Update _FloatN header support for C++ in GCC 13

GCC 13 adds support for _FloatN and _FloatNx types in C++, so breaking
the installed glibc headers that assume such support is not present.
GCC mostly works around this with fixincludes, but that doesn't help
for building glibc and its tests (glibc doesn't itself contain C++
code, but there's C++ code built for tests).  Update glibc's
bits/floatn-common.h and bits/floatn.h headers to handle the GCC 13
support directly.

In general the changes match those made by fixincludes, though I think
the ones in sysdeps/powerpc/bits/floatn.h, where the header tests
__LDBL_MANT_DIG__ == 113 or uses #elif, wouldn't match the existing
fixincludes patterns.

Some places involving special C++ handling in relation to _FloatN
support are not changed.  There's no need to change the
__HAVE_FLOATN_NOT_TYPEDEF definition (also in a form that wouldn't be
matched by the fixincludes fixes) because it's only used in relation
to macro definitions using features not supported for C++
(__builtin_types_compatible_p and _Generic).  And there's no need to
change the inline function overloads for issignaling, iszero and
iscanonical in C++ because cases where types have the same format but
are no longer compatible types are handled automatically by the C++
overload resolution rules.

This patch also does not change the overload handling for iseqsig, and
there I think changes *are* needed, beyond those in this patch or made
by fixincludes.  The way that overload is defined, via a template
parameter to a structure type, requires overloads whenever the types
are incompatible, even if they have the same format.  So I think we
need to add overloads with GCC 13 for every supported _FloatN and
_FloatNx type, rather than just having one for _Float128 when it has a
different ABI to long double as at present (but for older GCC, such
overloads must not be defined for types that end up defined as
typedefs for another type).

Tested with build-many-glibcs.py: compilers build for
aarch64-linux-gnu ia64-linux-gnu mips64-linux-gnu powerpc-linux-gnu
powerpc64le-linux-gnu x86_64-linux-gnu; glibcs build for
aarch64-linux-gnu ia64-linux-gnu i686-linux-gnu mips-linux-gnu
mips64-linux-gnu-n32 powerpc-linux-gnu powerpc64le-linux-gnu
x86_64-linux-gnu.

1 files changed, 20 insertions, 20 deletions

diff --git a/bits/floatn-common.h b/bits/floatn-common.h
index 92982d6..67519db 100644
--- a/bits/floatn-common.h
+++ b/bits/floatn-common.h
@@ -78,7 +78,7 @@
    or _FloatNx types, if __HAVE_<type> is 1.  The corresponding
    literal suffixes exist since GCC 7, for C only.  */
 # if __HAVE_FLOAT16
-#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#  if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 /* No corresponding suffix available for this type.  */
 #   define __f16(x) ((_Float16) x##f)
 #  else
@@ -87,7 +87,7 @@
 # endif
 
 # if __HAVE_FLOAT32
-#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#  if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 #   define __f32(x) x##f
 #  else
 #   define __f32(x) x##f32
@@ -95,7 +95,7 @@
 # endif
 
 # if __HAVE_FLOAT64
-#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#  if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 #   ifdef __NO_LONG_DOUBLE_MATH
 #    define __f64(x) x##l
 #   else
@@ -107,7 +107,7 @@
 # endif
 
 # if __HAVE_FLOAT32X
-#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#  if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 #   define __f32x(x) x
 #  else
 #   define __f32x(x) x##f32x
@@ -115,7 +115,7 @@
 # endif
 
 # if __HAVE_FLOAT64X
-#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#  if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 #   if __HAVE_FLOAT64X_LONG_DOUBLE
 #    define __f64x(x) x##l
 #   else
@@ -127,7 +127,7 @@
 # endif
 
 # if __HAVE_FLOAT128X
-#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#  if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 #   error "_Float128X supported but no constant suffix"
 #  else
 #   define __f128x(x) x##f128x
@@ -136,7 +136,7 @@
 
 /* Defined to a complex type if __HAVE_<type> is 1.  */
 # if __HAVE_FLOAT16
-#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#  if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 typedef _Complex float __cfloat16 __attribute__ ((__mode__ (__HC__)));
 #   define __CFLOAT16 __cfloat16
 #  else
@@ -145,7 +145,7 @@ typedef _Complex float __cfloat16 __attribute__ ((__mode__ (__HC__)));
 # endif
 
 # if __HAVE_FLOAT32
-#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#  if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 #   define __CFLOAT32 _Complex float
 #  else
 #   define __CFLOAT32 _Complex _Float32
@@ -153,7 +153,7 @@ typedef _Complex float __cfloat16 __attribute__ ((__mode__ (__HC__)));
 # endif
 
 # if __HAVE_FLOAT64
-#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#  if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 #   ifdef __NO_LONG_DOUBLE_MATH
 #    define __CFLOAT64 _Complex long double
 #   else
@@ -165,7 +165,7 @@ typedef _Complex float __cfloat16 __attribute__ ((__mode__ (__HC__)));
 # endif
 
 # if __HAVE_FLOAT32X
-#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#  if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 #   define __CFLOAT32X _Complex double
 #  else
 #   define __CFLOAT32X _Complex _Float32x
@@ -173,7 +173,7 @@ typedef _Complex float __cfloat16 __attribute__ ((__mode__ (__HC__)));
 # endif
 
 # if __HAVE_FLOAT64X
-#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#  if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 #   if __HAVE_FLOAT64X_LONG_DOUBLE
 #    define __CFLOAT64X _Complex long double
 #   else
@@ -185,7 +185,7 @@ typedef _Complex float __cfloat16 __attribute__ ((__mode__ (__HC__)));
 # endif
 
 # if __HAVE_FLOAT128X
-#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#  if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 #   error "_Float128X supported but no complex type"
 #  else
 #   define __CFLOAT128X _Complex _Float128x
@@ -195,7 +195,7 @@ typedef _Complex float __cfloat16 __attribute__ ((__mode__ (__HC__)));
 /* The remaining of this file provides support for older compilers.  */
 # if __HAVE_FLOAT16
 
-#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#  if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 typedef float _Float16 __attribute__ ((__mode__ (__HF__)));
 #  endif
 
@@ -210,7 +210,7 @@ typedef float _Float16 __attribute__ ((__mode__ (__HF__)));
 
 # if __HAVE_FLOAT32
 
-#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#  if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 typedef float _Float32;
 #  endif
 
@@ -234,7 +234,7 @@ typedef float _Float32;
 
 #  ifdef __NO_LONG_DOUBLE_MATH
 
-#   if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#   if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 typedef long double _Float64;
 #   endif
 
@@ -247,7 +247,7 @@ typedef long double _Float64;
 
 #  else
 
-#   if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#   if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 typedef double _Float64;
 #   endif
 
@@ -264,7 +264,7 @@ typedef double _Float64;
 
 # if __HAVE_FLOAT32X
 
-#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#  if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 typedef double _Float32x;
 #  endif
 
@@ -281,7 +281,7 @@ typedef double _Float32x;
 
 #  if __HAVE_FLOAT64X_LONG_DOUBLE
 
-#   if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#   if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 typedef long double _Float64x;
 #   endif
 
@@ -294,7 +294,7 @@ typedef long double _Float64x;
 
 #  else
 
-#   if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#   if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 typedef _Float128 _Float64x;
 #   endif
 
@@ -311,7 +311,7 @@ typedef _Float128 _Float64x;
 
 # if __HAVE_FLOAT128X
 
-#  if !__GNUC_PREREQ (7, 0) || defined __cplusplus
+#  if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
 #   error "_Float128x supported but no type"
 #  endif