Bad performance with bitwise operations

Hello, I noticed this is noticably slower with ifort 14.0.0 than with gfortran. Is there anything to make the result run faster?

  use iso_fortran_env

  real(real32) :: x32
  integer(int64) :: t1, t2, trate

  call system_clock(count_rate=trate)
  call system_clock(count=t1)
  do i=1,int(2E9)
    x32 = swapb32(x32)
  end do
  call system_clock(count=t2)
  print *,x32,"time",real(t2-t1)/trate

contains
    function swapb32(x) result(res)
      real(real32) :: res
      real(real32),intent(in) :: x
      character(4) :: bytes
      integer(int32) :: t
      
      bytes = transfer(x,bytes) !equivalence very slightly faster, but problematic.

      t = ichar(bytes(4:4),int64)

      t = ior( ishftc(ichar(bytes(3:3),int32),8),  t )

      t = ior( ishftc(ichar(bytes(2:2),int32),16), t )

      t = ior( ishftc(ichar(bytes(1:1),int32),24), t )

      res = transfer(t, res)
        
    end function
end

> gfortran-4.9 -Ofast bitperf.f90 
> ./a.out 
   0.00000000     time   5.00823069    
> ifort -fast bitperf.f90 
ipo: remark #11001: performing single-file optimizations
ipo: remark #11006: generating object file /tmp/ipo_ifort0hhp0O.o
> ./a.out 
  0.0000000E+00 time   13.35413