On 05/06/15 14:14, Kyrill Tkachov wrote:
>
> On 05/06/15 14:11, Richard Earnshaw wrote:
>> On 05/06/15 14:08, Kyrill Tkachov wrote:
>>> Hi Shiva,
>>>
>>> On 05/06/15 10:42, Shiva Chen wrote:
>>>> Hi, Kyrill
>>>>
>>>> I add the testcase as stl-cond.c.
>>>>
>>>> Could you help to check the testcase ?
>>>>
>>>> If it's OK, Could you help me to apply the patch ?
>>>>
>>> This looks ok to me.
>>> One nit on the testcase:
>>>
>>> diff --git a/gcc/testsuite/gcc.target/arm/stl-cond.c
>>> b/gcc/testsuite/gcc.target/arm/stl-cond.c
>>> new file mode 100755
>>> index 0000000..44c6249
>>> --- /dev/null
>>> +++ b/gcc/testsuite/gcc.target/arm/stl-cond.c
>>> @@ -0,0 +1,18 @@
>>> +/* { dg-do compile } */
>>> +/* { dg-require-effective-target arm_arch_v8a_ok } */
>>> +/* { dg-options "-O2" } */
>>>
>>> This should also have -marm as the problem exhibited itself in arm state.
>>> I'll commit this patch with this change in 24 hours on your behalf if no
>>> one
>>> objects.
>>>
>> Explicit use of -marm will break multi-lib testing.  I've forgotten the
>> correct hook, but there's most-likely something that will give you the
>> right behaviour, even if it means that thumb-only multi-lib testing
>> skips this test.
>
> So I think what we want is:
>
> dg-require-effective-target arm_arm_ok
>
> The comment in target-supports.exp is:
> # Return 1 if this is an ARM target where -marm causes ARM to be
> # used (not Thumb)
>

I've committed the attached patch to trunk on Shiva's behalf with r224269.
It gates the test on arm_arm_ok and adds -marm, like other similar tests.
The ChangeLog I used is below:

2015-06-09  Shiva Chen  <shiva0217@gmail.com>

     * sync.md (atomic_load<mode>): Add conditional code for lda/ldr
     (atomic_store<mode>): Likewise.

2015-06-09  Shiva Chen  <shiva0217@gmail.com>

     * gcc.target/arm/stl-cond.c: New test.


