`Option<f64>::Some` behaves incorrectly in 64-bit host

[lifthrasiir]

Minimal example:

fn f() { assert!(false); }
struct A(f64);
struct B { x: Option<A> }
fn main() { let mut t = B { x: None }; t.x = Some(A(100.0)); println(fmt!("%?", t.x)); }

This should print Some(A(100f64)), but in 64-bit host (to be exact, x86_64-unknown-linux-gnu) this results in Some(A(0f64)) and behaves like that. Confirmed in 0.8 and (AFAIK) pre-0.9.

Notes:

• The function f is nothing to do with the example, but it somehow prohibits the inlining of Some().
• Only f64 triggers this bug. f32 or i64 does not.
• Only tuple-like struct exhibits this bug. struct A { y: f64 } or enum A { A(f64) } does not, and the latter can be used a workaround for this bug.

It bears some resemblance with #9719 but the connection is unclear.

[lifthrasiir]

Ugh, it seems to be fixed in the master (I had mistaken pre-0.8 master results as pre-0.9 ones), and the current master does not have this problem. Sorry for mistake.