Add iseqsig.

TS 18661-1 adds an iseqsig type-generic comparison macro to <math.h>.
This macro is like the == operator except that unordered operands
result in the "invalid" exception and errno being set to EDOM.

This patch implements this macro for glibc.  Given the need to set
errno, this is implemented with out-of-line functions __iseqsigf,
__iseqsig and __iseqsigl (of which the last only exists at all if long
double is ABI-distinct from double, so no function aliases or compat
support are needed).  The present patch ignores excess precision
issues; I intend to deal with those in a followup patch.  (Like
comparison operators, type-generic comparison macros should *not*
convert operands to their semantic types but should preserve excess
range and precision, meaning that for some argument types and values
of FLT_EVAL_METHOD, an underlying function should be called for a
wider type than that of the arguments.)

The underlying functions are implemented with the type-generic
template machinery.  Comparing x <= y && x >= y is sufficient in ISO C
to achieve an equality comparison with "invalid" raised for unordered
operands (and the results of those two comparisons can also be used to
tell whether errno needs to be set).  However, some architectures have
GCC bugs meaning that unordered comparison instructions are used
instead of ordered ones.  Thus, a mechanism is provided for
architectures to use an explicit call to feraiseexcept to raise
exceptions if required.  If your architecture has such a bug you
should add a fix-fp-int-compare-invalid.h header for it, with a
comment pointing to the relevant GCC bug report; if such a GCC bug is
fixed, that header's contents should have a __GNUC_PREREQ conditional
added so that the workaround can eventually be removed for that
architecture.

Tested for x86_64, x86, mips64, arm and powerpc.

	* math/math.h [__GLIBC_USE (IEC_60559_BFP_EXT)] (iseqsig): New
	macro.
	* math/bits/mathcalls.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(__iseqsig): New declaration.
	* math/s_iseqsig_template.c: New file.
	* math/Versions (__iseqsigf): New libm symbol at version
	GLIBC_2.25.
	(__iseqsig): Likewise.
	(__iseqsigl): Likewise.
	* math/libm-test.inc (iseqsig_test_data): New array.
	(iseqsig_test): New function.
	(main): Call iseqsig_test.
	* math/Makefile (gen-libm-calls): Add s_iseqsigF.
	* manual/arith.texi (FP Comparison Functions): Document iseqsig.
	* manual/libm-err-tab.pl: Update comment on interfaces without
	ulps tabulated.
	* sysdeps/generic/fix-fp-int-compare-invalid.h: New file.
	* sysdeps/powerpc/fpu/fix-fp-int-compare-invalid.h: Likewise.
	* sysdeps/x86/fpu/fix-fp-int-compare-invalid.h: Likewise.
	* sysdeps/nacl/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/aarch64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/alpha/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/arm/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/hppa/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/i386/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/ia64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/m68k/coldfire/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/m68k/m680x0/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/microblaze/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips32/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/nios2/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm-le.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-32/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sh/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc32/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/tile/tilepro/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist: Likewise.

6 files changed, 125 insertions, 3 deletions

diff --git a/math/Makefile b/math/Makefile
index d2b4fd1153..a9f06080f4 100644
--- a/math/Makefile
+++ b/math/Makefile
@@ -51,7 +51,7 @@ gen-libm-calls = cargF conjF cimagF crealF cabsF s_cacosF		  \
 		 k_casinhF s_csinhF k_casinhF s_csinhF s_catanhF s_catanF \
 		 s_ctanF s_ctanhF s_cexpF s_clogF s_cprojF s_csqrtF	  \
 		 s_cpowF s_clog10F s_fdimF s_nextdownF s_fmaxF s_fminF	  \
-		 s_nanF
+		 s_nanF s_iseqsigF
 
 libm-calls =								  \
 	e_acosF e_acoshF e_asinF e_atan2F e_atanhF e_coshF e_expF e_fmodF \
diff --git a/math/Versions b/math/Versions
index f702051451..e658a1037c 100644
--- a/math/Versions
+++ b/math/Versions
@@ -216,6 +216,6 @@ libm {
   }
   GLIBC_2.25 {
     fesetexcept; fetestexceptflag; fegetmode; fesetmode;
-    __iscanonicall;
+    __iscanonicall; __iseqsigf; __iseqsig; __iseqsigl;
   }
 }
diff --git a/math/bits/mathcalls.h b/math/bits/mathcalls.h
index 951a3d0090..4fc18659f8 100644
--- a/math/bits/mathcalls.h
+++ b/math/bits/mathcalls.h
@@ -380,6 +380,9 @@ __END_NAMESPACE_C99
 #endif
 
 #if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Test equality.  */
+__MATHDECL_1 (int, __iseqsig,, (_Mdouble_ __x, _Mdouble_ __y));
+
 /* Test for signaling NaN.  */
 __MATHDECL_1 (int, __issignaling,, (_Mdouble_ __value))
      __attribute__ ((__const__));
diff --git a/math/libm-test.inc b/math/libm-test.inc
index cbc7226aea..4573482f65 100644
--- a/math/libm-test.inc
+++ b/math/libm-test.inc
@@ -47,7 +47,7 @@
    fabs, fdim, finite, floor, fma, fmax, fmin, fmod, fpclassify,
    frexp, gamma, hypot,
    ilogb, iscanonical, isfinite, isinf, isnan, isnormal, issignaling,
-   issubnormal, iszero, isless, islessequal, isgreater,
+   issubnormal, iszero, iseqsig, isless, islessequal, isgreater,
    isgreaterequal, islessgreater, isunordered, j0, j1, jn,
    ldexp, lgamma, log, log10, log1p, log2, logb,
    modf, nearbyint, nextafter, nexttoward,
@@ -8185,6 +8185,64 @@ iscanonical_test (void)
   ALL_RM_TEST (iscanonical, 1, iscanonical_test_data, RUN_TEST_LOOP_f_b_tg, END);
 }
 
