From: Joseph Myers <joseph@codesourcery.com>
Date: Sat, 3 Nov 2012 19:48:53 +0000 (+0000)
Subject: Make fma use of Dekker and Knuth algorithms use round-to-nearest (bug 14796).
X-Git-Tag: glibc-2.17~274
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5b5b04d6282df0364424c6f2c0462e5c1a4394b0;p=thirdparty%2Fglibc.git

Make fma use of Dekker and Knuth algorithms use round-to-nearest (bug 14796).
---

diff --git a/ChangeLog b/ChangeLog
index d40c31c3eb5..7b0c9d43646 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,46 @@
 2012-11-03  Joseph Myers  <joseph@codesourcery.com>
 
+	[BZ #14796]
+	* sysdeps/ieee754/dbl-64/s_fma.c (__fma): Set rounding mode to
+	FE_TONEAREST before applying Dekker multiplication and Knuth
+	addition.  Clear inexact exceptions and check for exact zero
+	results afterwards.
+	* sysdeps/ieee754/ldbl-128/s_fmal.c (__fmal): Likewise.
+	* sysdeps/ieee754/ldbl-96/s_fma.c (__fma): Likewise.
+	* sysdeps/ieee754/ldbl-96/s_fmal.c (__fmal): Likewise.
+	* math/libm-test.inc (fma_test): Add more tests.
+	(fma_test_towardzero): Likewise.
+	(fma_test_downward): Likewise.
+	(fma_test_upward): Likewise.
+	* sysdeps/generic/math_private.h (default_libc_fesetround): New
+	function.
+	(libc_fesetround): New macro.
+	(libc_fesetroundf): Likewise.
+	(libc_fesetroundl): Likewise.
+	* sysdeps/i386/fpu/fenv_private.h (libc_fesetround_sse): New
+	function.
+	(libc_fesetround_387): Likewise.
+	(libc_fesetroundf): New macro.
+	(libc_fesetround): Likewise.
+	(libc_fesetroundl): Likewise.
+	* sysdeps/sparc/fpu/fenv_private.h (libc_fesetround): New
+	function.
+	(libc_fesetroundf): New macro.
+	(libc_fesetround): Likewise.
+	(libc_fesetroundl): Likewise.
+	* include/fenv.h (feclearexcept): Add libm_hidden_proto.
+	* math/fclrexcpt.c (feclearexcept): Add libm_hidden_ver.
+	* sysdeps/i386/fpu/fclrexcpt.c (feclearexcept): Add
+	libm_hidden_ver.
+	* sysdeps/powerpc/fpu/fclrexcpt.c (feclearexcept): Likewise.
+	* sysdeps/s390/fpu/fclrexcpt.c (feclearexcept): Add
+	libm_hidden_def.
+	* sysdeps/sh/sh4/fpu/fclrexcpt.c (feclearexcept): Likewise.
+	* sysdeps/sparc/fpu/fclrexcpt.c (feclearexcept): Add
+	libm_hidden_ver.
+	* sysdeps/x86_64/fpu/fclrexcpt.c (feclearexcept): Add
+	libm_hidden_def.
+
 	[BZ #3439]
 	* sysdeps/powerpc/bits/fenv.h (FE_INEXACT): Define macro to
 	integer constant usable in #if and use that to give value to enum
diff --git a/NEWS b/NEWS
index fba6689023a..25af21ce1aa 100644
--- a/NEWS
+++ b/NEWS
@@ -18,7 +18,7 @@ Version 2.17
   14532, 14538, 14543, 14544, 14545, 14557, 14562, 14568, 14576, 14579,
   14583, 14587, 14595, 14602, 14610, 14621, 14638, 14645, 14648, 14652,
   14660, 14661, 14669, 14683, 14694, 14716, 14743, 14767, 14783, 14784,
-  14785.
+  14785, 14796.
 
 * Support for STT_GNU_IFUNC symbols added for s390 and s390x.
   Optimized versions of memcpy, memset, and memcmp added for System z10 and
diff --git a/include/fenv.h b/include/fenv.h
index 67ef385bbff..ed6d1394ba5 100644
--- a/include/fenv.h
+++ b/include/fenv.h
@@ -20,6 +20,7 @@ libm_hidden_proto (fesetround)
 libm_hidden_proto (feholdexcept)
 libm_hidden_proto (feupdateenv)
 libm_hidden_proto (fetestexcept)
+libm_hidden_proto (feclearexcept)
 #endif
 
 #endif
diff --git a/math/fclrexcpt.c b/math/fclrexcpt.c
index dcdcfbbe997..bbf1011a652 100644
--- a/math/fclrexcpt.c
+++ b/math/fclrexcpt.c
@@ -30,6 +30,7 @@ __feclearexcept (int excepts)
 strong_alias (__feclearexcept, __old_feclearexcept)
 compat_symbol (libm, __old_feclearexcept, feclearexcept, GLIBC_2_1);
 #endif
+libm_hidden_ver (__feclearexcept, feclearexcept)
 versioned_symbol (libm, __feclearexcept, feclearexcept, GLIBC_2_2);
 
