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Re: [PATCH], PowerPC long double transistion, patch #2
On Thu, Jun 14, 2018 at 07:00:52PM -0500, Segher Boessenkool wrote:
> Hi Mike,
>
> On Wed, Jun 13, 2018 at 05:16:37PM -0400, Michael Meissner wrote:
> > This fixes some of the PowerPC tests that had implicit assumptions about the
> > long double format. The fixes involved:
> >
> > 1) Using long double __complex instead of using a KC attribute;
>
> Why? Does KC not work? It should work.
No KC does not work if long double is IEEE, just like IC does not work if long
double is IBM extended double. This is part of the __float128/__ibm128 changes
that eliminated using separate types all of the time.
> > 2) Explicitly adding -mabi=ibmlongdouble; (or)
>
> What in these tests requires IBM long double? It is not clear.
These are tests that test things like the format of IBM extended double (things
like pack, unpack, making sure the various __builtin_is<xxx> work for carefully
crafted numbers).
>
> > 3) Using __ibm128 instead of long double if long double is IEEE 128-bit.
>
> Can't you do that *always*? Why not?
Because __ibm128 is only defined if we have __float128 support. It is not
defined on non-VSX Linux systems.
--
Michael Meissner, IBM
IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA
email: meissner@linux.ibm.com, phone: +1 (978) 899-4797