fix for #1941, taken from 22d435b689

test/val/bug1941-shift-by-zero.c

@@ -0,0 +1,28 @@
+/* Bug 1941 - Bitwise shift char types by 0 count results in out-of-range access */
+
+#include <stdio.h>
+#include <stdint.h>
+
+uint8_t foo = 42U;      /* "Low byte" */
+uint8_t goo = 1U;       /* "High byte" - you need it to reproduce the issue */
+int16_t bar = 256;      /* ...or just do it with this */
+
+_Static_assert (sizeof (foo >> 0) == sizeof (int), "Shift result should be int-promoted");
+_Static_assert (sizeof ((int8_t)bar << 0) == sizeof (int), "Shift result should be int-promoted");
+
+unsigned failures;
+
+int main(void)
+{
+    if (foo >> 0 != foo) {
+        ++failures;
+        printf("foo failed\n");
+    }
+
+    if ((int8_t)bar << 0 != (int8_t)bar) {
+        ++failures;
+        printf("bar failed\n");
+    }
+
+    return failures;
+}