 stub_warning (feclearexcept)
diff --git a/math/libm-test.inc b/math/libm-test.inc
index 258c960ec16..48241e02f89 100644
--- a/math/libm-test.inc
+++ b/math/libm-test.inc
@@ -4649,6 +4649,10 @@ fma_test (void)
   TEST_fff_f (fma, 0x1p-149, -0x1p-149, 0x1p-149, 0x1p-149, UNDERFLOW_EXCEPTION);
   TEST_fff_f (fma, 0x1p-149, 0x1p-149, -0x1p-149, -0x1p-149, UNDERFLOW_EXCEPTION);
   TEST_fff_f (fma, 0x1p-149, -0x1p-149, -0x1p-149, -0x1p-149, UNDERFLOW_EXCEPTION);
+  TEST_fff_f (fma, 0x0.fffp0, 0x0.fffp0, -0x0.ffep0, 0x1p-24);
+  TEST_fff_f (fma, 0x0.fffp0, -0x0.fffp0, 0x0.ffep0, -0x1p-24);
+  TEST_fff_f (fma, -0x0.fffp0, 0x0.fffp0, 0x0.ffep0, -0x1p-24);
+  TEST_fff_f (fma, -0x0.fffp0, -0x0.fffp0, -0x0.ffep0, 0x1p-24);
 #endif
 #if defined (TEST_DOUBLE) && DBL_MANT_DIG == 53
   TEST_fff_f (fma, 0x1.7fp+13, 0x1.0000000000001p+0, 0x1.ffep-48, 0x1.7f00000000001p+13);
@@ -4695,6 +4699,10 @@ fma_test (void)
   TEST_fff_f (fma, 0x1p-1074, -0x1p-1074, 0x1p-1074, 0x1p-1074, UNDERFLOW_EXCEPTION);
   TEST_fff_f (fma, 0x1p-1074, 0x1p-1074, -0x1p-1074, -0x1p-1074, UNDERFLOW_EXCEPTION);
   TEST_fff_f (fma, 0x1p-1074, -0x1p-1074, -0x1p-1074, -0x1p-1074, UNDERFLOW_EXCEPTION);
+  TEST_fff_f (fma, 0x0.fffffffffffff8p0, 0x0.fffffffffffff8p0, -0x0.fffffffffffffp0, 0x1p-106);
+  TEST_fff_f (fma, 0x0.fffffffffffff8p0, -0x0.fffffffffffff8p0, 0x0.fffffffffffffp0, -0x1p-106);
+  TEST_fff_f (fma, -0x0.fffffffffffff8p0, 0x0.fffffffffffff8p0, 0x0.fffffffffffffp0, -0x1p-106);
+  TEST_fff_f (fma, -0x0.fffffffffffff8p0, -0x0.fffffffffffff8p0, -0x0.fffffffffffffp0, 0x1p-106);
 #endif
 #if defined (TEST_LDOUBLE) && LDBL_MANT_DIG == 64
   TEST_fff_f (fma, -0x8.03fcp+3696L, 0xf.fffffffffffffffp-6140L, 0x8.3ffffffffffffffp-2450L, -0x8.01ecp-2440L);
@@ -4727,6 +4735,10 @@ fma_test (void)
   TEST_fff_f (fma, 0x1p-16445L, -0x1p-16445L, 0x1p-16445L, 0x1p-16445L, UNDERFLOW_EXCEPTION);
   TEST_fff_f (fma, 0x1p-16445L, 0x1p-16445L, -0x1p-16445L, -0x1p-16445L, UNDERFLOW_EXCEPTION);
   TEST_fff_f (fma, 0x1p-16445L, -0x1p-16445L, -0x1p-16445L, -0x1p-16445L, UNDERFLOW_EXCEPTION);
+  TEST_fff_f (fma, 0x0.ffffffffffffffffp0L, 0x0.ffffffffffffffffp0L, -0x0.fffffffffffffffep0L, 0x1p-128L);
+  TEST_fff_f (fma, 0x0.ffffffffffffffffp0L, -0x0.ffffffffffffffffp0L, 0x0.fffffffffffffffep0L, -0x1p-128L);
+  TEST_fff_f (fma, -0x0.ffffffffffffffffp0L, 0x0.ffffffffffffffffp0L, 0x0.fffffffffffffffep0L, -0x1p-128L);
+  TEST_fff_f (fma, -0x0.ffffffffffffffffp0L, -0x0.ffffffffffffffffp0L, -0x0.fffffffffffffffep0L, 0x1p-128L);
 #endif
 #if defined (TEST_LDOUBLE) && LDBL_MANT_DIG == 113
   TEST_fff_f (fma, 0x1.bb2de33e02ccbbfa6e245a7c1f71p-2584L, -0x1.6b500daf0580d987f1bc0cadfcddp-13777L, 0x1.613cd91d9fed34b33820e5ab9d8dp-16378L, -0x1.3a79fb50eb9ce887cffa0f09bd9fp-16360L);
@@ -4766,6 +4778,10 @@ fma_test (void)
   TEST_fff_f (fma, 0x1p-16494L, -0x1p-16494L, 0x1p-16494L, 0x1p-16494L, UNDERFLOW_EXCEPTION);
   TEST_fff_f (fma, 0x1p-16494L, 0x1p-16494L, -0x1p-16494L, -0x1p-16494L, UNDERFLOW_EXCEPTION);
   TEST_fff_f (fma, 0x1p-16494L, -0x1p-16494L, -0x1p-16494L, -0x1p-16494L, UNDERFLOW_EXCEPTION);
+  TEST_fff_f (fma, 0x0.ffffffffffffffffffffffffffff8p0L, 0x0.ffffffffffffffffffffffffffff8p0L, -0x0.ffffffffffffffffffffffffffffp0L, 0x1p-226L);
+  TEST_fff_f (fma, 0x0.ffffffffffffffffffffffffffff8p0L, -0x0.ffffffffffffffffffffffffffff8p0L, 0x0.ffffffffffffffffffffffffffffp0L, -0x1p-226L);
+  TEST_fff_f (fma, -0x0.ffffffffffffffffffffffffffff8p0L, 0x0.ffffffffffffffffffffffffffff8p0L, 0x0.ffffffffffffffffffffffffffffp0L, -0x1p-226L);
+  TEST_fff_f (fma, -0x0.ffffffffffffffffffffffffffff8p0L, -0x0.ffffffffffffffffffffffffffff8p0L, -0x0.ffffffffffffffffffffffffffffp0L, 0x1p-226L);
 #endif
 
   END (fma);
@@ -4846,6 +4862,10 @@ fma_test_towardzero (void)
       TEST_fff_f (fma, 0x1p-149, -0x1p-149, 0x1p-149, plus_zero, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-149, 0x1p-149, -0x1p-149, minus_zero, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-149, -0x1p-149, -0x1p-149, -0x1p-149, UNDERFLOW_EXCEPTION);
+      TEST_fff_f (fma, 0x0.fffp0, 0x0.fffp0, -0x0.ffep0, 0x1p-24);
+      TEST_fff_f (fma, 0x0.fffp0, -0x0.fffp0, 0x0.ffep0, -0x1p-24);
+      TEST_fff_f (fma, -0x0.fffp0, 0x0.fffp0, 0x0.ffep0, -0x1p-24);
+      TEST_fff_f (fma, -0x0.fffp0, -0x0.fffp0, -0x0.ffep0, 0x1p-24);
 #endif
 #if defined (TEST_DOUBLE) && DBL_MANT_DIG == 53
       TEST_fff_f (fma, 0x1.4p-1022, 0x1.0000000000002p-1, 0x1p-1024, 0x1.c000000000002p-1023, UNDERFLOW_EXCEPTION);
@@ -4872,6 +4892,10 @@ fma_test_towardzero (void)
       TEST_fff_f (fma, 0x1p-1074, -0x1p-1074, 0x1p-1074, plus_zero, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-1074, 0x1p-1074, -0x1p-1074, minus_zero, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-1074, -0x1p-1074, -0x1p-1074, -0x1p-1074, UNDERFLOW_EXCEPTION);
+      TEST_fff_f (fma, 0x0.fffffffffffff8p0, 0x0.fffffffffffff8p0, -0x0.fffffffffffffp0, 0x1p-106);
+      TEST_fff_f (fma, 0x0.fffffffffffff8p0, -0x0.fffffffffffff8p0, 0x0.fffffffffffffp0, -0x1p-106);
+      TEST_fff_f (fma, -0x0.fffffffffffff8p0, 0x0.fffffffffffff8p0, 0x0.fffffffffffffp0, -0x1p-106);
+      TEST_fff_f (fma, -0x0.fffffffffffff8p0, -0x0.fffffffffffff8p0, -0x0.fffffffffffffp0, 0x1p-106);
 #endif
 #if defined (TEST_LDOUBLE) && LDBL_MANT_DIG == 64
       TEST_fff_f (fma, 0x1.4p-16382L, 0x1.0000000000000004p-1L, 0x1p-16384L, 0x1.c000000000000004p-16383L, UNDERFLOW_EXCEPTION);
@@ -4898,6 +4922,10 @@ fma_test_towardzero (void)
       TEST_fff_f (fma, 0x1p-16445L, -0x1p-16445L, 0x1p-16445L, plus_zero, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-16445L, 0x1p-16445L, -0x1p-16445L, minus_zero, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-16445L, -0x1p-16445L, -0x1p-16445L, -0x1p-16445L, UNDERFLOW_EXCEPTION);
+      TEST_fff_f (fma, 0x0.ffffffffffffffffp0L, 0x0.ffffffffffffffffp0L, -0x0.fffffffffffffffep0L, 0x1p-128L);
+      TEST_fff_f (fma, 0x0.ffffffffffffffffp0L, -0x0.ffffffffffffffffp0L, 0x0.fffffffffffffffep0L, -0x1p-128L);
+      TEST_fff_f (fma, -0x0.ffffffffffffffffp0L, 0x0.ffffffffffffffffp0L, 0x0.fffffffffffffffep0L, -0x1p-128L);
+      TEST_fff_f (fma, -0x0.ffffffffffffffffp0L, -0x0.ffffffffffffffffp0L, -0x0.fffffffffffffffep0L, 0x1p-128L);
 #endif
 #if defined (TEST_LDOUBLE) && LDBL_MANT_DIG == 113
       TEST_fff_f (fma, 0x1.4p-16382L, 0x1.0000000000000000000000000002p-1L, 0x1p-16384L, 0x1.c000000000000000000000000002p-16383L, UNDERFLOW_EXCEPTION);
@@ -4924,6 +4952,10 @@ fma_test_towardzero (void)
       TEST_fff_f (fma, 0x1p-16494L, -0x1p-16494L, 0x1p-16494L, plus_zero, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-16494L, 0x1p-16494L, -0x1p-16494L, minus_zero, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-16494L, -0x1p-16494L, -0x1p-16494L, -0x1p-16494L, UNDERFLOW_EXCEPTION);
+      TEST_fff_f (fma, 0x0.ffffffffffffffffffffffffffff8p0L, 0x0.ffffffffffffffffffffffffffff8p0L, -0x0.ffffffffffffffffffffffffffffp0L, 0x1p-226L);
+      TEST_fff_f (fma, 0x0.ffffffffffffffffffffffffffff8p0L, -0x0.ffffffffffffffffffffffffffff8p0L, 0x0.ffffffffffffffffffffffffffffp0L, -0x1p-226L);
+      TEST_fff_f (fma, -0x0.ffffffffffffffffffffffffffff8p0L, 0x0.ffffffffffffffffffffffffffff8p0L, 0x0.ffffffffffffffffffffffffffffp0L, -0x1p-226L);
+      TEST_fff_f (fma, -0x0.ffffffffffffffffffffffffffff8p0L, -0x0.ffffffffffffffffffffffffffff8p0L, -0x0.ffffffffffffffffffffffffffffp0L, 0x1p-226L);
 #endif
     }
 
