Reimplement <tgmath.h> on top of __generic().

The macro construction used now, is almost identical to the code
provided in C11 proposal N1404. This new version doesn't seem to
introduce any regressions according to the regression test in tools/,
but still seems to malfunction with Clang on certain aspects.

The new code does work successfully with GCC 4.2, 4.6 and 4.7. With 4.7,
it also works when __generic() is implemented on top of _Generic().

Discussed with:	stefanf

1 files changed, 66 insertions, 45 deletions

diff --git a/include/tgmath.h b/include/tgmath.h
index 7ff8dd4..9673dd4 100644
--- a/include/tgmath.h
+++ b/include/tgmath.h
@@ -2,6 +2,9 @@
  * Copyright (c) 2004 Stefan Farfeleder.
  * All rights reserved.
  *
+ * Copyright (c) 2012 Ed Schouten <ed@FreeBSD.org>
+ * All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
@@ -33,64 +36,83 @@
 #include <math.h>
 
 /*
- * This implementation of <tgmath.h> requires two implementation-dependent
- * macros to be defined:
- * __tg_impl_simple(x, y, z, fn, fnf, fnl, ...)
+ * This implementation of <tgmath.h> uses the two following macros,
+ * which are based on the macros described in C11 proposal N1404:
+ * __tg_impl_simple(x, y, z, fnl, fn, fnf, ...)
  *	Invokes fnl() if the corresponding real type of x, y or z is long
  *	double, fn() if it is double or any has an integer type, and fnf()
  *	otherwise.
- * __tg_impl_full(x, y, z, fn, fnf, fnl, cfn, cfnf, cfnl, ...)
- *	Invokes [c]fnl() if the corresponding real type of x, y or z is long
+ * __tg_impl_full(x, y, cfnl, cfn, cfnf, fnl, fn, fnf, ...)
+ *	Invokes [c]fnl() if the corresponding real type of x or y is long
  *	double, [c]fn() if it is double or any has an integer type, and
  *	[c]fnf() otherwise.  The function with the 'c' prefix is called if
- *	any of x, y or z is a complex number.
+ *	any of x or y is a complex number.
  * Both macros call the chosen function with all additional arguments passed
  * to them, as given by __VA_ARGS__.
  *
  * Note that these macros cannot be implemented with C's ?: operator,
  * because the return type of the whole expression would incorrectly be long
  * double complex regardless of the argument types.
+ *
+ * The _Complex_I distinction should not be needed, but due to a bug in
+ * GCC 4.2, _Complex_I is not of type float _Complex.
  */
 
-#if __GNUC_PREREQ__(3, 1)
-#define	__tg_type(e, t)	__builtin_types_compatible_p(__typeof__(e), t)
-#define	__tg_type3(e1, e2, e3, t)					\
-	(__tg_type(e1, t) || __tg_type(e2, t) || __tg_type(e3, t))
-#define	__tg_type_corr(e1, e2, e3, t)					\
-	(__tg_type3(e1, e2, e3, t) || __tg_type3(e1, e2, e3, t _Complex))
-#define	__tg_integer(e1, e2, e3)					\
-	(((__typeof__(e1))1.5 == 1) || ((__typeof__(e2))1.5 == 1) ||	\
-	    ((__typeof__(e3))1.5 == 1))
-#define	__tg_is_complex(e1, e2, e3)					\
-	(__tg_type3(e1, e2, e3, float _Complex) ||			\
-	    __tg_type3(e1, e2, e3, double _Complex) ||			\
-	    __tg_type3(e1, e2, e3, long double _Complex) ||		\
-	    __tg_type3(e1, e2, e3, __typeof__(_Complex_I)))
-
-#define	__tg_impl_simple(x, y, z, fn, fnf, fnl, ...)			\
-	__builtin_choose_expr(__tg_type_corr(x, y, z, long double),	\
-	    fnl(__VA_ARGS__), __builtin_choose_expr(			\
-		__tg_type_corr(x, y, z, double) || __tg_integer(x, y, z),\
-		fn(__VA_ARGS__), fnf(__VA_ARGS__)))
-
-#define	__tg_impl_full(x, y, z, fn, fnf, fnl, cfn, cfnf, cfnl, ...)	\
-	__builtin_choose_expr(__tg_is_complex(x, y, z),			\
-	    __tg_impl_simple(x, y, z, cfn, cfnf, cfnl, __VA_ARGS__),	\
-	    __tg_impl_simple(x, y, z, fn, fnf, fnl, __VA_ARGS__))
-
-#else	/* __GNUC__ */
+#ifndef __generic
 #error "<tgmath.h> not implemented for this compiler"
-#endif	/* !__GNUC__ */
+#endif
+
+#define	__tg_generic_simple(x, fnl, fn, fnf)				\
+	__generic(x, long double _Complex, fnl,				\
+	    __generic(x, double _Complex, fn,				\
+	        __generic(x, float _Complex, fnf,			\
+	            __generic(x, __typeof(_Complex_I), fnf,		\
+	                __generic(x, long double, fnl,			\
+	                    __generic(x, float, fnf, fn))))))
+#define	__tg_impl_simple(x, y, z, fnl, fn, fnf, ...)			\
+	__tg_generic_simple(x,						\
+	    __tg_generic_simple(y,					\
+	        __tg_generic_simple(z, fnl, fnl, fnl),			\
+	        __tg_generic_simple(z, fnl, fnl, fnl),			\
+	        __tg_generic_simple(z, fnl, fnl, fnl)),			\
+	    __tg_generic_simple(y,					\
+	        __tg_generic_simple(z, fnl, fnl, fnl),			\
+	        __tg_generic_simple(z, fnl, fn , fn ),			\
+	        __tg_generic_simple(z, fnl, fn , fn )),			\
+	    __tg_generic_simple(y,					\
+	        __tg_generic_simple(z, fnl, fnl, fnl),			\
+	        __tg_generic_simple(z, fnl, fn , fn ),			\
+	        __tg_generic_simple(z, fnl, fn , fnf)))(__VA_ARGS__)
+#define	__tg_generic_full(x, cfnl, cfn, cfnf, fnl, fn, fnf)		\
+	__generic(x, long double _Complex, cfnl,			\
+	    __generic(x, double _Complex, cfn,				\
+	        __generic(x, float _Complex, cfnf,			\
+	            __generic(x, __typeof(_Complex_I), cfnf,		\
+	                __generic(x, long double, fnl,			\
+	                    __generic(x, float, fnf, fn))))))
+#define	__tg_impl_full(x, y, cfnl, cfn, cfnf, fnl, fn, fnf, ...)	\
+	__tg_generic_full(x,						\
+	    __tg_generic_full(y, cfnl, cfnl, cfnl, cfnl, cfnl, cfnl),	\
+	    __tg_generic_full(y, cfnl, cfn , cfn , cfnl, cfn , cfn ),	\
+	    __tg_generic_full(y, cfnl, cfn , cfnf, cfnl, cfn , cfnf),	\
+	    __tg_generic_full(y, cfnl, cfnl, cfnl, fnl , fnl , fnl ),	\
+	    __tg_generic_full(y, cfnl, cfn , cfn , fnl , fn  , fn  ),	\
+	    __tg_generic_full(y, cfnl, cfn , cfnf, fnl , fn  , fnf ))	\
+	    (__VA_ARGS__)
 
