On Fri, 19 Dec 2025 09:02:38 GMT, Marc Chevalier <[email protected]> wrote:
>> I was suggesting that we should do what mainline does if
>> `!InlineTypePassFieldsAsArgs`, would that make sense?
>>
>> I.e. do `store_check(masm, dst.base(), dst);`
>
> That is the else-branch, right? Right now we have
>
> if (tmp3 != noreg) {
> __ mov(tmp3, dst.base());
> store_check(masm, tmp3, dst);
> } else {
> // It's OK to corrupt the dst.base() register.
> store_check(masm, dst.base(), dst);
> }
>
> If I understand well, you're suggesting to write
>
> if (InlineTypePassFieldsAsArgs) {
> if (tmp3 != noreg) {
> __ mov(tmp3, dst.base());
> store_check(masm, tmp3, dst);
> } else {
> // It's OK to corrupt the dst.base() register.
> store_check(masm, dst.base(), dst);
> }
> } else {
> // as mainline
> store_check(masm, dst.base(), dst);
> }
>
> but to me, it looks equivalent to
>
>
> if (InlineTypePassFieldsAsArgs && tmp3 != noreg) {
> __ mov(tmp3, dst.base());
> store_check(masm, tmp3, dst);
> } else {
> // It's OK to corrupt the dst.base() register.
> store_check(masm, dst.base(), dst);
> }
>
> since both else-branch are identical.
>
> And this, I experimentally found that it's failing quite a lot, with
> backtraces as I mentioned. Is there an obvious mistake in my logic I'm
> missing?
Ah, you are right. I missed the outer `if (tmp3 != noreg) {` which is Valhalla
specific. As we discussed off-thread, it would be good to get a better
understanding of why this fails in Valhalla. Thanks a lot!
-------------
PR Review Comment:
https://git.openjdk.org/valhalla/pull/1824#discussion_r2634372893
