[llvm] [SDAG] Use shifts if ISD::MUL is illegal when lowering ISD::CTPOP (PR #86505)

[Wang Pengcheng via llvm-commits]

wangpc-pp wrote:

> Can you also make the mirror GlobalISel change?
> 
> https://github.com/llvm/llvm-project/blob/5c663aa9ae4656c46d09914994859118759b426b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp#L6313

Sure! I have added it! But I'm not familiar with GISel, please double check it!

https://github.com/llvm/llvm-project/pull/86505