/*      $NetBSD: expr_range.c,v 1.6 2024/11/13 04:32:49 rillig Exp $    */
# 3 "expr_range.c"

/*
 * In a switch statement that has (expr & constant) as the controlling
 * expression, complain if a case branch is unreachable because the case
 * label can never match the controlling expression.
 *
 * GCC 10 does not complain about the unreachable branch.  It knows that the
 * branch is unreachable though, since it doesn't generate any code for it.
 * GCC once had the option -Wunreachable-code, but that option was made a
 * no-op in 2011.
 *
 * Clang 10 does not complain about this either, and just like GCC it doesn't
 * generate any code for this branch.  The code for tracking an expression's
 * possible values may be related to RangeConstraintManager, just guessing.
 */

/* lint1-extra-flags: -chap -X 351 */

void println(const char *);

void
example(unsigned x)
{
        switch (x & 6) {
        case 0:
                println("0 is reachable");
                break;
        case 1:
                /* expect-1: warning: 'case' statement not reached [193] */
                println("1 is not reachable");
                break;
        case 2:
                println("2 is reachable");
                break;
        case 6:
                println("6 is reachable");
                break;
        case 7:
                /* expect-1: warning: 'case' statement not reached [193] */
                println("7 is not reachable");
                break;
        }
}