[PATCH 0/3] PowerPC: Fix up tests for IEEE 128-bit long double

[Michael Meissner <meissner@linux.ibm.com>]

In November, I submitted a patch to fix up some of the tests for when IEEE
128-bit is used as the long double format.  Segher had some suggestions.  These
patches are based on those suggestions:
https://gcc.gnu.org/pipermail/gcc-patches/2020-November/559836.html

These patches add several more selections to target-supports.exp:

    *	3 selections for the current long double format;
    *	3 selections if we can change the long double format to a particular
	value.
    *	3 functions to return the options needed to switch the long double
	format for use with dg-add-options.

And there are the 2 tests (pr70117, convert-bfp-11.c) that need to be
configured run with IBM 128-bit long double because the test itself was written
knowing about the format of IBM 128-bit floating point.

I have run tests on a little endian power9 system with 3 compilers:
    *	One compiler using the default IBM 128-bit format;
    *	One compiler using the IEEE 128-bit format; (and)
    *	One compiler using 64-bit long doubles.

I have also tested compilers on a big endian power8 system with a compiler
defaulting to power8 code generation and another with the default cpu set.

-- 
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