Re: [PATCH] PR ipa/63909 ICE: SIGSEGV in ipa_icf_gimple::func_checker::compare_bb()

[Richard Biener <richard dot guenther at gmail dot com>]

On Tue, Dec 9, 2014 at 4:52 PM, Martin LiÅka <mliska@suse.cz> wrote:
> On 11/21/2014 01:23 PM, Richard Biener wrote:
>>
>> On Fri, Nov 21, 2014 at 12:52 PM, Martin LiÅka <mliska@suse.cz> wrote:
>>>
>>> On 11/20/2014 05:41 PM, Richard Biener wrote:
>>>>
>>>>
>>>> On Thu, Nov 20, 2014 at 5:30 PM, Martin LiÅka <mliska@suse.cz> wrote:
>>>>>
>>>>>
>>>>> Hello.
>>>>>
>>>>> Following patch fixes ICE in IPA ICF. Problem was that number of
>>>>> non-debug
>>>>> statements in a BB can
>>>>> change (for instance by IPA split), so that the number is recomputed.
>>>>
>>>>
>>>>
>>>> Huh, so can it get different for both candidates?  I think the stmt
>>>> compare
>>>> loop should be terminated on gsi_end_p of either iterator and return
>>>> false for any remaining non-debug-stmts on the other.
>>>>
>>>> Thus, not walk all stmts twice here.
>>>
>>>
>>>
>>> Hello.
>>>
>>> Sorry for the previous patch, you are right it can be fixed in purer way.
>>> Please take a look at attached patch.
>>>
>>>>
>>>> As IPA split is run early I don't see how it should affect a real IPA
>>>> pass though?
>>>
>>>
>>>
>>>
>>>
>>> Sorry for non precise information, the problematic BB is changed here:
>>> #0  gsi_split_seq_before (i=0x7fffffffd550, pnew_seq=0x7fffffffd528) at
>>> ../../gcc/gimple-iterator.c:429
>>> #1  0x0000000000b95a2a in gimple_split_block (bb=0x7ffff6c41548,
>>> stmt=0x0)
>>> at ../../gcc/tree-cfg.c:5707
>>> #2  0x00000000007563cf in split_block (bb=0x7ffff6c41548, i=i@entry=0x0)
>>> at
>>> ../../gcc/cfghooks.c:508
>>> #3  0x0000000000756b44 in split_block_after_labels (bb=<optimized out>)
>>> at
>>> ../../gcc/cfghooks.c:549
>>> #4  make_forwarder_block (bb=<optimized out>,
>>> redirect_edge_p=redirect_edge_p@entry=0x75d4e0
>>> <mfb_keep_just(edge_def*)>,
>>> new_bb_cbk=new_bb_cbk@entry=0x0) at ../../gcc/cfghooks.c:842
>>> #5  0x000000000076085a in create_preheader (loop=0x7ffff6d56948,
>>> flags=<optimized out>) at ../../gcc/cfgloopmanip.c:1563
>>> #6  0x0000000000760aea in create_preheaders (flags=1) at
>>> ../../gcc/cfgloopmanip.c:1613
>>> #7  0x00000000009bc6b0 in apply_loop_flags (flags=15) at
>>> ../../gcc/loop-init.c:75
>>> #8  0x00000000009bc7d3 in loop_optimizer_init (flags=15) at
>>> ../../gcc/loop-init.c:136
>>> #9  0x0000000000957914 in estimate_function_body_sizes
>>> (node=0x7ffff6c47620,
>>> early=false) at ../../gcc/ipa-inline-analysis.c:2480
>>> #10 0x000000000095948b in compute_inline_parameters (node=0x7ffff6c47620,
>>> early=false) at ../../gcc/ipa-inline-analysis.c:2907
>>> #11 0x000000000095bd88 in inline_analyze_function (node=0x7ffff6c47620)
>>> at
>>> ../../gcc/ipa-inline-analysis.c:3994
>>> #12 0x000000000095bed3 in inline_generate_summary () at
>>> ../../gcc/ipa-inline-analysis.c:4045
>>> #13 0x0000000000a70b71 in execute_ipa_summary_passes (ipa_pass=0x1dcb9e0)
>>> at
>>
>>
>> So inline_summary is generated after IPA-ICF does its job?
>>
>> But the bug is obviously that an IPA analysis phase does a code transform
>> (here initializes loops without AVOID_CFG_MANIPULATIONS).
>> Honza - if that is really needed then I think we should make sure
>> loops are initialized at the start of the IPA analysis phase, not randomly
>> inbetween.
>>
>> Thanks,
>> Richard.
>
>
> Hello.
>
> Even thought the root of problem is hidden somewhere in loop creation, I
> would
> like to apply the patch which makes iteration of non-debug gimple statement
> more clearly?
>
> What do you think Richard?

Works for me - but we have to address the underlying issue.

Richard.

> Thanks,
> Martin
>
>
>>
>>> ../../gcc/passes.c:2137
>>> #14 0x0000000000777a15 in ipa_passes () at ../../gcc/cgraphunit.c:2074
>>> #15 symbol_table::compile (this=this@entry=0x7ffff6c3a000) at
>>> ../../gcc/cgraphunit.c:2187
>>> #16 0x0000000000778bcd in symbol_table::finalize_compilation_unit
>>> (this=0x7ffff6c3a000) at ../../gcc/cgraphunit.c:2340
>>> #17 0x00000000006580ee in c_write_global_declarations () at
>>> ../../gcc/c/c-decl.c:10777
>>> #18 0x0000000000b5bb8b in compile_file () at ../../gcc/toplev.c:584
>>> #19 0x0000000000b5def1 in do_compile () at ../../gcc/toplev.c:2041
>>> #20 0x0000000000b5e0fa in toplev::main (this=0x7fffffffdc9f, argc=20,
>>> argv=0x7fffffffdd98) at ../../gcc/toplev.c:2138
>>> #21 0x000000000063f1d9 in main (argc=20, argv=0x7fffffffdd98) at
>>> ../../gcc/main.c:38
>>>
>>>
>>> Patch can bootstrap on x86_64-linux-pc and no regression has been seen.
>>> Ready for trunk?
>>>
>>>
>>> Thanks,
>>> Martin
>>>
>>>>
>>>> Thanks,
>>>> Richard.
>>>>
>>>>> Patch can bootstrap on x86_64-linux-pc and no regression has been seen.
>>>>> Ready for trunk?
>>>>>
>>>>> Thanks,
>>>>> Martin
>>>
>>>
>>>
>