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 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.

> ../../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
>
>