[llvm-branch-commits] [mlir] d789a23 - Revert "[mlir][IR] Generalize `DenseElementsAttr` to custom element types (#1…"

via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Mon Feb 16 07:48:24 PST 2026


Author: Matthias Springer
Date: 2026-02-16T17:48:21+02:00
New Revision: d789a2392b6d2bec6f5c26aeeb4cb48eade48682

URL: https://github.com/llvm/llvm-project/commit/d789a2392b6d2bec6f5c26aeeb4cb48eade48682
DIFF: https://github.com/llvm/llvm-project/commit/d789a2392b6d2bec6f5c26aeeb4cb48eade48682.diff

LOG: Revert "[mlir][IR] Generalize `DenseElementsAttr` to custom element types (#1…"

This reverts commit f13301084923ed131aaea7fbadb9307a76bb21f6.

Added: 
    

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: 
    mlir/test/IR/dense-elements-type-interface.mlir


################################################################################
diff  --git a/mlir/include/mlir/IR/BuiltinAttributes.td b/mlir/include/mlir/IR/BuiltinAttributes.td
index dced379d1f979..798d3c84f9618 100644
--- a/mlir/include/mlir/IR/BuiltinAttributes.td
+++ b/mlir/include/mlir/IR/BuiltinAttributes.td
@@ -239,48 +239,29 @@ def Builtin_DenseIntOrFPElementsAttr : Builtin_Attr<
     "DenseElementsAttr"
   > {
   let summary = "An Attribute containing a dense multi-dimensional array of "
-                "values";
+                "integer or floating-point values";
   let description = [{
-    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.
+    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`.
 
     Examples:
 
     ```
-    // Literal-first syntax: A splat tensor of integer values.
+    // A splat tensor of integer values.
     dense<10> : tensor<2xi32>
-
-    // Literal-first syntax: A tensor of 2 float32 elements.
+    // 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 9425d554b427c..5f14517d8dd71 100644
--- a/mlir/include/mlir/IR/BuiltinTypeInterfaces.h
+++ b/mlir/include/mlir/IR/BuiltinTypeInterfaces.h
@@ -19,29 +19,6 @@ 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 93c8c0694b467..9ef08b7020b99 100644
--- a/mlir/include/mlir/IR/BuiltinTypeInterfaces.td
+++ b/mlir/include/mlir/IR/BuiltinTypeInterfaces.td
@@ -41,70 +41,12 @@ 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",
-    [DenseElementTypeInterface, VectorElementTypeInterface]> {
+    [VectorElementTypeInterface]> {
   let cppNamespace = "::mlir";
   let description = [{
     This type interface should be implemented by all floating-point types. It
@@ -141,21 +83,6 @@ 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 e7d0a03a85e7d..806064faeda00 100644
--- a/mlir/include/mlir/IR/BuiltinTypes.td
+++ b/mlir/include/mlir/IR/BuiltinTypes.td
@@ -45,10 +45,7 @@ def ValueSemantics : NativeTypeTrait<"ValueSemantics"> {
 // ComplexType
 //===----------------------------------------------------------------------===//
 
-def Builtin_Complex : Builtin_Type<"Complex", "complex",
-    [DeclareTypeInterfaceMethods<DenseElementTypeInterface,
-      ["getDenseElementBitSize", "convertToAttribute", "convertFromAttribute"]>
-    ]> {
+def Builtin_Complex : Builtin_Type<"Complex", "complex"> {
   let summary = "Complex number with a parameterized element type";
   let description = [{
     Syntax:
@@ -563,9 +560,7 @@ def Builtin_Graph : Builtin_FunctionLike<"Graph", "graph">;
 //===----------------------------------------------------------------------===//
 
 def Builtin_Index : Builtin_Type<"Index", "index",
-    [DeclareTypeInterfaceMethods<DenseElementTypeInterface,
-      ["getDenseElementBitSize", "convertToAttribute", "convertFromAttribute"]>,
-     VectorElementTypeInterface]> {
+    [VectorElementTypeInterface]> {
   let summary = "Integer-like type with unknown platform-dependent bit width";
   let description = [{
     Syntax:
@@ -596,10 +591,7 @@ def Builtin_Index : Builtin_Type<"Index", "index",
 //===----------------------------------------------------------------------===//
 
 def Builtin_Integer : Builtin_Type<"Integer", "integer",
-    [VectorElementTypeInterface, QuantStorageTypeInterface,
-     DeclareTypeInterfaceMethods<DenseElementTypeInterface, [
-         "getDenseElementBitSize", "convertToAttribute",
-         "convertFromAttribute"]>]> {
+    [VectorElementTypeInterface, QuantStorageTypeInterface]> {
   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 dc9744a42b730..5978a11d06bc9 100644
--- a/mlir/lib/AsmParser/AttributeParser.cpp
+++ b/mlir/lib/AsmParser/AttributeParser.cpp
@@ -16,7 +16,6 @@
 #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"
@@ -954,119 +953,6 @@ 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();
@@ -1074,16 +960,7 @@ Attribute Parser::parseDenseElementsAttr(Type attrType) {
   if (parseToken(Token::less, "expected '<' after 'dense'"))
     return nullptr;
 
-  // 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.
+  // Parse the literal data if necessary.
   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 b3242f838fc1d..81455699421cc 100644
--- a/mlir/lib/IR/AsmPrinter.cpp
+++ b/mlir/lib/IR/AsmPrinter.cpp
@@ -507,18 +507,11 @@ class AsmPrinter::Impl {
   /// Print a dense string elements attribute.
   void printDenseStringElementsAttr(DenseStringElementsAttr attr);
 
