[llvm] r188426 - R600/SI: Choose the correct MOV instruction for copying immediates

Michael Gottesman mgottesman at apple.com
Wed Aug 21 16:25:41 PDT 2013


No worries. Thanks for the effort = ).

Michael

On Aug 21, 2013, at 3:10 PM, Tom Stellard <tom at stellard.net> wrote:

> On Tue, Aug 20, 2013 at 03:27:14PM -0700, Tom Stellard wrote:
>> On Sat, Aug 17, 2013 at 06:57:21PM -0700, Michael Gottesman wrote:
>>> From the commit message, it seems that this patch is fixing a bug (I.e. emitting an incorrect mov instruction). If my understanding is correct, is it possible to make a test case for this?
>>> 
>> 
>> Yes, I can add a test case for this.
> 
> As it turns out, adding a test case for this was harder that I thought.
> When I first wrote this patch it was to fix a bug that was uncovered
> while working on the change that became the very next commit.  However, the
> final version of that change which I committed actually does not hit
> this bug.
> 
> I was unable to come up with a test case for this bug, but it may be
> possible to write a good test case once we have added more features and
> optimizations to the backend, so maybe I'll be able to write one sometime
> in the future.
> 
> -Tom
> 
>> 
>> -Tom
>> 
>>> Just trying to be helpful,
>>> Michael
>>> 
>>> On Aug 16, 2013, at 5:00 PM, Tom Stellard <tom at stellard.net> wrote:
>>> 
>>>> On Thu, Aug 15, 2013 at 11:16:43AM +0400, Alexey Samsonov wrote:
>>>>> Hi Tom!
>>>>> 
>>>>> This commit breaks our ASan bootstrap bot.
>>>>> The test
>>>>> LLVM :: CodeGen/R600/indirect-addressing-si.ll
>>>>> fails with the following report:
>>>>> =================================================================
>>>>> ==5720==ERROR: AddressSanitizer: global-buffer-overflow on address
>>>>> 0x000002f35010 at pc 0xf0a316 bp 0x7fff36b19a90 sp 0x7fff36b19a88
>>>>> READ of size 2 at 0x000002f35010 thread T0
>>>>>   #0 0xf0a315 in (anonymous
>>>>> namespace)::AMDGPUDAGToDAGISel::getOperandRegClass(llvm::SDNode*, unsigned
>>>>> int) const llvm/lib/Target/R600/AMDGPUISelDAGToDAG.cpp:118
>>>>>   #1 0xf04780 in (anonymous
>>>>> namespace)::AMDGPUDAGToDAGISel::CheckNodePredicate(llvm::SDNode*, unsigned
>>>>> int) const llvm_build_asan/lib/Target/R600/AMDGPUGenDAGISel.inc:14035
>>>>>   #2 0x191500a in llvm::SelectionDAGISel::SelectCodeCommon(llvm::SDNode*,
>>>>> unsigned char const*, unsigned int)
>>>>> llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:1976
>>>>>   #3 0xeff4eb in SelectCode
>>>>> llvm_build_asan/lib/Target/R600/AMDGPUGenDAGISel.inc:13723
>>>>>   #4 0xeff4eb in (anonymous
>>>>> namespace)::AMDGPUDAGToDAGISel::Select(llvm::SDNode*)
>>>>> llvm/lib/Target/R600/AMDGPUISelDAGToDAG.cpp:496
>>>>>   #5 0x1906f07 in llvm::SelectionDAGISel::DoInstructionSelection()
>>>>> llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:790
>>>>>   #6 0x1903823 in llvm::SelectionDAGISel::CodeGenAndEmitDAG()
>>>>> llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:691
>>>>>   #7 0x18fefad in
>>>>> llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&)
>>>>> llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:1134
>>>>>   #8 0x18f898e in
>>>>> llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&)
>>>>> llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:387
>>>>>   #9 0x1e3c1cb in
>>>>> llvm::MachineFunctionPass::runOnFunction(llvm::Function&)
>>>>> llvm/lib/CodeGen/MachineFunctionPass.cpp:33
>>>>>   #10 0x279c42c in llvm::FPPassManager::runOnFunction(llvm::Function&)
>>>>> llvm/lib/IR/PassManager.cpp:1530
>>>>>   #11 0x279c9f5 in llvm::FPPassManager::runOnModule(llvm::Module&)
