The i586 targets on x86 are defined to be 32-bit and lacking in sse/sse2 unlike
the i686 target which has sse2 turned on by default. I was mostly curious what
would happen when turning on this target, and it turns out quite a few tests
failed!
Most of the tests here had to do with calling functions with ABI mismatches
where the callee wasn't `#[inline(always)]`. Various pieces have been updated
now and we should be passing all tests.
Only one instruction assertion ended up changing where the function generates a
different instruction with sse2 ambiently enabled and without it enabled.
This commit adds CI for a few more targets:
* i686-unknown-linux-gnu
* arm-unknown-linux-gnueabihf
* armv7-unknown-linux-gnueabihf
* aarch64-unknown-linux-gnu
The CI here is structured around using a Docker container to set up a test
environment and then QEMU is used to actually execute code from these platforms.
QEMU's emulation actually makes it so we can continue to just use `cargo test`,
as processes can be spawned from QEMU like `objdump` and files can be read (for
libbacktrace). Ends up being a relatively seamless experience!
Note that a number of intrinsics were disabled on i686 because they were failing
tests, and otherwise a few ARM touch-ups were made to get tests passing.
Alex Crichton