Thanks,
Kyrill

> Kyrill
>
>
>> R.
>>
>>> Ramana, Richard, we need to backport it to GCC 5 as well, right?
>>>
>>> Thanks,
>>> Kyrill
>>>
>>>
>>>> Thanks,
>>>>
>>>> Shiva
>>>>
>>>> 2015-06-05 16:34 GMT+08:00 Kyrill Tkachov <kyrylo.tkachov@foss.arm.com>:
>>>>> Hi Shiva,
>>>>>
>>>>> On 05/06/15 09:29, Shiva Chen wrote:
>>>>>> Hi, Kyrill
>>>>>>
>>>>>> I update the patch as Richard's suggestion.
>>>>>>
>>>>>> -      return \"str<sync_sfx>\t%1, %0\";
>>>>>> +      return \"str%(<sync_sfx>%)\t%1, %0\";
>>>>>>         else
>>>>>> -      return \"stl<sync_sfx>\t%1, %0\";
>>>>>> +      return \"stl<sync_sfx>%?\t%1, %0\";
>>>>>>       }
>>>>>> -)
>>>>>> +  [(set_attr "predicable" "yes")
>>>>>> +   (set_attr "predicable_short_it" "no")])
>>>>>> +  [(set_attr "predicable" "yes")
>>>>>> +   (set_attr "predicable_short_it" "no")])
>>>>>>
>>>>>>
>>>>>> Let me sum up.
>>>>>>
>>>>>> We add predicable attribute to allow gcc do if-conversion in
>>>>>> ce1/ce2/ce3 not only in final phase by final_prescan_insn finite state
>>>>>> machine.
>>>>>>
>>>>>> We set predicalble_short_it to "no" to restrict conditional code
>>>>>> generation on armv8 with thumb mode.
>>>>>>
>>>>>> However, we could use the flags -mno-restrict-it to force generating
>>>>>> conditional code on thumb mode.
>>>>>>
>>>>>> Therefore, we have to consider the assembly output format for strb
>>>>>> with condition code on arm/thumb mode.
>>>>>>
>>>>>> Because arm/thumb mode use different syntax for strb,
>>>>>> we output the assembly as str%(<sync_sfx>%)
>>>>>> which will put the condition code in the right place according to
>>>>>> TARGET_UNIFIED_ASM.
>>>>>>
>>>>>> Is there still missing something ?
>>>>> That's all correct, and well summarised :)
>>>>> The patch looks good to me, but please include the testcase
>>>>> (test.c from earlier) appropriately marked up for the testsuite.
>>>>> I think to the level of dg-assemble, just so we know everything is
>>>>> wired up properly.
>>>>>
>>>>> Thanks for dealing with this.
>>>>> Kyrill
>>>>>
>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Shiva
>>>>>>
>>>>>> 2015-06-04 18:00 GMT+08:00 Kyrill Tkachov
>>>>>> <kyrylo.tkachov@foss.arm.com>:
>>>>>>> Hi Shiva,
>>>>>>>
>>>>>>> On 04/06/15 10:57, Shiva Chen wrote:
>>>>>>>> Hi, Kyrill
>>>>>>>>
>>>>>>>> Thanks for the tips of syntax.
>>>>>>>>
>>>>>>>> It seems that correct syntax for
>>>>>>>>
>>>>>>>> ldrb with condition code is ldreqb
>>>>>>>>
>>>>>>>> ldab with condition code is ldabeq
>>>>>>>>
>>>>>>>>
>>>>>>>> So I modified the pattern as follow
>>>>>>>>
>>>>>>>>       {
>>>>>>>>         enum memmodel model = (enum memmodel) INTVAL (operands[2]);
>>>>>>>>         if (model == MEMMODEL_RELAXED
>>>>>>>>             || model == MEMMODEL_CONSUME
>>>>>>>>             || model == MEMMODEL_RELEASE)
>>>>>>>>           return \"ldr%?<sync_sfx>\\t%0, %1\";
>>>>>>>>         else
>>>>>>>>           return \"lda<sync_sfx>%?\\t%0, %1\";
>>>>>>>>       }
>>>>>>>>       [(set_attr "predicable" "yes")
>>>>>>>>        (set_attr "predicable_short_it" "no")])
>>>>>>>>
>>>>>>>> It seems we don't have to worry about thumb mode,
>>>>>>> I suggest you use Richard's suggestion from:
>>>>>>> https://gcc.gnu.org/ml/gcc-patches/2015-06/msg00384.html
>>>>>>> to write this in a clean way.
>>>>>>>
>>>>>>>> Because we already set "predicable" "yes" and predicable_short_it"
>>>>>>>> "no"
>>>>>>>> for the pattern.
>>>>>>> That's not quite true. The user may compile for armv8-a with
>>>>>>> -mno-restrict-it which will turn off this
>>>>>>> restriction for Thumb and allow the conditional execution of this.
>>>>>>> In any case, I think Richard's suggestion above should work.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Kyrill
>>>>>>>
>>>>>>>
>>>>>>>> The new patch could build gcc and run gcc regression test
>>>>>>>> successfully.
>>>>>>>>
>>>>>>>> Please correct me if I still missing something.
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>>
>>>>>>>> Shiva
>>>>>>>>
>>>>>>>> -----Original Message-----
>>>>>>>> From: Richard Earnshaw [mailto:Richard.Earnshaw@foss.arm.com]
>>>>>>>> Sent: Thursday, June 04, 2015 4:42 PM
>>>>>>>> To: Kyrill Tkachov; Shiva Chen
>>>>>>>> Cc: Ramana Radhakrishnan; GCC Patches; nickc@redhat.com; Shiva Chen
>>>>>>>> Subject: Re: [GCC, ARM] armv8 linux toolchain asan testcase fail
>>>>>>>> due to
>>>>>>>> stl missing conditional code
>>>>>>>>
>>>>>>>> On 04/06/15 09:17, Kyrill Tkachov wrote:
>>>>>>>>> Hi Shiva,
>>>>>>>>>
>>>>>>>>> On 04/06/15 04:13, Shiva Chen wrote:
>>>>>>>>>> Hi, Ramana
