Remove --enable-checking=rtl var-tracking verification (PR debug/46867)

Hi!

As the testcase below shows, even the strip_pointer_flags hack can't
cure in some cases the differences caused by REG_POINTER vs. lack thereof,
as simplify-rtx.c doesn't try to swap anything if both operands have the
same precedence.

The following patch just nukes the extra checking, other alternative would
be only to hack up swap_commutative_operands_p etc. to consider some
global flag which var-tracking.c would set and which would say that
REG_POINTER/MEM_POINTER should be disregarded.

Bootstrapped/regtested on x86_64-linux and i686-linux (with rtl checking),
ok for trunk?

2010-12-10  Jakub Jelinek  <jakub@redhat.com>

	PR debug/46867
	* var-tracking.c (emitted_notes, string_pointer_flags): Removed.
	(emit_note_insn_var_location): Remove ENABLE_RTL_CHECKING verification.
	(vt_emit_notes): Don't initialize and destroy emitted_notes.

	* gcc.dg/pr46867.c: New test.


	Jakub

On Fri, Dec 10, 2010 at 8:48 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> As the testcase below shows, even the strip_pointer_flags hack can't
> cure in some cases the differences caused by REG_POINTER vs. lack thereof,
> as simplify-rtx.c doesn't try to swap anything if both operands have the
> same precedence.
>
> The following patch just nukes the extra checking, other alternative would
> be only to hack up swap_commutative_operands_p etc. to consider some
> global flag which var-tracking.c would set and which would say that
> REG_POINTER/MEM_POINTER should be disregarded.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux (with rtl checking),
> ok for trunk?

Ok.

Thanks,
Richard.

> 2010-12-10  Jakub Jelinek  <jakub@redhat.com>
>
>        PR debug/46867
>        * var-tracking.c (emitted_notes, string_pointer_flags): Removed.
>        (emit_note_insn_var_location): Remove ENABLE_RTL_CHECKING verification.
>        (vt_emit_notes): Don't initialize and destroy emitted_notes.
>
>        * gcc.dg/pr46867.c: New test.
>
> --- gcc/var-tracking.c.jj       2010-12-02 11:51:32.000000000 +0100
> +++ gcc/var-tracking.c  2010-12-10 15:16:06.000000000 +0100
> @@ -7095,24 +7095,6 @@ vt_expand_loc_dummy (rtx loc, htab_t var
>   return ret;
>  }
>
> -#ifdef ENABLE_RTL_CHECKING
> -/* Used to verify that cur_loc_changed updating is safe.  */
> -static struct pointer_map_t *emitted_notes;
> -
> -/* Strip REG_POINTER from REGs and MEM_POINTER from MEMs in order to
> -   avoid differences in commutative operand simplification.  */
> -static rtx
> -strip_pointer_flags (rtx x, const_rtx old_rtx ATTRIBUTE_UNUSED,
> -                    void *data ATTRIBUTE_UNUSED)
> -{
> -  if (REG_P (x) && REG_POINTER (x))
> -    return gen_rtx_REG (GET_MODE (x), REGNO (x));
> -  if (MEM_P (x) && MEM_POINTER (x))
> -    return gen_rtx_MEM (GET_MODE (x), XEXP (x, 0));
> -  return NULL_RTX;
> -}
> -#endif
> -
>  /* Emit the NOTE_INSN_VAR_LOCATION for variable *VARP.  DATA contains
>    additional parameters: WHERE specifies whether the note shall be emitted
>    before or after instruction INSN.  */
> @@ -7157,10 +7139,8 @@ emit_note_insn_var_location (void **varp
>       if (var->n_var_parts == 0)
>        var->cur_loc_changed = true;
>     }
> -#ifndef ENABLE_RTL_CHECKING
>   if (!var->cur_loc_changed)
>     goto clear;
> -#endif
>   for (i = 0; i < var->n_var_parts; i++)
>     {
>       enum machine_mode mode, wider_mode;
> @@ -7302,36 +7282,6 @@ emit_note_insn_var_location (void **varp
>                                      parallel, (int) initialized);
>     }
>
> -#ifdef ENABLE_RTL_CHECKING
> -  if (note_vl)
> -    {
> -      void **note_slot = pointer_map_insert (emitted_notes, decl);
> -      rtx pnote = (rtx) *note_slot;
> -      if (!var->cur_loc_changed && (pnote || PAT_VAR_LOCATION_LOC (note_vl)))
> -       {
> -         rtx old_vl, new_vl;
> -         gcc_assert (pnote);
> -         old_vl = PAT_VAR_LOCATION_LOC (pnote);
> -         new_vl = PAT_VAR_LOCATION_LOC (note_vl);
> -         if (!rtx_equal_p (old_vl, new_vl))
> -           {
> -             /* There might be differences caused by REG_POINTER
> -                differences.  REG_POINTER affects
> -                swap_commutative_operands_p.  */
> -             old_vl = simplify_replace_fn_rtx (old_vl, NULL_RTX,
> -                                               strip_pointer_flags, NULL);
> -             new_vl = simplify_replace_fn_rtx (new_vl, NULL_RTX,
> -                                               strip_pointer_flags, NULL);
> -             gcc_assert (rtx_equal_p (old_vl, new_vl));
> -             PAT_VAR_LOCATION_LOC (note_vl) = new_vl;
> -           }
> -       }
> -      *note_slot = (void *) note_vl;
> -    }
> -  if (!var->cur_loc_changed)
> -    goto clear;
> -#endif
> -
>   if (where != EMIT_NOTE_BEFORE_INSN)
>     {
>       note = emit_note_after (NOTE_INSN_VAR_LOCATION, insn);
> @@ -7960,9 +7910,6 @@ vt_emit_notes (void)
>   basic_block bb;
>   dataflow_set cur;
>
> -#ifdef ENABLE_RTL_CHECKING
> -  emitted_notes = pointer_map_create ();
> -#endif
>   gcc_assert (!htab_elements (changed_variables));
>
>   /* Free memory occupied by the out hash tables, as they aren't used
> @@ -8022,9 +7969,6 @@ vt_emit_notes (void)
>       VEC_free (rtx, heap, changed_values_stack);
>     }
>
> -#ifdef ENABLE_RTL_CHECKING
> -  pointer_map_destroy (emitted_notes);
> -#endif
>   emit_notes = false;
>  }
>
> --- gcc/testsuite/gcc.dg/pr46867.c.jj   2010-12-10 16:21:14.000000000 +0100
> +++ gcc/testsuite/gcc.dg/pr46867.c      2010-12-10 15:20:53.000000000 +0100
> @@ -0,0 +1,32 @@
> +/* PR debug/46867 */
> +/* { dg-do compile } */
> +/* { dg-options "-O -g" } */
> +
> +typedef __PTRDIFF_TYPE__ ptrdiff_t;
> +
> +extern void *bar (void);
> +
> +void
> +foo (int x, char *r1, char *r2, __INTPTR_TYPE__ *rp, char *t)
> +{
> +  char *tx = tx;
> +  char **cc = bar ();
> +  ptrdiff_t rx = r1 - r2;
> +  for (;;)
> +    {
> +      char *cp1 = (char *) *rp;
> +      char *cp2 = t;
> +      char *s;
> +      ptrdiff_t len = cp1 - tx + rx * (cp2 - cp1);
> +      while (len)
> +       ;
> +      for (s = tx; s; s++)
> +       ;
> +      while (s)
> +       if (s == cc[s - r1])
> +         if (x)
> +           bar ();
> +      if (cp1)
> +       tx = cp2;
> +    }
> +}
>
>        Jakub
>