[PATCH] PowerPC: Restrict long double test to use IBM long double.

[Michael Meissner]

On Tue, Nov 17, 2020 at 11:33:29PM -0600, will schmidt wrote:
> On Sun, 2020-11-15 at 12:23 -0500, Michael Meissner via Gcc-patches wrote:
> > PowerPC: Restrict long double test to use IBM long double.
> > 
> > I posted this patch previously as a set of 3 testsuite patches.  I have
> > separated them into separate patches.  This patch marks the convert-bfp-11.c
> > patch as needing IBM extended double.  If you look at the code, it is
> > specifically designed around testing the limits of the IBM 128-bit extended
> > double representation.  I added a new target-supports that says the test
> > requires IBM extended long double, and changed the test to require this
> > effective test.  Can I check this into the master branch?
> 
> 
> It's harder to review that without all the history handy here.
> 
> This will stand alone better if you lead with what you are adding and
> keep it clean.  i.e.

The patch I was referring to was posted on October 22nd:
https://gcc.gnu.org/pipermail/gcc-patches/2020-October/556865.html
 
> Subject: PowerPC: Add ppc_long_double_ibm effective-target check
> 
> "Add a ppc_long_double_ibm dg-require-effective-target check to ensure
> tests that require LONG_DOUBLE_IBM128 . "
> An additional statement to clarify it's relationship with IEEEEEEEE128
> wouldn't  hurt if that is the case.  i.e. 
> "This is a counterpart to LONG_DOUBLE_IEEEEEEE 128 " 

At the moment, we don't need a target supports for long double IEEE 128-bit or
long double 64-bit.  I can add them if needed.

> Hmm, I have those backwards in my head apparently.  Can the return 1 if
> not-defined logic be flattened out so we see the direct relationship?

I'm not sure what you are asking.  These are preprocessor macros that are only
defined in certain cases.  And remember this is main returning a value, so
returning 0 is true and 1 is false.

In particular:

If your long double is 128-bits and uses the IEEE 128-bit representation, the
following macros are defined:

	__LONG_DOUBLE_128__
	__LONG_DOUBLE_IEEE128__

If your long double is 128-bit and uses the IBM 128-bit representation (current
default0, the following macros are defined:

	__LONG_DOUBLE_128__
	__LONG_DOUBLE_IBM128__

If your long double is 64 bits, neither of those two macros are defined.

-- 
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