[llvm] r195317 - Teach ISel not to optimize 'optnone' functions.

NAKAMURA Takumi geek4civic at gmail.com
Thu Nov 21 03:49:22 PST 2013


It had been still crashing for i686-*. Reverted in r195339.

2013/11/21 Kostya Serebryany <kcc at google.com>:
> Should be fixed by r195333.
>
>
> On Thu, Nov 21, 2013 at 1:23 PM, Kostya Serebryany <kcc at google.com> wrote:
>>
>> The test uses -debug flag of llc, which is not available in the
>> LLVM_ENABLE_ASSERTIONS=OFF build.
>> Can we somehow limit this test to only run when assertions are enabled?
>>
>>
>>
>> On Thu, Nov 21, 2013 at 1:11 PM, Kostya Serebryany <kcc at google.com> wrote:
>>>
>>> We observe failures on this test too... investigating...
>>>
>>>
>>> On Thu, Nov 21, 2013 at 11:30 AM, Renato Golin <renato.golin at linaro.org>
>>> wrote:
>>>>
>>>> Hi Paul,
>>>>
>>>> I know our bot is a bit unstable lately, but this seems like a real test
>>>> error:
>>>>
>>>>
>>>> http://lab.llvm.org:8011/builders/clang-native-arm-cortex-a9/builds/13534
>>>>
>>>> cheers,
>>>> --renato
>>>>
>>>>
>>>> On 21 November 2013 06:33, Paul Robinson
>>>> <paul_robinson at playstation.sony.com> wrote:
>>>>>
>>>>> Author: probinson
>>>>> Date: Thu Nov 21 00:33:32 2013
>>>>> New Revision: 195317
>>>>>
>>>>> URL: http://llvm.org/viewvc/llvm-project?rev=195317&view=rev
>>>>> Log:
>>>>> Teach ISel not to optimize 'optnone' functions.
>>>>>
>>>>> Based on work by Andrea Di Biagio.
>>>>>
>>>>> Added:
>>>>>     llvm/trunk/test/CodeGen/Generic/isel-optnone.ll
>>>>> Modified:
>>>>>     llvm/trunk/include/llvm/MC/MCCodeGenInfo.h
>>>>>     llvm/trunk/include/llvm/Target/TargetMachine.h
>>>>>     llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
>>>>>     llvm/trunk/lib/Target/TargetMachine.cpp
>>>>>
>>>>> Modified: llvm/trunk/include/llvm/MC/MCCodeGenInfo.h
>>>>> URL:
>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCCodeGenInfo.h?rev=195317&r1=195316&r2=195317&view=diff
>>>>>
>>>>> ==============================================================================
>>>>> --- llvm/trunk/include/llvm/MC/MCCodeGenInfo.h (original)
>>>>> +++ llvm/trunk/include/llvm/MC/MCCodeGenInfo.h Thu Nov 21 00:33:32 2013
>>>>> @@ -42,6 +42,9 @@ namespace llvm {
>>>>>      CodeModel::Model getCodeModel() const { return CMModel; }
>>>>>
>>>>>      CodeGenOpt::Level getOptLevel() const { return OptLevel; }
>>>>> +
>>>>> +    // Allow overriding OptLevel on a per-function basis.
>>>>> +    void setOptLevel(CodeGenOpt::Level Level) { OptLevel = Level; }
>>>>>    };
>>>>>  } // namespace llvm
>>>>>
>>>>>
>>>>> Modified: llvm/trunk/include/llvm/Target/TargetMachine.h
>>>>> URL:
>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/TargetMachine.h?rev=195317&r1=195316&r2=195317&view=diff
>>>>>
>>>>> ==============================================================================
>>>>> --- llvm/trunk/include/llvm/Target/TargetMachine.h (original)
>>>>> +++ llvm/trunk/include/llvm/Target/TargetMachine.h Thu Nov 21 00:33:32
>>>>> 2013
>>>>> @@ -75,7 +75,8 @@ protected: // Can only create subclasses
>>>>>    std::string TargetFS;
>>>>>
>>>>>    /// CodeGenInfo - Low level target information such as relocation
>>>>> model.