>>>>> llvm/lib/IR/PassManager.cpp:1550
>>>>>   #12 0x279d21b in llvm::MPPassManager::runOnModule(llvm::Module&)
>>>>> llvm/lib/IR/PassManager.cpp:1608
>>>>>   #13 0x279e433 in llvm::PassManagerImpl::run(llvm::Module&)
>>>>> llvm/lib/IR/PassManager.cpp:1703
>>>>>   #14 0x53351f in compileModule llvm/tools/llc/llc.cpp:376
>>>>>   #15 0x53351f in main llvm/tools/llc/llc.cpp:197
>>>>>   #16 0x7fee21eb276c in __libc_start_main
>>>>> /build/buildd/eglibc-2.15/csu/libc-start.c:226
>>>>>   #17 0x52effc in _start (llvm_build_asan/bin/llc+0x52effc)
>>>>> 0x000002f35010 is located 48 bytes to the left of global variable
>>>>> 'llvm::OperandInfo69' from
>>>>> 'llvm/lib/Target/R600/MCTargetDesc/AMDGPUMCTargetDesc.cpp' (0x2f35040) of
>>>>> size 48
>>>>> 0x000002f35010 is located 0 bytes to the right of global variable
>>>>> 'llvm::OperandInfo68' from
>>>>> 'llvm/lib/Target/R600/MCTargetDesc/AMDGPUMCTargetDesc.cpp' (0x2f34fe0) of
>>>>> size 48
>>>>> SUMMARY: AddressSanitizer: global-buffer-overflow
>>>>> llvm/lib/Target/R600/AMDGPUISelDAGToDAG.cpp:118 (anonymous
>>>>> namespace)::AMDGPUDAGToDAGISel::getOperandRegClass(llvm::SDNode*, unsigned
>>>>> int) const
>>>>> 
>>>>> 
>>>>> I've commited a tentative fix to bring the bot back in r188448. Not sure if
>>>>> the fix is correct - probably you should fix the caller and add an assert
>>>>> to getOperandRegClass function.
>>>>> 
>>>> 
>>>> Your fix actually looks good to me as is.  Thanks for catching this.
>>>> 
>>>> -Tom
>>>> 
>>>>> 
>>>>> On Thu, Aug 15, 2013 at 3:24 AM, Tom Stellard <thomas.stellard at amd.com>wrote:
>>>>> 
>>>>>> Author: tstellar
>>>>>> Date: Wed Aug 14 18:24:24 2013
>>>>>> New Revision: 188426
>>>>>> 
>>>>>> URL: http://llvm.org/viewvc/llvm-project?rev=188426&view=rev
>>>>>> Log:
>>>>>> R600/SI: Choose the correct MOV instruction for copying immediates
>>>>>> 
>>>>>> The instruction selector will now try to infer the destination register
>>>>>> so it can decided whether to use V_MOV_B32 or S_MOV_B32 when copying
>>>>>> immediates.
>>>>>> 
>>>>>> Modified:
>>>>>>   llvm/trunk/lib/Target/R600/AMDGPUISelDAGToDAG.cpp
>>>>>>   llvm/trunk/lib/Target/R600/SIInstrInfo.td
>>>>>>   llvm/trunk/lib/Target/R600/SIInstructions.td
>>>>>>   llvm/trunk/lib/Target/R600/SIRegisterInfo.cpp
>>>>>>   llvm/trunk/lib/Target/R600/SIRegisterInfo.h
>>>>>> 
>>>>>> Modified: llvm/trunk/lib/Target/R600/AMDGPUISelDAGToDAG.cpp
>>>>>> URL:
>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/R600/AMDGPUISelDAGToDAG.cpp?rev=188426&r1=188425&r2=188426&view=diff
>>>>>> 
>>>>>> ==============================================================================
>>>>>> --- llvm/trunk/lib/Target/R600/AMDGPUISelDAGToDAG.cpp (original)
>>>>>> +++ llvm/trunk/lib/Target/R600/AMDGPUISelDAGToDAG.cpp Wed Aug 14 18:24:24
>>>>>> 2013
>>>>>> @@ -77,6 +77,7 @@ private:
>>>>>>  bool isLocalLoad(const LoadSDNode *N) const;
>>>>>>  bool isRegionLoad(const LoadSDNode *N) const;
>>>>>> 
>>>>>> +  const TargetRegisterClass *getOperandRegClass(SDNode *N, unsigned OpNo)
>>>>>> const;
>>>>>>  bool SelectGlobalValueConstantOffset(SDValue Addr, SDValue& IntPtr);
>>>>>>  bool SelectGlobalValueVariableOffset(SDValue Addr,
>>>>>>      SDValue &BaseReg, SDValue& Offset);
>>>>>> @@ -102,6 +103,34 @@ AMDGPUDAGToDAGISel::AMDGPUDAGToDAGISel(T
>>>>>> AMDGPUDAGToDAGISel::~AMDGPUDAGToDAGISel() {
>>>>>> }
>>>>>> 
>>>>>> +/// \brief Determine the register class for \p OpNo
>>>>>> +/// \returns The register class of the virtual register that will be used
>>>>>> for
>>>>>> +/// the given operand number \OpNo or NULL if the register class cannot be
>>>>>> +/// determined.
