Make iseqsig handle excess precision.

iseqsig, like other type-generic comparison macros, should behave like
a comparison operator in not removing excess range and precision from
its arguments (see C11 F.10.11).  This patch implements this by making
definitions of iseqsig appropriately conditional on
__FLT_EVAL_METHOD__ (including support for TS 18661-3 values of that
macro), with a corresponding testcase (that failed for 32-bit x86 in
the absence of the math.h changes) being added.  (Of course the
definitions may need reworking when float128 support is added, just as
with other type-generic macros.)

Tested for x86_64 and x86.

	* math/math.h [__GLIBC_USE (IEC_60559_BFP_EXT)] (iseqsig): Define
	conditional on value of [__FLT_EVAL_METHOD__].
	* math/test-iseqsig-excess-precision.c: New file.
	* math/Makefile (tests): Add test-iseqsig-excess-precision.

diff --git a/ChangeLog b/ChangeLog
index e50a214aab5e47b2ee831f88d884be0a40c389b8..cd17710e7c7a601a7feee82f8c0834762b0151ec 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2016-10-07  Joseph Myers  <joseph@codesourcery.com>
+
+       * math/math.h [__GLIBC_USE (IEC_60559_BFP_EXT)] (iseqsig): Define
+       conditional on value of [__FLT_EVAL_METHOD__].
+       * math/test-iseqsig-excess-precision.c: New file.
+       * math/Makefile (tests): Add test-iseqsig-excess-precision.
+
 2016-10-07  Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 
        * math/s_iseqsig_template.c: Include math-private.h.

diff --git a/math/Makefile b/math/Makefile
index a9f06080f48bd29e5fbd369de3ebfaa4b725bc77..ca07f9d1fd39fdbc6b8ba5fde7a6284ff57e4abc 100644 (file)
--- a/math/Makefile
+++ b/math/Makefile
@@ -156,7 +156,8 @@ tests = test-matherr test-fenv atest-exp atest-sincos atest-exp2 basic-test \
        test-signgam-ullong-init test-nan-overflow test-nan-payload \
        test-fexcept test-fexcept-traps test-fesetexcept \
        test-fesetexcept-traps test-fetestexceptflag test-femode \
-       test-femode-traps test-iszero-excess-precision $(tests-static)
+       test-femode-traps test-iszero-excess-precision \
+       test-iseqsig-excess-precision $(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 \
@@ -267,6 +268,7 @@ CFLAGS-test-signgam-ullong-init-static.c = -std=c99
 CFLAGS-test-math-isinff.cc = -std=gnu++11
 
 CFLAGS-test-iszero-excess-precision.c = -fexcess-precision=standard
+CFLAGS-test-iseqsig-excess-precision.c = -fexcess-precision=standard
 
 # The -lieee module sets the _LIB_VERSION_ switch to IEEE mode
 # for error handling in the -lm functions.

diff --git a/math/math.h b/math/math.h
index 394cefae020bd1ff76a17e10bc516b7842a62320..880b4a018c7afb8d5ef9e99dba92c48bb7443807 100644 (file)
--- a/math/math.h
+++ b/math/math.h
@@ -535,17 +535,32 @@ extern int matherr (struct exception *__exc);
 /* 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)                                \
+#  if (__FLT_EVAL_METHOD__ == 1                        \
+       || __FLT_EVAL_METHOD__ == 2             \
+       || __FLT_EVAL_METHOD__ > 32)
+#   define iseqsig(x, y) __iseqsig ((x), (y))
+#  else
+#   define iseqsig(x, y)                       \
   (sizeof ((x) + (y)) == sizeof (float)                \
    ? __iseqsigf ((x), (y))                     \
    : __iseqsig ((x), (y)))
+#  endif
 # else
-#  define iseqsig(x, y)                                \
+#  if __FLT_EVAL_METHOD__ == 2 || __FLT_EVAL_METHOD__ > 64
+#   define iseqsig(x, y) __iseqsigl ((x), (y))
+#  elif __FLT_EVAL_METHOD__ == 1 || __FLT_EVAL_METHOD__ > 32
+#   define iseqsig(x, y)                       \
+  (sizeof ((x) + (y)) <= sizeof (double)       \
+   ? __iseqsig ((x), (y))                      \
+   : __iseqsigl ((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
 #endif
 

diff --git a/math/test-iseqsig-excess-precision.c b/math/test-iseqsig-excess-precision.c
new file mode 100644 (file)
index 0000000..01dea1c
--- /dev/null
+++ b/math/test-iseqsig-excess-precision.c
@@ -0,0 +1,80 @@
+/* Test iseqsig with excess precision.
+   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 <float.h>
+#include <math.h>
+#include <stdio.h>
+
+static int
+do_test (void)
+{
+  int result = 0;
+
+  if (FLT_EVAL_METHOD == 1 || FLT_EVAL_METHOD == 2 || FLT_EVAL_METHOD > 32)
+    {
+      /* Excess precision for float.  */
+      if (iseqsig (1.0f, 1.0f + (float) DBL_EPSILON))
+       {
+         puts ("iseqsig removes excess precision float -> double");
+         result = 1;
+       }
+      else
+       puts ("iseqsig preserves excess precision float -> double");
+      if (iseqsig (__builtin_inff (), FLT_MAX * FLT_MAX))
+       {
+         puts ("iseqsig removes excess range float -> double");
+         result = 1;
+       }
+      else
+       puts ("iseqsig preserves excess range float -> double");
+    }
+
+  if (FLT_EVAL_METHOD == 2 || FLT_EVAL_METHOD > 64)
+    {
+      /* Excess precision for float and double.  */
+      if (iseqsig (1.0f, 1.0f + (float) LDBL_EPSILON))
+       {
+         puts ("iseqsig removes excess precision float -> long double");
+         result = 1;
+       }
+      else
+       puts ("iseqsig preserves excess precision float -> long double");
+      if (iseqsig (1.0, 1.0 + (double) LDBL_EPSILON))
+       {
+         puts ("iseqsig removes excess precision double -> long double");
+         result = 1;
+       }
+      else
+       puts ("iseqsig preserves excess precision double -> long double");
+      if (LDBL_MAX_EXP >= 2 * DBL_MAX_EXP)
+       {
+         if (iseqsig (__builtin_inf (), DBL_MAX * DBL_MAX))
+           {
+             puts ("iseqsig removes excess range double -> long double");
+             result = 1;
+           }
+           else
+             puts ("iseqsig preserves excess range double -> long double");
+       }
+    }
+
+  return result;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"