diff --git a/include/tgmath.h b/include/tgmath.h
index 9de0afe4248b..9302302658fb 100644
--- a/include/tgmath.h
+++ b/include/tgmath.h
@@ -53,19 +53,23 @@
  * 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 structure of the C11 implementation of these macros can in
+ * principle be reused for non-C11 compilers, but due to an integer
+ * promotion bug for complex types in GCC 4.2, simply let non-C11
+ * compilers use an inefficient yet reliable version.
  */
 
-#ifndef __generic
-#error "<tgmath.h> not implemented for this compiler"
-#endif
-
-#if 0 /* XXX: Much shorter and faster to compile, but broken with GCC 4.2. */
+#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
 #define	__tg_generic(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, long double, fnl,			\
-	                __generic(x, float, fnf, fn)))))
+	_Generic(x,							\
+		long double _Complex: cfnl,				\
+		double _Complex: cfn,					\
+		float _Complex: cfnf,					\
+		long double: fnl,					\
+		default: fn,						\
+		float: fnf						\
+	)
 #define	__tg_type(x)							\
 	__tg_generic(x, (long double _Complex)0, (double _Complex)0,	\
 	    (float _Complex)0, (long double)0, (double)0, (float)0)
@@ -77,7 +81,7 @@
 	__tg_generic(							\
 	    __tg_type(x) + __tg_type(y),				\
 	    cfnl, cfn, cfnf, fnl, fn, fnf)(__VA_ARGS__)
-#else
+#elif defined(__generic)
 #define	__tg_generic_simple(x, fnl, fn, fnf)				\
 	__generic(x, long double _Complex, fnl,				\
 	    __generic(x, double _Complex, fn,				\
@@ -113,6 +117,8 @@
 	    __tg_generic_full(y, cfnl, cfn , cfn , fnl , fn  , fn  ),	\
 	    __tg_generic_full(y, cfnl, cfn , cfnf, fnl , fn  , fnf ))	\
 	    (__VA_ARGS__)
+#else
+#error "<tgmath.h> not implemented for this compiler"
 #endif
 
 /* Macros to save lots of repetition below */