Re: [PATCH 33/72] softfloat: Use uadd64_carry, usub64_borrow in softfloat-macros.h

[Richard Henderson]

On 5/13/21 5:00 AM, Alex Bennée wrote:
> Richard Henderson <richard.henderson@linaro.org> writes:
>
> > Use compiler support for carry arithmetic.
>
> Didn't we have a series that attempted to take advantage of compiler
> support for Int128? Is the compiler end up smart enough to use 128 bit
> wide ops if it can?

That was one of the iterations of this patch set, yes.  In the end it turned 
out to be easier to be able to address frac_hi and frac_lo directly.

It's likely that this choice would have been different if we didn't have to 
deal with 32-bit hosts and could rely on the compiler having the 128-bit type.


r~