@@ -5007,6 +5039,10 @@ fma_test_downward (void)
       TEST_fff_f (fma, 0x1p-149, -0x1p-149, 0x1p-149, plus_zero, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-149, 0x1p-149, -0x1p-149, -0x1p-149, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-149, -0x1p-149, -0x1p-149, -0x1p-148, UNDERFLOW_EXCEPTION);
+      TEST_fff_f (fma, 0x0.fffp0, 0x0.fffp0, -0x0.ffep0, 0x1p-24);
+      TEST_fff_f (fma, 0x0.fffp0, -0x0.fffp0, 0x0.ffep0, -0x1p-24);
+      TEST_fff_f (fma, -0x0.fffp0, 0x0.fffp0, 0x0.ffep0, -0x1p-24);
+      TEST_fff_f (fma, -0x0.fffp0, -0x0.fffp0, -0x0.ffep0, 0x1p-24);
 #endif
 #if defined (TEST_DOUBLE) && DBL_MANT_DIG == 53
       TEST_fff_f (fma, 0x1.4p-1022, 0x1.0000000000002p-1, 0x1p-1024, 0x1.c000000000002p-1023, UNDERFLOW_EXCEPTION);
@@ -5033,6 +5069,10 @@ fma_test_downward (void)
       TEST_fff_f (fma, 0x1p-1074, -0x1p-1074, 0x1p-1074, plus_zero, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-1074, 0x1p-1074, -0x1p-1074, -0x1p-1074, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-1074, -0x1p-1074, -0x1p-1074, -0x1p-1073, UNDERFLOW_EXCEPTION);
+      TEST_fff_f (fma, 0x0.fffffffffffff8p0, 0x0.fffffffffffff8p0, -0x0.fffffffffffffp0, 0x1p-106);
+      TEST_fff_f (fma, 0x0.fffffffffffff8p0, -0x0.fffffffffffff8p0, 0x0.fffffffffffffp0, -0x1p-106);
+      TEST_fff_f (fma, -0x0.fffffffffffff8p0, 0x0.fffffffffffff8p0, 0x0.fffffffffffffp0, -0x1p-106);
+      TEST_fff_f (fma, -0x0.fffffffffffff8p0, -0x0.fffffffffffff8p0, -0x0.fffffffffffffp0, 0x1p-106);
 #endif
 #if defined (TEST_LDOUBLE) && LDBL_MANT_DIG == 64
       TEST_fff_f (fma, 0x1.4p-16382L, 0x1.0000000000000004p-1L, 0x1p-16384L, 0x1.c000000000000004p-16383L, UNDERFLOW_EXCEPTION);
@@ -5059,6 +5099,10 @@ fma_test_downward (void)
       TEST_fff_f (fma, 0x1p-16445L, -0x1p-16445L, 0x1p-16445L, plus_zero, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-16445L, 0x1p-16445L, -0x1p-16445L, -0x1p-16445L, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-16445L, -0x1p-16445L, -0x1p-16445L, -0x1p-16444L, UNDERFLOW_EXCEPTION);
+      TEST_fff_f (fma, 0x0.ffffffffffffffffp0L, 0x0.ffffffffffffffffp0L, -0x0.fffffffffffffffep0L, 0x1p-128L);
+      TEST_fff_f (fma, 0x0.ffffffffffffffffp0L, -0x0.ffffffffffffffffp0L, 0x0.fffffffffffffffep0L, -0x1p-128L);
+      TEST_fff_f (fma, -0x0.ffffffffffffffffp0L, 0x0.ffffffffffffffffp0L, 0x0.fffffffffffffffep0L, -0x1p-128L);
+      TEST_fff_f (fma, -0x0.ffffffffffffffffp0L, -0x0.ffffffffffffffffp0L, -0x0.fffffffffffffffep0L, 0x1p-128L);
 #endif
 #if defined (TEST_LDOUBLE) && LDBL_MANT_DIG == 113
       TEST_fff_f (fma, 0x1.4p-16382L, 0x1.0000000000000000000000000002p-1L, 0x1p-16384L, 0x1.c000000000000000000000000002p-16383L, UNDERFLOW_EXCEPTION);
@@ -5085,6 +5129,10 @@ fma_test_downward (void)
       TEST_fff_f (fma, 0x1p-16494L, -0x1p-16494L, 0x1p-16494L, plus_zero, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-16494L, 0x1p-16494L, -0x1p-16494L, -0x1p-16494L, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-16494L, -0x1p-16494L, -0x1p-16494L, -0x1p-16493L, UNDERFLOW_EXCEPTION);
+      TEST_fff_f (fma, 0x0.ffffffffffffffffffffffffffff8p0L, 0x0.ffffffffffffffffffffffffffff8p0L, -0x0.ffffffffffffffffffffffffffffp0L, 0x1p-226L);
+      TEST_fff_f (fma, 0x0.ffffffffffffffffffffffffffff8p0L, -0x0.ffffffffffffffffffffffffffff8p0L, 0x0.ffffffffffffffffffffffffffffp0L, -0x1p-226L);
+      TEST_fff_f (fma, -0x0.ffffffffffffffffffffffffffff8p0L, 0x0.ffffffffffffffffffffffffffff8p0L, 0x0.ffffffffffffffffffffffffffffp0L, -0x1p-226L);
+      TEST_fff_f (fma, -0x0.ffffffffffffffffffffffffffff8p0L, -0x0.ffffffffffffffffffffffffffff8p0L, -0x0.ffffffffffffffffffffffffffffp0L, 0x1p-226L);
 #endif
     }
 