>>>>>> +const TargetRegisterClass *AMDGPUDAGToDAGISel::getOperandRegClass(SDNode
>>>>>> *N,
>>>>>> +                                                          unsigned OpNo)
>>>>>> const {
>>>>>> +  if (!N->isMachineOpcode()) {
>>>>>> +    return NULL;
>>>>>> +  }
>>>>>> +  switch (N->getMachineOpcode()) {
>>>>>> +  default: {
>>>>>> +    const MCInstrDesc &Desc =
>>>>>> TM.getInstrInfo()->get(N->getMachineOpcode());
>>>>>> +    int RegClass = Desc.OpInfo[Desc.getNumDefs() + OpNo].RegClass;
>>>>>> +    if (RegClass == -1) {
>>>>>> +      return NULL;
>>>>>> +    }
>>>>>> +    return TM.getRegisterInfo()->getRegClass(RegClass);
>>>>>> +  }
>>>>>> +  case AMDGPU::REG_SEQUENCE: {
>>>>>> +    const TargetRegisterClass *SuperRC =
>>>>>> TM.getRegisterInfo()->getRegClass(
>>>>>> +
>>>>>> cast<ConstantSDNode>(N->getOperand(0))->getZExtValue());
>>>>>> +    unsigned SubRegIdx =
>>>>>> +            dyn_cast<ConstantSDNode>(N->getOperand(OpNo +
>>>>>> 1))->getZExtValue();
>>>>>> +    return TM.getRegisterInfo()->getSubClassWithSubReg(SuperRC,
>>>>>> SubRegIdx);
>>>>>> +  }
>>>>>> +  }
>>>>>> +}
>>>>>> +
>>>>>> SDValue AMDGPUDAGToDAGISel::getSmallIPtrImm(unsigned int Imm) {
>>>>>>  return CurDAG->getTargetConstant(Imm, MVT::i32);
>>>>>> }
>>>>>> 
>>>>>> Modified: llvm/trunk/lib/Target/R600/SIInstrInfo.td
>>>>>> URL:
>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/R600/SIInstrInfo.td?rev=188426&r1=188425&r2=188426&view=diff
>>>>>> 
>>>>>> ==============================================================================
>>>>>> --- llvm/trunk/lib/Target/R600/SIInstrInfo.td (original)
>>>>>> +++ llvm/trunk/lib/Target/R600/SIInstrInfo.td Wed Aug 14 18:24:24 2013
>>>>>> @@ -58,6 +58,22 @@ class InlineImm <ValueType vt> : PatLeaf
>>>>>>    (*(const SITargetLowering *)getTargetLowering()).analyzeImmediate(N)
>>>>>> == 0;
>>>>>> }]>;
>>>>>> 
>>>>>> +class SGPRImm <dag frag> : PatLeaf<frag, [{
>>>>>> +  if (TM.getSubtarget<AMDGPUSubtarget>().getGeneration() <
>>>>>> +      AMDGPUSubtarget::SOUTHERN_ISLANDS) {
>>>>>> +    return false;
>>>>>> +  }
>>>>>> +  const SIRegisterInfo *SIRI =
>>>>>> +                       static_cast<const
>>>>>> SIRegisterInfo*>(TM.getRegisterInfo());
>>>>>> +  for (SDNode::use_iterator U = N->use_begin(), E = SDNode::use_end();
>>>>>> +                                                U != E; ++U) {
>>>>>> +    if (SIRI->isSGPRClass(getOperandRegClass(*U, U.getOperandNo()))) {
>>>>>> +      return true;
>>>>>> +    }
>>>>>> +  }
>>>>>> +  return false;
>>>>>> +}]>;
>>>>>> +
>>>>>> 
>>>>>> //===----------------------------------------------------------------------===//
>>>>>> // SI assembler operands
>>>>>> 
>>>>>> //===----------------------------------------------------------------------===//
>>>>>> 
>>>>>> Modified: llvm/trunk/lib/Target/R600/SIInstructions.td
>>>>>> URL:
>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/R600/SIInstructions.td?rev=188426&r1=188425&r2=188426&view=diff
>>>>>> 
>>>>>> ==============================================================================
