Added several flow control tests.

test/misc/flow-while-02.c

@@ -0,0 +1,74 @@
+int a;
+
+static int f1(void)
+{
+    while (1) {
+        while (0) {
+            /* Unreachable */
+            ++a;
+        }
+    }
+    /* Unreachable */
+    a = 2;
+    return a;
+}
+
+static int f2(void)
+{
+    while (1) {
+        do {
+            return a;
+        } while (0);
+        /* Unreachable */
+        break;
+    }
+    /* Unreachable but no warning */
+    a = 2;
+    return a;
+}
+
+static int f3(void)
+{
+    do {
+        while (1) {
+            break;
+        }
+    } while (1);
+    /* Unreachable */
+    a = 2;
+    return a;
+}
+
+static int f4(void)
+{
+    do {
+        while (1) {
+            return a;
+        }
+    } while (0);
+    /* Unreachable */
+    a = 2;
+    return a;
+}
+
+static int f5(void)
+{
+    do {
+        do {
+            if (a == 2) {
+                return a;
+            } else {
+                continue;
+            }
+        } while (0);
+    } while (0);
+    /* Unreachable */
+    a = 2;
+    return a;
+}
+
+int main(void)
+{
+    return f1()/ + f2() + f3() + f4() + f5();
+}
+