diff --git a/gcc/c-family/c-common.cc b/gcc/c-family/c-common.cc
index f044db5b797b5f73ae81d336cf13c4be8cf2ea03..0efdc677217fbf38a3c4244da417a30da64a5461 100644
--- a/gcc/c-family/c-common.cc
+++ b/gcc/c-family/c-common.cc
@@ -3828,12 +3828,13 @@ c_common_get_alias_set (tree t)
   if (!TYPE_P (t))
     return -1;
 
-  /* Unlike char, char8_t doesn't alias. */
-  if (flag_char8_t && t == char8_type_node)
+  /* Unlike char, char8_t doesn't alias in C++.  (In C, char8_t is not
+     a distinct type.)  */
+  if (flag_char8_t && t == char8_type_node && c_dialect_cxx ())
     return -1;
 
   /* The C standard guarantees that any object may be accessed via an
-     lvalue that has narrow character type (except char8_t).  */
+     lvalue that has narrow character type.  */
   if (t == char_type_node
       || t == signed_char_type_node
       || t == unsigned_char_type_node)
diff --git a/gcc/testsuite/c-c++-common/alias-1.c b/gcc/testsuite/c-c++-common/alias-1.c
new file mode 100644
index 0000000000000000000000000000000000000000..d72fec47f7601b1f4b806b853124cb274a8cd263
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/alias-1.c
@@ -0,0 +1,23 @@
+/* PR c/111884 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wall" } */
+/* { dg-additional-options "-std=c++20" { target c++ } } */
+/* { dg-additional-options "-std=c2x" { target c } } */
+
+int f(int i)
+{
+    int f = 1;
+    return i[(unsigned char *)&f];
+}
+
+int g(int i)
+{
+    int f = 1;
+    return i[(signed char *)&f];
+}
+
+int h(int i)
+{
+    int f = 1;
+    return i[(char *)&f];
+}