@@ -5168,6 +5216,10 @@ fma_test_upward (void)
       TEST_fff_f (fma, 0x1p-149, -0x1p-149, 0x1p-149, 0x1p-149, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-149, 0x1p-149, -0x1p-149, minus_zero, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-149, -0x1p-149, -0x1p-149, -0x1p-149, UNDERFLOW_EXCEPTION);
+      TEST_fff_f (fma, 0x0.fffp0, 0x0.fffp0, -0x0.ffep0, 0x1p-24);
+      TEST_fff_f (fma, 0x0.fffp0, -0x0.fffp0, 0x0.ffep0, -0x1p-24);
+      TEST_fff_f (fma, -0x0.fffp0, 0x0.fffp0, 0x0.ffep0, -0x1p-24);
+      TEST_fff_f (fma, -0x0.fffp0, -0x0.fffp0, -0x0.ffep0, 0x1p-24);
 #endif
 #if defined (TEST_DOUBLE) && DBL_MANT_DIG == 53
       TEST_fff_f (fma, 0x1.4p-1022, 0x1.0000000000002p-1, 0x1p-1024, 0x1.c000000000004p-1023, UNDERFLOW_EXCEPTION);
@@ -5194,6 +5246,10 @@ fma_test_upward (void)
       TEST_fff_f (fma, 0x1p-1074, -0x1p-1074, 0x1p-1074, 0x1p-1074, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-1074, 0x1p-1074, -0x1p-1074, minus_zero, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-1074, -0x1p-1074, -0x1p-1074, -0x1p-1074, UNDERFLOW_EXCEPTION);
+      TEST_fff_f (fma, 0x0.fffffffffffff8p0, 0x0.fffffffffffff8p0, -0x0.fffffffffffffp0, 0x1p-106);
+      TEST_fff_f (fma, 0x0.fffffffffffff8p0, -0x0.fffffffffffff8p0, 0x0.fffffffffffffp0, -0x1p-106);
+      TEST_fff_f (fma, -0x0.fffffffffffff8p0, 0x0.fffffffffffff8p0, 0x0.fffffffffffffp0, -0x1p-106);
+      TEST_fff_f (fma, -0x0.fffffffffffff8p0, -0x0.fffffffffffff8p0, -0x0.fffffffffffffp0, 0x1p-106);
 #endif
 #if defined (TEST_LDOUBLE) && LDBL_MANT_DIG == 64
       TEST_fff_f (fma, 0x1.4p-16382L, 0x1.0000000000000004p-1L, 0x1p-16384L, 0x1.c000000000000008p-16383L, UNDERFLOW_EXCEPTION);
@@ -5220,6 +5276,10 @@ fma_test_upward (void)
       TEST_fff_f (fma, 0x1p-16445L, -0x1p-16445L, 0x1p-16445L, 0x1p-16445L, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-16445L, 0x1p-16445L, -0x1p-16445L, minus_zero, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-16445L, -0x1p-16445L, -0x1p-16445L, -0x1p-16445L, UNDERFLOW_EXCEPTION);
+      TEST_fff_f (fma, 0x0.ffffffffffffffffp0L, 0x0.ffffffffffffffffp0L, -0x0.fffffffffffffffep0L, 0x1p-128L);
+      TEST_fff_f (fma, 0x0.ffffffffffffffffp0L, -0x0.ffffffffffffffffp0L, 0x0.fffffffffffffffep0L, -0x1p-128L);
+      TEST_fff_f (fma, -0x0.ffffffffffffffffp0L, 0x0.ffffffffffffffffp0L, 0x0.fffffffffffffffep0L, -0x1p-128L);
+      TEST_fff_f (fma, -0x0.ffffffffffffffffp0L, -0x0.ffffffffffffffffp0L, -0x0.fffffffffffffffep0L, 0x1p-128L);
 #endif
 #if defined (TEST_LDOUBLE) && LDBL_MANT_DIG == 113
       TEST_fff_f (fma, 0x1.4p-16382L, 0x1.0000000000000000000000000002p-1L, 0x1p-16384L, 0x1.c000000000000000000000000004p-16383L, UNDERFLOW_EXCEPTION);
@@ -5246,6 +5306,10 @@ fma_test_upward (void)
       TEST_fff_f (fma, 0x1p-16494L, -0x1p-16494L, 0x1p-16494L, 0x1p-16494L, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-16494L, 0x1p-16494L, -0x1p-16494L, minus_zero, UNDERFLOW_EXCEPTION);
       TEST_fff_f (fma, 0x1p-16494L, -0x1p-16494L, -0x1p-16494L, -0x1p-16494L, UNDERFLOW_EXCEPTION);
+      TEST_fff_f (fma, 0x0.ffffffffffffffffffffffffffff8p0L, 0x0.ffffffffffffffffffffffffffff8p0L, -0x0.ffffffffffffffffffffffffffffp0L, 0x1p-226L);
+      TEST_fff_f (fma, 0x0.ffffffffffffffffffffffffffff8p0L, -0x0.ffffffffffffffffffffffffffff8p0L, 0x0.ffffffffffffffffffffffffffffp0L, -0x1p-226L);
+      TEST_fff_f (fma, -0x0.ffffffffffffffffffffffffffff8p0L, 0x0.ffffffffffffffffffffffffffff8p0L, 0x0.ffffffffffffffffffffffffffffp0L, -0x1p-226L);
+      TEST_fff_f (fma, -0x0.ffffffffffffffffffffffffffff8p0L, -0x0.ffffffffffffffffffffffffffff8p0L, -0x0.ffffffffffffffffffffffffffffp0L, 0x1p-226L);
 #endif
     }
 
diff --git a/ports/ChangeLog.alpha b/ports/ChangeLog.alpha
index de1837ed7d1..ca446c8a898 100644
--- a/ports/ChangeLog.alpha
+++ b/ports/ChangeLog.alpha
@@ -1,5 +1,8 @@
 2012-11-03  Joseph Myers  <joseph@codesourcery.com>
 
+	* sysdeps/alpha/fpu/fclrexcpt.c (feclearexcept): Add
+	libm_hidden_ver.
+
 	[BZ #3439]
 	* sysdeps/alpha/fpu/bits/fenv.h (FE_DENORMAL): Define macro to
 	integer constant usable in #if and use that to give value to enum
diff --git a/ports/ChangeLog.am33 b/ports/ChangeLog.am33
index c018fbaabfa..4e6d40b4c51 100644
--- a/ports/ChangeLog.am33
+++ b/ports/ChangeLog.am33
@@ -1,5 +1,8 @@
 2012-11-03  Joseph Myers  <joseph@codesourcery.com>
 
