- return FloatAttr::get(eltTy, *floatIt);
- }
- if (auto complexTy = llvm::dyn_cast<ComplexType>(eltTy)) {
- auto complexEltTy = complexTy.getElementType();
- ComplexIntElementIterator complexIntIt(owner, index);
- if (llvm::isa<IntegerType>(complexEltTy)) {
- auto value = *complexIntIt;
- auto real = IntegerAttr::get(complexEltTy, value.real());
- auto imag = IntegerAttr::get(complexEltTy, value.imag());
- return ArrayAttr::get(complexTy.getContext(),
- ArrayRef<Attribute>{real, imag});
- }
- ComplexFloatElementIterator complexFloatIt(
- llvm::cast<FloatType>(complexEltTy).getFloatSemantics(), complexIntIt);
- auto value = *complexFloatIt;
- auto real = FloatAttr::get(complexEltTy, value.real());
- auto imag = FloatAttr::get(complexEltTy, value.imag());
- return ArrayAttr::get(complexTy.getContext(),
- ArrayRef<Attribute>{real, imag});
- }
+ // Handle strings specially.
if (llvm::isa<DenseStringElementsAttr>(owner)) {
ArrayRef<StringRef> vals = owner.getRawStringData();
return StringAttr::get(owner.isSplat() ? vals.front() : vals[index], eltTy);
}
- llvm_unreachable("unexpected element type");
+
+ // All other types should implement DenseElementTypeInterface.
+ auto denseEltTy = llvm::cast<DenseElementType>(eltTy);
+ ArrayRef<char> rawData = owner.getRawData();
+ // Storage is byte-aligned: align bit size up to next byte boundary.
+ size_t bitSize = denseEltTy.getDenseElementBitSize();
+ size_t byteSize = llvm::divideCeil(bitSize, CHAR_BIT);
+ size_t offset = owner.isSplat() ? 0 : index * byteSize;
+ return denseEltTy.convertToAttribute(rawData.slice(offset, byteSize));
}
//===----------------------------------------------------------------------===//
@@ -888,79 +872,28 @@ DenseElementsAttr DenseElementsAttr::get(ShapedType type,
assert(hasSameNumElementsOrSplat(type, values));
Type eltType = type.getElementType();
- // Take care complex type case first.
- if (auto complexType = llvm::dyn_cast<ComplexType>(eltType)) {
- if (complexType.getElementType().isIntOrIndex()) {
- SmallVector<std::complex<APInt>> complexValues;
- complexValues.reserve(values.size());
- for (Attribute attr : values) {
- assert(llvm::isa<ArrayAttr>(attr) && "expected ArrayAttr for complex");
- auto arrayAttr = llvm::cast<ArrayAttr>(attr);
- assert(arrayAttr.size() == 2 && "expected 2 element for complex");
- auto attr0 = arrayAttr[0];
- auto attr1 = arrayAttr[1];
- complexValues.push_back(
- std::complex<APInt>(llvm::cast<IntegerAttr>(attr0).getValue(),
- llvm::cast<IntegerAttr>(attr1).getValue()));
- }
- return DenseElementsAttr::get(type, complexValues);
- }
- // Must be float.
- SmallVector<std::complex<APFloat>> complexValues;
- complexValues.reserve(values.size());
- for (Attribute attr : values) {
- assert(llvm::isa<ArrayAttr>(attr) && "expected ArrayAttr for complex");
- auto arrayAttr = llvm::cast<ArrayAttr>(attr);
- assert(arrayAttr.size() == 2 && "expected 2 element for complex");
- auto attr0 = arrayAttr[0];
- auto attr1 = arrayAttr[1];
- complexValues.push_back(
- std::complex<APFloat>(llvm::cast<FloatAttr>(attr0).getValue(),
- llvm::cast<FloatAttr>(attr1).getValue()));
- }
- return DenseElementsAttr::get(type, complexValues);
- }
-
- // If the element type is not based on int/float/index, assume it is a string
- // type.
- if (!eltType.isIntOrIndexOrFloat()) {
+ // Handle strings specially.
+ if (!llvm::isa<DenseElementType>(eltType)) {
SmallVector<StringRef, 8> stringValues;
stringValues.reserve(values.size());
for (Attribute attr : values) {
assert(llvm::isa<StringAttr>(attr) &&
- "expected string value for non integer/index/float element");
+ "expected string value for non-DenseElementType element");
stringValues.push_back(llvm::cast<StringAttr>(attr).getValue());
}
return get(type, stringValues);
}
- // Otherwise, get the raw storage width to use for the allocation.
