From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <hubicka@kam.mff.cuni.cz>
Received: from nikam.ms.mff.cuni.cz (nikam.ms.mff.cuni.cz [195.113.20.16])
 by sourceware.org (Postfix) with ESMTPS id 641E73857439
 for <gcc-patches@gcc.gnu.org>; Thu, 18 Nov 2021 18:22:15 +0000 (GMT)
DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 641E73857439
Received: by nikam.ms.mff.cuni.cz (Postfix, from userid 16202)
 id 035AF28094C; Thu, 18 Nov 2021 19:22:13 +0100 (CET)
Date: Thu, 18 Nov 2021 19:22:12 +0100
From: Jan Hubicka <hubicka@kam.mff.cuni.cz>
To: Martin =?iso-8859-2?Q?Li=B9ka?= <mliska@suse.cz>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] IPA: fix reproducibility in IPA MOD REF
Message-ID: <20211118182212.GF76860@kam.mff.cuni.cz>
References: <3b0ef8c4-45df-1d84-158d-f6d98a493a32@suse.cz>
 <20211118181133.GE76860@kam.mff.cuni.cz>
 <3d12d111-7ba0-b1a5-4e89-00ddfd8ae61f@suse.cz>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <3d12d111-7ba0-b1a5-4e89-00ddfd8ae61f@suse.cz>
User-Agent: Mutt/1.10.1 (2018-07-13)
X-Spam-Status: No, score=-5.8 required=5.0 tests=BAYES_00, DKIM_SIGNED,
 DKIM_VALID, DKIM_VALID_AU, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE,
 SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on
 server2.sourceware.org
X-BeenThere: gcc-patches@gcc.gnu.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Gcc-patches mailing list <gcc-patches.gcc.gnu.org>
List-Unsubscribe: <https://gcc.gnu.org/mailman/options/gcc-patches>,
 <mailto:gcc-patches-request@gcc.gnu.org?subject=unsubscribe>
List-Archive: <https://gcc.gnu.org/pipermail/gcc-patches/>
List-Post: <mailto:gcc-patches@gcc.gnu.org>
List-Help: <mailto:gcc-patches-request@gcc.gnu.org?subject=help>
List-Subscribe: <https://gcc.gnu.org/mailman/listinfo/gcc-patches>,
 <mailto:gcc-patches-request@gcc.gnu.org?subject=subscribe>
X-List-Received-Date: Thu, 18 Nov 2021 18:22:17 -0000

> Supported LTO compression algorithms: zlib zstd
> gcc version 12.0.0 20211118 (experimental) (GCC)
> /usr/bin/ld: ./xxx.ltrans0.ltrans.o: warning: relocation against `lm_read_ctl_dict_size_n_lmclass_used' in read-only section `.text'
> /usr/bin/ld: ./xxx.ltrans0.ltrans.o: relocation R_X86_64_PC32 against symbol `__ckd_calloc___elem_size' can not be used when making a shared object; recompile with -fPIC
> /usr/bin/ld: final link failed: bad value
> collect2: error: ld returned 1 exit status
> /usr/bin/ld: ./yyy.ltrans0.ltrans.o: warning: relocation against `__ckd_calloc___n_elem' in read-only section `.text'
> /usr/bin/ld: ./yyy.ltrans0.ltrans.o: relocation R_X86_64_PC32 against symbol `__ckd_calloc___elem_size' can not be used when making a shared object; recompile with -fPIC
> /usr/bin/ld: final link failed: bad value
> collect2: error: ld returned 1 exit status
> diff: yyy.ltrans0.ltrans*optimized: No such file or directory
> 54,55d53
> < 	movslq	lm_read_ctl_dict_size_n_lmclass_used(%rip), %rax
> < 	movl	$0, 0(%rbp,%rax,4)
> 
> I tracked that it differs in tree DSE dump.
> 
> May I install the patch?

No, I think it is bug of symbol_summary that get is causing a
difference.  It should be pure function. I think it is:
  /* Getter for summary callgraph node pointer.  */
  T* get (cgraph_node *node) ATTRIBUTE_PURE
    {
       return exists (node) ? (*m_vector)[node->get_summary_id ()] : NULL;
    }
It should not be using get_summary_id (which allocates it for no good
reaosn) and simply check that summary_id is non-negative.

Still I wonder how this can make code different - that looks like
another bug somewhere.

Honza