>>>>>> --- llvm/trunk/lib/Target/R600/SIInstructions.td (original)
>>>>>> +++ llvm/trunk/lib/Target/R600/SIInstructions.td Wed Aug 14 18:24:24 2013
>>>>>> @@ -1583,6 +1583,16 @@ def : Pat <
>>>>>> /********** ================== **********/
>>>>>> 
>>>>>> def : Pat <
>>>>>> +  (SGPRImm<(i32 imm)>:$imm),
>>>>>> +  (S_MOV_B32 imm:$imm)
>>>>>> +>;
>>>>>> +
>>>>>> +def : Pat <
>>>>>> +  (SGPRImm<(f32 fpimm)>:$imm),
>>>>>> +  (S_MOV_B32 fpimm:$imm)
>>>>>> +>;
>>>>>> +
>>>>>> +def : Pat <
>>>>>>  (i32 imm:$imm),
>>>>>>  (V_MOV_B32_e32 imm:$imm)
>>>>>>> ;
>>>>>> 
>>>>>> Modified: llvm/trunk/lib/Target/R600/SIRegisterInfo.cpp
>>>>>> URL:
>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/R600/SIRegisterInfo.cpp?rev=188426&r1=188425&r2=188426&view=diff
>>>>>> 
>>>>>> ==============================================================================
>>>>>> --- llvm/trunk/lib/Target/R600/SIRegisterInfo.cpp (original)
>>>>>> +++ llvm/trunk/lib/Target/R600/SIRegisterInfo.cpp Wed Aug 14 18:24:24 2013
>>>>>> @@ -70,3 +70,14 @@ const TargetRegisterClass *SIRegisterInf
>>>>>>  }
>>>>>>  return NULL;
>>>>>> }
>>>>>> +
>>>>>> +bool SIRegisterInfo::isSGPRClass(const TargetRegisterClass *RC) const {
>>>>>> +  if (!RC) {
>>>>>> +    return false;
>>>>>> +  }
>>>>>> +  return RC == &AMDGPU::SReg_32RegClass ||
>>>>>> +         RC == &AMDGPU::SReg_64RegClass ||
>>>>>> +         RC == &AMDGPU::SReg_128RegClass ||
>>>>>> +         RC == &AMDGPU::SReg_256RegClass ||
>>>>>> +         RC == &AMDGPU::SReg_512RegClass;
>>>>>> +}
>>>>>> 
>>>>>> Modified: llvm/trunk/lib/Target/R600/SIRegisterInfo.h
>>>>>> URL:
>>>>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/R600/SIRegisterInfo.h?rev=188426&r1=188425&r2=188426&view=diff
>>>>>> 
>>>>>> ==============================================================================
>>>>>> --- llvm/trunk/lib/Target/R600/SIRegisterInfo.h (original)
>>>>>> +++ llvm/trunk/lib/Target/R600/SIRegisterInfo.h Wed Aug 14 18:24:24 2013
>>>>>> @@ -45,6 +45,9 @@ struct SIRegisterInfo : public AMDGPUReg
>>>>>>  /// \brief Return the 'base' register class for this register.
>>>>>>  /// e.g. SGPR0 => SReg_32, VGPR => VReg_32 SGPR0_SGPR1 -> SReg_32, etc.
>>>>>>  const TargetRegisterClass *getPhysRegClass(unsigned Reg) const;
>>>>>> +
>>>>>> +  /// \returns true if this class contains only SGPR registers
>>>>>> +  bool isSGPRClass(const TargetRegisterClass *RC) const;
>>>>>> };
>>>>>> 
>>>>>> } // End namespace llvm
>>>>>> 
>>>>>> 
>>>>>> _______________________________________________
>>>>>> llvm-commits mailing list
>>>>>> llvm-commits at cs.uiuc.edu
>>>>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> -- 
>>>>> Alexey Samsonov, MSK
>>>> 
>>>>> _______________________________________________
>>>>> llvm-commits mailing list
>>>>> llvm-commits at cs.uiuc.edu
>>>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>>>> 
>>>> _______________________________________________
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>>> 
>> _______________________________________________
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