- size_t bitWidth = getDenseElementBitWidth(eltType);
- size_t storageBitWidth = getDenseElementStorageWidth(bitWidth);
-
- // Compress the attribute values into a character buffer.
- SmallVector<char, 8> data(
- llvm::divideCeil(storageBitWidth * values.size(), CHAR_BIT));
- APInt intVal;
- for (unsigned i = 0, e = values.size(); i < e; ++i) {
- if (auto floatAttr = llvm::dyn_cast<FloatAttr>(values[i])) {
- assert(floatAttr.getType() == eltType &&
- "expected float attribute type to equal element type");
- intVal = floatAttr.getValue().bitcastToAPInt();
- } else if (auto intAttr = llvm::dyn_cast<IntegerAttr>(values[i])) {
- assert(intAttr.getType() == eltType &&
- "expected integer attribute type to equal element type");
- intVal = intAttr.getValue();
- } else {
- // Unsupported attribute type.
+ // All other types go through DenseElementTypeInterface.
+ auto denseEltType = llvm::dyn_cast<DenseElementType>(eltType);
+ assert(denseEltType &&
+ "attempted to get DenseElementsAttr with unsupported element type");
+ SmallVector<char> data;
+ for (Attribute attr : values) {
+ LogicalResult result = denseEltType.convertFromAttribute(attr, data);
+ if (failed(result))
return {};
- }
-
- assert(intVal.getBitWidth() == bitWidth &&
- "expected value to have same bitwidth as element type");
- writeBits(data.data(), i * storageBitWidth, intVal);
}
-
return DenseIntOrFPElementsAttr::getRaw(type, data);
}
diff --git a/mlir/lib/IR/BuiltinTypeInterfaces.cpp b/mlir/lib/IR/BuiltinTypeInterfaces.cpp
index 2f063be3e7cd0..29303d95eb003 100644
--- a/mlir/lib/IR/BuiltinTypeInterfaces.cpp
+++ b/mlir/lib/IR/BuiltinTypeInterfaces.cpp
@@ -6,9 +6,12 @@
//
//===----------------------------------------------------------------------===//
+#include "mlir/IR/BuiltinAttributes.h"
#include "mlir/IR/BuiltinTypes.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/Support/CheckedArithmetic.h"
+#include "llvm/Support/MathExtras.h"
+#include <climits>
using namespace mlir;
using namespace mlir::detail;
@@ -19,6 +22,37 @@ using namespace mlir::detail;
#include "mlir/IR/BuiltinTypeInterfaces.cpp.inc"
+//===----------------------------------------------------------------------===//
+// DenseElementTypeInterface implementations for float types
+//===----------------------------------------------------------------------===//
+
+size_t mlir::detail::getFloatTypeDenseElementBitSize(Type type) {
+ return cast<FloatType>(type).getWidth();
+}
+
+Attribute mlir::detail::convertFloatTypeToAttribute(Type type,
+ ArrayRef<char> rawData) {
+ auto floatType = cast<FloatType>(type);
+ APInt intVal = readBits(rawData.data(), /*bitPos=*/0, floatType.getWidth());
+ APFloat floatVal(floatType.getFloatSemantics(), intVal);
+ return FloatAttr::get(type, floatVal);
+}
+
+LogicalResult
+mlir::detail::convertFloatTypeFromAttribute(Type type, Attribute attr,
+ SmallVectorImpl<char> &result) {
+ auto floatType = cast<FloatType>(type);
+ auto floatAttr = dyn_cast<FloatAttr>(attr);
+ if (!floatAttr || floatAttr.getType() != type)
+ return failure();
+ size_t byteSize =
+ llvm::divideCeil(floatType.getWidth(), static_cast<unsigned>(CHAR_BIT));
+ size_t bitPos = result.size() * CHAR_BIT;
+ result.resize(result.size() + byteSize);
+ writeBits(result.data(), bitPos, floatAttr.getValue().bitcastToAPInt());
+ return success();
+}
+
//===----------------------------------------------------------------------===//
// FloatType
//===----------------------------------------------------------------------===//
diff --git a/mlir/lib/IR/BuiltinTypes.cpp b/mlir/lib/IR/BuiltinTypes.cpp
index 1e198043c590a..786c30851a071 100644
--- a/mlir/lib/IR/BuiltinTypes.cpp
+++ b/mlir/lib/IR/BuiltinTypes.cpp
@@ -12,14 +12,17 @@
#include "mlir/IR/AffineMap.h"
#include "mlir/IR/BuiltinAttributes.h"
#include "mlir/IR/BuiltinDialect.h"
+#include "mlir/IR/BuiltinTypeInterfaces.h"
#include "mlir/IR/Diagnostics.h"
#include "mlir/IR/Dialect.h"
#include "mlir/IR/TensorEncoding.h"
#include "mlir/IR/TypeUtilities.h"
#include "llvm/ADT/APFloat.h"
+#include "llvm/ADT/APInt.h"
#include "llvm/ADT/Sequence.h"
#include "llvm/ADT/TypeSwitch.h"
