[NFC] Move llvm.fptrunc.round to Floating-Point Conversion Intrinsics class (llvm#155854)

Floating-Point Conversion Intrinsics - is a new category of intrinsics,
that do not fall into other categories and can be used for conversions
with explicit rounding modes and mini-floats conversions.

Signed-off-by: Sidorov, Dmitry <[email protected]>

Author: MrSidims

llvm/docs/LangRef.rst

@@ -21122,6 +21122,53 @@ Example:
       %c = call i8 @llvm.fptosi.sat.i8.f32(float 999.0)              ; yields i8:  127
       %d = call i8 @llvm.fptosi.sat.i8.f32(float 0xFFF8000000000000) ; yields i8:    0
 
+Floating-Point Conversion Intrinsics
+------------------------------------
+
+This class of intrinsics is designed for floating-point conversions that do
+not fall into other categories. For example conversions with specified rounding
+mode or mini-float conversions.
+
+'``llvm.fptrunc.round``' Intrinsic
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Syntax:
+"""""""
+
+::
+
+      declare <ty2>
+      @llvm.fptrunc.round(<type> <value>, metadata <rounding mode>)
+
+Overview:
+"""""""""
+
+The '``llvm.fptrunc.round``' intrinsic truncates
+:ref:`floating-point <t_floating>` ``value`` to type ``ty2``
+with a specified rounding mode.
+
+Arguments:
+""""""""""
+
+The '``llvm.fptrunc.round``' intrinsic takes a :ref:`floating-point
+<t_floating>` value to cast and a :ref:`floating-point <t_floating>` type
+to cast it to. This argument must be larger in size than the result.
+
+The second argument specifies the rounding mode as described in the constrained
+intrinsics section.
+For this intrinsic, the "round.dynamic" mode is not supported.
+
+Semantics:
+""""""""""
+
+The '``llvm.fptrunc.round``' intrinsic casts a ``value`` from a larger
+:ref:`floating-point <t_floating>` type to a smaller :ref:`floating-point
+<t_floating>` type.
+This intrinsic is assumed to execute in the default :ref:`floating-point
+environment <floatenv>` *except* for the rounding mode.
+This intrinsic is not supported on all targets. Some targets may not support
+all rounding modes.
+
 Convergence Intrinsics
 ----------------------
 
@@ -31295,42 +31342,3 @@ Semantics:
 The '``llvm.preserve.struct.access.index``' intrinsic produces the same result
 as a getelementptr with base ``base`` and access operands ``{0, gep_index}``.
 
-'``llvm.fptrunc.round``' Intrinsic
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-Syntax:
-"""""""
-
-::
-
-      declare <ty2>
-      @llvm.fptrunc.round(<type> <value>, metadata <rounding mode>)
-
-Overview:
-"""""""""
-
-The '``llvm.fptrunc.round``' intrinsic truncates
-:ref:`floating-point <t_floating>` ``value`` to type ``ty2``
-with a specified rounding mode.
-
-Arguments:
-""""""""""
-
-The '``llvm.fptrunc.round``' intrinsic takes a :ref:`floating-point
-<t_floating>` value to cast and a :ref:`floating-point <t_floating>` type
-to cast it to. This argument must be larger in size than the result.
-
-The second argument specifies the rounding mode as described in the constrained
-intrinsics section.
-For this intrinsic, the "round.dynamic" mode is not supported.
-
-Semantics:
-""""""""""
-
-The '``llvm.fptrunc.round``' intrinsic casts a ``value`` from a larger
-:ref:`floating-point <t_floating>` type to a smaller :ref:`floating-point
-<t_floating>` type.
-This intrinsic is assumed to execute in the default :ref:`floating-point
-environment <floatenv>` *except* for the rounding mode.
-This intrinsic is not supported on all targets. Some targets may not support
-all rounding modes.