>>>>> -  const MCCodeGenInfo *CodeGenInfo;
>>>>> +  /// Non-const to allow resetting optimization level per-function.
>>>>> +  MCCodeGenInfo *CodeGenInfo;
>>>>>
>>>>>    /// AsmInfo - Contains target specific asm information.
>>>>>    ///
>>>>> @@ -213,6 +214,9 @@ public:
>>>>>    /// Default, or Aggressive.
>>>>>    CodeGenOpt::Level getOptLevel() const;
>>>>>
>>>>> +  /// \brief Overrides the optimization level.
>>>>> +  void setOptLevel(CodeGenOpt::Level Level) const;
>>>>> +
>>>>>    void setFastISel(bool Enable) { Options.EnableFastISel = Enable; }
>>>>>
>>>>>    bool shouldPrintMachineCode() const { return
>>>>> Options.PrintMachineCode; }
>>>>>
>>>>> Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
>>>>> URL:
>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp?rev=195317&r1=195316&r2=195317&view=diff
>>>>>
>>>>> ==============================================================================
>>>>> --- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp (original)
>>>>> +++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp Thu Nov 21
>>>>> 00:33:32 2013
>>>>> @@ -223,6 +223,39 @@ defaultListDAGScheduler("default", "Best
>>>>>
>>>>>  namespace llvm {
>>>>>
>>>>> //===--------------------------------------------------------------------===//
>>>>> +  /// \brief This struct is used by SelectionDAGISel to temporarily
>>>>> override
>>>>> +  /// the optimization level on a per-function basis.
>>>>> +  class OptLevelChanger {
>>>>> +    SelectionDAGISel &IS;
>>>>> +    CodeGenOpt::Level SavedOptLevel;
>>>>> +
>>>>> +  public:
>>>>> +    OptLevelChanger(SelectionDAGISel &ISel,
>>>>> +                    CodeGenOpt::Level NewOptLevel) : IS(ISel) {
>>>>> +      SavedOptLevel = IS.OptLevel;
>>>>> +      if (NewOptLevel == SavedOptLevel)
>>>>> +        return;
>>>>> +      IS.OptLevel = NewOptLevel;
>>>>> +      IS.TM.setOptLevel(NewOptLevel);
>>>>> +      DEBUG(dbgs() << "\nChanging optimization level for Function "
>>>>> +            << IS.MF->getFunction()->getName() << "\n");
>>>>> +      DEBUG(dbgs() << "\tBefore: -O" << SavedOptLevel
>>>>> +            << " ; After: -O" << NewOptLevel << "\n");
>>>>> +    }
>>>>> +
>>>>> +    ~OptLevelChanger() {
>>>>> +      if (IS.OptLevel == SavedOptLevel)
>>>>> +        return;
>>>>> +      DEBUG(dbgs() << "\nRestoring optimization level for Function "
>>>>> +            << IS.MF->getFunction()->getName() << "\n");
>>>>> +      DEBUG(dbgs() << "\tBefore: -O" << IS.OptLevel
>>>>> +            << " ; After: -O" << SavedOptLevel << "\n");
>>>>> +      IS.OptLevel = SavedOptLevel;
>>>>> +      IS.TM.setOptLevel(SavedOptLevel);
>>>>> +    }
>>>>> +  };
>>>>> +
>>>>> +
>>>>> //===--------------------------------------------------------------------===//
>>>>>    /// createDefaultScheduler - This creates an instruction scheduler
>>>>> appropriate
>>>>>    /// for the target.
>>>>>    ScheduleDAGSDNodes* createDefaultScheduler(SelectionDAGISel *IS,
>>>>> @@ -370,6 +403,12 @@ bool SelectionDAGISel::runOnMachineFunct
>>>>>    ST.resetSubtargetFeatures(MF);
>>>>>    TM.resetTargetOptions(MF);
>>>>>
>>>>> +  // Reset OptLevel to None for optnone functions.
