On 10/15/23 02:12, Roger Sayle wrote:
This patch adds a pre-reload splitter to arc.md, to use the bset (set
specific bit instruction) to implement 1<<x (i.e. left shifts of one)
on ARC processors that don't have a barrel shifter.
Currently,
int foo(int x) {
return 1 << x;
}
FYI conceptually this would be helpful on the H8 port as well since it
does a loop. But unfortunately the bset instruction on the H8 masks the
bit position with 0x7, so a straightforward implementation would only
work in QImode which is pretty uninteresting.
While I could probably cobble together something on the H8 for HI/SI by
detecting when there's a suitable mask in the IL, but I doubt that
happens much in practice.
jeff
