Re: RFA: one more version of the patch for PR61360

[Uros Bizjak <ubizjak at gmail dot com>]

On Thu, Oct 2, 2014 at 10:13 PM, Vladimir Makarov <vmakarov@redhat.com> wrote:

>>>> I guess we achieved the consensus about the following patch to fix
>>>> PR61360
>>>>
>>>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61360
>>>>
>>>> The patch was successfully bootstrapped and tested (w/wo
>>>> -march=amdfam10) on x86/x86-64.
>>>>
>>>> Is it ok to commit to trunk?
>>>
>>>
>>> I've tested your patch and unfortunately it doesn't work:
>>>
>>> In file included from
>>> /var/tmp/moz-build-dir/js/src/shell/Unified_cpp_js_src_shell0.cpp:15:0:
>>> /var/tmp/mozilla-central/js/src/shell/js.cpp: In function âvoid
>>> Process(JSContext*, JSObject*, const char*, bool)â:
>>> /var/tmp/mozilla-central/js/src/shell/js.cpp:592:1: internal compiler
>>> error: in lra_update_insn_recog_data, at lra.c:1221
>>>   }
>>>   ^
>>> 0xa9d9ec lra_update_insn_recog_data(rtx_insn*)
>>>          ../../gcc/gcc/lra.c:1220
>>> 0xab450f eliminate_regs_in_insn
>>>          ../../gcc/gcc/lra-eliminations.c:1077
>>> 0xab450f process_insn_for_elimination
>>>          ../../gcc/gcc/lra-eliminations.c:1344
>>> 0xab450f lra_eliminate(bool, bool)
>>>          ../../gcc/gcc/lra-eliminations.c:1408
>>> 0xa9f2da lra(_IO_FILE*)
>>>          ../../gcc/gcc/lra.c:2270
>>> 0xa5d659 do_reload
>>>          ../../gcc/gcc/ira.c:5311
>>> 0xa5d659 execute
>>>          ../../gcc/gcc/ira.c:5470
>>
>>
>> Testcase is attached:
>>
>>   % g++ -c -march=amdfam10 -w -O2 js.ii
>> js.ii: In function âvoid RunFile(C)â:
>> js.ii:64:1: internal compiler error: in lra_update_insn_recog_data, at
>> lra.c:1221
>>
>
> Thanks for reporting this, Marcus.  The problem now is in
> optimize_function_for_size_p.  It is false, when we define and cache enable
> attributes at early stages (instantation of virtual regs) and true later.
>
> It is returning us to the same problem.  I believe that we should not have
> enable attributes depending on optimization options or on the current
> running pass if we don't want the current solution in the trunk (with
> recog_init).  Setting right value for optimize_function_for_size_p does not
> solve the problem as we can have different options for different functions
> in the same compilation file.
>
> So minimal solution would be removing optimize_function_for_size_p from the
> attribute definition.  But I guess we could remove all condition.
> Unfortunately, Ganesh did not post is it really beneficial to switch off
> this alternative for AMD CPUs even if AMD optimization guide recommends it.

I propose to split the pattern into size-optimized and normal pattern.
The patch implements this proposal.

Uros.

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