Add fetestexceptflag.

TS 18661-1 defines an fetestexceptflag function to test the exception
state saved in an fexcept_t object by fegetexceptflag.

This patch implements this function for glibc.  Almost all
architectures save exception state in such a way that it can be
directly ANDed with exception flag bits, so rather than having lots of
fetestexceptflag implementations that all do the same thing, the math/
implementation is made to use this generic logic (which is also OK in
the fallback case where FE_ALL_EXCEPT is zero).  The only architecture
that seems to need anything different is s390.

(fegetexceptflag and fesetexceptflag use abbreviated filenames
fgetexcptflg.c and fsetexcptflg.c.  Because we are no longer concerned
by 14-character filename limits, fetestexceptflag uses the obvious
filename fetestexceptflag.c.)

The NEWS entry is intended to be expanded along the lines given in
<https://sourceware.org/ml/libc-alpha/2016-08/msg00356.html> when
fegetmode and fesetmode are added.

Tested for x86_64, x86, mips64 and powerpc.

	* math/fetestexceptflag.c: New file.
	* sysdeps/s390/fpu/fetestexceptflag.c: Likewise.  Comment by
	Stefan Liebler.
	* math/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(fetestexceptflag): New function declaration.
	* manual/arith.texi (fetestexceptflag): Document function.
	* math/Versions (fetestexceptflag): New libm symbol at version
	GLIBC_2.25.
	* math/Makefile (libm-support): Add fetestexceptflag.
	(tests): Add test-fetestexceptflag.
	* math/test-fetestexceptflag.c: New file.
	* 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.

5 files changed, 166 insertions, 3 deletions

diff --git a/math/Makefile b/math/Makefile
index 03cbd1d4a9..dbc2a179dc 100644
--- a/math/Makefile
+++ b/math/Makefile
@@ -41,7 +41,7 @@ libm-support = s_lib_version s_matherr s_signgam			\
 	       fclrexcpt fgetexcptflg fraiseexcpt fsetexcptflg		\
 	       ftestexcept fegetround fesetround fegetenv feholdexcpt	\
 	       fesetenv feupdateenv t_exp fedisblxcpt feenablxcpt	\
-	       fegetexcept fesetexcept
+	       fegetexcept fesetexcept fetestexceptflag
 
 # Wrappers for these functions generated per type using a file named
 # <func>_template.c and the appropriate math-type-macros-<TYPE>.h.
@@ -153,7 +153,7 @@ tests = test-matherr test-fenv atest-exp atest-sincos atest-exp2 basic-test \
 	test-signgam-uint test-signgam-uint-init test-signgam-ullong \
 	test-signgam-ullong-init test-nan-overflow test-nan-payload \
 	test-fexcept test-fexcept-traps test-fesetexcept \
-	test-fesetexcept-traps $(tests-static)
+	test-fesetexcept-traps test-fetestexceptflag $(tests-static)
 tests-static = test-fpucw-static test-fpucw-ieee-static \
 	       test-signgam-uchar-static test-signgam-uchar-init-static \
 	       test-signgam-uint-static test-signgam-uint-init-static \
diff --git a/math/Versions b/math/Versions
index ff4e4d4292..1c1683fed4 100644
--- a/math/Versions
+++ b/math/Versions
@@ -215,6 +215,6 @@ libm {
     nextdown; nextdownf; nextdownl;
   }
   GLIBC_2.25 {
-    fesetexcept;
+    fesetexcept; fetestexceptflag;
   }
 }
diff --git a/math/fenv.h b/math/fenv.h
index 7f4ceb744c..10d32db909 100644
--- a/math/fenv.h
+++ b/math/fenv.h
@@ -85,6 +85,12 @@ extern int fesetexceptflag (const fexcept_t *__flagp, int __excepts) __THROW;
    currently set.  */
 extern int fetestexcept (int __excepts) __THROW;
 
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Determine which of subset of the exceptions specified by EXCEPTS
+   are set in *FLAGP.  */
+extern int fetestexceptflag (const fexcept_t *__flagp, int __excepts) __THROW;
+#endif
+
 
