Handle more _FloatN, _FloatNx types in tgmath.h.

Continuing the preparation for additional _FloatN / _FloatNx type
support, this patch improves how <tgmath.h> handles such types.

Use of #error is added for cases of distinct types that are not
supported by the header, to indicate that additional work on the
header would be needed if, for example, _Float16 support were added to
glibc.  Given that #error, types with the same format as other types
are handled automatically by the sizeof-based logic, so the only case
needing special handling is that where _Float64x exists, has the same
format as _Float128, does not have the same format as long double, and
is not a typedef for _Float128.  In this case (which will apply for
powerpc64le once _Float64x support is added to glibc), the
__builtin_types_compatible_p calls testing for _Float128 need
corresponding calls testing for _Float64x, which this patch adds.

Tested for x86_64.

	* math/tgmath.h [__HAVE_DISTINCT_FLOAT16
	|| __HAVE_DISTINCT_FLOAT32 || __HAVE_DISTINCT_FLOAT64
	|| __HAVE_DISTINCT_FLOAT32X || __HAVE_DISTINCT_FLOAT64X
	|| __HAVE_DISTINCT_FLOAT128X]: Use #error.
	[__HAVE_DISTINCT_FLOAT128 && __GLIBC_USE (IEC_60559_TYPES_EXT)
	&& __HAVE_FLOAT64X && !__HAVE_FLOAT64X_LONG_DOUBLE
	&& __HAVE_FLOATN_NOT_TYPEDEF] (__TGMATH_F128): Handle _Float64x
	the same as _Float128.
	[__HAVE_DISTINCT_FLOAT128 && __GLIBC_USE (IEC_60559_TYPES_EXT)
	&& __HAVE_FLOAT64X && !__HAVE_FLOAT64X_LONG_DOUBLE
	&& __HAVE_FLOATN_NOT_TYPEDEF] (__TGMATH_CF128): Likewise.

2 files changed, 41 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index aa115b62fa..e8913ba3db 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,17 @@
 2017-11-03  Joseph Myers  <joseph@codesourcery.com>
 
+	* math/tgmath.h [__HAVE_DISTINCT_FLOAT16
+	|| __HAVE_DISTINCT_FLOAT32 || __HAVE_DISTINCT_FLOAT64
+	|| __HAVE_DISTINCT_FLOAT32X || __HAVE_DISTINCT_FLOAT64X
+	|| __HAVE_DISTINCT_FLOAT128X]: Use #error.
+	[__HAVE_DISTINCT_FLOAT128 && __GLIBC_USE (IEC_60559_TYPES_EXT)
+	&& __HAVE_FLOAT64X && !__HAVE_FLOAT64X_LONG_DOUBLE
+	&& __HAVE_FLOATN_NOT_TYPEDEF] (__TGMATH_F128): Handle _Float64x
+	the same as _Float128.
+	[__HAVE_DISTINCT_FLOAT128 && __GLIBC_USE (IEC_60559_TYPES_EXT)
+	&& __HAVE_FLOAT64X && !__HAVE_FLOAT64X_LONG_DOUBLE
+	&& __HAVE_FLOATN_NOT_TYPEDEF] (__TGMATH_CF128): Likewise.
+
 	* stdlib/stdlib.h
 	[__HAVE_FLOAT16 && __GLIBC_USE (IEC_60559_TYPES_EXT)] (strtof16):
 	Declare.
diff --git a/math/tgmath.h b/math/tgmath.h
index 243813cdc0..108c1a19c7 100644
--- a/math/tgmath.h
+++ b/math/tgmath.h
@@ -115,18 +115,45 @@
 			     __real_integer_type (__typeof__ (+(expr))), \
 			     __complex_integer_type (__typeof__ (+(expr))))
 
+# if (__HAVE_DISTINCT_FLOAT16			\
+      || __HAVE_DISTINCT_FLOAT32		\
+      || __HAVE_DISTINCT_FLOAT64		\
+      || __HAVE_DISTINCT_FLOAT32X		\
+      || __HAVE_DISTINCT_FLOAT64X		\
+      || __HAVE_DISTINCT_FLOAT128X)
+#  error "Unsupported _FloatN or _FloatNx types for <tgmath.h>."
+# endif
+
 /* Expand to text that checks if ARG_COMB has type _Float128, and if
    so calls the appropriately suffixed FCT (which may include a cast),
    or FCT and CFCT for complex functions, with arguments ARG_CALL.  */
 # if __HAVE_DISTINCT_FLOAT128 && __GLIBC_USE (IEC_60559_TYPES_EXT)
-#  define __TGMATH_F128(arg_comb, fct, arg_call) \
+#  if (!__HAVE_FLOAT64X				\
+       || __HAVE_FLOAT64X_LONG_DOUBLE		\
+       || !__HAVE_FLOATN_NOT_TYPEDEF)
+#   define __TGMATH_F128(arg_comb, fct, arg_call)			\
   __builtin_types_compatible_p (__typeof (+(arg_comb)), _Float128)	\
   ? fct ## f128 arg_call :
-#  define __TGMATH_CF128(arg_comb, fct, cfct, arg_call)			\
+#   define __TGMATH_CF128(arg_comb, fct, cfct, arg_call)		\
   __builtin_types_compatible_p (__typeof (+__real__ (arg_comb)), _Float128) \
   ? (__expr_is_real (arg_comb)						\
      ? fct ## f128 arg_call						\
      : cfct ## f128 arg_call) :
+#  else
+/* _Float64x is a distinct type at the C language level, which must be
+   handled like _Float128.  */
+#   define __TGMATH_F128(arg_comb, fct, arg_call)			\
+  (__builtin_types_compatible_p (__typeof (+(arg_comb)), _Float128)	\
+   || __builtin_types_compatible_p (__typeof (+(arg_comb)), _Float64x)) \
+  ? fct ## f128 arg_call :
+#   define __TGMATH_CF128(arg_comb, fct, cfct, arg_call)		\
+  (__builtin_types_compatible_p (__typeof (+__real__ (arg_comb)), _Float128) \
+   || __builtin_types_compatible_p (__typeof (+__real__ (arg_comb)),	\
+				    _Float64x))				\
+  ? (__expr_is_real (arg_comb)						\
+     ? fct ## f128 arg_call						\
+     : cfct ## f128 arg_call) :
+#  endif
 # else
 #  define __TGMATH_F128(arg_comb, fct, arg_call) /* Nothing.  */
 #  define __TGMATH_CF128(arg_comb, fct, cfct, arg_call) /* Nothing.  */