#include "llvm/Support/CheckedArithmetic.h"
+#include <cstring>
using namespace mlir;
using namespace mlir::detail;
@@ -58,6 +61,39 @@ LogicalResult ComplexType::verify(function_ref<InFlightDiagnostic()> emitError,
return success();
}
+size_t ComplexType::getDenseElementBitSize() const {
+ auto elemTy = cast<DenseElementType>(getElementType());
+ return llvm::alignTo<8>(elemTy.getDenseElementBitSize()) * 2;
+}
+
+Attribute ComplexType::convertToAttribute(ArrayRef<char> rawData) const {
+ auto elemTy = cast<DenseElementType>(getElementType());
+ size_t singleElementBytes =
+ llvm::alignTo<8>(elemTy.getDenseElementBitSize()) / 8;
+ Attribute real =
+ elemTy.convertToAttribute(rawData.take_front(singleElementBytes));
+ Attribute imag =
+ elemTy.convertToAttribute(rawData.take_back(singleElementBytes));
+ return ArrayAttr::get(getContext(), {real, imag});
+}
+
+LogicalResult
+ComplexType::convertFromAttribute(Attribute attr,
+ SmallVectorImpl<char> &result) const {
+ auto arrayAttr = dyn_cast<ArrayAttr>(attr);
+ if (!arrayAttr || arrayAttr.size() != 2)
+ return failure();
+ auto elemTy = cast<DenseElementType>(getElementType());
+ SmallVector<char> realData, imagData;
+ if (failed(elemTy.convertFromAttribute(arrayAttr[0], realData)))
+ return failure();
+ if (failed(elemTy.convertFromAttribute(arrayAttr[1], imagData)))
+ return failure();
+ result.append(realData);
+ result.append(imagData);
+ return success();
+}
+
//===----------------------------------------------------------------------===//
// Integer Type
//===----------------------------------------------------------------------===//
@@ -85,6 +121,57 @@ IntegerType IntegerType::scaleElementBitwidth(unsigned scale) {
return IntegerType::get(getContext(), scale * getWidth(), getSignedness());
}
+size_t IntegerType::getDenseElementBitSize() const {
+ // Return the actual bit width. Storage alignment is handled separately.
+ return getWidth();
+}
+
+Attribute IntegerType::convertToAttribute(ArrayRef<char> rawData) const {
+ APInt value = detail::readBits(rawData.data(), /*bitPos=*/0, getWidth());
+ return IntegerAttr::get(*this, value);
+}
+
+static void writeAPIntToVector(APInt apInt, SmallVectorImpl<char> &result) {
+ size_t byteSize = llvm::divideCeil(apInt.getBitWidth(), CHAR_BIT);
+ size_t bitPos = result.size() * CHAR_BIT;
+ result.resize(result.size() + byteSize);
+ detail::writeBits(result.data(), bitPos, apInt);
+}
+
+LogicalResult
+IntegerType::convertFromAttribute(Attribute attr,
+ SmallVectorImpl<char> &result) const {
+ auto intAttr = dyn_cast<IntegerAttr>(attr);
+ if (!intAttr || intAttr.getType() != *this)
+ return failure();
+ writeAPIntToVector(intAttr.getValue(), result);
+ return success();
+}
+
+//===----------------------------------------------------------------------===//
+// Index Type
+//===----------------------------------------------------------------------===//
+
+size_t IndexType::getDenseElementBitSize() const {
+ return kInternalStorageBitWidth;
+}
+
+Attribute IndexType::convertToAttribute(ArrayRef<char> rawData) const {
+ APInt value =
+ detail::readBits(rawData.data(), /*bitPos=*/0, kInternalStorageBitWidth);
+ return IntegerAttr::get(*this, value);
+}
+
+LogicalResult
+IndexType::convertFromAttribute(Attribute attr,
+ SmallVectorImpl<char> &result) const {
+ auto intAttr = dyn_cast<IntegerAttr>(attr);
+ if (!intAttr || intAttr.getType() != *this)
+ return failure();
+ writeAPIntToVector(intAttr.getValue(), result);
+ return success();
+}
+
//===----------------------------------------------------------------------===//
// Float Types
//===----------------------------------------------------------------------===//
diff --git a/mlir/test/IR/dense-elements-type-interface.mlir b/mlir/test/IR/dense-elements-type-interface.mlir
new file mode 100644
index 0000000000000..8749e562087c2
--- /dev/null
+++ b/mlir/test/IR/dense-elements-type-interface.mlir
@@ -0,0 +1,83 @@
+// RUN: mlir-opt %s -verify-diagnostics -split-input-file | FileCheck %s
+
+// Test dense elements attribute with custom element type using DenseElementTypeInterface.
