diff --git a/flang/module/cudadevice.f90 b/flang/module/cudadevice.f90
index 262a8d09ff7df..28577ee495368 100644
--- a/flang/module/cudadevice.f90
+++ b/flang/module/cudadevice.f90
@@ -709,6 +709,34 @@ attributes(device) real(8) function sinpi(x) bind(c,name='__nv_sinpi')
     end function
   end interface
 
+  interface __ull2float_rd
+    attributes(device) real function __ull2float_rd(i) bind(c, name='__nv_ull2float_rd')
+      !dir$ ignore_tkr (d) i
+      integer(8), value :: i
+    end function
+  end interface
+
+  interface __ull2float_rn
+    attributes(device) real function __ull2float_rn(i) bind(c, name='__nv_ull2float_rn')
+      !dir$ ignore_tkr (d) i
+      integer(8), value :: i
+    end function
+  end interface
+
+  interface __ull2float_ru
+    attributes(device) real function __ull2float_ru(i) bind(c, name='__nv_ull2float_ru')
+      !dir$ ignore_tkr (d) i
+      integer(8), value :: i
+    end function
+  end interface
+
+  interface __ull2float_rz
+    attributes(device) real function __ull2float_rz(i) bind(c, name='__nv_ull2float_rz')
+      !dir$ ignore_tkr (d) i
+      integer(8), value :: i
+    end function
+  end interface
+
   interface __mul24
     attributes(device) integer function __mul24(i,j) bind(c, name='__nv_mul24')
       !dir$ ignore_tkr (d) i, (d) j
diff --git a/flang/test/Lower/CUDA/cuda-libdevice.cuf b/flang/test/Lower/CUDA/cuda-libdevice.cuf
index a1592c036d2fe..06515b1c5f6df 100644
--- a/flang/test/Lower/CUDA/cuda-libdevice.cuf
+++ b/flang/test/Lower/CUDA/cuda-libdevice.cuf
@@ -20,6 +20,21 @@ end subroutine
 ! CHECK-LABEL: _QPtest_usad
 ! CHECK: %{{.*}} = fir.call @__nv_usad(%{{.*}}, %{{.*}}, %{{.*}}) proc_attrs<bind_c> fastmath<contract> : (i32, i32, i32) -> i32
 
+attributes(global) subroutine test_ull2dloat_rX()
+  real :: res
+  integer(8) :: i
+  res = __ull2float_rd(i)
+  res = __ull2float_rn(i)
+  res = __ull2float_ru(i)
+  res = __ull2float_rz(i)
+end subroutine
+
+! CHECK-LABEL: _QPtest_ull2dloat_rx
+! CHECK: %{{.*}} = fir.call @__nv_ull2float_rd(%{{.*}}) proc_attrs<bind_c> fastmath<contract> : (i64) -> f32
+! CHECK: %{{.*}} = fir.call @__nv_ull2float_rn(%{{.*}}) proc_attrs<bind_c> fastmath<contract> : (i64) -> f32
+! CHECK: %{{.*}} = fir.call @__nv_ull2float_ru(%{{.*}}) proc_attrs<bind_c> fastmath<contract> : (i64) -> f32
+! CHECK: %{{.*}} = fir.call @__nv_ull2float_rz(%{{.*}}) proc_attrs<bind_c> fastmath<contract> : (i64) -> f32
+
 attributes(global) subroutine test_log()
   real :: res
   real :: r
@@ -50,4 +65,3 @@ end subroutine
 
 ! CHECK-LABEL: _QPtest_tanf
 ! CHECK: %{{.*}} = fir.call @__nv_tanf(%{{.*}}) proc_attrs<bind_c> fastmath<contract> : (f32) -> f32
-