[C11] Claim conformance to N1464

That's on the CMPLX macros which Clang supports via __builtin_complex.

Author: AaronBallman

clang/test/C/C11/n1464.c

@@ -0,0 +1,22 @@
+// RUN: %clang_cc1 -verify %s
+// expected-no-diagnostics
+
+/* WG14 N1464: ???
+ * Creation of complex value
+ */
+
+// The paper is about the CMPLX macros, which Clang supports via the
+// __builtin_complex builtin function. Test the basic functionality.
+_Static_assert(__builtin_complex(5.0, 2.0) == 5.0 + 1.0j * 2.0, "");
+_Static_assert(__builtin_complex(5.0f, 2.0f) == 5.0f + 1.0j * 2.0f, "");
+_Static_assert(__builtin_complex(5.0L, 2.0L) == 5.0L + 1.0j * 2.0L, "");
+
+// Test the edge case involving NaN or infinity.
+#define INF(type) (type)__builtin_inf()
+#define NAN(type) (type)__builtin_nan("")
+_Static_assert(__builtin_complex(5.0f, INF(float)) != 5.0f + 1.0j * INF(float), "");
+_Static_assert(__builtin_complex(5.0, INF(double)) != 5.0 + 1.0j * INF(double), "");
+_Static_assert(__builtin_complex(5.0L, INF(long double)) != 5.0L + 1.0j * INF(long double), "");
+_Static_assert(__builtin_complex(5.0f, NAN(float)) != 5.0f + 1.0j * NAN(float), "");
+_Static_assert(__builtin_complex(5.0, NAN(double)) != 5.0 + 1.0j * NAN(double), "");
+_Static_assert(__builtin_complex(5.0L, NAN(long double)) != 5.0L + 1.0j * NAN(long double), "");

clang/www/c_status.html

@@ -561,7 +561,7 @@ <h2 id="c11">C11 implementation status</h2>
     <tr>
       <td>Creation of complex value</td>
       <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1464.htm">N1464</a></td>
-      <td class="unknown" align="center">Unknown</td>
+      <td class="full" align="center">Clang 12</td>
     </tr>
     <tr>
       <td>Recommendations for extended identifier characters for C and C++</td>