Memory corruption with switch-local buffer

[dfandrich]

A buffer placed in the scope of a switch statement results in memory corruption. The following code:

#include <stdio.h>
int main(void) {
   /* char switchbuf[32]; // Placing the buffer here works fine */
  int a=1234;
  printf("a: %d\n", a);
  switch (a) {
    char switchbuf[32];
    case 1234:
      printf("a: %d\n", a);
      break;
  }
  printf("a: %d\n", a);
  return 0;
}

results in the output:

a: 1234
a: 0
a: 0

when it should result in:

a: 1234
a: 1234
a: 1234

Moving the switchbuf variable outside the switch statement works as expected.

This is using the code from git from about 2 months ago.

[dfandrich]

The test program was compiled with zcc +cpm -create-app switchvar.c I've confirmed that the problem still exists with at HEAD 162135b.

[suborb]

Impressive edge case - I've not come across code that does that.

It may take me a while to figure out how to solve this one nicely.

[dfandrich]

Speaking of edge cases, I should see if zcc supports Duff's device ☺

[suborb]

I believe it does!