Fix var-tracking ICE (PR debug/46387)

On Thu, Nov 11, 2010 at 11:45:50AM +0100, Richard Guenther wrote:
> I see.  I'm not sure I like the special just-for-vartracking function in alias.c
> too much (in fact I hoped we can share it for selsched).

Ok, here is a simpler version where it can't be reverted (except for
init_alias_analysis) and var-tracking doesn't try to revert it.

Bootstrapped/regtested on x86_64-linux and i686-linux, tested on the
testcase with ia64-linux cross, ok for trunk?

2010-11-11  Jakub Jelinek  <jakub@redhat.com>

	PR debug/46387
	* rtl.h (equate_reg_base_value): New prototype.
	* alias.c (equate_reg_base_value): New function.
	* var-tracking.c (vt_init_cfa_base): Use it.

	* gcc.dg/pr46387.c: New test.



	Jakub

On Thu, Nov 11, 2010 at 4:28 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Thu, Nov 11, 2010 at 11:45:50AM +0100, Richard Guenther wrote:
>> I see.  I'm not sure I like the special just-for-vartracking function in alias.c
>> too much (in fact I hoped we can share it for selsched).
>
> Ok, here is a simpler version where it can't be reverted (except for
> init_alias_analysis) and var-tracking doesn't try to revert it.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, tested on the
> testcase with ia64-linux cross, ok for trunk?

After much discussion and no real solution to commonize all needs
I think this patch is ok if you add a comment to the function comment
that the function is private to var-tracking (and maybe rename it
to vt_equate_reg_base_value).

Thanks,
Richard.

> 2010-11-11  Jakub Jelinek  <jakub@redhat.com>
>
>        PR debug/46387
>        * rtl.h (equate_reg_base_value): New prototype.
>        * alias.c (equate_reg_base_value): New function.
>        * var-tracking.c (vt_init_cfa_base): Use it.
>
>        * gcc.dg/pr46387.c: New test.
>
> --- gcc/rtl.h.jj        2010-11-10 13:14:41.000000000 +0100
> +++ gcc/rtl.h   2010-11-11 12:52:52.000000000 +0100
> @@ -2503,6 +2503,7 @@ extern int may_alias_p (const_rtx, const
>  extern void init_alias_target (void);
>  extern void init_alias_analysis (void);
>  extern void end_alias_analysis (void);
> +extern void equate_reg_base_value (const_rtx, const_rtx);
>  extern bool memory_modified_in_insn_p (const_rtx, const_rtx);
>  extern rtx find_base_term (rtx);
>  extern rtx gen_hard_reg_clobber (enum machine_mode, unsigned int);
> --- gcc/alias.c.jj      2010-11-10 13:14:41.000000000 +0100
> +++ gcc/alias.c 2010-11-11 12:54:01.000000000 +0100
> @@ -2906,6 +2906,14 @@ init_alias_analysis (void)
>   timevar_pop (TV_ALIAS_ANALYSIS);
>  }
>
> +/* Equate REG_BASE_VALUE (reg1) to REG_BASE_VALUE (reg2).  */
> +
> +void
> +equate_reg_base_value (const_rtx reg1, const_rtx reg2)
> +{
> +  VEC_replace (rtx, reg_base_value, REGNO (reg1), REG_BASE_VALUE (reg2));
> +}
> +
>  void
>  end_alias_analysis (void)
>  {
> --- gcc/var-tracking.c.jj       2010-11-10 13:14:41.000000000 +0100
> +++ gcc/var-tracking.c  2010-11-11 12:53:27.000000000 +0100
> @@ -8229,6 +8229,11 @@ vt_init_cfa_base (void)
>   if (!MAY_HAVE_DEBUG_INSNS)
>     return;
>
> +  /* Tell alias analysis that cfa_base_rtx should share
> +     find_base_term value with stack pointer or hard frame pointer.  */
> +  equate_reg_base_value (cfa_base_rtx,
> +                        frame_pointer_needed
> +                        ? hard_frame_pointer_rtx : stack_pointer_rtx);
>   val = cselib_lookup_from_insn (cfa_base_rtx, GET_MODE (cfa_base_rtx), 1,
>                                 get_insns ());
>   preserve_value (val);
> --- gcc/testsuite/gcc.dg/pr46387.c.jj   2010-11-11 12:52:52.000000000 +0100
> +++ gcc/testsuite/gcc.dg/pr46387.c      2010-11-11 12:52:52.000000000 +0100
> @@ -0,0 +1,32 @@
> +/* PR debug/46387 */
> +/* { dg-do compile } */
> +/* { dg-options "-g -O2" } */
> +
> +struct S { double x; double y; short z; };
> +int a = 0, b = 0, c;
> +void bar (int, int, int);
> +void baz (int *, int *, int *);
> +
> +void
> +foo (struct S *v)
> +{
> +  int x, y, z;
> +  if (!a && b != 0)
> +    return;
> +  if (v->z)
> +    baz (&x, &y, &z);
> +  else
> +    {
> +      x = v->x;
> +      y = v->y;
> +    }
> +  x = x / (5 + 1);
> +  y = y / (5 + 1);
> +  if (x < 0)
> +    x = 0;
> +  if (x > c - 1)
> +    x = c - 1;
> +  if (b == 0)
> +    bar (x, y, 1);
> +  return;
> +}
>
>
>        Jakub
>