On 12/12/23 20:54, Palmer Dabbelt wrote:
I can't actually find anything in the ISA manual that makes Ztso imply
A. In theory the memory ordering is just a different thing that the set
of availiable instructions (ie, Ztso without A would still imply TSO for
loads and stores). It also seems like a configuration that could be
sane to build: without A it's all but impossible to write any meaningful
multi-core code, and TSO is really cheap for a single core.
That said, I think it's kind of reasonable to provide A to users asking
for Ztso. So maybe even if this was a mistake it's the right thing to
do?
gcc/ChangeLog:
* common/config/riscv/riscv-common.cc (riscv_implied_info):
Remove {"ztso", "a"}.
I'd tend to think step #1 is to determine what the ISA intent is,
meaning engagement with RVI.
We've got time for that engagement and to adjust based on the result.
So I'd tend to defer until we know if Ztso should imply A or not.
jeff
