1 files changed, 32 insertions, 8 deletions

diff --git a/tests/test-stddef.c b/tests/test-stddef.c
index 470c7a6b..5bceb18a 100644
--- a/tests/test-stddef.c
+++ b/tests/test-stddef.c
@@ -1,5 +1,5 @@
 /* Test of <stddef.h> substitute.
-   Copyright (C) 2009-2022 Free Software Foundation, Inc.
+   Copyright (C) 2009-2024 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -19,14 +19,12 @@
 #include <config.h>
 
 #include <stddef.h>
-#include <limits.h>
-#include <stdalign.h>
 
 /* Check that appropriate types are defined.  */
 wchar_t a = 'c';
 ptrdiff_t b = 1;
 size_t c = 2;
-max_align_t x;
+max_align_t mat;
 
 /* Check that NULL can be passed through varargs as a pointer type,
    per POSIX 2008.  */
@@ -45,10 +43,6 @@ struct d
 static_assert (sizeof (offsetof (struct d, e)) == sizeof (size_t));
 static_assert (offsetof (struct d, f) == 1);
 
-/* offsetof promotes to an unsigned integer if and only if sizes do
-   not fit in int.  */
-static_assert ((offsetof (struct d, e) < -1) == (INT_MAX < (size_t) -1));
-
 /* Check max_align_t's alignment.  */
 static_assert (alignof (double) <= alignof (max_align_t));
 static_assert (alignof (int) <= alignof (max_align_t));
@@ -69,6 +63,36 @@ static_assert (__alignof__ (wchar_t) <= __alignof__ (max_align_t));
 static_assert (__alignof__ (struct d) <= __alignof__ (max_align_t));
 #endif
 
+int test_unreachable_optimization (int x);
+_Noreturn void test_unreachable_noreturn (void);
+
+int
+test_unreachable_optimization (int x)
+{
+  /* Check that the compiler uses 'unreachable' for optimization.
+     This function, when compiled with optimization, should have code
+     equivalent to
+       return x + 3;
+     Use 'objdump --disassemble test-stddef.o' to verify this.  */
+  if (x < 4)
+    unreachable ();
+  return (x > 1 ? x + 3 : 2 * x + 10);
+}
+
+_Noreturn void
+test_unreachable_noreturn (void)
+{
+  /* Check that the compiler's data-flow analysis recognizes 'unreachable ()'.
+     This function should not elicit a warning.  */
+  unreachable ();
+}
+
+#include <limits.h> /* INT_MAX */
+
+/* offsetof promotes to an unsigned integer if and only if sizes do
+   not fit in int.  */
+static_assert ((offsetof (struct d, e) < -1) == (INT_MAX < (size_t) -1));
+
 int
 main (void)
 {