 /* Macros to save lots of repetition below */
 #define	__tg_simple(x, fn)						\
-	__tg_impl_simple(x, x, x, fn, fn##f, fn##l, x)
+	__tg_impl_simple(x, x, x, fn##l, fn, fn##f, x)
 #define	__tg_simple2(x, y, fn)						\
-	__tg_impl_simple(x, x, y, fn, fn##f, fn##l, x, y)
+	__tg_impl_simple(x, x, y, fn##l, fn, fn##f, x, y)
+#define	__tg_simple3(x, y, z, fn)					\
+	__tg_impl_simple(x, y, z, fn##l, fn, fn##f, x, y, z)
 #define	__tg_simplev(x, fn, ...)					\
-	__tg_impl_simple(x, x, x, fn, fn##f, fn##l, __VA_ARGS__)
+	__tg_impl_simple(x, x, x, fn##l, fn, fn##f, __VA_ARGS__)
 #define	__tg_full(x, fn)						\
-	__tg_impl_full(x, x, x, fn, fn##f, fn##l, c##fn, c##fn##f, c##fn##l, x)
+	__tg_impl_full(x, x, c##fn##l, c##fn, c##fn##f, fn##l, fn, fn##f, x)
+#define	__tg_full2(x, y, fn)						\
+	__tg_impl_full(x, y, c##fn##l, c##fn, c##fn##f, fn##l, fn, fn##f, x, y)
 
 /* 7.22#4 -- These macros expand to real or complex functions, depending on
  * the type of their arguments. */
@@ -108,13 +130,12 @@
 #define	tanh(x)		__tg_full(x, tanh)
 #define	exp(x)		__tg_full(x, exp)
 #define	log(x)		__tg_full(x, log)
-#define	pow(x, y)	__tg_impl_full(x, x, y, pow, powf, powl,	\
-			    cpow, cpowf, cpowl, x, y)
+#define	pow(x, y)	__tg_full2(x, y, pow)
 #define	sqrt(x)		__tg_full(x, sqrt)
 
 /* "The corresponding type-generic macro for fabs and cabs is fabs." */
-#define	fabs(x)		__tg_impl_full(x, x, x, fabs, fabsf, fabsl,	\
-    			    cabs, cabsf, cabsl, x)
+#define	fabs(x)		__tg_impl_full(x, x, cabsl, cabs, cabsf,	\
+    			    fabsl, fabs, fabsf, x)
 
 /* 7.22#5 -- These macros are only defined for arguments with real type. */
 #define	atan2(x, y)	__tg_simple2(x, y, atan2)
@@ -127,7 +148,7 @@
 #define	expm1(x)	__tg_simple(x, expm1)
 #define	fdim(x, y)	__tg_simple2(x, y, fdim)
 #define	floor(x)	__tg_simple(x, floor)
-#define	fma(x, y, z)	__tg_impl_simple(x, y, z, fma, fmaf, fmal, x, y, z)
+#define	fma(x, y, z)	__tg_simple3(x, y, z, fma)
 #define	fmax(x, y)	__tg_simple2(x, y, fmax)
 #define	fmin(x, y)	__tg_simple2(x, y, fmin)
 #define	fmod(x, y)	__tg_simple2(x, y, fmod)
@@ -148,8 +169,8 @@
 #define	nextafter(x, y)	__tg_simple2(x, y, nextafter)
 #define	nexttoward(x, y) __tg_simplev(x, nexttoward, x, y)
 #define	remainder(x, y)	__tg_simple2(x, y, remainder)
-#define	remquo(x, y, z)	__tg_impl_simple(x, x, y, remquo, remquof,	\
-			    remquol, x, y, z)
+#define	remquo(x, y, z)	__tg_impl_simple(x, x, y, remquol, remquo,	\
+			    remquof, x, y, z)
 #define	rint(x)		__tg_simple(x, rint)
 #define	round(x)	__tg_simple(x, round)
 #define	scalbn(x, y)	__tg_simplev(x, scalbn, x, y)