[Bug rtl-optimization/38245] [4.4 Regression] stack corruption when a call is removed but not the outgoing argument pushes

["jakub at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #17 from jakub at gcc dot gnu dot org  2008-12-19 10:41 -------
Better testcase:
/* PR rtl-optimization/38245 */
/* { dg-do run } */
/* { dg-options "-O2" } */

extern int bar (long, long, long, long, long, long, long, long,
                long, long, long, long, long, long, long, long,
                long, long, long, long, long, long, long, long,
                long, long, long, long, long, long, long, long)
     __attribute__((pure));

struct A { int i, j; union { short s[4]; long long l; }; char pad[512]; } a;

void __attribute__((noinline))
foo (void)
{
  a.s[2] = bar (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21,
                6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21);
  a.l = 6;
}

int
main (void)
{
  char buf[256];
  int i;
  for (i = 0; i < (int) sizeof buf; i++)
    buf[i] = i;
  asm volatile ("" : : "r" (buf) : "memory");
  foo ();
  asm volatile ("" : : "r" (buf) : "memory");
  for (i = 0; i < (int) sizeof buf; i++)
    if (buf[i] != (char) i)
      __builtin_abort ();
  return 0;
}

BTW, e.g. on powerpc64-linux or ia64-linux the stack arguments aren't in
CALL_INSN_FUNCTION_USAGE at all, only the register arguments.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38245