--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/cpp/ucnid-11-utf8.c	Thu Feb 13 11:34:05 2020 +0900
@@ -0,0 +1,30 @@
+/* Test spelling differences in UCNs are properly diagnosed for macro
+   redefinitions.  */
+/* { dg-do preprocess } */
+/* { dg-options "-std=c99 -pedantic-errors" } */
+
+/* Different spelling of UCN in expansion.  */
+#define m1 \u00c1 /* { dg-message "-:previous definition" } */
+#define m1 Á /* { dg-error "-:redefined" } */
+
+#define m1ok Á
+#define m1ok Á
+
+/* Different spelling of UCN in argument name.  */
+#define m2(\u00c1) /* { dg-message "-:previous definition" } */
+#define m2(Á) /* { dg-error "-:redefined" } */
+
+#define m2ok(Á)
+#define m2ok(Á)
+
+/* Same spelling in argument name but different spelling when used in
+   expansion.  */
+#define m3(\u00c1) \u00c1 /* { dg-message "-:previous definition" } */
+#define m3(\u00c1) Á /* { dg-error "-:redefined" } */
+
+#define m3ok(\u00c1) Á
+#define m3ok(\u00c1) Á
+
+/* Different spelling of the macro name itself is OK.  */
+#define m4ok\u00c1
+#define m4okÁ