[llvm-commits] [llvm] r172534 - /llvm/trunk/test/Transforms/LoopStrengthReduce/post-inc-icmpzero.ll

Mon Jan 21 11:37:38 PST 2013

Hi Manish, 

Thank you for looking at this. Recently opt started using the "-mtriple" command line flag to initialize the TargetMachine for IR-level transformations that use it. Currently only the following passes are using this feature: LSR, LowerSwitch, BBVectorizer and LoopVectorizer. If you look at the tests in LoopVectorize you will see that the target-dependent tests are in target-dependent directories.

Thanks,
Nadav

On Jan 21, 2013, at 9:07 AM, Manish Verma <Manish.Verma at arm.com> wrote:

> Hi Andy,
> 
> I have been able track down the reason for the difference in output
> generated by
> opt. The difference is caused when the target triple specified in the
> test-case
> is not a supported target for opt/clang/llvm. In this case, opt doesn't thow
> an
> error and hence, later in LSR the NoTTI::isLegalAddressingMode is called
> which
> results in the different output.
> 
> The clang-native-arm build-bot builds clang with ARM being the only
> supported
> target[1]. This is the reason the failure occured only on this build-bot.
> The
> problem can be reproduced on x86-hosted clang, if you only build it with
> only
> ARM as the supported target.
> 
> I think this problem is responsible for other failures on non-x86
> build-bots.
> 
> There a few possible solutions to this problem, but I am not sure which one
> is
> the right solution:
> 
> (a) Error out if *explicitly* specified target-triple is not supported.
>    However, this may cause a number of tests to fail on non-X86 hosted
>    build-bots as:
>    Tests (with explicit target-triple): 1050
>    Tests (i686,x86) : 738
>    Tests (arm/thumb) : 132
>    Tests (powerpc) : 128
>    Tests (mips) : 11
> 
> (b) Skip tests if *explicitly* specified target-triple is not supported.
>    However, this will result in a number of test being skipped on non-x86
> build-bots.
> 
> (c) Modify the tests to cope with the case when the specified target is not
>    available.
> 
> Let me know what do you think? I would be glad to be involved in defining a
> proper
> solution in this case. I am happy to open a PR if you think is the best way
> to
> resolve this issue.
> 
> Regards,
> Manish
> 
> 
> [1] Configure command:
> /home/buildslave/slave_as-bldslv1/clang-native-arm-cortex-a9/llvm/configure
> --disable-bindings --build=armv7l-unknown-linux-gnueabihf
> --host=armv7l-unknown-linux-gnueabihf
> --target=armv7l-unknown-linux-gnueabihf --with-cpu=cortex-a9 --with-fpu=neon
> --with-float=hard --enable-targets=arm --without-llvmgcc --without-llvmgxx
> --prefix=/home/buildslave/slave_as-bldslv1/clang-native-arm-cortex-a9/None
> --enable-optimized --enable-assertions
> 
> 
>> -----Original Message-----
>> From: Andrew Trick [mailto:atrick at apple.com]
>> Sent: 18 January 2013 22:23
>> To: Manish Verma
>> Cc: 'Dmitri Gribenko'; Renato Golin; llvm-commits at cs.uiuc.edu
>> Subject: Re: [llvm-commits] [llvm] r172534 -
>> /llvm/trunk/test/Transforms/LoopStrengthReduce/post-inc-icmpzero.ll
>> 
>> Manish,
>> 
>> For some reason, the arm-hosted LSR does not seem to recognize -1 as
>> a legal address here.
>> 
>> I'm baffled at how a fundamental problem would only show up in one
