Re: [PATCH][auto-inc-dec.c] Account for cost of move operation in FORM_PRE_ADD and FORM_POST_ADD cases

[Kyrill Tkachov <kyrylo.tkachov@arm.com>]

On 28/10/15 17:45, Kyrill Tkachov wrote:
>
> On 28/10/15 17:23, Christophe Lyon wrote:
>> Hi Kyrill,
>
> Hi Christophe,
>
>>
>> On 26 October 2015 at 12:52, Kyrill Tkachov <kyrylo.tkachov@arm.com> wrote:
>>> On 26/10/15 11:28, Bernd Schmidt wrote:
>>>> On 10/26/2015 12:12 PM, Bernd Schmidt wrote:
>>>>>
>>>>> But isn't that balanced by the fact that it doesn't seem to take into
>>>>> account the gain of removing the inc_insn either? So I think this can't
>>>>> be right.
>>>>
>>>> Argh, misread the code. The patch is OK with the change I suggested.
>>>>
>>> Thanks!
>>> Here's what I committed with r229344.
>>>
>> Since this commit, I've noticed:
>>
>> FAIL: gcc.target/arm/lp1243022.c scan-rtl-dump subreg2 "REG_INC"
>> with --target arm-none-eabi --with-thumb --with-cpu=cortex-a9
>
> I think this is a testcase issue, I'll look into updating it separately.
>
>> as well as ICEs:
>>    gcc.target/aarch64/advsimd-intrinsics/vldX.c   -O2  (internal compiler error)
>>    gcc.target/aarch64/advsimd-intrinsics/vldX.c   -O2 -flto
>> -fno-use-linker-plugin -flto-partition=none  (internal compiler error)
>>
>> with --target arm-none-linux-gnueabihf --with-thumb
>> --with-cpu=cortex-a15 --with-fpu=neon-vfpv4
>> and --target arm-none-linux-gnueabihf --with-thumb
>> --with-cpu=cortex-a57 --with-fpu=crypto-neon-fp-armv8
>>
>> See for a more synthetic view:
>> http://people.linaro.org/~christophe.lyon/cross-validation/gcc/trunk/229344/report-build-info.html
>>
>> Can you have a look?
>
> The ICE backtrace is:
> 0x7a4494 change_address_1
>         $SRC/gcc/emit-rtl.c:2132
> 0x7a7453 adjust_address_1(rtx_def*, machine_mode, long, int, int, int, long)
>         $SRC/gcc/emit-rtl.c:2270
> 0xab792d gen_lowpart_general(machine_mode, rtx_def*)
>         $SRC/gcc/rtlhooks.c:90
> 0xfd721d gen_split_47(rtx_insn*, rtx_def**)
>         $SRC/gcc/config/arm/arm.md:4336
> 0x12473f2 split_11
>         $SRC/gcc/config/arm/arm.md:4331
> 0x12473f2 split_insns(rtx_def*, rtx_insn*)
>         $SRC/gcc/config/arm/sync.md:361
> 0x7af30e try_split(rtx_def*, rtx_insn*, int)
>         $SRC/gcc/emit-rtl.c:3664
> 0xa53dc5 split_insn
>         $SRC/gcc/recog.c:2874
> 0xa5ccf5 split_all_insns()
>         $SRC/gcc/recog.c:2964
> 0xa5cde3 rest_of_handle_split_after_reload
>         $SRC/gcc/recog.c:3900
> 0xa5cde3 execute
>         $SRC/gcc/recog.c:3929
>
>
> Looks like a latent issue exposed by my patch.
> Could you please file a BZ entry if get the chance?
>

I've filed https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68149 for this one.

Kyrill

> Thanks,
> Kyrill
>
>
>> Thanks,
>>
>> Christophe.
>>
>>> Kyrill
>>>
>>> 2015-10-26  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
>>>
>>>      * auto-inc-dec.c (insert_move_insn_before): Delete.
>>>      (attempt_change): Remember to cost the simple move in the
>>>      FORM_PRE_ADD and FORM_POST_ADD cases.
>>>
>>>> Bernd
>>>>
>