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sergey-kozubsergey-kozub
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[MLIR] Add f6E3M2FN type (#105573).
`f6E3M2FN` type is proposed in [OpenCompute MX Specification](https://www.opencompute.org/documents/ocp-microscaling-formats-mx-v1-0-spec-final-pdf). It defines a 6-bit floating point number with bit layout S1E3M2. Unlike IEEE-754 types, there are no infinity or NaN values. ```c f6E3M2FN - Exponent bias: 3 - Maximum stored exponent value: 7 (binary 111) - Maximum unbiased exponent value: 7 - 3 = 4 - Minimum stored exponent value: 1 (binary 001) - Minimum unbiased exponent value: 1 − 3 = −2 - Has Positive and Negative zero - Doesn't have infinity - Doesn't have NaNs Additional details: - Zeros (+/-): S.000.00 - Max normal number: S.111.11 = ±2^(4) x (1 + 0.75) = ±28 - Min normal number: S.001.00 = ±2^(-2) = ±0.25 - Max subnormal number: S.000.11 = ±2^(-2) x 0.75 = ±0.1875 - Min subnormal number: S.000.01 = ±2^(-2) x 0.25 = ±0.0625 ``` Related PRs: - [PR-94735](#94735) [APFloat] Add APFloat support for FP6 data types - [PR-97118](#97118) [MLIR] Add f8E4M3 type - was used as a template for this PR
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‎llvm/unittests/ADT/APFloatTest.cpp

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@@ -2084,8 +2084,14 @@ TEST(APFloatTest, getSmallestNormalized) {
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EXPECT_FALSE(test.isDenormal());
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EXPECT_TRUE(test.bitwiseIsEqual(expected));
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EXPECT_TRUE(test.isSmallestNormalized());
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test = APFloat::getSmallestNormalized(APFloat::Float6E3M2FN(), false);
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expected = APFloat(APFloat::Float6E3M2FN(), "0x1p-2");
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EXPECT_FALSE(test.isNegative());
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EXPECT_TRUE(test.isFiniteNonZero());
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EXPECT_FALSE(test.isDenormal());
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EXPECT_TRUE(test.bitwiseIsEqual(expected));
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EXPECT_TRUE(test.isSmallestNormalized());
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test = APFloat::getSmallestNormalized(APFloat::Float4E2M1FN(), false);
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expected = APFloat(APFloat::Float4E2M1FN(), "0x1p0");

‎mlir/include/mlir-c/BuiltinTypes.h

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@@ -149,6 +149,16 @@ MLIR_CAPI_EXPORTED bool mlirTypeIsAFloat8E3M4(MlirType type);
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/// context.
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MLIR_CAPI_EXPORTED MlirType mlirFloat8E3M4TypeGet(MlirContext ctx);
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/// Returns the typeID of an Float6E3M2FN type.
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MLIR_CAPI_EXPORTED MlirTypeID mlirFloat6E3M2FNTypeGetTypeID(void);
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/// Checks whether the given type is an f6E3M2FN type.
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MLIR_CAPI_EXPORTED bool mlirTypeIsAFloat6E3M2FN(MlirType type);
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/// Creates an f8E3M2FN type in the given context. The type is owned by the
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/// context.
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MLIR_CAPI_EXPORTED MlirType mlirFloat6E3M2FNTypeGet(MlirContext ctx);
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/// Returns the typeID of an BFloat16 type.
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MLIR_CAPI_EXPORTED MlirTypeID mlirBFloat16TypeGetTypeID(void);
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‎mlir/include/mlir/IR/Builders.h

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@@ -67,6 +67,7 @@ class Builder {
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FloatType getFloat8E4M3FNUZType();
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FloatType getFloat8E4M3B11FNUZType();
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FloatType getFloat8E3M4Type();
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FloatType getFloat6E3M2FNType();
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FloatType getBF16Type();
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FloatType getF16Type();
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FloatType getTF32Type();

‎mlir/include/mlir/IR/BuiltinTypes.h

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@@ -67,6 +67,7 @@ class FloatType : public Type {
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static FloatType getFloat8E4M3FNUZ(MLIRContext *ctx);
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static FloatType getFloat8E4M3B11FNUZ(MLIRContext *ctx);
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static FloatType getFloat8E3M4(MLIRContext *ctx);
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static FloatType getFloat6E3M2FN(MLIRContext *ctx);
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/// Methods for support type inquiry through isa, cast, and dyn_cast.
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static bool classof(Type type);
@@ -415,9 +416,9 @@ inline bool BaseMemRefType::isValidElementType(Type type) {
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inline bool FloatType::classof(Type type) {
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return llvm::isa<Float8E5M2Type, Float8E4M3Type, Float8E4M3FNType,
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Float8E5M2FNUZType, Float8E4M3FNUZType,
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Float8E4M3B11FNUZType, Float8E3M4Type, BFloat16Type,
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Float16Type, FloatTF32Type, Float32Type, Float64Type,
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Float80Type, Float128Type>(type);
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Float8E4M3B11FNUZType, Float8E3M4Type, Float6E3M2FNType,
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BFloat16Type, Float16Type, FloatTF32Type, Float32Type,
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Float64Type, Float80Type, Float128Type>(type);
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}
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inline FloatType FloatType::getFloat8E5M2(MLIRContext *ctx) {
@@ -448,6 +449,10 @@ inline FloatType FloatType::getFloat8E3M4(MLIRContext *ctx) {
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return Float8E3M4Type::get(ctx);
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}
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inline FloatType FloatType::getFloat6E3M2FN(MLIRContext *ctx) {
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return Float6E3M2FNType::get(ctx);
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}
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inline FloatType FloatType::getBF16(MLIRContext *ctx) {
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return BFloat16Type::get(ctx);
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}

