[llvm] r270885 - Do not rename registers that do not start an independent live range

[Krzysztof Parzyszek via llvm-commits]

Hi,
It doesn't show why it fails, there is only "Exit Code: 1".  Do you have 
steps to reproduce this problem?

-Krzysztof


On 5/27/2016 1:15 PM, Evgenii Stepanov wrote:
> Hi,
>
> this test is failing on ASan:
> http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-bootstrap/builds/11794/steps/check-llvm%20asan/logs/stdio
>
> On Thu, May 26, 2016 at 11:22 AM, Krzysztof Parzyszek via llvm-commits
> <llvm-commits at lists.llvm.org> wrote:
>> Author: kparzysz
>> Date: Thu May 26 13:22:53 2016
>> New Revision: 270885
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=270885&view=rev
>> Log:
>> Do not rename registers that do not start an independent live range
>>
>> Added:
>>     llvm/trunk/test/CodeGen/MIR/Hexagon/
>>     llvm/trunk/test/CodeGen/MIR/Hexagon/anti-dep-partial.mir
>> Modified:
>>     llvm/trunk/lib/CodeGen/AggressiveAntiDepBreaker.cpp
>>
>> Modified: llvm/trunk/lib/CodeGen/AggressiveAntiDepBreaker.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AggressiveAntiDepBreaker.cpp?rev=270885&r1=270884&r2=270885&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/CodeGen/AggressiveAntiDepBreaker.cpp (original)
>> +++ llvm/trunk/lib/CodeGen/AggressiveAntiDepBreaker.cpp Thu May 26 13:22:53 2016
>> @@ -787,6 +787,8 @@ unsigned AggressiveAntiDepBreaker::Break
>>    DEBUG(dbgs() << '\n');
>>  #endif
>>
>> +  BitVector RegAliases(TRI->getNumRegs());
>> +
>>    // Attempt to break anti-dependence edges. Walk the instructions
>>    // from the bottom up, tracking information about liveness as we go
>>    // to help determine which registers are available.
>> @@ -898,6 +900,29 @@ unsigned AggressiveAntiDepBreaker::Break
>>            }
>>
>>            if (AntiDepReg == 0) continue;
>> +
>> +          // If the definition of the anti-dependency register does not start
>> +          // a new live range, bail out. This can happen if the anti-dep
>> +          // register is a sub-register of another register whose live range
>> +          // spans over PathSU. In such case, PathSU defines only a part of
>> +          // the larger register.
>> +          RegAliases.reset();
>> +          for (MCRegAliasIterator AI(AntiDepReg, TRI, true); AI.isValid(); ++AI)
>> +            RegAliases.set(*AI);
>> +          for (SDep S : PathSU->Succs) {
>> +            SDep::Kind K = S.getKind();
>> +            if (K != SDep::Data && K != SDep::Output && K != SDep::Anti)
>> +              continue;
>> +            unsigned R = S.getReg();
>> +            if (!RegAliases[R])
>> +              continue;
>> +            if (R == AntiDepReg || TRI->isSubRegister(AntiDepReg, R))
>> +              continue;
>> +            AntiDepReg = 0;
>> +            break;
>> +          }
>> +
>> +          if (AntiDepReg == 0) continue;
>>          }
>>
>>          assert(AntiDepReg != 0);
>>
>> Added: llvm/trunk/test/CodeGen/MIR/Hexagon/anti-dep-partial.mir
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/MIR/Hexagon/anti-dep-partial.mir?rev=270885&view=auto
>> ==============================================================================
>> --- llvm/trunk/test/CodeGen/MIR/Hexagon/anti-dep-partial.mir (added)
>> +++ llvm/trunk/test/CodeGen/MIR/Hexagon/anti-dep-partial.mir Thu May 26 13:22:53 2016
>> @@ -0,0 +1,35 @@
>> +# RUN: llc -march=hexagon -post-RA-scheduler -run-pass post-RA-sched %s 2>&1 -o /dev/null | FileCheck %s
>> +
>> +--- |
>> +  declare void @check(i64, i32, i32, i64)
>> +  define void @foo() {
>> +    ret void
>> +  }
>> +...
>> +
>> +---
>> +name: foo
>> +tracksRegLiveness: true
>> +allVRegsAllocated: true
>> +body: |
>> +  bb.0:
>> +    successors:
>> +    liveins: %r0, %r1, %d1, %d2, %r16, %r17, %r19, %r22, %r23
>> +        %r2 = A2_add %r23, killed %r17
>> +        %r6 = M2_mpyi %r16, %r16
>> +        %r22 = M2_accii %r22, killed %r2, 2
>> +        %r7 = A2_tfrsi 12345678
>> +        %r3 = A2_tfr killed %r16
>> +        %d2 = A2_tfrp killed %d0
>> +        %r2 = L2_loadri_io %r29, 28
>> +        %r2 = M2_mpyi killed %r6, killed %r2
>> +        %r23 = S2_asr_i_r %r22, 31
>> +        S2_storeri_io killed %r29, 0, killed %r7
>> +        ; The anti-dependency on r23 between the first A2_add and the
>> +        ; S2_asr_i_r was causing d11 to be renamed, while r22 remained
>> +        ; unchanged. Check that the renaming of d11 does not happen.
>> +        ; CHECK: d11
>> +        %d0 = A2_tfrp killed %d11
>> +        J2_call @check, implicit-def %d0, implicit-def %d1, implicit-def %d2, implicit %d0, implicit %d1, implicit %d2
>> +...
>> +
>>
>>
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