>>>>>>>>>>
>>>>>>>>>> Currently, I work for Marvell and the company have copyright
>>>>>>>>>> assignment
>>>>>>>>>> on file.
>>>>>>>>>>
>>>>>>>>>> Hi, all
>>>>>>>>>>
>>>>>>>>>> After adding the attribute and rebuild gcc, I got the assembler
>>>>>>>>>> error
>>>>>>>>>> message
>>>>>>>>>>
>>>>>>>>>> load_n.s:39: Error: bad instruction `ldrbeq r0,[r0]'
>>>>>>>>>>
>>>>>>>>>> When i look into armv8 ISA document, it seems ldrb Encoding A1 have
>>>>>>>>>> conditional code field.
>>>>>>>>>>
>>>>>>>>>> Does it mean we should also patch assembler or I just miss
>>>>>>>>>> understanding something ?
>>>>>>>>>>
>>>>>>>>>> Following command use to generate load_n.s:
>>>>>>>>>>
>>>>>>>>>> /home/shivac/build-system-trunk/Release/build/armv8-marvell-linux-gnu
>>>>>>>>>>
>>>>>>>>>> eabihf-hard/gcc-final/./gcc/cc1 -fpreprocessed load_n.i -quiet
>>>>>>>>>> -dumpbase load_n.c -march=armv8-a -mfloat-abi=hard -mfpu=fp-armv8
>>>>>>>>>> -mtls-dialect=gnu -auxbase-strip .libs/load_1_.o -g3 -O2 -Wall
>>>>>>>>>> -Werror -version -fPIC -funwind-tables -o load_n.s
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> The test.c is a simple test case to reproduce missing conditional
>>>>>>>>>> code in mmap.c.
>>>>>>>>>>
>>>>>>>>>> Any suggestion ?
>>>>>>>>> I reproduced the assembler failure with your patch.
>>>>>>>>>
>>>>>>>>> The reason is that for arm mode we use divided syntax, where the
>>>>>>>>> condition field goes in a different place. So, while ldrbeq
>>>>>>>>> r0,[r0] is
>>>>>>>>> rejected, ldreqb r0, [r0] works.
>>>>>>>>> Since we always use divided syntax for arm mode, I think you'll need
>>>>>>>>> to put the condition field in the right place depending on arm or
>>>>>>>>> thumb
>>>>>>>>> mode.
>>>>>>>>> Ugh, this is becoming ugly :(
>>>>>>>>>
>>>>>>>> Use %(<suffix%) around the bit that changes for unified/divided
>>>>>>>> syntax.
>>>>>>>>      The compiler will then put the condition in the correct place.
>>>>>>>>
>>>>>>>> So:
>>>>>>>>
>>>>>>>> +      return \"str%(<sync_sfx>%)\t%1, %0\";
>>>>>>>>
>>>>>>>> R.
>>>>>>>>
>>>>>>>>> Kyrill
>>>>>>>>>
>>>>>>>>>> Shiva
>>>>>>>>>>
>>>>>>>>>> 2015-06-03 17:29 GMT+08:00 Shiva Chen <shiva0217@gmail.com>:
>>>>>>>>>>> Hi, Ramana
>>>>>>>>>>>
>>>>>>>>>>> I'm not sure what copyright assignment means ?
>>>>>>>>>>>
>>>>>>>>>>> Does it mean the patch have copyright assignment or not ?
>>>>>>>>>>>
>>>>>>>>>>> I update the patch to add "predicable" and "predicable_short_it"
>>>>>>>>>>> attribute as suggestion.
>>>>>>>>>>>
>>>>>>>>>>> However, I don't have svn write access yet.
>>>>>>>>>>>
>>>>>>>>>>> Shiva
>>>>>>>>>>>
>>>>>>>>>>> 2015-06-03 16:36 GMT+08:00 Kyrill Tkachov
>>>>>>>>>>> <kyrylo.tkachov@arm.com>:
>>>>>>>>>>>> On 03/06/15 09:32, Ramana Radhakrishnan wrote:
>>>>>>>>>>>>>> This pattern is not predicable though, i.e. it doesn't have the
>>>>>>>>>>>>>> "predicable" attribute set to "yes".
>>>>>>>>>>>>>> Therefore the compiler should be trying to branch around here
>>>>>>>>>>>>>> rather than try to do a cond_exec.
>>>>>>>>>>>>>> Why does the generated code above look like it's converted to
>>>>>>>>>>>>>> conditional execution?
>>>>>>>>>>>>>> Could you produce a self-contained reduced testcase for this?
>>>>>>>>>>>>> CCFSM state machine in ARM state.
>>>>>>>>>>>>>
>>>>>>>>>>>>> arm.c (final_prescan_insn).
>>>>>>>>>>>> Ah ok.
>>>>>>>>>>>> This patch makes sense then.
>>>>>>>>>>>> As Ramana mentioned, please mark the pattern with "predicable"
>>>>>>>>>>>> and
>>>>>>>>>>>> also set the "predicable_short_it" attribute to "no" so that it
>>>>>>>>>>>> will not be conditionalised in Thumb2 mode or when
>>>>>>>>>>>> -mrestrict-it is
>>>>>>>>>>>> enabled.
>>>>>>>>>>>>
>>>>>>>>>>>> Thanks,
>>>>>>>>>>>> Kyrill
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>>> Ramana
>>>>>>>>>>>>>
>>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>>> Kyrill
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> @@ -91,9 +91,9 @@
>>>>>>>>>>>>>>>            {
>>>>>>>>>>>>>>>              enum memmodel model = memmodel_from_int (INTVAL
>>>>>>>>>>>>>>> (operands[2]));
>>>>>>>>>>>>>>>              if (is_mm_relaxed (model) || is_mm_consume
>>>>>>>>>>>>>>> (model) ||
>>>>>>>>>>>>>>> is_mm_acquire (model))
>>>>>>>>>>>>>>> -      return \"str<sync_sfx>\t%1, %0\";
>>>>>>>>>>>>>>> +      return \"str<sync_sfx>%?\t%1, %0\";
>>>>>>>>>>>>>>>              else
>>>>>>>>>>>>>>> -      return \"stl<sync_sfx>\t%1, %0\";
>>>>>>>>>>>>>>> +      return \"stl<sync_sfx>%?\t%1, %0\";
>>>>>>>>>>>>>>>            }
>>>>>>>>>>>>>>>          )
>>>>>>>>>>>>>>>
>