[Bug target/30665] New: peephole2 misapplied on postinc mem

[hp at gcc dot gnu dot org]

This testcase is miscompiled on all versions of GCC (visible on r111226):
int  __attribute__ ((__noinline__)) f (unsigned *p, int *x)
{
  int y = *p++ & 0xfff;
  *x++ = y;
  *x = *p;
  return y;
}

int main (void)
{
  unsigned u[2] = { 0xbaad, 0xdad1 };
  int x[2] = {17689, 23456};

  if (f (u, x) != 0xaad || x[0] != 0xaad || x[1] != 0xdad1)
    abort ();
  exit (0);
}

It's caused by the cris.md peephole2 marked "andu (casesi+45)" allowing
post-inc memory in operand 1, effectively "shrinking" the post-inc.
The fix is to replace all "(GET_CODE (operands[1]) != MEM || ! MEM_VOLATILE_P
(operands[1]))" with "!side_effects_p (operands[1])" everywhere.


-- 
           Summary: peephole2 misapplied on postinc mem
           Product: gcc
           Version: 3.2.1
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: hp at gcc dot gnu dot org
        ReportedBy: hp at gcc dot gnu dot org
GCC target triplet: cris-*


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30665