+	* sysdeps/am33/fpu/fclrexcpt.c (feclearexcept): Add
+	libm_hidden_ver.
+
 	[BZ #3439]
 	* sysdeps/am33/fpu/bits/fenv.h (FE_INEXACT): Define macro to
 	integer constant usable in #if and use that to give value to enum
diff --git a/ports/ChangeLog.arm b/ports/ChangeLog.arm
index 54c5cf0392e..234883e17ac 100644
--- a/ports/ChangeLog.arm
+++ b/ports/ChangeLog.arm
@@ -1,5 +1,7 @@
 2012-11-03  Joseph Myers  <joseph@codesourcery.com>
 
+	* sysdeps/arm/fclrexcpt.c (feclearexcept): Add libm_hidden_ver.
+
 	[BZ #3439]
 	* sysdeps/arm/bits/fenv.h (FE_INVALID): Define macro to integer
 	constant usable in #if and use that to give value to enum
diff --git a/ports/ChangeLog.hppa b/ports/ChangeLog.hppa
index a5da64a0964..3e8d522a07f 100644
--- a/ports/ChangeLog.hppa
+++ b/ports/ChangeLog.hppa
@@ -1,5 +1,8 @@
 2012-11-03  Joseph Myers  <joseph@codesourcery.com>
 
+	* sysdeps/hppa/fpu/fclrexcpt.c (feclearexcept): Add
+	libm_hidden_def.
+
 	[BZ #3439]
 	* sysdeps/hppa/fpu/bits/fenv.h (FE_INVALID): Define macro to
 	integer constant usable in #if and use that to give value to enum
diff --git a/ports/ChangeLog.ia64 b/ports/ChangeLog.ia64
index 0d629c613e9..0b3361af081 100644
--- a/ports/ChangeLog.ia64
+++ b/ports/ChangeLog.ia64
@@ -1,5 +1,8 @@
 2012-11-03  Joseph Myers  <joseph@codesourcery.com>
 
+	* sysdeps/ia64/fpu/fclrexcpt.c (feclearexcept): Add
+	libm_hidden_def.
+
 	[BZ #3439]
 	* sysdeps/ia64/bits/fenv.h (FE_INEXACT): Define macro to integer
 	constant usable in #if and use that to give value to enum
diff --git a/ports/ChangeLog.m68k b/ports/ChangeLog.m68k
index 2bc29908a92..206702e1fee 100644
--- a/ports/ChangeLog.m68k
+++ b/ports/ChangeLog.m68k
@@ -1,5 +1,8 @@
 2012-11-03  Joseph Myers  <joseph@codesourcery.com>
 
+	* sysdeps/m68k/fpu/fclrexcpt.c (feclearexcept): Add
+	libm_hidden_ver.
+
 	[BZ #3439]
 	* sysdeps/m68k/fpu/bits/fenv.h (FE_INEXACT): Define macro to
 	integer constant usable in #if and use that to give value to enum
diff --git a/ports/ChangeLog.mips b/ports/ChangeLog.mips
index f0f796a7347..548d95e1d48 100644
--- a/ports/ChangeLog.mips
+++ b/ports/ChangeLog.mips
@@ -1,5 +1,8 @@
 2012-11-03  Joseph Myers  <joseph@codesourcery.com>
 
+	* sysdeps/mips/fpu/fclrexcpt.c (feclearexcept): Add
+	libm_hidden_def.
+
 	[BZ #3439]
 	* sysdeps/mips/bits/fenv.h (FE_INEXACT): Define macro to integer
 	constant usable in #if and use that to give value to enum
diff --git a/ports/ChangeLog.powerpc b/ports/ChangeLog.powerpc
index 758853ed8e1..a6fd7821fc5 100644
--- a/ports/ChangeLog.powerpc
+++ b/ports/ChangeLog.powerpc
@@ -1,3 +1,8 @@
+2012-11-03  Joseph Myers  <joseph@codesourcery.com>
+
+	* sysdeps/powerpc/nofpu/fclrexcpt.c (feclearexcept): Add
+	libm_hidden_ver.
+
 2012-10-31  Andreas Schwab  <schwab@linux-m68k.org>
 
 	* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/nptl/libc.abilist:
diff --git a/ports/sysdeps/alpha/fpu/fclrexcpt.c b/ports/sysdeps/alpha/fpu/fclrexcpt.c
index 2d2bd94db72..84596529c2a 100644
--- a/ports/sysdeps/alpha/fpu/fclrexcpt.c
+++ b/ports/sysdeps/alpha/fpu/fclrexcpt.c
@@ -1,5 +1,5 @@
 /* Clear given exceptions in current floating-point environment.
-   Copyright (C) 1997,99,2000,01 Free Software Foundation, Inc.
+   Copyright (C) 1997-2012 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Richard Henderson <rth@tamu.edu>, 1997.
 
@@ -43,4 +43,5 @@ strong_alias (__feclearexcept, __old_feclearexcept)
 compat_symbol (libm, __old_feclearexcept, feclearexcept, GLIBC_2_1);
 #endif
 
+libm_hidden_ver (__feclearexcept, feclearexcept)
 versioned_symbol (libm, __feclearexcept, feclearexcept, GLIBC_2_2);
diff --git a/ports/sysdeps/am33/fpu/fclrexcpt.c b/ports/sysdeps/am33/fpu/fclrexcpt.c
index 2b15f45a636..492ea38ba39 100644
--- a/ports/sysdeps/am33/fpu/fclrexcpt.c
+++ b/ports/sysdeps/am33/fpu/fclrexcpt.c
@@ -1,5 +1,5 @@
 /* Clear given exceptions in current floating-point environment.
-   Copyright (C) 1998, 1999, 2000, 2002, 2004 Free Software Foundation, Inc.
+   Copyright (C) 1998-2012 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Alexandre Oliva <aoliva@redhat.com>
    based on corresponding file in the MIPS port.
@@ -48,4 +48,5 @@ __feclearexcept (int excepts)
   return 0;
 }
 
+libm_hidden_ver (__feclearexcept, feclearexcept)
 versioned_symbol (libm, __feclearexcept, feclearexcept, GLIBC_2_2);
diff --git a/ports/sysdeps/arm/fclrexcpt.c b/ports/sysdeps/arm/fclrexcpt.c
index 23435fba78d..fb106a5cc66 100644
--- a/ports/sysdeps/arm/fclrexcpt.c
+++ b/ports/sysdeps/arm/fclrexcpt.c
@@ -54,4 +54,5 @@ strong_alias (__feclearexcept, __old_feclearexcept)
 compat_symbol (libm, __old_feclearexcept, feclearexcept, GLIBC_2_1);
 #endif
 
+libm_hidden_ver (__feclearexcept, feclearexcept)
 versioned_symbol (libm, __feclearexcept, feclearexcept, GLIBC_2_2);
diff --git a/ports/sysdeps/hppa/fpu/fclrexcpt.c b/ports/sysdeps/hppa/fpu/fclrexcpt.c
index 5d1e593105a..bbc2c70803a 100644
--- a/ports/sysdeps/hppa/fpu/fclrexcpt.c
+++ b/ports/sysdeps/hppa/fpu/fclrexcpt.c
@@ -1,5 +1,5 @@
 /* Clear given exceptions in current floating-point environment.
-   Copyright (C) 2000 Free Software Foundation, Inc.
+   Copyright (C) 2000-2012 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by David Huggins-Daines <dhd@debian.org>, 2000
 
