libgfortran: Use __builtin_issignaling in libgfortran [PR105105]

The following patch makes use of the new __builtin_issignaling,
so it no longer needs the fallback implementation and can use
the builtin even where glibc provides the macro.

2022-08-26  Jakub Jelinek  <jakub@redhat.com>

	PR fortran/105105
	* ieee/ieee_helper.c: Don't include issignaling_fallback.h.
	(CLASSMACRO): Use __builtin_issignaling instead of issignaling.
	* ieee/issignaling_fallback.h: Removed.

2 files changed, 1 insertions, 259 deletions

diff --git a/libgfortran/ieee/ieee_helper.c b/libgfortran/ieee/ieee_helper.c
index 7e310f2c5b0..1351b1ff54c 100644
--- a/libgfortran/ieee/ieee_helper.c
+++ b/libgfortran/ieee/ieee_helper.c
@@ -26,13 +26,6 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #include "libgfortran.h"
 
 
-/* Check support for issignaling macro.  If not, we include our own
-   fallback implementation.  */
-#ifndef issignaling
-# include "issignaling_fallback.h"
-#endif
-
-
 /* Prototypes.  */
 
 extern int ieee_class_helper_4 (GFC_REAL_4 *);
@@ -94,7 +87,7 @@ enum {
  \
     if (res == IEEE_QUIET_NAN) \
     { \
-      if (issignaling (*value)) \
+      if (__builtin_issignaling (*value)) \
 	return IEEE_SIGNALING_NAN; \
       else \
 	return IEEE_QUIET_NAN; \
diff --git a/libgfortran/ieee/issignaling_fallback.h b/libgfortran/ieee/issignaling_fallback.h
deleted file mode 100644
index 698c3f2edc9..00000000000
--- a/libgfortran/ieee/issignaling_fallback.h
+++ /dev/null
@@ -1,251 +0,0 @@
-/* Fallback implementation of issignaling macro.
-   Copyright (C) 2022 Free Software Foundation, Inc.
-   Contributed by Francois-Xavier Coudert <fxcoudert@gcc.gnu.org>
-
-This file is part of the GNU Fortran runtime library (libgfortran).
-
-Libgfortran is free software; you can redistribute it and/or
-modify it under the terms of the GNU General Public
-License as published by the Free Software Foundation; either
-version 3 of the License, or (at your option) any later version.
-
-Libgfortran 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 General Public License for more details.
-
-Under Section 7 of GPL version 3, you are granted additional
-permissions described in the GCC Runtime Library Exception, version
-3.1, as published by the Free Software Foundation.
-
-You should have received a copy of the GNU General Public License and
-a copy of the GCC Runtime Library Exception along with this program;
-see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
-<http://www.gnu.org/licenses/>.  */
-
-#include "libgfortran.h"
-
-/* This header provides an implementation of the type-generic issignaling macro.
-   Some points of note:
-
-     - This header is only included if the issignaling macro is not defined.
-     - All targets for which Fortran IEEE modules are supported currently have
-       the high-order bit of the NaN mantissa clear for signaling (and set
-       for quiet), as recommended by IEEE.
-     - We use the __*_IS_IEC_60559__ macros to make sure we only deal with formats
-       we know. For other floating-point formats, we consider all NaNs as quiet.
-
- */
-
-typedef union
-{
-  float value;
-  uint32_t word;
-} ieee_float_shape_type;
-
-static inline int
-__issignalingf (float x)
-{
-#if __FLT_IS_IEC_60559__
-  uint32_t xi;
-  ieee_float_shape_type u;
-
-  u.value = x;
-  xi = u.word;
-
-  xi ^= 0x00400000;
-  return (xi & 0x7fffffff) > 0x7fc00000;
-#else
-  return 0;
-#endif
-}
-
-
-typedef union
-{
-  double value;
-  uint64_t word;
-} ieee_double_shape_type;
-
-static inline int
-__issignaling (double x)
-{
-#if __DBL_IS_IEC_60559__
