[MLIR] Add f8E3M4 IEEE 754 type (#101230)

This PR adds `f8E3M4` type to mlir.

`f8E3M4` type  follows IEEE 754 convention

```c
f8E3M4 (IEEE 754)
- Exponent bias: 3
- Maximum stored exponent value: 6 (binary 110)
- Maximum unbiased exponent value: 6 - 3 = 3
- Minimum stored exponent value: 1 (binary 001)
- Minimum unbiased exponent value: 1 − 3 = −2
- Precision specifies the total number of bits used for the significand (mantissa), 
    including implicit leading integer bit = 4 + 1 = 5
- Follows IEEE 754 conventions for representation of special values
- Has Positive and Negative zero
- Has Positive and Negative infinity
- Has NaNs

Additional details:
- Max exp (unbiased): 3
- Min exp (unbiased): -2
- Infinities (+/-): S.111.0000
- Zeros (+/-): S.000.0000
- NaNs: S.111.{0,1}⁴ except S.111.0000
- Max normal number: S.110.1111 = +/-2^(6-3) x (1 + 15/16) = +/-2^3 x 31 x 2^(-4) = +/-15.5
- Min normal number: S.001.0000 = +/-2^(1-3) x (1 + 0) = +/-2^(-2)
- Max subnormal number: S.000.1111 = +/-2^(-2) x 15/16 = +/-2^(-2) x 15 x 2^(-4) = +/-15 x 2^(-6)
- Min subnormal number: S.000.0001 = +/-2^(-2) x 1/16 =  +/-2^(-2) x 2^(-4) = +/-2^(-6)
```

Related PRs:
- [PR-99698](llvm/llvm-project#99698) [APFloat]
Add support for f8E3M4 IEEE 754 type
- [PR-97118](llvm/llvm-project#97118) [MLIR] Add
f8E4M3 IEEE 754 type

Author: apivovarov

mlir/include/mlir-c/BuiltinTypes.h

@@ -139,6 +139,16 @@ MLIR_CAPI_EXPORTED bool mlirTypeIsAFloat8E4M3B11FNUZ(MlirType type);
 /// context.
 MLIR_CAPI_EXPORTED MlirType mlirFloat8E4M3B11FNUZTypeGet(MlirContext ctx);
 
+/// Returns the typeID of an Float8E3M4 type.
+MLIR_CAPI_EXPORTED MlirTypeID mlirFloat8E3M4TypeGetTypeID(void);
+
+/// Checks whether the given type is an f8E3M4 type.
+MLIR_CAPI_EXPORTED bool mlirTypeIsAFloat8E3M4(MlirType type);
+
+/// Creates an f8E3M4 type in the given context. The type is owned by the
+/// context.
+MLIR_CAPI_EXPORTED MlirType mlirFloat8E3M4TypeGet(MlirContext ctx);
+
 /// Returns the typeID of an BFloat16 type.
 MLIR_CAPI_EXPORTED MlirTypeID mlirBFloat16TypeGetTypeID(void);
 

mlir/lib/Bindings/Python/IRTypes.cpp

@@ -246,6 +246,26 @@ class PyFloat8E5M2FNUZType
   }
 };
 
+/// Floating Point Type subclass - Float8E3M4Type.
+class PyFloat8E3M4Type : public PyConcreteType<PyFloat8E3M4Type, PyFloatType> {
+public:
+  static constexpr IsAFunctionTy isaFunction = mlirTypeIsAFloat8E3M4;
+  static constexpr GetTypeIDFunctionTy getTypeIdFunction =
+      mlirFloat8E3M4TypeGetTypeID;
+  static constexpr const char *pyClassName = "Float8E3M4Type";
+  using PyConcreteType::PyConcreteType;
+
+  static void bindDerived(ClassTy &c) {
+    c.def_static(
+        "get",
+        [](DefaultingPyMlirContext context) {
+          MlirType t = mlirFloat8E3M4TypeGet(context->get());
+          return PyFloat8E3M4Type(context->getRef(), t);
+        },
+        py::arg("context") = py::none(), "Create a float8_e3m4 type.");
+  }
+};
+
 /// Floating Point Type subclass - BF16Type.
 class PyBF16Type : public PyConcreteType<PyBF16Type, PyFloatType> {
 public:
@@ -864,6 +884,7 @@ void mlir::python::populateIRTypes(py::module &m) {
   PyFloat8E4M3FNUZType::bind(m);
   PyFloat8E4M3B11FNUZType::bind(m);
   PyFloat8E5M2FNUZType::bind(m);
+  PyFloat8E3M4Type::bind(m);
   PyBF16Type::bind(m);
   PyF16Type::bind(m);
   PyTF32Type::bind(m);

mlir/lib/CAPI/IR/BuiltinTypes.cpp

@@ -157,6 +157,18 @@ MlirType mlirFloat8E4M3B11FNUZTypeGet(MlirContext ctx) {
   return wrap(FloatType::getFloat8E4M3B11FNUZ(unwrap(ctx)));
 }
 
+MlirTypeID mlirFloat8E3M4TypeGetTypeID() {
+  return wrap(Float8E3M4Type::getTypeID());
+}
+
+bool mlirTypeIsAFloat8E3M4(MlirType type) {
+  return unwrap(type).isFloat8E3M4();
+}
+
+MlirType mlirFloat8E3M4TypeGet(MlirContext ctx) {
+  return wrap(FloatType::getFloat8E3M4(unwrap(ctx)));
+}
+
 MlirTypeID mlirBFloat16TypeGetTypeID() {
   return wrap(BFloat16Type::getTypeID());
 }

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

@@ -120,6 +120,7 @@ __all__ = [
     "F32Type",
     "F64Type",
     "FlatSymbolRefAttr",
+    "Float8E3M4Type",
     "Float8E4M3B11FNUZType",
     "Float8E4M3FNType",
     "Float8E4M3FNUZType",
@@ -1537,6 +1538,19 @@ class FlatSymbolRefAttr(Attribute):
         Returns the value of the FlatSymbolRef attribute as a string
         """
 
+class Float8E3M4Type(FloatType):
+    static_typeid: ClassVar[TypeID]
+    @staticmethod
+    def get(context: Optional[Context] = None) -> Float8E3M4Type:
+        """
+        Create a float8_e3m4 type.
+        """
+    @staticmethod
+    def isinstance(other: Type) -> bool: ...
+    def __init__(self, cast_from_type: Type) -> None: ...
+    @property
+    def typeid(self) -> TypeID: ...
+
 class Float8E4M3B11FNUZType(FloatType):
     static_typeid: ClassVar[TypeID]
     @staticmethod

mlir/python/mlir/extras/types.py

@@ -12,6 +12,7 @@
     F16Type,
     F32Type,
     F64Type,
+    Float8E3M4Type,
     Float8E4M3B11FNUZType,
     Float8E4M3FNType,
     Float8E4M3Type,
@@ -72,6 +73,7 @@ def ui(width):
 f8E4M3 = lambda: Float8E4M3Type.get()
 f8E4M3FN = lambda: Float8E4M3FNType.get()
 f8E4M3B11FNUZ = lambda: Float8E4M3B11FNUZType.get()
+f8E3M4 = lambda: Float8E3M4Type.get()
 
 none = lambda: NoneType.get()