@@ -33,3 +33,4 @@ feclearexcept (int excepts)
   /* Success.  */
   return 0;
 }
+libm_hidden_def (feclearexcept)
diff --git a/ports/sysdeps/ia64/fpu/fclrexcpt.c b/ports/sysdeps/ia64/fpu/fclrexcpt.c
index 84f83277b9a..c099fd35abb 100644
--- a/ports/sysdeps/ia64/fpu/fclrexcpt.c
+++ b/ports/sysdeps/ia64/fpu/fclrexcpt.c
@@ -1,5 +1,5 @@
 /* Clear given exceptions in current floating-point environment.
-   Copyright (C) 1997, 1999, 2000 Free Software Foundation, Inc.
+   Copyright (C) 1997-2012 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Christian Boissat <Christian.Boissat@cern.ch>, 1999 and
                   Jes Sorensen <Jes.Sorensen@cern.ch>, 2000
@@ -36,3 +36,4 @@ feclearexcept (int excepts)
   /* success */
   return 0;
 }
+libm_hidden_def (feclearexcept)
diff --git a/ports/sysdeps/m68k/fpu/fclrexcpt.c b/ports/sysdeps/m68k/fpu/fclrexcpt.c
index ceda99cb98f..cfc8d9e2582 100644
--- a/ports/sysdeps/m68k/fpu/fclrexcpt.c
+++ b/ports/sysdeps/m68k/fpu/fclrexcpt.c
@@ -1,5 +1,5 @@
 /* Clear given exceptions in current floating-point environment.
-   Copyright (C) 1997,99,2000,01 Free Software Foundation, Inc.
+   Copyright (C) 1997-2012 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Andreas Schwab <schwab@issan.informatik.uni-dortmund.de>
 
@@ -46,4 +46,5 @@ strong_alias (__feclearexcept, __old_feclearexcept)
 compat_symbol (libm, __old_feclearexcept, feclearexcept, GLIBC_2_1);
 #endif
 
+libm_hidden_ver (__feclearexcept, feclearexcept)
 versioned_symbol (libm, __feclearexcept, feclearexcept, GLIBC_2_2);
diff --git a/ports/sysdeps/mips/fpu/fclrexcpt.c b/ports/sysdeps/mips/fpu/fclrexcpt.c
index f97d892605c..f4709b4d28b 100644
--- a/ports/sysdeps/mips/fpu/fclrexcpt.c
+++ b/ports/sysdeps/mips/fpu/fclrexcpt.c
@@ -1,5 +1,5 @@
 /* Clear given exceptions in current floating-point environment.
-   Copyright (C) 1998, 1999, 2000, 2002 Free Software Foundation, Inc.
+   Copyright (C) 1998-2012 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Andreas Jaeger <aj@suse.de>, 1998.
 
@@ -44,3 +44,4 @@ feclearexcept (int excepts)
   /* Success.  */
   return 0;
 }
+libm_hidden_def (feclearexcept)
diff --git a/ports/sysdeps/powerpc/nofpu/fclrexcpt.c b/ports/sysdeps/powerpc/nofpu/fclrexcpt.c
index 768fd8ff84f..f4b9016ea0e 100644
--- a/ports/sysdeps/powerpc/nofpu/fclrexcpt.c
+++ b/ports/sysdeps/powerpc/nofpu/fclrexcpt.c
@@ -1,5 +1,5 @@
 /* Clear floating-point exceptions (soft-float edition).
-   Copyright (C) 2002 Free Software Foundation, Inc.
+   Copyright (C) 2002-2012 Free Software Foundation, Inc.
    Contributed by Aldy Hernandez <aldyh@redhat.com>, 2002.
    This file is part of the GNU C Library.
 
@@ -33,4 +33,5 @@ strong_alias (__feclearexcept, __old_feclearexcept)
 compat_symbol (libm, __old_feclearexcept, feclearexcept, GLIBC_2_1);
 #endif
 
+libm_hidden_ver (__feclearexcept, feclearexcept)
 versioned_symbol (libm, __feclearexcept, feclearexcept, GLIBC_2_2);
diff --git a/sysdeps/generic/math_private.h b/sysdeps/generic/math_private.h
index b375bc0c565..7661788e6d8 100644
--- a/sysdeps/generic/math_private.h
+++ b/sysdeps/generic/math_private.h
@@ -401,6 +401,22 @@ default_libc_feholdexcept (fenv_t *e)
 # define libc_feholdexceptl default_libc_feholdexcept
 #endif
 
+static __always_inline void
+default_libc_fesetround (int r)
+{
+  (void) fesetround (r);
+}
+
+#ifndef libc_fesetround
+# define libc_fesetround  default_libc_fesetround
+#endif
+#ifndef libc_fesetroundf
+# define libc_fesetroundf default_libc_fesetround
+#endif
+#ifndef libc_fesetroundl
+# define libc_fesetroundl default_libc_fesetround
+#endif
+
 static __always_inline void
 default_libc_feholdexcept_setround (fenv_t *e, int r)
 {
diff --git a/sysdeps/i386/fpu/fclrexcpt.c b/sysdeps/i386/fpu/fclrexcpt.c
index f24d07f3d1c..f28ef6b3fa4 100644
--- a/sysdeps/i386/fpu/fclrexcpt.c
+++ b/sysdeps/i386/fpu/fclrexcpt.c
@@ -1,5 +1,5 @@
 /* Clear given exceptions in current floating-point environment.
-   Copyright (C) 1997,99,2000, 2001, 2003, 2004 Free Software Foundation, Inc.
+   Copyright (C) 1997-2012 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
 
@@ -65,4 +65,5 @@ strong_alias (__feclearexcept, __old_feclearexcept)
 compat_symbol (libm, __old_feclearexcept, feclearexcept, GLIBC_2_1);
 #endif
 
+libm_hidden_ver (__feclearexcept, feclearexcept)
 versioned_symbol (libm, __feclearexcept, feclearexcept, GLIBC_2_2);
diff --git a/sysdeps/i386/fpu/fenv_private.h b/sysdeps/i386/fpu/fenv_private.h
index f33f57c39c7..03f4c97a9cb 100644
--- a/sysdeps/i386/fpu/fenv_private.h
+++ b/sysdeps/i386/fpu/fenv_private.h
@@ -76,6 +76,24 @@ libc_feholdexcept_387 (fenv_t *e)
 		    "st(4)", "st(5)", "st(6)", "st(7)");
 }
 
+static __always_inline void
+libc_fesetround_sse (int r)
+{
+  unsigned int mxcsr;
+  asm (STMXCSR " %0" : "=m" (*&mxcsr));
+  mxcsr = (mxcsr & ~0x6000) | (r << 3);
+  asm volatile (LDMXCSR " %0" : : "m" (*&mxcsr));
+}
+
+static __always_inline void
+libc_fesetround_387 (int r)
+{
+  fpu_control_t cw;
+  _FPU_GETCW (cw);
+  cw = (cw & ~0xc00) | r;
+  _FPU_SETCW (cw);
+}
+
 static __always_inline void
 libc_feholdexcept_setround_sse (fenv_t *e, int r)
 {
@@ -247,6 +265,7 @@ libc_feresetround_387 (fenv_t *e)
 