-  ieee_double_shape_type u;
-  uint64_t xi;
-
-  u.value = x;
-  xi = u.word;
-
-  xi ^= UINT64_C (0x0008000000000000);
-  return (xi & UINT64_C (0x7fffffffffffffff)) > UINT64_C (0x7ff8000000000000);
-#else
-  return 0;
-#endif
-}
-
-
-#if __LDBL_DIG__ == __DBL_DIG__
-
-/* Long double is the same as double.  */
-static inline int
-__issignalingl (long double x)
-{
-  return __issignaling (x);
-}
-
-#elif (__LDBL_DIG__ == 18) && __LDBL_IS_IEC_60559__
-
-/* Long double is x86 extended type.  */
-
-typedef union
-{
-  long double value;
-  struct
-  {
-#if __FLOAT_WORD_ORDER__ == __ORDER_BIG_ENDIAN__
-    int sign_exponent:16;
-    unsigned int empty:16;
-    uint32_t msw;
-    uint32_t lsw;
-#elif __FLOAT_WORD_ORDER__ == __ORDER_LITTLE_ENDIAN__
-    uint32_t lsw;
-    uint32_t msw;
-    int sign_exponent:16;
-    unsigned int empty:16;
-#endif
-  } parts;
-} ieee_long_double_shape_type;
-
-static inline int
-__issignalingl (long double x)
-{
-  int ret;
-  uint32_t exi, hxi, lxi;
-  ieee_long_double_shape_type u;
-
-  u.value = x;
-  exi = u.parts.sign_exponent;
-  hxi = u.parts.msw;
-  lxi = u.parts.lsw;
-
-  /* Pseudo numbers on x86 are always signaling.  */
-  ret = (exi & 0x7fff) && ((hxi & 0x80000000) == 0);
-
-  hxi ^= 0x40000000;
-  hxi |= (lxi | -lxi) >> 31;
-  return ret || (((exi & 0x7fff) == 0x7fff) && (hxi > 0xc0000000));
-}
-
-#elif (__LDBL_DIG__ == 31)
-
-/* Long double is 128-bit IBM extended type.  */
-
-static inline int
-__issignalingl (long double x)
-{
-  union { long double value; double parts[2]; } u;
-
-  u.value = x;
-  return __issignaling (u.parts[0]);
-}
-
-#elif (__LDBL_DIG__ == 33) && __LDBL_IS_IEC_60559__
-
-/* Long double is 128-bit type.  */
-
-typedef union
-{
-  long double value;
-  struct
-  {
-#if __FLOAT_WORD_ORDER__ == __ORDER_BIG_ENDIAN__
-    uint64_t msw;
-    uint64_t lsw;
-#elif __FLOAT_WORD_ORDER__ == __ORDER_LITTLE_ENDIAN__
-    uint64_t lsw;
-    uint64_t msw;
-#endif
-  } parts64;
-} ieee854_long_double_shape_type;
-
-static inline int
-__issignalingl (long double x)
-{
-  uint64_t hxi, lxi;
-  ieee854_long_double_shape_type u;
-
-  u.value = x;
-  hxi = u.parts64.msw;
-  lxi = u.parts64.lsw;
-
-  hxi ^= UINT64_C (0x0000800000000000);
-  hxi |= (lxi | -lxi) >> 63;
-  return (hxi & UINT64_C (0x7fffffffffffffff)) > UINT64_C (0x7fff800000000000);
-}
-
-#else
-
-static inline int
-__issignalingl (long double x)
-{
-  return 0;
-}
-
-#endif
-
-
-#if defined(GFC_REAL_16_IS_FLOAT128)
-
-/* We have a _Float128 type.  */
-
-typedef union
-{
-  _Float128 value;
-  struct
-  {
-#if __FLOAT_WORD_ORDER__ == __ORDER_BIG_ENDIAN__
-    uint64_t msw;
-    uint64_t lsw;
-#elif __FLOAT_WORD_ORDER__ == __ORDER_LITTLE_ENDIAN__
-    uint64_t lsw;
-    uint64_t msw;
-#endif
-  } parts64;
-} ieee854_float128_shape_type;
-
-static inline int
-__issignalingf128 (_Float128 x)
-{
-  uint64_t hxi, lxi;
-  ieee854_float128_shape_type u;
-
-  u.value = x;
-  hxi = u.parts64.msw;
-  lxi = u.parts64.lsw;
-
-  hxi ^= UINT64_C (0x0000800000000000);
-  hxi |= (lxi | -lxi) >> 63;
-  return (hxi & UINT64_C (0x7fffffffffffffff)) > UINT64_C (0x7fff800000000000);
-}
-
-#endif
-
-
-/* Define the type-generic macro based on the functions above.  */
-
-#if defined(GFC_REAL_16_IS_FLOAT128)
-# define issignaling(X) \
-  _Generic ((X), \
-	    _Float128: __issignalingf128, \
-	    float: __issignalingf, \
-	    double: __issignaling, \
-	    long double: __issignalingl)(X)
-#else
-# define issignaling(X) \
-  _Generic ((X), \
-	    float: __issignalingf, \
-	    double: __issignaling, \
-	    long double: __issignalingl)(X)
-#endif
-