1 files changed, 25 insertions, 0 deletions
diff --git a/gcc/testsuite/gcc.dg/charset/builtin1.c b/gcc/testsuite/gcc.dg/charset/builtin1.c
new file mode 100644
index 00000000000..c15c06ed73c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/charset/builtin1.c
@@ -0,0 +1,25 @@
+/* isdigit(c) can be optimized to ((unsigned)c) - '0' <= 9, but only if
+   we know the correct value of '0'.  PR 18785.  */
+
+/* { dg-do run } */
+/* { dg-options "-O2 -fno-inline -fexec-charset=IBM-1047" } */
+
+extern int isdigit(int);
+extern void abort(void);
+
+static int str1(void) { return '1'; }
+static int strA(void) { return 'A'; }
+
+int
+main(void)
+{
+  if (!isdigit('1'))
+    abort();
+  if (isdigit('A'))
+    abort();
+  if (!isdigit(str1()))
+    abort();
+  if (isdigit(strA()))
+    abort();
+  return 0;
+}