Use unspec_volatile instead of unspec for those cache operations,
because those operations have side effects, instruction scheduler
might reorder those CMO operations if you use unspec.
> diff --git a/gcc/config/riscv/riscv.md b/gcc/config/riscv/riscv.md
> index b3c5bce842a..d60843df490 100644
> -
From: yulong
This commit adds cbo.clea,cbo.flush,cbo.inval,cbo.zero,prefetch.i,prefetch.r
and prefetch.w instructions.
diff with the previous two versions:
1.We change the instruction format from "prefetch.i\t%0" to "prefetch.i\t%a0"
about the prefetch.i, cbo.clean, cbo.flush, cbo.inval, cbo.ze
