Cast from f64 to f32 not working with latest nightly on Windows

I'm compiling the following program with the latest nightly binary for Windows (with gcc 4.7.2):

``` rust
fn main() {
    let a = 3.14;
    let b = a as f32;
    println!("{:?}", b);
}
```

This prints `126443840048f32` instead of `3.14f32`.

If I change the code to the following, it does work as expected:

``` rust
fn main() {
    let a = 3.14;
    let b: f32 = a;
    println!("{:?}", b);
}
```
