[Bug testsuite/98771] [10/11 regression] gcc.dg/strcmpopt_8.c FAILs

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98771

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2021-01-22
             Status|UNCONFIRMED                 |WAITING

--- Comment #2 from Martin Sebor <msebor at gcc dot gnu.org> ---
I can't reproduce these failures with my solaris2.11 cross.  The dump and the
warnings indicate that it's only the strncmp calls with a bound of SIZE_MAX
that aren't folded in your environment, like this one:

  void f (void)
  { 
    if (!(0 > __builtin_strncmp ("123", "12345", __SIZE_MAX__)))
      __builtin_abort ();   // should be eliminated
  }

All other calls, including those with SIZE_MAX - 1, are folded successfully. 
The folding happens in fold_const_call() in fold-const-call.c:

    case CFN_BUILT_IN_STRNCMP:
      if (!host_size_t_cst_p (arg2, &s2))
        return NULL_TREE;
      if (s2 == 0
          && !TREE_SIDE_EFFECTS (arg0)
          && !TREE_SIDE_EFFECTS (arg1))
        return build_int_cst (type, 0);
      else if ((p0 = c_getstr (arg0)) && (p1 = c_getstr (arg1)))
        return build_int_cst (type, strncmp (p0, p1, s2));
      return NULL_TREE;

I wonder if the host_size_t_cst_p() test passes for you.  If the native GCC's
size_t is a 32-bit type then that might explain why it would fail, but then I'm
not sure what lets the calls with SIZE_MAX - 1 be folded.