[PATCH] Silence some dwarf2out UNSPEC related notes (PR debug/88723)

[Richard Biener]

On Mon, 7 Jan 2019, Jakub Jelinek wrote:

> Hi!
> 
> Apparently my recent patch turned on many non-delegitimized UNSPEC notes
> (it is checking only note, goes away in release builds, but anyway).
> 
> The problem is that formerly UNSPECs were diagnosed that way only when
> inside of CONST, but now also outside of them.  The patch keeps ignoring
> them if they don't have all constant arguments though as before, only tries
> to handle them if they have all constant arguments and thus normally would
> appear inside of CONST but we are processing parts of the CONST
> individually.
> 
> The following patch fixes it by determining first if they have all
> CONSTANT_P arguments, and only if they do, follows that with
> const_ok_for_output_1 verification which can emit this diagnostics.
> 
> The patch also removes what appears to be a badly applied patch in r255862,
> the posted patch contained just addition of if (CONST_POLY_INT_P (rtl)) return false;
> to the function, but added also the hunk I'm removing, so we have now
>   if (targetm.const_not_ok_for_debug_p (rtl))
>     {
>       if (GET_CODE (rtl) != UNSPEC)
> 	{
> 	  diagnostics;
> 	  return false;
> 	}
>       another diagnostics;
>       return false;
>     }
>   if (CONST_POLY_INT_P (rtl))
>     return false;
>   if (targetm.const_not_ok_for_debug_p (rtl))
>     {
>       diagnostics;
>       return false;
>     }
> Calling it twice will not help in any way.
> 
> Bootstrapped/regtested on x86_64-linux and i686-linux, plus tested on the
> testcase with -> sparc-solaris cross-compiler, ok for trunk?

OK.

Richard.

> 2019-01-07  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR debug/88723
> 	* dwarf2out.c (const_ok_for_output_1): Remove redundant call to
> 	const_not_ok_for_debug_p target hook.
> 	(mem_loc_descriptor) <case UNSPEC>: Only call const_ok_for_output_1
> 	on UNSPEC and subexpressions thereof if all subexpressions of the
> 	UNSPEC are CONSTANT_P.
> 
> --- gcc/dwarf2out.c.jj	2019-01-05 12:10:36.630753817 +0100
> +++ gcc/dwarf2out.c	2019-01-06 21:33:58.583426865 +0100
> @@ -14445,13 +14445,6 @@ const_ok_for_output_1 (rtx rtl)
>    if (CONST_POLY_INT_P (rtl))
>      return false;
>  
> -  if (targetm.const_not_ok_for_debug_p (rtl))
> -    {
> -      expansion_failed (NULL_TREE, rtl,
> -			"Expression rejected for debug by the backend.\n");
> -      return false;
> -    }
> -
>    /* FIXME: Refer to PR60655. It is possible for simplification
>       of rtl expressions in var tracking to produce such expressions.
>       We should really identify / validate expressions
> @@ -15660,8 +15653,17 @@ mem_loc_descriptor (rtx rtl, machine_mod
>  	  bool not_ok = false;
>  	  subrtx_var_iterator::array_type array;
>  	  FOR_EACH_SUBRTX_VAR (iter, array, rtl, ALL)
> -	    if ((*iter != rtl && !CONSTANT_P (*iter))
> -		|| !const_ok_for_output_1 (*iter))
> +	    if (*iter != rtl && !CONSTANT_P (*iter))
> +	      {
> +		not_ok = true;
> +		break;
> +	      }
> +
> +	  if (not_ok)
> +	    break;
> +
> +	  FOR_EACH_SUBRTX_VAR (iter, array, rtl, ALL)
> +	    if (!const_ok_for_output_1 (*iter))
>  	      {
>  		not_ok = true;
>  		break;
> 
> 
> 	Jakub
> 
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)