+static const struct test_ff_i_data iseqsig_test_data[] =
+  {
+    TEST_ff_i (iseqsig, minus_zero, minus_zero, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_ff_i (iseqsig, minus_zero, plus_zero, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_ff_i (iseqsig, minus_zero, (FLOAT) 1, 0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_ff_i (iseqsig, minus_zero, qnan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, minus_zero, -qnan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, minus_zero, snan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, minus_zero, -snan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, plus_zero, minus_zero, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_ff_i (iseqsig, plus_zero, plus_zero, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_ff_i (iseqsig, plus_zero, (FLOAT) 1, 0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_ff_i (iseqsig, plus_zero, qnan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, plus_zero, -qnan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, plus_zero, snan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, plus_zero, -snan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, (FLOAT) 1, minus_zero, 0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_ff_i (iseqsig, (FLOAT) 1, plus_zero, 0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_ff_i (iseqsig, (FLOAT) 1, (FLOAT) 1, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_ff_i (iseqsig, (FLOAT) 1, qnan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, (FLOAT) 1, -qnan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, (FLOAT) 1, snan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, (FLOAT) 1, -snan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, qnan_value, minus_zero, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, -qnan_value, minus_zero, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, qnan_value, plus_zero, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, -qnan_value, plus_zero, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, qnan_value, (FLOAT) 1, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, -qnan_value, (FLOAT) 1, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, snan_value, minus_zero, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, -snan_value, minus_zero, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, snan_value, plus_zero, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, -snan_value, plus_zero, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, snan_value, (FLOAT) 1, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, -snan_value, (FLOAT) 1, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, qnan_value, qnan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, qnan_value, -qnan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, -qnan_value, qnan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, -qnan_value, -qnan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, snan_value, qnan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, snan_value, -qnan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, -snan_value, qnan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, -snan_value, -qnan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, qnan_value, snan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, qnan_value, -snan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, -qnan_value, snan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, -qnan_value, -snan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, snan_value, snan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, snan_value, -snan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, -snan_value, snan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_ff_i (iseqsig, -snan_value, -snan_value, 0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+  };
+
+static void
+iseqsig_test (void)
+{
+  ALL_RM_TEST (iseqsig, 1, iseqsig_test_data, RUN_TEST_LOOP_ff_i_tg, END);
+}
 static const struct test_f_i_data isfinite_test_data[] =
   {
     TEST_f_b (isfinite, 0, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
@@ -12834,6 +12892,7 @@ main (int argc, char **argv)
   fma_test ();
 
   /* Comparison macros:  */
+  iseqsig_test ();
   isgreater_test ();
   isgreaterequal_test ();
   isless_test ();
diff --git a/math/math.h b/math/math.h
index 8cd641688d..394cefae02 100644
--- a/math/math.h
+++ b/math/math.h
@@ -531,6 +531,24 @@ extern int matherr (struct exception *__exc);
 
 #endif
 
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Return X == Y but raising "invalid" and setting errno if X or Y is
+   a NaN.  */
+# ifdef __NO_LONG_DOUBLE_MATH
+#  define iseqsig(x, y)				\
+  (sizeof ((x) + (y)) == sizeof (float)		\
+   ? __iseqsigf ((x), (y))			\
+   : __iseqsig ((x), (y)))
+# else
+#  define iseqsig(x, y)				\
+  (sizeof ((x) + (y)) == sizeof (float)		\
+   ? __iseqsigf ((x), (y))			\
+   : sizeof ((x) + (y)) == sizeof (double)	\
+   ? __iseqsig ((x), (y))			\
+   : __iseqsigl ((x), (y)))
+# endif
+#endif
+
 __END_DECLS
 
 
diff --git a/math/s_iseqsig_template.c b/math/s_iseqsig_template.c
new file mode 100644
index 0000000000..ebdae6493c
--- /dev/null
+++ b/math/s_iseqsig_template.c
@@ -0,0 +1,42 @@
+/* Test whether X == Y.
+   Copyright (C) 2016 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/>.  */
+
+#include <errno.h>
+#include <fenv.h>
+#include <math.h>
+#include <stdbool.h>
+#include <fix-fp-int-compare-invalid.h>
+
+int
+M_DECL_FUNC (__iseqsig) (FLOAT x, FLOAT y)
+{
+  /* Comparing <= and >= is sufficient to determine both whether X and
+     Y are equal, and whether they are unordered, while raising the
+     "invalid" exception if they are unordered.  */
+  bool cmp1 = x <= y;
+  bool cmp2 = x >= y;
+  if (cmp1 && cmp2)
+    return 1;
+  else if (!cmp1 && !cmp2)
+    {
+      if (FIX_COMPARE_INVALID)
+	feraiseexcept (FE_INVALID);
+      __set_errno (EDOM);
+    }
+  return 0;
+}