+// Uses the new type-first syntax: dense<TYPE : [ATTR, ...]>
+// Note: The type is embedded in the attribute, so it's not printed again at the end.
+
+// CHECK-LABEL: func @dense_custom_element_type
+func.func @dense_custom_element_type() {
+ // CHECK: "test.dummy"() {attr = dense<tensor<3x!test.dense_element> : [1 : i32, 2 : i32, 3 : i32]>}
+ "test.dummy"() {attr = dense<tensor<3x!test.dense_element> : [1 : i32, 2 : i32, 3 : i32]>} : () -> ()
+ return
+}
+
+// -----
+
+// CHECK-LABEL: func @dense_custom_element_type_2d
+func.func @dense_custom_element_type_2d() {
+ // CHECK: "test.dummy"() {attr = dense<tensor<2x2x!test.dense_element> : {{\[}}{{\[}}1 : i32, 2 : i32], [3 : i32, 4 : i32]]>}
+ "test.dummy"() {attr = dense<tensor<2x2x!test.dense_element> : [[1 : i32, 2 : i32], [3 : i32, 4 : i32]]>} : () -> ()
+ return
+}
+
+// -----
+
+// CHECK-LABEL: func @dense_custom_element_splat
+func.func @dense_custom_element_splat() {
+ // CHECK: "test.dummy"() {attr = dense<tensor<4x!test.dense_element> : 42 : i32>}
+ "test.dummy"() {attr = dense<tensor<4x!test.dense_element> : 42 : i32>} : () -> ()
+ return
+}
+
+// -----
+
+// CHECK-LABEL func @dense_i32_1d
+func.func @dense_i32_1d() {
+ // The default assembly format for int, index, float, complex element types is
+ // the literal-first syntax. Such a dense elements attribute can be parsed
+ // with the type-first syntax, but it will come back with the literal-first
+ // syntax.
+ // CHECK: "test.dummy"() {attr = dense<[1, 2, 3]> : tensor<3xi32>} : () -> ()
+ "test.dummy"() {attr = dense<tensor<3xi32> : [1 : i32, 2 : i32, 3 : i32]>} : () -> ()
+ return
+}
+
+// -----
+
+func.func @invalid_element() {
+ // expected-error @+1 {{expected attribute value}}
+ "test.dummy"() {attr = dense<tensor<3xi32> : [foo]>} : () -> ()
+ return
+}
+
+// -----
+
+func.func @incompatible_attribute() {
+ // expected-error @+1 {{incompatible attribute for element type}}
+ "test.dummy"() {attr = dense<tensor<3xi32> : ["foo"]>} : () -> ()
+ return
+}
+
+// -----
+
+func.func @shape_mismatch() {
+ // expected-error @+1 {{expected 3 elements in dimension, got 2}}
+ "test.dummy"() {attr = dense<tensor<3xi32> : [1 : i32, 2 : i32]>} : () -> ()
+ return
+}
+
+// -----
+
+func.func @dynamic_shape() {
+ // expected-error @+1 {{dense elements type must have static shape}}
+ "test.dummy"() {attr = dense<tensor<?xi32> : [1 : i32, 2 : i32, 3 : i32]>} : () -> ()
+ return
+}
+
+// -----
+
+func.func @invalid_type() {
+ // expected-error @+1 {{expected a shaped type for dense elements}}
+ "test.dummy"() {attr = dense<i32 : [1 : i32, 2 : i32, 3 : i32]>} : () -> ()
+ return
+}
diff --git a/mlir/test/lib/Dialect/Test/TestTypeDefs.td b/mlir/test/lib/Dialect/Test/TestTypeDefs.td
index 964792ceebc07..08600ce713a17 100644
--- a/mlir/test/lib/Dialect/Test/TestTypeDefs.td
+++ b/mlir/test/lib/Dialect/Test/TestTypeDefs.td
@@ -18,6 +18,7 @@ include "TestDialect.td"
include "TestAttrDefs.td"
include "TestInterfaces.td"
include "mlir/IR/BuiltinTypes.td"
+include "mlir/IR/BuiltinTypeInterfaces.td"
include "mlir/Interfaces/DataLayoutInterfaces.td"
include "mlir/Dialect/Bufferization/IR/BufferizationTypeInterfaces.td"
@@ -512,4 +513,15 @@ def TestTypeNewlineAndIndent : Test_Type<"TestTypeNewlineAndIndent"> {
let hasCustomAssemblyFormat = 1;
}
+def TestTypeDenseElement : Test_Type<"TestDenseElement",
+ [DeclareTypeInterfaceMethods<DenseElementTypeInterface,
+ ["getDenseElementBitSize", "convertToAttribute", "convertFromAttribute"]>
+ ]> {
+ let mnemonic = "dense_element";
+ let description = [{
+ A test type that implements DenseElementTypeInterface to test dense
+ elements with custom element types. Elements are stored as 32-bit integers.
