[PATCH v3 2/2] powerpc: add support for csum_add()

[David Laight]

From: Scott Wood ...
> > I'd also have thought that the 64bit C version above would be generally 'good'.
> 
> It doesn't generate the addc/addze sequence.  At least with GCC 4.8.2,
> it does something like:
> 
> 	mr	tmp0, csum
> 	li	tmp1, 0
> 	li	tmp2, 0
> 	addc	tmp3, addend, tmp0
> 	adde	csum, tmp2, tmp1
> 	add	csum, csum, tmp3

I was thinking of all 64bit targets, not 32bit ones.

	David