diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -15148,6 +15148,27 @@
 vectorized into a single instruction that raises each unique exception a single
 time.
 
+Required Function Attributes:
+"""""""""""""""""""""""""""""
+
+Proper :ref:`function attributes <fnattrs>` usage is required for the
+constrained intrinsics to function correctly.
+
+All function *calls* done in a function that uses constrained floating
+point intrinsics must have the ``strictfp`` attribute.
+
+All function *definitions* that use constrained floating point intrinsics
+must use a set of function attributes. All attributes are required. The
+complete list of required function attributes:
+
+::
+
+      strictfp
+      noimplicitfloat
+
+The constrained floating point intrinsics are still experimental and the above
+list may be subject to change.
+
 
 '``llvm.experimental.constrained.fadd``' Intrinsic
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^