>> test, but as a quick sanity check you can add an unreachable
>> statement to X86TargetLowering::isLegalAddressingMode and make sure
>> LSR is hitting it.
>> 
>> I suggest opening a PR.
>> 
>> -Andy
>> 
>> On Jan 15, 2013, at 11:45 AM, Manish Verma <Manish.Verma at arm.com>
>> wrote:
>> 
>>> Hi,
>>> 
>>> I thought it would be my first harmless commit to LLVM. Apparently
>> not! :-)
>>> 
>>> I am attaching the output generated by debug and release version of
>> ARM
>>> native opt, and the output generated by the release version of x86
>> opt.
>>> 
>>> - post-inc-icmpzero.arm.debug.ll
>>> - post-inc-icmpzero.arm.opt.ll
>>> - post-inc-icmpzero.x86.opt.ll
>>> 
>>> Upon diff'ing the files, you can see that post-inc-
>> icmpzero.arm.opt.ll
>>> is different the other two files.
>>> 
>>> My setup is also fairly similar to Renato's. The ARM native opt is
>> built
>>> using autoconf, while x86 opt is built using CMake. I don't think
>>> this should make a difference, but I am rebuilding my x86 compiler
>> with
>>> autoconf to be sure.
>>> 
>>> 
>>> Manish
>>> 
>>>> -----Original Message-----
>>>> From: Dmitri Gribenko [mailto:gribozavr at gmail.com]
>>>> Sent: 15 January 2013 19:21
>>>> To: Renato Golin
>>>> Cc: Rafael Espíndola; llvm-commits at cs.uiuc.edu for LLVM; Manish
>> Verma
>>>> Subject: Re: [llvm-commits] [llvm] r172534 -
>>>> /llvm/trunk/test/Transforms/LoopStrengthReduce/post-inc-
>> icmpzero.ll
>>>> 
>>>> On Tue, Jan 15, 2013 at 9:16 PM, Renato Golin
>>>> <rengolin at systemcall.org> wrote:
>>>>> On 15 January 2013 18:55, Dmitri Gribenko <gribozavr at gmail.com>
>>>> wrote:
>>>>>>> Back to the issue at hand, I couldn't find any difference on
>> the
>>>>>>> outputs on x86_64, A9 and A15, (literally, identical outputs),
>>>> which
>>>>>>> shows that the issue has nothing to do with ARM and the test
>>>> should
>>>>>>> also be failing on other architectures as of r171697-ish.
>>>>>>> 
>>>>>>> All outputs had:
>>>>>>> 
>>>>>>> %4 = sub i64 %sub.ptr.lhs.cast, %sub.ptr.rhs.cast
>>>>>> 
>>>>>> OK, but the outputs are different *now*.
>>>>> 
>>>>> And why I asked if it shouldn't be failing on x86 as well, but it
>>>> seems not:
>>>>> 
>>>>> http://lab.llvm.org:8011/builders/llvm-x86_64-ubuntu/builds/6935
>>>>> 
>>>>> That's after r171697 and before 172534, so it *should* be
>> failing,
>>>> but
>>>>> it didn't.
>>>>> 
>>>>> Don't ask me why not. As far as I can see, it should fail on all
>>>>> architectures. The only differences between my Intel binaries and
>>>> my
>>>>> ARM  ones is that I used CMake to build the Intel ones and
>> autoconf
>>>> on
>>>>> ARM ones, and I'm building outside the tree, when the buildbots
>> are
>>>>> not.
>>>> 
>>>> So what is the difference between outputs on ARM and x86 right
>> now?
>>>> 
>>>> Dmitri
>>>> 
>>>> --
>>>> main(i,j){for(i=2;;i++){for(j=2;j<i;j++){if(!(i%j)){j=0;break;}}if
>>>> (j){printf("%d\n",i);}}} /*Dmitri Gribenko <gribozavr at gmail.com>*/
>>> <post-inc-icmpzero.arm.opt.ll><post-inc-
>> icmpzero.arm.debug.ll><post-inc-
>> icmpzero.x86.opt.ll>_______________________________________________
>>> llvm-commits mailing list
>>> llvm-commits at cs.uiuc.edu
>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>> 
> 
> 
> 
> 
> 
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