 /* Rounding control.  */
 
diff --git a/math/fetestexceptflag.c b/math/fetestexceptflag.c
new file mode 100644
index 0000000000..6e3d218186
--- /dev/null
+++ b/math/fetestexceptflag.c
@@ -0,0 +1,27 @@
+/* Test exception in saved exception state.
+   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 <fenv.h>
+
+int
+fetestexceptflag (const fexcept_t *flagp, int excepts)
+{
+  /* Most versions of fegetexceptflag store exceptions in a form such
+     that this works.  */
+  return *flagp & excepts & FE_ALL_EXCEPT;
+}
diff --git a/math/test-fetestexceptflag.c b/math/test-fetestexceptflag.c
new file mode 100644
index 0000000000..8122f261f2
--- /dev/null
+++ b/math/test-fetestexceptflag.c
@@ -0,0 +1,130 @@
+/* Test fetestexceptflag.
+   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 <fenv.h>
+#include <stdio.h>
+#include <math-tests.h>
+
+static int
+test_one (int exc_test, int exc_set, int exc_save)
+{
+  int result = 0;
+
+  printf ("Individual test: %x %x %x\n", (unsigned int) exc_test,
+	  (unsigned int) exc_set, (unsigned int) exc_save);
+
+  feclearexcept (FE_ALL_EXCEPT);
+  int ret = fesetexcept (exc_set);
+  if (ret != 0)
+    {
+      puts ("fesetexcept failed");
+      if (exc_set == 0 || EXCEPTION_TESTS (float))
+	{
+	  puts ("failure of fesetexcept was unexpected");
+	  result = 1;
+	}
+      else
+	puts ("failure of fesetexcept OK, skipping further tests");
+      return result;
+    }
+  fexcept_t saved;
+  ret = fegetexceptflag (&saved, exc_save);
+  if (ret == 0)
+    puts ("fegetexceptflag succeeded");
+  else
+    {
+      puts ("fegetexceptflag failed");
+      result = 1;
+      return result;
+    }
+  ret = fetestexceptflag (&saved, exc_test);
+  if (ret == (exc_set & exc_test))
+    puts ("fetestexceptflag result correct");
+  else
+    {
+      printf ("fetestexceptflag returned %x, expected %x\n", ret,
+	      exc_set & exc_test);
+      result = 1;
+    }
+  if (exc_save == FE_ALL_EXCEPT)
+    {
+      /* Also test fetestexceptflag testing all exceptions but
+	 possibly with only some set.  */
+      ret = fetestexceptflag (&saved, FE_ALL_EXCEPT);
+      if (ret == exc_set)
+	puts ("fetestexceptflag (FE_ALL_EXCEPT) result correct");
+      else
+	{
+	  printf ("fetestexceptflag (FE_ALL_EXCEPT) returned %x, expected %x\n",
+		  ret, exc_set);
+	  result = 1;
+	}
+    }
+  return result;
+}
+
+static int
+test_fetestexceptflag (int exc, const char *exc_name)
+{
+  int result = 0;
+
+  printf ("Testing %s\n", exc_name);
+
+  /* Test each case of: whether this exception is set or clear;
+     whether other exceptions are set or clear; whether the whole
+     state is saved or just the state for this exception.  */
+  result |= test_one (exc, 0, exc);
+  result |= test_one (exc, 0, FE_ALL_EXCEPT);
+  result |= test_one (exc, exc, exc);
+  result |= test_one (exc, exc, FE_ALL_EXCEPT);
+  result |= test_one (exc, FE_ALL_EXCEPT & ~exc, exc);
+  result |= test_one (exc, FE_ALL_EXCEPT & ~exc, FE_ALL_EXCEPT);
+  result |= test_one (exc, FE_ALL_EXCEPT, exc);
+  result |= test_one (exc, FE_ALL_EXCEPT, FE_ALL_EXCEPT);
+
+  return result;
+}
+
+static int
+do_test (void)
+{
+  int result = 0;
+
+  result |= test_fetestexceptflag (0, "0");
+  result |= test_fetestexceptflag (FE_ALL_EXCEPT, "FE_ALL_EXCEPT");
+#ifdef FE_DIVBYZERO
+  result |= test_fetestexceptflag (FE_DIVBYZERO, "FE_DIVBYZERO");
+#endif
+#ifdef FE_INEXACT
+  result |= test_fetestexceptflag (FE_INEXACT, "FE_INEXACT");
+#endif
+#ifdef FE_INVALID
+  result |= test_fetestexceptflag (FE_INVALID, "FE_INVALID");
+#endif
+#ifdef FE_OVERFLOW
+  result |= test_fetestexceptflag (FE_OVERFLOW, "FE_OVERFLOW");
+#endif
+#ifdef FE_UNDERFLOW
+  result |= test_fetestexceptflag (FE_UNDERFLOW, "FE_UNDERFLOW");
+#endif
+
+  return result;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"