message: use libstd methods for floating-point <-> bytes conversion
diff: #![allow(unknown_lints)]
  #![allow(float_cmp)]
  -use std::mem::transmute;
  use rustc::ty::layout::TargetDataLayout;
  use error::{EvalError, EvalResult};
  use memory::{Memory, MemoryPointer, HasMemory};
  pub(super) fn bytes_to_f32(bytes: u128) -> f32 {
  - unsafe { transmute::<u32, f32>(bytes as u32) }
  + f32::from_bits(bytes as u32)
  }
  pub(super) fn bytes_to_f64(bytes: u128) -> f64 {
  - unsafe { transmute::<u64, f64>(bytes as u64) }
  + f64::from_bits(bytes as u64)
  }
  pub(super) fn f32_to_bytes(f: f32) -> u128 {
  - unsafe { transmute::<f32, u32>(f) as u128 }
  + f.to_bits() as u128
  }
  pub(super) fn f64_to_bytes(f: f64) -> u128 {
  - unsafe { transmute::<f64, u64>(f) as u128 }
  + f.to_bits() as u128
  }
  /// A `Value` represents a single self-contained Rust value.
  