From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-patches-return-257435-listarch-gcc-patches=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 8202 invoked by alias); 22 Feb 2010 16:37:52 -0000
Received: (qmail 8179 invoked by uid 22791); 22 Feb 2010 16:37:50 -0000
X-SWARE-Spam-Status: No, hits=-2.4 required=5.0 	tests=AWL,BAYES_00
X-Spam-Check-By: sourceware.org
Received: from ksp.mff.cuni.cz (HELO atrey.karlin.mff.cuni.cz) (195.113.26.206)     by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 22 Feb 2010 16:37:45 +0000
Received: by atrey.karlin.mff.cuni.cz (Postfix, from userid 4018) 	id 32804F0A81; Mon, 22 Feb 2010 17:37:43 +0100 (CET)
Date: Mon, 22 Feb 2010 16:49:00 -0000
From: Jan Hubicka <hubicka@ucw.cz>
To: Martin Jambor <mjambor@suse.cz>
Cc: GCC Patches <gcc-patches@gcc.gnu.org>, Jan Hubicka <hubicka@ucw.cz>
Subject: Re: [PATCH 5/6] Indirect inlining of virtual calls
Message-ID: <20100222163742.GF3140@atrey.karlin.mff.cuni.cz>
References: <20100213180136.555197900@alvy.suse.cz> <20100213180157.538628963@alvy.suse.cz>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20100213180157.538628963@alvy.suse.cz>
User-Agent: Mutt/1.5.18 (2008-05-17)
X-IsSubscribed: yes
Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-patches.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-patches/>
List-Post: <mailto:gcc-patches@gcc.gnu.org>
List-Help: <mailto:gcc-patches-help@gcc.gnu.org>
Sender: gcc-patches-owner@gcc.gnu.org
X-SW-Source: 2010-02/txt/msg00882.txt.bz2

> Index: icln/gcc/ipa-prop.c
> ===================================================================
> --- icln.orig/gcc/ipa-prop.c
> +++ icln/gcc/ipa-prop.c
> +/* Given that an actual argument is an SSA_NAME that is a result of a phi
> +   statement PHI, try to find out whether NAME is in fact a
> +   multiple-inheritance typecast from a descendant into an ancestor of a formal
> +   parameter and thus can be described by an ancestor jump function and if so,
> +   write the appropriate function into JFUNC.
> +
> +   Essentially we want to match the following pattern:
> +
> +     if (obj_2(D) != 0B)
> +       goto <bb 3>;
> +     else
> +       goto <bb 4>;
> +
> +   <bb 3>:
> +     iftmp.1_3 = &obj_2(D)->D.1762;
> +
> +   <bb 4>:
> +     # iftmp.1_1 = PHI <iftmp.1_3(3), 0B(2)>
> +     D.1879_6 = middleman_1 (iftmp.1_1, i_5(D));
> +     return D.1879_6;  */

Hmm, fragile, but this is old code, right?

> +/* Try to find a base info of BINFO that would have its field decl at offset
> +   OFFSET within the BINFO type and which i of EXPECTED_TYPE.  If it can be
> +   found, return, otherwise return NULL_TREE.  */

I guess stuff like this (supporting the overall devirtualization in gimple) should go
into tree.c or similar common place.  It would be nice if someone C++ FE aware took a look
on this.
> +
> +static tree
> +get_binfo_at_offset (tree binfo, HOST_WIDE_INT offset, tree expected_type)
> +{
> +  tree type;
> +
> +  if (offset == 0)
> +    return binfo;
> +
> +  type = TREE_TYPE (binfo);
> +  while (offset > 0)
> +    {
> +      tree base_binfo, found_binfo;
> +      HOST_WIDE_INT pos, size;
> +      tree fld;
> +      int i;
> +
> +      if (TREE_CODE (type) != RECORD_TYPE)
> +	return NULL_TREE;
> +
> +      for (fld = TYPE_FIELDS (type); fld; fld = TREE_CHAIN (fld))
> +	{
> +	  if (TREE_CODE (fld) != FIELD_DECL)
> +	    continue;
> +
> +	  pos = int_bit_position (fld);
> +	  size = tree_low_cst (DECL_SIZE (fld), 1);
> +	  if (pos <= offset && (pos + size) > offset)
> +	    break;
> +	}
> +      if (!fld)
> +	return NULL_TREE;
> +
> +      found_binfo = NULL_TREE;
> +      for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
> +	if (TREE_TYPE (base_binfo) == TREE_TYPE (fld))
> +	  {
> +	    found_binfo = base_binfo;
> +	    break;
> +	  }
> +
> +      if (!found_binfo)
> +	return NULL_TREE;
> +
> +      type = TREE_TYPE (fld);
> +      binfo = found_binfo;
> +      offset -= pos;
> +    }
> +  if (type != expected_type)
> +    return NULL_TREE;
> +  return binfo;
> +}
> +

Patch is OK for pretty-ipa.

Honza