‎mlir/include/mlir/IR/BuiltinTypes.td

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@@ -233,6 +233,24 @@ def Builtin_Float8E3M4 : Builtin_FloatType<"Float8E3M4", "f8E3M4"> {
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}];
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}
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//===----------------------------------------------------------------------===//
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// Float6E3M2FNType
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def Builtin_Float6E3M2FN : Builtin_FloatType<"Float6E3M2FN", "f6E3M2FN"> {
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let summary = "6-bit floating point with 3 bits exponent and 2 bit mantissa";
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let description = [{
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An 6-bit floating point type with 1 sign bit, 3 bits exponent and 2 bits
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mantissa. This is not a standard type as defined by IEEE-754, but it
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follows similar conventions with the following characteristics:
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* bit encoding: S1E3M2
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* exponent bias: 3
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* infinities: Not supported
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* NaNs: Not supported
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* denormals when exponent is 0
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}];
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}
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//===----------------------------------------------------------------------===//
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// BFloat16Type
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‎mlir/include/mlir/IR/CommonTypeConstraints.td

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@@ -344,6 +344,8 @@ def F8E5M2FNUZ : Type<CPred<"$_self.isFloat8E5M2FNUZ()">, "f8E5M2FNUZ type">,
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BuildableType<"$_builder.getFloat8E5M2FNUZType()">;
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def F8E3M4 : Type<CPred<"$_self.isFloat8E3M4()">, "f8E3M4 type">,
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BuildableType<"$_builder.getFloat8E3M4Type()">;
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def F6E3M2FN : Type<CPred<"$_self.isFloat6E3M2FN()">, "f6E3M2FN type">,
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BuildableType<"$_builder.getFloat6E3M2FNType()">;
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def AnyComplex : Type<CPred<"::llvm::isa<::mlir::ComplexType>($_self)">,
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"complex-type", "::mlir::ComplexType">;

‎mlir/include/mlir/IR/Types.h

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@@ -132,6 +132,7 @@ class Type {
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bool isFloat8E4M3FNUZ() const;
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bool isFloat8E4M3B11FNUZ() const;
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bool isFloat8E3M4() const;
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bool isFloat6E3M2FN() const;
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bool isBF16() const;
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bool isF16() const;
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bool isTF32() const;

‎mlir/lib/AsmParser/TokenKinds.def

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@@ -101,6 +101,7 @@ TOK_KEYWORD(f8E5M2FNUZ)
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TOK_KEYWORD(f8E4M3FNUZ)
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TOK_KEYWORD(f8E4M3B11FNUZ)
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TOK_KEYWORD(f8E3M4)
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TOK_KEYWORD(f6E3M2FN)
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TOK_KEYWORD(f128)
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TOK_KEYWORD(false)
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TOK_KEYWORD(floordiv)

‎mlir/lib/AsmParser/TypeParser.cpp

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@@ -46,6 +46,7 @@ OptionalParseResult Parser::parseOptionalType(Type &type) {
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case Token::kw_f8E4M3FNUZ:
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case Token::kw_f8E4M3B11FNUZ:
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case Token::kw_f8E3M4:
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case Token::kw_f6E3M2FN:
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case Token::kw_bf16:
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case Token::kw_f16:
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case Token::kw_tf32:
@@ -324,6 +325,9 @@ Type Parser::parseNonFunctionType() {
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case Token::kw_f8E3M4:
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consumeToken(Token::kw_f8E3M4);
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return builder.getFloat8E3M4Type();
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case Token::kw_f6E3M2FN:
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consumeToken(Token::kw_f6E3M2FN);
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return builder.getFloat6E3M2FNType();
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case Token::kw_bf16:
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consumeToken(Token::kw_bf16);
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return builder.getBF16Type();

‎mlir/lib/Bindings/Python/IRTypes.cpp

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@@ -266,6 +266,27 @@ class PyFloat8E3M4Type : public PyConcreteType<PyFloat8E3M4Type, PyFloatType> {
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}
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};
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/// Floating Point Type subclass - Float6E3M2FNType.
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class PyFloat6E3M2FNType
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: public PyConcreteType<PyFloat6E3M2FNType, PyFloatType> {
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public:
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static constexpr IsAFunctionTy isaFunction = mlirTypeIsAFloat6E3M2FN;
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static constexpr GetTypeIDFunctionTy getTypeIdFunction =
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mlirFloat6E3M2FNTypeGetTypeID;
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static constexpr const char *pyClassName = "Float6E3M2FNType";
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using PyConcreteType::PyConcreteType;
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static void bindDerived(ClassTy &c) {
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c.def_static(
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"get",
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[](DefaultingPyMlirContext context) {
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MlirType t = mlirFloat6E3M2FNTypeGet(context->get());
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return PyFloat6E3M2FNType(context->getRef(), t);
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},
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py::arg("context") = py::none(), "Create a float6_e3m2fn type.");
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}
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};
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/// Floating Point Type subclass - BF16Type.
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class PyBF16Type : public PyConcreteType<PyBF16Type, PyFloatType> {
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public:
@@ -885,6 +906,7 @@ void mlir::python::populateIRTypes(py::module &m) {
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PyFloat8E4M3B11FNUZType::bind(m);
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PyFloat8E5M2FNUZType::bind(m);
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PyFloat8E3M4Type::bind(m);
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PyFloat6E3M2FNType::bind(m);
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PyBF16Type::bind(m);
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PyF16Type::bind(m);
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PyTF32Type::bind(m);

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