Add float128 support for ia64.

This patch enables float128 support for ia64, so that all the
configurations where GCC supports _Float128 / __float128 as an
ABI-distinct type now have glibc support as well.  bits/floatn.h
declares the support to be available for GCC 4.4 and later, which is
when the libgcc support was added.  The removal of
sysdeps/ia64/fpu/k_rem_pio2.c is because the generic k_rem_pio2.c
defines a function required by the float128 code.

Tested (compilation only) with build-many-glibcs.py for ia64 (GCC 6
and GCC 7).

Given how long it is since libm-test-ulps has been updated for ia64, I
think truncating the file and regenerating it from scratch would be a
good idea when doing a regeneration to add float128 ulps.  I expect
various ia64 libm issues (at least some already filed in Bugzilla) to
result in test failures even after ulps regeneration, but hopefully
the float128 code will pass tests as it's the same as used on other
architectures.

	* sysdeps/ia64/Implies: Add ieee754/float128.
	* sysdeps/ia64/bits/floatn.h: New file.
	* sysdeps/ia64/float128-abi.h: Likewise.
	* manual/math.texi (Mathematics): Document support for _Float128
	on ia64.
	* sysdeps/ia64/Makefile [$(subdir) = math] (CPPFLAGS): Append to
	Makefile variable.
	* sysdeps/ia64/fpu/e_sqrtf128.c: New file.
	* sysdeps/ia64/fpu/k_rem_pio2.c: Remove file.
	* sysdeps/ia64/fpu/sfp-machine.h: New file.  Based on libgcc.
	* sysdeps/ia64/math-tests.h: New file.
	* math/libm-test-support.h (XFAIL_FLOAT128_PAYLOAD): Also define
	based on TEST_COND_binary128 for [__ia64__].
	* sysdeps/unix/sysv/linux/ia64/libc.abilist: Update.
	* sysdeps/unix/sysv/linux/ia64/libm.abilist: Likewise,

1 files changed, 25 insertions, 0 deletions

diff --git a/sysdeps/ia64/math-tests.h b/sysdeps/ia64/math-tests.h
new file mode 100644
index 0000000000..439ac75e5d
--- /dev/null
+++ b/sysdeps/ia64/math-tests.h
@@ -0,0 +1,25 @@
+/* Configuration for math tests.  ia64 version.
+   Copyright (C) 2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* Before GCC 7, there is no built-in function to provide a __float128
+   sNaN, so most sNaN tests for this type cannot work.  */
+#if !__GNUC_PREREQ (7, 0)
+# define SNAN_TESTS_float128	0
+#endif
+
+#include_next <math-tests.h>