--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/c11-align-2.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,92 @@
+/* Test C11 alignment support.  Test valid code using stdalign.h.  */
+/* { dg-do run } */
+/* { dg-options "-std=c11 -pedantic-errors" } */
+
+#include <stdalign.h>
+#include <stddef.h>
+
+extern int strcmp (const char *, const char *);
+
+extern void exit (int);
+extern void abort (void);
+
+alignas (alignof (max_align_t)) char c;
+extern alignas (max_align_t) char c;
+extern char c;
+
+extern alignas (max_align_t) short s;
+alignas (max_align_t) short s;
+
+alignas (int) int i;
+extern int i;
+
+alignas (max_align_t) long l;
+
+alignas (max_align_t) long long ll;
+
+alignas (max_align_t) float f;
+
+alignas (max_align_t) double d;
+
+alignas (max_align_t) _Complex long double cld;
+
+alignas (0) alignas (int) alignas (char) char ca[10];
+
+alignas ((int) alignof (max_align_t) + 0) int x;
+
+enum e { E = alignof (max_align_t) };
+alignas (E) int y;
+
+void
+func (void)
+{
+  alignas (max_align_t) long long auto_ll;
+}
+
+/* Valid, but useless.  */
+alignas (0) struct s; /* { dg-warning "useless" } */
+
+#ifndef alignas
+#error "alignas not defined"
+#endif
+
+#ifndef alignof
+#error "alignof not defined"
+#endif
+
+#ifndef __alignas_is_defined
+#error "__alignas_is_defined not defined"
+#endif
+
+#if __alignas_is_defined != 1
+#error "__alignas_is_defined not 1"
+#endif
+
+#ifndef __alignof_is_defined
+#error "__alignof_is_defined not defined"
+#endif
+
+#if __alignof_is_defined != 1
+#error "__alignof_is_defined not 1"
+#endif
+
+#define str(x) #x
+#define xstr(x) str(x)
+
+const char *s1 = xstr(alignas);
+const char *s2 = xstr(alignof);
+const char *s3 = xstr(__alignas_is_defined);
+const char *s4 = xstr(__alignof_is_defined);
+
+int
+main (void)
+{
+  if (strcmp (s1, "_Alignas") != 0)
+    abort ();
+  if (strcmp (s2, "_Alignof") != 0)
+    abort ();
+  if (strcmp (s3, "1") != 0)
+    abort ();
+  if (strcmp (s4, "1") != 0)
+    abort ();
+}