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6_8_31_switch_char_extremes.c (698B)

      1 /* signed char selector at the extremes of i8 range. A jump-table
      2  * lowering that pre-promotes the selector to a wider type without
      3  * preserving signedness would silently miscompile case INT8_MIN. */
      4 static int pick(signed char c) {
      5   switch (c) {
      6     case -128:
      7       return 1;
      8     case -127:
      9       return 2;
     10     case 0:
     11       return 3;
     12     case 126:
     13       return 4;
     14     case 127:
     15       return 5;
     16     default:
     17       return 9;
     18   }
     19 }
     20 
     21 int test_main(void) {
     22   int s = 0;
     23   s += pick((signed char)-128);
     24   s += pick((signed char)-127);
     25   s += pick((signed char)0);
     26   s += pick((signed char)127);
     27   s += pick((signed char)42); /* miss -> 9 */
     28   return s - 15;              /* 1+2+3+5+9 - 15 = 5 */
     29 }