+ }];
+}
+
#endif // TEST_TYPEDEFS
diff --git a/mlir/test/lib/Dialect/Test/TestTypes.cpp b/mlir/test/lib/Dialect/Test/TestTypes.cpp
index 71dd25b0093e0..ef3396fc4f610 100644
--- a/mlir/test/lib/Dialect/Test/TestTypes.cpp
+++ b/mlir/test/lib/Dialect/Test/TestTypes.cpp
@@ -15,6 +15,7 @@
#include "TestDialect.h"
#include "mlir/Dialect/LLVMIR/LLVMTypes.h"
#include "mlir/IR/Builders.h"
+#include "mlir/IR/BuiltinAttributes.h"
#include "mlir/IR/DialectImplementation.h"
#include "mlir/IR/ExtensibleDialect.h"
#include "mlir/IR/Types.h"
@@ -22,6 +23,7 @@
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/TypeSwitch.h"
#include "llvm/Support/TypeSize.h"
+#include <cstring>
#include <optional>
using namespace mlir;
@@ -605,3 +607,29 @@ void TestTypeNewlineAndIndentType::print(::mlir::AsmPrinter &printer) const {
printer.printNewline();
printer << ">";
}
+
+//===----------------------------------------------------------------------===//
+// TestDenseElementType - DenseElementTypeInterface Implementation
+//===----------------------------------------------------------------------===//
+
+// Elements are stored as 32-bit integers.
+size_t TestDenseElementType::getDenseElementBitSize() const { return 32; }
+
+Attribute
+TestDenseElementType::convertToAttribute(ArrayRef<char> rawData) const {
+ assert(rawData.size() == 4 && "expected 4 bytes for TestDenseElement");
+ int32_t value;
+ std::memcpy(&value, rawData.data(), sizeof(value));
+ return IntegerAttr::get(IntegerType::get(getContext(), 32), value);
+}
+
+LogicalResult TestDenseElementType::convertFromAttribute(
+ Attribute attr, SmallVectorImpl<char> &result) const {
+ auto intAttr = dyn_cast<IntegerAttr>(attr);
+ if (!intAttr || intAttr.getType().getIntOrFloatBitWidth() != 32)
+ return failure();
+ int32_t value = intAttr.getValue().getSExtValue();
+ result.append(reinterpret_cast<const char *>(&value),
+ reinterpret_cast<const char *>(&value) + sizeof(value));
+ return success();
+}
diff --git a/mlir/test/lib/Dialect/Test/TestTypes.h b/mlir/test/lib/Dialect/Test/TestTypes.h
index 6499a96f495d0..705fb86e9e9b3 100644
--- a/mlir/test/lib/Dialect/Test/TestTypes.h
+++ b/mlir/test/lib/Dialect/Test/TestTypes.h
@@ -19,6 +19,7 @@
#include "TestTraits.h"
#include "mlir/Dialect/Bufferization/IR/BufferizationTypeInterfaces.h"
+#include "mlir/IR/BuiltinTypeInterfaces.h"
#include "mlir/IR/Diagnostics.h"
#include "mlir/IR/Dialect.h"
#include "mlir/IR/DialectImplementation.h"
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