Imported Upstream version 0.11.2upstream/0.11.2upstream

1 files changed, 131 insertions, 0 deletions

diff --git a/m4/ac_cxx_float_exact_output.m4 b/m4/ac_cxx_float_exact_output.m4
new file mode 100644
index 000000000..870e03488
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+++ b/m4/ac_cxx_float_exact_output.m4
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+dnl A function to detect whether C++ provides exact output for floats.
+dnl Copyright (C) 2001-2010 Roberto Bagnara <bagnara@cs.unipr.it>
+dnl Copyright (C) 2010-2011 BUGSENG srl (http://bugseng.com)
+dnl
+dnl This file is part of the Parma Polyhedra Library (PPL).
+dnl
+dnl The PPL is free software; you can redistribute it and/or modify it
+dnl under the terms of the GNU General Public License as published by the
+dnl Free Software Foundation; either version 3 of the License, or (at your
+dnl option) any later version.
+dnl
+dnl The PPL is distributed in the hope that it will be useful, but WITHOUT
+dnl ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+dnl FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+dnl for more details.
+dnl
+dnl You should have received a copy of the GNU General Public License
+dnl along with this program; if not, write to the Free Software Foundation,
+dnl Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111-1307, USA.
+dnl
+dnl For the most up-to-date information see the Parma Polyhedra Library
+dnl site: http://www.cs.unipr.it/ppl/ .
+
+AC_DEFUN([AC_CXX_FLOAT_EXACT_OUTPUT],
+[
+dnl AC_REQUIRE([AC_CXX_FLOAT_BINARY_FORMAT])
+ac_save_CPPFLAGS="$CPPFLAGS"
+ac_save_LIBS="$LIBS"
+AC_LANG_PUSH(C++)
+
+AC_MSG_CHECKING([whether C++ provides exact output for floats])
+
+AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#include <limits>
+#ifdef HAVE_STDINT_H
+#ifndef __STDC_LIMIT_MACROS
+#define __STDC_LIMIT_MACROS 1
+#endif
+#include <stdint.h>
+#endif
+#ifdef HAVE_INTTYPES_H
+#include <inttypes.h>
+#endif
+#include <sstream>
+
+/* Unique (nonzero) code for the IEEE 754 Single Precision
+   floating point format.  */
+# define PPL_FLOAT_IEEE754_SINGLE 1
+
+/* Unique (nonzero) code for the IEEE 754 Double Precision
+   floating point format.  */
+# define PPL_FLOAT_IEEE754_DOUBLE 2
+
+/* Unique (nonzero) code for the IEEE 754 Quad Precision
+   floating point format.  */
+# define PPL_FLOAT_IEEE754_QUAD 3
+
+/* Unique (nonzero) code for the Intel Double-Extended
+   floating point format.  */
+# define PPL_FLOAT_INTEL_DOUBLE_EXTENDED 4
+
+bool
+check(float value, const char* text) {
+  std::ostringstream ss;
+  ss.precision(10000);
+  ss << value;
+  return ss.str() == text;
+}
+
+#if SIZEOF_FLOAT == 4
+
+float
+convert(uint32_t x) {
+  union {
+    float value;
+    uint32_t word;
+  } u;
+
+  u.word = x;
+  return u.value;
+}
+
+#if PPL_CXX_FLOAT_BINARY_FORMAT == PPL_FLOAT_IEEE754_SINGLE
+
+int
+main() {
+  if (check(convert(0xaaacccaaU),
+            "-3.069535185924732179074680971098132431507110595703125e-13")
+      && check(convert(0xcccaaaccU),
+               "-106255968")
+      && check(convert(0x00000001U),
+               "1.40129846432481707092372958328991613128026194187651577175706828388979108268586060148663818836212158203125e-45")
+      && check(convert(0x80000001U),
+               "-1.40129846432481707092372958328991613128026194187651577175706828388979108268586060148663818836212158203125e-45"))
+    return 0;
+  else
+    return 1;
+}
+
+#else // PPL_CXX_FLOAT_BINARY_FORMAT != FLOAT_IEEE754_SINGLE
+
+int
+main() {
+  return 1;
+}
+
+#endif // PPL_CXX_FLOAT_BINARY_FORMAT != FLOAT_IEEE754_SINGLE
+
+#else // SIZEOF_FLOAT != 4
+
+int
+main() {
+  return 1;
+}
+
+#endif // SIZEOF_FLOAT != 4
+]])],
+  AC_MSG_RESULT(yes)
+  ac_cxx_float_exact_output=1,
+  AC_MSG_RESULT(no)
+  ac_cxx_float_exact_output=0,
+  AC_MSG_RESULT([assuming not])
+  ac_cxx_float_exact_output=0)
+
+AC_DEFINE_UNQUOTED(PPL_CXX_FLOAT_EXACT_OUTPUT, $ac_cxx_float_exact_output,
+  [Not zero if C++ supports exact output for floats.])
+
+AC_LANG_POP(C++)
+CPPFLAGS="$ac_save_CPPFLAGS"
+LIBS="$ac_save_LIBS"
+])