On Wed, Sep 25, 2024 at 01:41:51PM +0200, Richard Biener wrote:
> wide_int_storage shows up high in the profile for the testcase in
> PR114855 where the apparent issue is that the conditional jump
> on 'precision' after the (inlined) memcpy stalls the pipeline due
> to the data dependence and required store-to-load forwarding. We
> can add scheduling freedom by instead testing precision as from the
> source which speeds up the function by 30%. I've applied the
> same logic to the copy CTOR.
>
> Bootstrap and regtest running on x86_64-unknown-linux-gnu.
>
> * wide-int.h (wide_int_storage::wide_int_storage): Branch
> on source precision to avoid data dependence on memcpy
> destination.
> (wide_int_storage::operator=): Likewise.
LGTM.
Jakub