 #ifdef __SSE_MATH__
 # define libc_feholdexceptf		libc_feholdexcept_sse
+# define libc_fesetroundf		libc_fesetround_sse
 # define libc_feholdexcept_setroundf	libc_feholdexcept_setround_sse
 # define libc_fetestexceptf		libc_fetestexcept_sse
 # define libc_fesetenvf			libc_fesetenv_sse
@@ -256,6 +275,7 @@ libc_feresetround_387 (fenv_t *e)
 # define libc_feresetroundf		libc_feresetround_sse
 #else
 # define libc_feholdexceptf		libc_feholdexcept_387
+# define libc_fesetroundf		libc_fesetround_387
 # define libc_feholdexcept_setroundf	libc_feholdexcept_setround_387
 # define libc_fetestexceptf		libc_fetestexcept_387
 # define libc_fesetenvf			libc_fesetenv_387
@@ -267,6 +287,7 @@ libc_feresetround_387 (fenv_t *e)
 
 #ifdef __SSE2_MATH__
 # define libc_feholdexcept		libc_feholdexcept_sse
+# define libc_fesetround		libc_fesetround_sse
 # define libc_feholdexcept_setround	libc_feholdexcept_setround_sse
 # define libc_fetestexcept		libc_fetestexcept_sse
 # define libc_fesetenv			libc_fesetenv_sse
@@ -276,6 +297,7 @@ libc_feresetround_387 (fenv_t *e)
 # define libc_feresetround		libc_feresetround_sse
 #else
 # define libc_feholdexcept		libc_feholdexcept_387
+# define libc_fesetround		libc_fesetround_387
 # define libc_feholdexcept_setround	libc_feholdexcept_setround_387
 # define libc_fetestexcept		libc_fetestexcept_387
 # define libc_fesetenv			libc_fesetenv_387
@@ -286,6 +308,7 @@ libc_feresetround_387 (fenv_t *e)
 #endif /* __SSE2_MATH__ */
 
 #define libc_feholdexceptl		libc_feholdexcept_387
+#define libc_fesetroundl		libc_fesetround_387
 #define libc_feholdexcept_setroundl	libc_feholdexcept_setround_387
 #define libc_fetestexceptl		libc_fetestexcept_387
 #define libc_fesetenvl			libc_fesetenv_387
diff --git a/sysdeps/ieee754/dbl-64/s_fma.c b/sysdeps/ieee754/dbl-64/s_fma.c
index 68c63a1987e..07fe715617f 100644
--- a/sysdeps/ieee754/dbl-64/s_fma.c
+++ b/sysdeps/ieee754/dbl-64/s_fma.c
@@ -167,6 +167,9 @@ __fma (double x, double y, double z)
   if (__builtin_expect ((x == 0 || y == 0) && z == 0, 0))
     return x * y + z;
 
+  fenv_t env;
+  libc_feholdexcept_setround (&env, FE_TONEAREST);
+
   /* Multiplication m1 + m2 = x * y using Dekker's algorithm.  */
 #define C ((1 << (DBL_MANT_DIG + 1) / 2) + 1)
   double x1 = x * C;
@@ -185,9 +188,20 @@ __fma (double x, double y, double z)
   t1 = m1 - t1;
   t2 = z - t2;
   double a2 = t1 + t2;
+  feclearexcept (FE_INEXACT);
 
-  fenv_t env;
-  libc_feholdexcept_setround (&env, FE_TOWARDZERO);
+  /* If the result is an exact zero, ensure it has the correct
+     sign.  */
+  if (a1 == 0 && m2 == 0)
+    {
+      libc_feupdateenv (&env);
+      /* Ensure that round-to-nearest value of z + m1 is not
+	 reused.  */
+      asm volatile ("" : "=m" (z) : "m" (z));
+      return z + m1;
+    }
+
+  libc_fesetround (FE_TOWARDZERO);
 
   /* Perform m2 + a2 addition with round to odd.  */
   u.d = a2 + m2;
diff --git a/sysdeps/ieee754/ldbl-128/s_fmal.c b/sysdeps/ieee754/ldbl-128/s_fmal.c
index c6a3d71f1c9..d576403b258 100644
--- a/sysdeps/ieee754/ldbl-128/s_fmal.c
+++ b/sysdeps/ieee754/ldbl-128/s_fmal.c
@@ -170,6 +170,10 @@ __fmal (long double x, long double y, long double z)
   if (__builtin_expect ((x == 0 || y == 0) && z == 0, 0))
     return x * y + z;
 
+  fenv_t env;
+  feholdexcept (&env);
+  fesetround (FE_TONEAREST);
+
   /* Multiplication m1 + m2 = x * y using Dekker's algorithm.  */
 #define C ((1LL << (LDBL_MANT_DIG + 1) / 2) + 1)
   long double x1 = x * C;
@@ -188,9 +192,19 @@ __fmal (long double x, long double y, long double z)
   t1 = m1 - t1;
   t2 = z - t2;
   long double a2 = t1 + t2;
+  feclearexcept (FE_INEXACT);
+
+  /* If the result is an exact zero, ensure it has the correct
+     sign.  */
+  if (a1 == 0 && m2 == 0)
+    {
+      feupdateenv (&env);
+      /* Ensure that round-to-nearest value of z + m1 is not
+	 reused.  */
+      asm volatile ("" : "=m" (z) : "m" (z));
+      return z + m1;
+    }
 
-  fenv_t env;
-  feholdexcept (&env);
   fesetround (FE_TOWARDZERO);
   /* Perform m2 + a2 addition with round to odd.  */
   u.d = a2 + m2;
diff --git a/sysdeps/ieee754/ldbl-96/s_fma.c b/sysdeps/ieee754/ldbl-96/s_fma.c
index 001d8063d4a..bf2d794c9b0 100644
--- a/sysdeps/ieee754/ldbl-96/s_fma.c
+++ b/sysdeps/ieee754/ldbl-96/s_fma.c
@@ -42,6 +42,10 @@ __fma (double x, double y, double z)
   if (__builtin_expect ((x == 0 || y == 0) && z == 0, 0))
     return x * y + z;
 
+  fenv_t env;
+  feholdexcept (&env);
+  fesetround (FE_TONEAREST);
+
   /* Multiplication m1 + m2 = x * y using Dekker's algorithm.  */
 #define C ((1ULL << (LDBL_MANT_DIG + 1) / 2) + 1)
   long double x1 = (long double) x * C;
@@ -60,9 +64,19 @@ __fma (double x, double y, double z)
   t1 = m1 - t1;
   t2 = z - t2;
   long double a2 = t1 + t2;
+  feclearexcept (FE_INEXACT);
+
+  /* If the result is an exact zero, ensure it has the correct
+     sign.  */
+  if (a1 == 0 && m2 == 0)
+    {
+      feupdateenv (&env);
+      /* Ensure that round-to-nearest value of z + m1 is not
+	 reused.  */
+      asm volatile ("" : "=m" (z) : "m" (z));
+      return z + m1;
+    }
 
-  fenv_t env;
-  feholdexcept (&env);
   fesetround (FE_TOWARDZERO);
   /* Perform m2 + a2 addition with round to odd.  */
   a2 = a2 + m2;
diff --git a/sysdeps/ieee754/ldbl-96/s_fmal.c b/sysdeps/ieee754/ldbl-96/s_fmal.c
index b5fdcba6bce..32e71a18ba9 100644
--- a/sysdeps/ieee754/ldbl-96/s_fmal.c
+++ b/sysdeps/ieee754/ldbl-96/s_fmal.c
@@ -168,6 +168,10 @@ __fmal (long double x, long double y, long double z)
   if (__builtin_expect ((x == 0 || y == 0) && z == 0, 0))
     return x * y + z;
 
