RE: [PATCH V3] DSE: Add LEN_MASK_STORE analysis into DSE and fix LEN_STORE

["Li, Pan2" <pan2.li@intel.com>]

Committed as passed both the bootstrap and regression test, thanks Richard.

Pan

-----Original Message-----
From: Gcc-patches <gcc-patches-bounces+pan2.li=intel.com@gcc.gnu.org> On Behalf Of Richard Biener via Gcc-patches
Sent: Monday, June 26, 2023 4:15 PM
To: Ju-Zhe Zhong <juzhe.zhong@rivai.ai>
Cc: gcc-patches@gcc.gnu.org; richard.sandiford@arm.com
Subject: Re: [PATCH V3] DSE: Add LEN_MASK_STORE analysis into DSE and fix LEN_STORE

On Mon, 26 Jun 2023, juzhe.zhong@rivai.ai wrote:

> From: Ju-Zhe Zhong <juzhe.zhong@rivai.ai>
> 
> Hi, Richi.
> 
> This patch is adding LEN_MASK_STORE into DSE.
> 
> My understanding is LEN_MASK_STORE is predicated by mask and len.
> No matter len is constant or not, the ao_ref should be the same as MASK_STORE.
> 
> Wheras for LEN_STORE, when len is constant, we use (len - bias), otherwise, it's
> the same as MASK_STORE/LEN_MASK_STORE.
> 
> Not sure whether I am on the same page with you, feel free to correct me.

OK if it passes bootstrap/regtest.

Thanks,
Richard.

> Thanks.
> 
> gcc/ChangeLog:
> 
>         * tree-ssa-dse.cc (initialize_ao_ref_for_dse): Add LEN_MASK_STORE and fix LEN_STORE.
>         (dse_optimize_stmt): Add LEN_MASK_STORE.
> 
> ---
>  gcc/tree-ssa-dse.cc | 47 ++++++++++++++++++++++++++++++---------------
>  1 file changed, 31 insertions(+), 16 deletions(-)
> 
> diff --git a/gcc/tree-ssa-dse.cc b/gcc/tree-ssa-dse.cc
> index 3c7a2e9992d..f8338037a61 100644
> --- a/gcc/tree-ssa-dse.cc
> +++ b/gcc/tree-ssa-dse.cc
> @@ -48,6 +48,7 @@ along with GCC; see the file COPYING3.  If not see
>  #include "tree-ssa-loop-niter.h"
>  #include "cfgloop.h"
>  #include "tree-data-ref.h"
> +#include "internal-fn.h"
>  
>  /* This file implements dead store elimination.
>  
> @@ -157,23 +158,36 @@ initialize_ao_ref_for_dse (gimple *stmt, ao_ref *write, bool may_def_ok = false)
>        switch (gimple_call_internal_fn (stmt))
>  	{
>  	case IFN_LEN_STORE:
> -	  ao_ref_init_from_ptr_and_size
> -	      (write, gimple_call_arg (stmt, 0),
> -	       int_const_binop (MINUS_EXPR,
> -				gimple_call_arg (stmt, 2),
> -				gimple_call_arg (stmt, 4)));
> -	  return true;
>  	case IFN_MASK_STORE:
> -	  /* We cannot initialize a must-def ao_ref (in all cases) but we
> -	     can provide a may-def variant.  */
> -	  if (may_def_ok)
> -	    {
> -	      ao_ref_init_from_ptr_and_size
> -		  (write, gimple_call_arg (stmt, 0),
> -		   TYPE_SIZE_UNIT (TREE_TYPE (gimple_call_arg (stmt, 3))));
> -	      return true;
> -	    }
> -	  break;
> +	case IFN_LEN_MASK_STORE:
> +	  {
> +	    int stored_value_index
> +	      = internal_fn_stored_value_index (gimple_call_internal_fn (stmt));
> +	    if (gimple_call_internal_fn (stmt) == IFN_LEN_STORE)
> +	      {
> +		tree len = gimple_call_arg (stmt, 2);
> +		tree bias = gimple_call_arg (stmt, 4);
> +		if (tree_fits_uhwi_p (len))
> +		  {
> +		    ao_ref_init_from_ptr_and_size (write,
> +						   gimple_call_arg (stmt, 0),
> +						   int_const_binop (MINUS_EXPR,
> +								    len, bias));
> +		    return true;
> +		  }
> +	      }
> +	    /* We cannot initialize a must-def ao_ref (in all cases) but we
> +	       can provide a may-def variant.  */
> +	    if (may_def_ok)
> +	      {
> +		ao_ref_init_from_ptr_and_size (
> +		  write, gimple_call_arg (stmt, 0),
> +		  TYPE_SIZE_UNIT (
> +		    TREE_TYPE (gimple_call_arg (stmt, stored_value_index))));
> +		return true;
> +	      }
> +	    break;
> +	  }
>  	default:;
>  	}
>      }
> @@ -1502,6 +1516,7 @@ dse_optimize_stmt (function *fun, gimple_stmt_iterator *gsi, sbitmap live_bytes)
>  	{
>  	case IFN_LEN_STORE:
>  	case IFN_MASK_STORE:
> +	case IFN_LEN_MASK_STORE:
>  	  {
>  	    enum dse_store_status store_status;
>  	    store_status = dse_classify_store (&ref, stmt, false, live_bytes);
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg,
Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
HRB 36809 (AG Nuernberg)