>>>>> +  CodeGenOpt::Level NewOptLevel = OptLevel;
>>>>> +  if (Fn.hasFnAttribute(Attribute::OptimizeNone))
>>>>> +    NewOptLevel = CodeGenOpt::None;
>>>>> +  OptLevelChanger OLC(*this, NewOptLevel);
>>>>> +
>>>>>    DEBUG(dbgs() << "\n\n\n=== " << Fn.getName() << "\n");
>>>>>
>>>>>    SplitCriticalSideEffectEdges(const_cast<Function&>(Fn), this);
>>>>> @@ -948,7 +987,7 @@ static void collectFailStats(const Instr
>>>>>  void SelectionDAGISel::SelectAllBasicBlocks(const Function &Fn) {
>>>>>    // Initialize the Fast-ISel state, if needed.
>>>>>    FastISel *FastIS = 0;
>>>>> -  if (TM.Options.EnableFastISel)
>>>>> +  if (TM.Options.EnableFastISel ||
>>>>> Fn.hasFnAttribute(Attribute::OptimizeNone))
>>>>>      FastIS = getTargetLowering()->createFastISel(*FuncInfo, LibInfo);
>>>>>
>>>>>    // Iterate over all basic blocks in the function.
>>>>>
>>>>> Modified: llvm/trunk/lib/Target/TargetMachine.cpp
>>>>> URL:
>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/TargetMachine.cpp?rev=195317&r1=195316&r2=195317&view=diff
>>>>>
>>>>> ==============================================================================
>>>>> --- llvm/trunk/lib/Target/TargetMachine.cpp (original)
>>>>> +++ llvm/trunk/lib/Target/TargetMachine.cpp Thu Nov 21 00:33:32 2013
>>>>> @@ -164,6 +164,11 @@ CodeGenOpt::Level TargetMachine::getOptL
>>>>>    return CodeGenInfo->getOptLevel();
>>>>>  }
>>>>>
>>>>> +void TargetMachine::setOptLevel(CodeGenOpt::Level Level) const {
>>>>> +  if (CodeGenInfo)
>>>>> +    CodeGenInfo->setOptLevel(Level);
>>>>> +}
>>>>> +
>>>>>  bool TargetMachine::getAsmVerbosityDefault() {
>>>>>    return AsmVerbosityDefault;
>>>>>  }
>>>>>
>>>>> Added: llvm/trunk/test/CodeGen/Generic/isel-optnone.ll
>>>>> URL:
>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Generic/isel-optnone.ll?rev=195317&view=auto
>>>>>
>>>>> ==============================================================================
>>>>> --- llvm/trunk/test/CodeGen/Generic/isel-optnone.ll (added)
>>>>> +++ llvm/trunk/test/CodeGen/Generic/isel-optnone.ll Thu Nov 21 00:33:32
>>>>> 2013
>>>>> @@ -0,0 +1,31 @@
>>>>> +; RUN: llc -debug < %s -o /dev/null 2>&1 | FileCheck %s
>>>>> +
>>>>> +; Verify that the backend correctly overrides the optimization level
>>>>> +; of optnone functions during instruction selection.
>>>>> +
>>>>> +define float @foo(float %x) #0 {
>>>>> +entry:
>>>>> +  %add = fadd fast float %x, %x
>>>>> +  %add1 = fadd fast float %add, %x
>>>>> +  ret float %add1
>>>>> +}
>>>>> +
>>>>> +; CHECK-NOT: Changing optimization level for Function foo
>>>>> +; CHECK-NOT: Restoring optimization level for Function foo
>>>>> +
>>>>> +; Function Attrs: noinline optnone
>>>>> +define float @fooWithOptnone(float %x) #1 {
>>>>> +entry:
>>>>> +  %add = fadd fast float %x, %x
>>>>> +  %add1 = fadd fast float %add, %x
>>>>> +  ret float %add1
>>>>> +}
>>>>> +
>>>>> +; CHECK: Changing optimization level for Function fooWithOptnone
>>>>> +; CHECK-NEXT: Before: -O2 ; After: -O0
>>>>> +
>>>>> +; CHECK: Restoring optimization level for Function fooWithOptnone
>>>>> +; CHECK-NEXT: Before: -O0 ; After: -O2
>>>>> +
>>>>> +attributes #0 = { "unsafe-fp-math"="true" }
>>>>> +attributes #1 = { noinline optnone "unsafe-fp-math"="true" }
>>>>>
>>>>>
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