ro added inline comments.
================
Comment at: clang/lib/Driver/ToolChains/Solaris.cpp:135
}
+ // LLVM lacks atomics support on 32-bit SPARC, so forcibly link with
+ // libatomic as a workaround.
----------------
glaubitz wrote:
> joerg wrote:
> > This comment is misleading. It's not so much that LLVM doesn't support
> > them, but that SPARCv8 doesn't have the necessary hardware support. The v8+
> > support is incomplete, which is a related problem though.
> As far as I know, 64-bit atomics are supported if you enable V8+ in GCC -
> without linking against `libatomic`:
>
> ```
> glaubitz@gcc202:~$ cat atomic.c
> #include <stdint.h>
>
> int main()
> {
> int64_t x = 0, y = 1;
> y = __sync_val_compare_and_swap(&x, x, y);
> return 0;
> }
> glaubitz@gcc202:~$ gcc -m32 -mv8plus atomic.c -o atomic
> glaubitz@gcc202:~$
> ```
I know, that's why I referred to my patch to default `clang` on
Solaris/sparc to V8+. I'll update the comment.
I'd tried to actually fix the underlying issue (`clang` not emitting
`casx` with `-m32 -mcpu=v9`), but ran into internal errors and
areas of LLVM I know nothing about. I might post a WIP patch
for reference since there are several issues there.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D118021/new/
https://reviews.llvm.org/D118021
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