[Bug bootstrap/63995] Bootstrap error with -mmpx -fcheck-pointer-bounds

[enkovich.gnu at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63995

--- Comment #7 from Ilya Enkovich <enkovich.gnu at gmail dot com> ---
In chkpopt pass calls to bndmk are moved down to uses to decrease register
pressure.  Debug info introduces new uses and therefore it affects a position
where bndmk calls appear.

-g0 case:

  <bb 4>:                                         
  r.field = -1;                                   
  __bound_tmp.1_13 = __builtin_ia32_bndmk (&r, 4);
  test2.chkp (&r, __bound_tmp.1_13);              

-g case:

  <bb 4>:
  # DEBUG c => &r
  __bound_tmp.1_13 = __builtin_ia32_bndmk (&r, 4);
  # DEBUG __chkp_bounds_of_c => NULL
  r.field = -1;
  test2.chkp (&r, __bound_tmp.1_13);

Will ignore debug statements when computing a new position for bounds
load/creation (BTW debug statement seems to be damaged by gsi_move_before
called for bndmk).  Testing following fix:

diff --git a/gcc/tree-chkp-opt.c b/gcc/tree-chkp-opt.c
index ff390d7..b8d5d0b 100644
--- a/gcc/tree-chkp-opt.c
+++ b/gcc/tree-chkp-opt.c
@@ -1175,7 +1175,9 @@ chkp_reduce_bounds_lifetime (void)

       FOR_EACH_IMM_USE_STMT (use_stmt, use_iter, op)
        {
-         if (dom_bb &&
+         if (is_gimple_debug (use_stmt))
+           continue;
+         else if (dom_bb &&
              dominated_by_p (CDI_DOMINATORS,
                              dom_bb, gimple_bb (use_stmt)))
            {