+  fenv_t env;
+  feholdexcept (&env);
+  fesetround (FE_TONEAREST);
+
   /* Multiplication m1 + m2 = x * y using Dekker's algorithm.  */
 #define C ((1LL << (LDBL_MANT_DIG + 1) / 2) + 1)
   long double x1 = x * C;
@@ -186,9 +190,19 @@ __fmal (long double x, long double y, long double z)
   t1 = m1 - t1;
   t2 = z - t2;
   long double a2 = t1 + t2;
+  feclearexcept (FE_INEXACT);
+
+  /* If the result is an exact zero, ensure it has the correct
+     sign.  */
+  if (a1 == 0 && m2 == 0)
+    {
+      feupdateenv (&env);
+      /* Ensure that round-to-nearest value of z + m1 is not
+	 reused.  */
+      asm volatile ("" : "=m" (z) : "m" (z));
+      return z + m1;
+    }
 
-  fenv_t env;
-  feholdexcept (&env);
   fesetround (FE_TOWARDZERO);
   /* Perform m2 + a2 addition with round to odd.  */
   u.d = a2 + m2;
diff --git a/sysdeps/powerpc/fpu/fclrexcpt.c b/sysdeps/powerpc/fpu/fclrexcpt.c
index 87376bfe97c..e99cc58ace6 100644
--- a/sysdeps/powerpc/fpu/fclrexcpt.c
+++ b/sysdeps/powerpc/fpu/fclrexcpt.c
@@ -1,5 +1,5 @@
 /* Clear given exceptions in current floating-point environment.
-   Copyright (C) 1997,99,2000,01 Free Software Foundation, Inc.
+   Copyright (C) 1997-2012 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
@@ -44,4 +44,5 @@ strong_alias (__feclearexcept, __old_feclearexcept)
 compat_symbol (libm, __old_feclearexcept, feclearexcept, GLIBC_2_1);
 #endif
 
+libm_hidden_ver (__feclearexcept, feclearexcept)
 versioned_symbol (libm, __feclearexcept, feclearexcept, GLIBC_2_2);
diff --git a/sysdeps/s390/fpu/fclrexcpt.c b/sysdeps/s390/fpu/fclrexcpt.c
index 2352d74b07c..3e8d9bb3aa4 100644
--- a/sysdeps/s390/fpu/fclrexcpt.c
+++ b/sysdeps/s390/fpu/fclrexcpt.c
@@ -1,5 +1,5 @@
 /* Clear given exceptions in current floating-point environment.
-   Copyright (C) 2000 Free Software Foundation, Inc.
+   Copyright (C) 2000-2012 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
@@ -37,3 +37,4 @@ feclearexcept (int excepts)
   /* Success.  */
   return 0;
 }
+libm_hidden_def (feclearexcept)
diff --git a/sysdeps/sh/sh4/fpu/fclrexcpt.c b/sysdeps/sh/sh4/fpu/fclrexcpt.c
index b4b2ead02c1..2d31fa65161 100644
--- a/sysdeps/sh/sh4/fpu/fclrexcpt.c
+++ b/sysdeps/sh/sh4/fpu/fclrexcpt.c
@@ -39,3 +39,4 @@ feclearexcept (int excepts)
 
   return 0;
 }
+libm_hidden_def (feclearexcept)
diff --git a/sysdeps/sparc/fpu/fclrexcpt.c b/sysdeps/sparc/fpu/fclrexcpt.c
index 82b6ac4e2ec..50ec4f4ff39 100644
--- a/sysdeps/sparc/fpu/fclrexcpt.c
+++ b/sysdeps/sparc/fpu/fclrexcpt.c
@@ -1,5 +1,5 @@
 /* Clear given exceptions in current floating-point environment.
-   Copyright (C) 1997, 1999, 2000 Free Software Foundation, Inc.
+   Copyright (C) 1997-2012 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
@@ -39,4 +39,5 @@ strong_alias (__feclearexcept, __old_feclearexcept)
 compat_symbol (libm, __old_feclearexcept, feclearexcept, GLIBC_2_1);
 #endif
 
+libm_hidden_ver (__feclearexcept, feclearexcept)
 versioned_symbol (libm, __feclearexcept, feclearexcept, GLIBC_2_2);
diff --git a/sysdeps/sparc/fpu/fenv_private.h b/sysdeps/sparc/fpu/fenv_private.h
index a6e8e95a55e..8690879ddca 100644
--- a/sysdeps/sparc/fpu/fenv_private.h
+++ b/sysdeps/sparc/fpu/fenv_private.h
@@ -13,6 +13,15 @@ libc_feholdexcept (fenv_t *e)
   __fenv_ldfsr(etmp);
 }
 
+static __always_inline void
+libc_fesetround (int r)
+{
+  fenv_t etmp;
+  __fenv_stfsr(etmp);
+  etmp = (etmp & ~__FE_ROUND_MASK) | (r);
+  __fenv_ldfsr(etmp);
+}
+
 static __always_inline void
 libc_feholdexcept_setround (fenv_t *e, int r)
 {
@@ -79,6 +88,7 @@ libc_feresetround (fenv_t *e)
 }
 
 #define libc_feholdexceptf		libc_feholdexcept
+#define libc_fesetroundf		libc_fesetround
 #define libc_feholdexcept_setroundf	libc_feholdexcept_setround
 #define libc_fetestexceptf		libc_fetestexcept
 #define libc_fesetenvf			libc_fesetenv
@@ -87,6 +97,7 @@ libc_feresetround (fenv_t *e)
 #define libc_feholdsetroundf		libc_feholdsetround
 #define libc_feresetroundf		libc_feresetround
 #define libc_feholdexcept		libc_feholdexcept
+#define libc_fesetround			libc_fesetround
 #define libc_feholdexcept_setround	libc_feholdexcept_setround
 #define libc_fetestexcept		libc_fetestexcept
 #define libc_fesetenv			libc_fesetenv
@@ -95,6 +106,7 @@ libc_feresetround (fenv_t *e)
 #define libc_feholdsetround		libc_feholdsetround
 #define libc_feresetround		libc_feresetround
 #define libc_feholdexceptl		libc_feholdexcept
+#define libc_fesetroundl		libc_fesetround
 #define libc_feholdexcept_setroundl	libc_feholdexcept_setround
 #define libc_fetestexceptl		libc_fetestexcept
 #define libc_fesetenvl			libc_fesetenv
diff --git a/sysdeps/x86_64/fpu/fclrexcpt.c b/sysdeps/x86_64/fpu/fclrexcpt.c
index 5ef316212a2..2d403133946 100644
--- a/sysdeps/x86_64/fpu/fclrexcpt.c
+++ b/sysdeps/x86_64/fpu/fclrexcpt.c
@@ -1,5 +1,5 @@
 /* Clear given exceptions in current floating-point environment.
-   Copyright (C) 2001 Free Software Foundation, Inc.
+   Copyright (C) 2001-2012 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
@@ -49,3 +49,4 @@ feclearexcept (int excepts)
   /* Success.  */
   return 0;
 }
+libm_hidden_def (feclearexcept)