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Date: Mon, 29 Jan 2024 09:34:56 +1100 (AEDT)
From: Finn Thain <fthain@linux-m68k.org>
To: Vincent MAILHOL <mailhol.vincent@wanadoo.fr>
cc: David Laight <David.Laight@aculab.com>, 
    Andrew Morton <akpm@linux-foundation.org>, 
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Subject: Re: [PATCH v4 2/5] m68k/bitops: use __builtin_{clz,ctzl,ffs} to
 evaluate constant expressions
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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.