[Bug target/86005] [RISCV] Invalid intermixing of __atomic_* libcalls and inline atomic instruction sequences

[wilson at tuliptree dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86005

--- Comment #5 from Jim Wilson <wilson at tuliptree dot org> ---
On Thu, 2018-05-31 at 05:40 +0000, asb at lowrisc dot org wrote:
> Actually I think this bug is wider in scope than I first thought. GCC
> will also
> intermix __atomic libcalls and inline instruction sequences with
> -march=rv32ia
> when values less than XLEN in size are accessed.

FYI I have a prototype patch to fix this.  I copied the subword atomic
support from the ppc port, and hacked it to work.  I haven't done the
fences yet, so it probably won't work if you have more than one thread,
but it works well enough to handle the gcc/g++ testsuites.  It also
needs some cleanup to remove more ppc specific stuff.  I don't know
when I will have time to finish it though.