SEGFAULT in u8x16::store

[bheisler]

This code segfaults when compiled by any version of rustc newer than nightly-2016-08-03 (in my case, I'm using 2016-09-30).

#[test]
fn test_store() {
    use simd::u8x16;
    let mut array = [0u8; 0x1000];
    let ones = u8x16::splat(1);
    ones.store(&mut array, 0);
    assert_eq!(array[0], 1);
    assert_eq!(array[15], 1);
    assert_eq!(array[16], 0);
}

Here's some output from gdb that might help:

0x000055555557b23f in simd::common::{{impl}}::store (self=..., array=..., idx=0) at /home/user/.cargo/git/checkouts/simd-a428b8cc9c1d1986/master/src/common.rs:137
137 *(place.as_mut_ptr() as *mut Unalign) = Unalign(self)

(gdb) p $_siginfo._sifields._sigfault
$3 = {si_addr = 0x0, _addr_lsb = 140727441239520, _addr_bnd = {_lower = 0x3, _upper = 0x1}}

Assuming GDB can be trusted here, it looks like rust is generating code that dereferences a null pointer.

[liebharc]

I remember that I also ran into issues with this lib around that time. Recent Rust versions resolved the issue for me and also your example seems to work now with rustc 1.14.0-nightly (f09420685 2016-10-20), meaning that there is no segfault and all asserts are passed successfully. Not sure however what change caused the segfaults and how it got resolved.