--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/c-c++-common/pr89888.c	Thu Feb 13 11:34:05 2020 +0900
@@ -0,0 +1,67 @@
+/* PR c/89888 */
+/* { dg-do compile { target { int32 } } } */
+/* { dg-options "" } */
+
+long long y;
+
+void
+foo (unsigned char x)
+{
+  switch (x)
+    {
+    case -1: y = -1; break;			/* { dg-message "previously used here" } */
+						/* { dg-warning "case label value is less than minimum value for type" "" { target *-*-* } .-1 } */
+    case 0xffffffff: y = 0xffffffff; break;	/* { dg-error "duplicate case value|narrowing" } */
+    case ~0U: y = ~0U; break;			/* { dg-error "duplicate case value|narrowing" } */
+    }
+}
+
+void
+bar (unsigned char x)
+{
+  switch (x)
+    {
+    case -1: y = -1; break;			/* { dg-message "previously used here" } */
+						/* { dg-warning "case label value is less than minimum value for type" "" { target *-*-* } .-1  } */
+    case -1: y = -1; break;			/* { dg-error "duplicate case value" } */
+    case -1: y = -1; break;			/* { dg-error "duplicate case value" } */
+    }
+}
+
+void
+baz (unsigned char x)
+{
+  switch (x)
+    {
+    case -7: y = -7; break;			/* { dg-warning "case label value is less than minimum value for type" } */
+    case -5 ... 2: y = -5; break;		/* { dg-warning "lower value in case label range less than minimum value for type" } */
+    case 18: y = 18; break;
+    case (unsigned char) -2 ... 4 + (unsigned char) -2: y = 2; break;	/* { dg-warning "upper value in case label range exceeds maximum value for type" } */
+    case 24 + (unsigned char) -2: y = 3; break;	/* { dg-warning "case label value exceeds maximum value for type" } */
+    }
+}
+
+void
+qux (unsigned char x)
+{
+  switch (x)
+    {
+    case (unsigned char) -1 ... 1 + (unsigned char) -1: y = 2; break;	/* { dg-warning "upper value in case label range exceeds maximum value for type" } */
+    case -12: y = -7; break;			/* { dg-warning "case label value is less than minimum value for type" } */
+    case 18: y = 18; break;
+    case 27 + (unsigned char) -1: y = 3; break;	/* { dg-warning "case label value exceeds maximum value for type" } */
+    case -1 ... 0: y = -5; break;		/* { dg-warning "lower value in case label range less than minimum value for type" } */
+    }
+}
+
+void
+quux (unsigned char x)
+{
+  switch (x)
+    {
+    case (unsigned char) -2 ... (unsigned char) -1: y = 2; break;
+    case 18: y = 18; break;
+    case 1 + (unsigned char) -1: y = 3; break;	/* { dg-warning "case label value exceeds maximum value for type" } */
+    case -2 ... -1: y = -5; break;		/* { dg-warning "case label value is less than minimum value for type" } */
+    }
+}