[MLIR] Add f8E8M0FNU type (#111028)

This PR adds `f8E8M0FNU` type to MLIR.

`f8E8M0FNU` type is proposed in [OpenCompute MX
Specification](https://www.opencompute.org/documents/ocp-microscaling-formats-mx-v1-0-spec-final-pdf).
It defines a 8-bit floating point number with bit layout S0E8M0. Unlike
IEEE-754 types, there are no infinity, denormals, zeros or negative
values.

```c
f8E8M0FNU
- Exponent bias: 127
- Maximum stored exponent value: 254 (binary 1111'1110)
- Maximum unbiased exponent value: 254 - 127 = 127
- Minimum stored exponent value: 0 (binary 0000'0000)
- Minimum unbiased exponent value: 0 − 127 = -127
- Doesn't have zero
- Doesn't have infinity
- NaN is encoded as binary 1111'1111

Additional details:
- Zeros cannot be represented
- Negative values cannot be represented
- Mantissa is always 1
```

Related PRs:
- [PR-107127](llvm/llvm-project#107127)
[APFloat] Add APFloat support for E8M0 type
- [PR-105573](llvm/llvm-project#105573) [MLIR]
Add f6E3M2FN type - was used as a template for this PR
- [PR-107999](llvm/llvm-project#107999) [MLIR]
Add f6E2M3FN type
- [PR-108877](llvm/llvm-project#108877) [MLIR]
Add f4E2M1FN type

Author: sergey-kozub

mlir/include/mlir-c/BuiltinTypes.h

@@ -179,6 +179,16 @@ MLIR_CAPI_EXPORTED bool mlirTypeIsAFloat8E3M4(MlirType type);
 /// context.
 MLIR_CAPI_EXPORTED MlirType mlirFloat8E3M4TypeGet(MlirContext ctx);
 
+/// Returns the typeID of an Float8E8M0FNU type.
+MLIR_CAPI_EXPORTED MlirTypeID mlirFloat8E8M0FNUTypeGetTypeID(void);
+
+/// Checks whether the given type is an f8E8M0FNU type.
+MLIR_CAPI_EXPORTED bool mlirTypeIsAFloat8E8M0FNU(MlirType type);
+
+/// Creates an f8E8M0FNU type in the given context. The type is owned by the
+/// context.
+MLIR_CAPI_EXPORTED MlirType mlirFloat8E8M0FNUTypeGet(MlirContext ctx);
+
 /// Returns the typeID of an BFloat16 type.
 MLIR_CAPI_EXPORTED MlirTypeID mlirBFloat16TypeGetTypeID(void);
 

mlir/lib/Bindings/Python/IRTypes.cpp

@@ -331,6 +331,27 @@ class PyFloat8E3M4Type : public PyConcreteType<PyFloat8E3M4Type, PyFloatType> {
   }
 };
 
+/// Floating Point Type subclass - Float8E8M0FNUType.
+class PyFloat8E8M0FNUType
+    : public PyConcreteType<PyFloat8E8M0FNUType, PyFloatType> {
+public:
+  static constexpr IsAFunctionTy isaFunction = mlirTypeIsAFloat8E8M0FNU;
+  static constexpr GetTypeIDFunctionTy getTypeIdFunction =
+      mlirFloat8E8M0FNUTypeGetTypeID;
+  static constexpr const char *pyClassName = "Float8E8M0FNUType";
+  using PyConcreteType::PyConcreteType;
+
+  static void bindDerived(ClassTy &c) {
+    c.def_static(
+        "get",
+        [](DefaultingPyMlirContext context) {
+          MlirType t = mlirFloat8E8M0FNUTypeGet(context->get());
+          return PyFloat8E8M0FNUType(context->getRef(), t);
+        },
+        py::arg("context") = py::none(), "Create a float8_e8m0fnu type.");
+  }
+};
+
 /// Floating Point Type subclass - BF16Type.
 class PyBF16Type : public PyConcreteType<PyBF16Type, PyFloatType> {
 public:
@@ -953,6 +974,7 @@ void mlir::python::populateIRTypes(py::module &m) {
   PyFloat8E4M3B11FNUZType::bind(m);
   PyFloat8E5M2FNUZType::bind(m);
   PyFloat8E3M4Type::bind(m);
+  PyFloat8E8M0FNUType::bind(m);
   PyBF16Type::bind(m);
   PyF16Type::bind(m);
   PyTF32Type::bind(m);

mlir/lib/CAPI/IR/BuiltinTypes.cpp

@@ -205,6 +205,18 @@ MlirType mlirFloat8E3M4TypeGet(MlirContext ctx) {
   return wrap(FloatType::getFloat8E3M4(unwrap(ctx)));
 }
 
+MlirTypeID mlirFloat8E8M0FNUTypeGetTypeID() {
+  return wrap(Float8E8M0FNUType::getTypeID());
+}
+
+bool mlirTypeIsAFloat8E8M0FNU(MlirType type) {
+  return unwrap(type).isFloat8E8M0FNU();
+}
+
+MlirType mlirFloat8E8M0FNUTypeGet(MlirContext ctx) {
+  return wrap(FloatType::getFloat8E8M0FNU(unwrap(ctx)));
+}
+
 MlirTypeID mlirBFloat16TypeGetTypeID() {
   return wrap(BFloat16Type::getTypeID());
 }

mlir/python/mlir/_mlir_libs/_mlir/ir.pyi

@@ -117,6 +117,7 @@ __all__ = [
     "Float8E4M3Type",
     "Float8E5M2FNUZType",
     "Float8E5M2Type",
+    "Float8E8M0FNUType",
     "FloatAttr",
     "FloatTF32Type",
     "FloatType",
@@ -1660,6 +1661,19 @@ class Float8E5M2Type(FloatType):
     @property
     def typeid(self) -> TypeID: ...
 
+class Float8E8M0FNUType(FloatType):
+    static_typeid: ClassVar[TypeID]
+    @staticmethod
+    def get(context: Context | None = None) -> Float8E8M0FNUType:
+        """
+        Create a float8_e8m0fnu type.
+        """
+    @staticmethod
+    def isinstance(other: Type) -> bool: ...
+    def __init__(self, cast_from_type: Type) -> None: ...
+    @property
+    def typeid(self) -> TypeID: ...
+
 class FloatAttr(Attribute):
     static_typeid: ClassVar[TypeID]
     @staticmethod

mlir/python/mlir/extras/types.py

@@ -20,6 +20,7 @@
     Float8E4M3FNType,
     Float8E4M3Type,
     Float8E5M2Type,
+    Float8E8M0FNUType,
     FunctionType,
     IndexType,
     IntegerType,
@@ -80,6 +81,7 @@ def ui(width):
 f4E2M1FN = lambda: Float4E2M1FNType.get()
 f6E2M3FN = lambda: Float6E2M3FNType.get()
 f6E3M2FN = lambda: Float6E3M2FNType.get()
+f8E8M0FNU = lambda: Float8E8M0FNUType.get()
 
 none = lambda: NoneType.get()