Re: [PATCH v4 2/5] m68k/bitops: use __builtin_{clz,ctzl,ffs} to evaluate constant expressions

[Finn Thain]

On Sun, 28 Jan 2024, Vincent MAILHOL wrote:

> > > The asm is meant to produce better results when the argument is not 
> > > a constant expression.

Is that because gcc's implementation has to satisfy requirements that are 
excessively stringent for the kernel's purposes? Or is it a compiler 
deficiency only affecting certain architectures?

> ... The only thing I am not ready to do is to compare the produced 
> assembly code and confirm whether or not it is better to remove asm 
> code.
> 

If you do the comparison and find no change, you get to say so in the 
commit log, and everyone is happy.