-  /// 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.
+  /// Print a dense elements attribute. 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);
 
@@ -2514,17 +2507,7 @@ void AsmPrinter::Impl::printAttributeImpl(Attribute attr,
       printElidedElementsAttr(os);
     } else {
       os << "dense<";
-      // 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;
-      }
+      printDenseIntOrFPElementsAttr(intOrFpEltAttr, /*allowHex=*/true);
       os << '>';
     }
 
@@ -2722,27 +2705,6 @@ 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 8505149afdd9c..1f268603cf37f 100644
--- a/mlir/lib/IR/AttributeDetail.h
+++ b/mlir/lib/IR/AttributeDetail.h
@@ -16,7 +16,6 @@
 #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"
@@ -33,9 +32,12 @@ namespace detail {
 
 /// Return the bit width which DenseElementsAttr should use for this type.
 inline size_t getDenseElementBitWidth(Type eltType) {
-  if (auto denseEltType = llvm::dyn_cast<DenseElementType>(eltType))
-    return denseEltType.getDenseElementBitSize();
-  llvm_unreachable("unsupported element type");
+  // 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();
 }
 
 /// 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 bbbc9198a68ab..1a29fc534b40f 100644
--- a/mlir/lib/IR/BuiltinAttributes.cpp
+++ b/mlir/lib/IR/BuiltinAttributes.cpp
@@ -10,7 +10,6 @@
 #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"
@@ -528,7 +527,7 @@ static void copyArrayToAPIntForBEmachine(const char *inArray, size_t numBytes,
 }
 
 /// Writes value to the bit position `bitPos` in array `rawData`.
-void mlir::detail::writeBits(char *rawData, size_t bitPos, APInt value) {
+static void writeBits(char *rawData, size_t bitPos, APInt value) {
   size_t bitWidth = value.getBitWidth();
 
   // The bit position is guaranteed to be byte aligned.
@@ -550,8 +549,7 @@ void mlir::detail::writeBits(char *rawData, size_t bitPos, APInt value) {
 
 /// Reads the next `bitWidth` bits from the bit position `bitPos` in array
 /// `rawData`.
-APInt mlir::detail::readBits(const char *rawData, size_t bitPos,
-                             size_t bitWidth) {
+static APInt 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);
@@ -597,21 +595,39 @@ 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});
+    }
 
-  // Handle strings specially.
+    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});
+  }
   if (llvm::isa<DenseStringElementsAttr>(owner)) {
     ArrayRef<StringRef> vals = owner.getRawStringData();
     return StringAttr::get(owner.isSplat() ? vals.front() : vals[index], eltTy);
   }
-
-  // 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));
+  llvm_unreachable("unexpected element type");
 }
 
 //===----------------------------------------------------------------------===//
@@ -872,28 +888,79 @@ DenseElementsAttr DenseElementsAttr::get(ShapedType type,
   assert(hasSameNumElementsOrSplat(type, values));
   Type eltType = type.getElementType();
 
-  // Handle strings specially.
-  if (!llvm::isa<DenseElementType>(eltType)) {
+  // 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()) {
     SmallVector<StringRef, 8> stringValues;
     stringValues.reserve(values.size());
     for (Attribute attr : values) {
       assert(llvm::isa<StringAttr>(attr) &&
-             "expected string value for non-DenseElementType element");
+             "expected string value for non integer/index/float element");
       stringValues.push_back(llvm::cast<StringAttr>(attr).getValue());
     }
     return get(type, stringValues);
   }
 
-  // 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))
+  // 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.
       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 29303d95eb003..2f063be3e7cd0 100644
--- a/mlir/lib/IR/BuiltinTypeInterfaces.cpp
+++ b/mlir/lib/IR/BuiltinTypeInterfaces.cpp
@@ -6,12 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
-#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;
@@ -22,37 +19,6 @@ 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 786c30851a071..1e198043c590a 100644
--- a/mlir/lib/IR/BuiltinTypes.cpp
+++ b/mlir/lib/IR/BuiltinTypes.cpp
@@ -12,17 +12,14 @@
 #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;
@@ -61,39 +58,6 @@ 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
 //===----------------------------------------------------------------------===//
@@ -121,57 +85,6 @@ 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
deleted file mode 100644
index 8749e562087c2..0000000000000
--- a/mlir/test/IR/dense-elements-type-interface.mlir
+++ /dev/null
@@ -1,83 +0,0 @@
-// 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 08600ce713a17..964792ceebc07 100644
--- a/mlir/test/lib/Dialect/Test/TestTypeDefs.td
+++ b/mlir/test/lib/Dialect/Test/TestTypeDefs.td
@@ -18,7 +18,6 @@ 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"
 
@@ -513,15 +512,4 @@ 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 ef3396fc4f610..71dd25b0093e0 100644
--- a/mlir/test/lib/Dialect/Test/TestTypes.cpp
+++ b/mlir/test/lib/Dialect/Test/TestTypes.cpp
@@ -15,7 +15,6 @@
 #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"
@@ -23,7 +22,6 @@
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/TypeSwitch.h"
 #include "llvm/Support/TypeSize.h"
-#include <cstring>
 #include <optional>
 
 using namespace mlir;
@@ -607,29 +605,3 @@ 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 705fb86e9e9b3..6499a96f495d0 100644
--- a/mlir/test/lib/Dialect/Test/TestTypes.h
+++ b/mlir/test/lib/Dialect/Test/TestTypes.h
@@ -19,7 +19,6 @@
 
 #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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