[Bug bootstrap/66801] [6 Regression] gcc miscompiled during PGO/LTO bootstrap

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66801

--- Comment #16 from Richard Biener <rguenth at gcc dot gnu.org> ---
So, if it is related to vectorization (if I ever get to reproduce it I'll try
-fno-tree-vectorize) then it might be the

/* If arg0 is derived from the address of an object or function, we may
   be able to fold this expression using the object or function's
   alignment.  */
(simplify
 (bit_and (convert? @0) INTEGER_CST@1)
 (if (POINTER_TYPE_P (TREE_TYPE (@0))
      && tree_nop_conversion_p (type, TREE_TYPE (@0)))
  (with
   {
     unsigned int align;
     unsigned HOST_WIDE_INT bitpos;
     get_pointer_alignment_1 (@0, &align, &bitpos);
   }
   (if (wi::ltu_p (@1, align / BITS_PER_UNIT))
    { wide_int_to_tree (type, wi::bit_and (@1, bitpos / BITS_PER_UNIT)); }))))

pattern somehow going wild (from triggering within CCP itself?).  Thus as
third step I'll try disabling that one.