[Bug sanitizer/82501] AddressSanitizer does not handle negative offset for first global variable

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82501

--- Comment #4 from Martin Liška <marxin at gcc dot gnu.org> ---
Small note: on powerpc sanitization does not work for last global variable:

volatile int v;

__attribute__((noipa)) void
foo (char *p, char *q)
{
  *p = 123;
//  v = p > q;
}

char __attribute__((used)) largest_global2[1] = {};
char small_global[1] = {};
//char __attribute__((used)) largest_global[1] = {};

int
main ()
{
  /* Global variables.  */
  char *p = &small_global[0];
  __asm ("" : "+g" (p));
  /* { dg-output "ERROR: AddressSanitizer: invalid-pointer-pair.*" } */
  foo (p - 1, p);

  return 0;
}