| /* NOCW */ |
| /* dggccbug.c */ |
| /* bug found by Eric Young (eay@cryptsoft.com) - May 1995 */ |
| |
| #include <stdio.h> |
| |
| /* |
| * There is a bug in gcc version 2.5.8 (88open OCS/BCS, DG-2.5.8.3, Oct 14 |
| * 1994) as shipped with DGUX 5.4R3.10 that can be bypassed by defining |
| * DG_GCC_BUG in my code. The bug manifests itself by the vaule of a pointer |
| * that is used only by reference, not having it's value change when it is |
| * used to check for exiting the loop. Probably caused by there being 2 |
| * copies of the valiable, one in a register and one being an address that is |
| * passed. |
| */ |
| |
| /*- |
| * compare the out put from |
| * gcc dggccbug.c; ./a.out |
| * and |
| * gcc -O dggccbug.c; ./a.out |
| * compile with -DFIXBUG to remove the bug when optimising. |
| */ |
| |
| void inc(a) |
| int *a; |
| { |
| (*a)++; |
| } |
| |
| main() |
| { |
| int p = 0; |
| #ifdef FIXBUG |
| int dummy; |
| #endif |
| |
| while (p < 3) { |
| fprintf(stderr, "%08X\n", p); |
| inc(&p); |
| #ifdef FIXBUG |
| dummy += p; |
| #endif |
| } |
| } |
