[llvm] r371508 - [AMDGPU]: PHI Elimination hooks added for custom COPY insertion.

Galina Kistanova via llvm-commits llvm-commits at lists.llvm.org
Wed Sep 11 13:40:46 PDT 2019


Hello Alexander,

This commit added broken test to the builder
llvm-clang-x86_64-expensive-checks-win.
http://lab.llvm.org:8011/builders/llvm-clang-x86_64-expensive-checks-win/builds/19594
:

. . .
Failing Tests (1):
    LLVM :: CodeGen/AMDGPU/phi-elimination-end-cf.mir

The builder was already red and did not send notifications on this.
Please have a look?

Thanks

Galina

On Tue, Sep 10, 2019 at 3:57 AM Alexander Timofeev via llvm-commits <
llvm-commits at lists.llvm.org> wrote:

> Author: alex-t
> Date: Tue Sep 10 03:58:57 2019
> New Revision: 371508
>
> URL: http://llvm.org/viewvc/llvm-project?rev=371508&view=rev
> Log:
> [AMDGPU]: PHI Elimination hooks added for custom COPY insertion.
>
>   Reviewers: rampitec, vpykhtin
>
>   Differential Revision: https://reviews.llvm.org/D67101
>
> Added:
>     llvm/trunk/test/CodeGen/AMDGPU/phi-elimination-end-cf.mir
> Modified:
>     llvm/trunk/include/llvm/CodeGen/TargetInstrInfo.h
>     llvm/trunk/lib/CodeGen/PHIElimination.cpp
>     llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp
>     llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.h
>     llvm/trunk/lib/Target/AMDGPU/SILowerControlFlow.cpp
>     llvm/trunk/test/CodeGen/AMDGPU/phi-elimination-assertion.mir
>
> Modified: llvm/trunk/include/llvm/CodeGen/TargetInstrInfo.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/TargetInstrInfo.h?rev=371508&r1=371507&r2=371508&view=diff
>
> ==============================================================================
> --- llvm/trunk/include/llvm/CodeGen/TargetInstrInfo.h (original)
> +++ llvm/trunk/include/llvm/CodeGen/TargetInstrInfo.h Tue Sep 10 03:58:57
> 2019
> @@ -22,6 +22,7 @@
>  #include "llvm/CodeGen/MachineCombinerPattern.h"
>  #include "llvm/CodeGen/MachineFunction.h"
>  #include "llvm/CodeGen/MachineInstr.h"
> +#include "llvm/CodeGen/MachineInstrBuilder.h"
>  #include "llvm/CodeGen/MachineLoopInfo.h"
>  #include "llvm/CodeGen/MachineOperand.h"
>  #include "llvm/CodeGen/MachineOutliner.h"
> @@ -1638,6 +1639,28 @@ public:
>      return false;
>    }
>
> +  /// During PHI eleimination lets target to make necessary checks and
> +  /// insert the copy to the PHI destination register in a target specific
> +  /// manner.
> +  virtual MachineInstr *createPHIDestinationCopy(
> +      MachineBasicBlock &MBB, MachineBasicBlock::iterator InsPt,
> +      const DebugLoc &DL, Register Src, Register Dst) const {
> +    return BuildMI(MBB, InsPt, DL, get(TargetOpcode::COPY), Dst)
> +        .addReg(Src);
> +  }
> +
> +  /// During PHI eleimination lets target to make necessary checks and
> +  /// insert the copy to the PHI destination register in a target specific
> +  /// manner.
> +  virtual MachineInstr *createPHISourceCopy(MachineBasicBlock &MBB,
> +                                            MachineBasicBlock::iterator
> InsPt,
> +                                            const DebugLoc &DL, Register
> Src,
> +                                            Register SrcSubReg,
> +                                            Register Dst) const {
> +    return BuildMI(MBB, InsPt, DL, get(TargetOpcode::COPY), Dst)
> +        .addReg(Src, 0, SrcSubReg);
> +  }
> +
>    /// Returns a \p outliner::OutlinedFunction struct containing
> target-specific
>    /// information for a set of outlining candidates.
>    virtual outliner::OutlinedFunction getOutliningCandidateInfo(
>
> Modified: llvm/trunk/lib/CodeGen/PHIElimination.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/PHIElimination.cpp?rev=371508&r1=371507&r2=371508&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/PHIElimination.cpp (original)
> +++ llvm/trunk/lib/CodeGen/PHIElimination.cpp Tue Sep 10 03:58:57 2019
> @@ -31,7 +31,9 @@
>  #include "llvm/CodeGen/MachineRegisterInfo.h"
>  #include "llvm/CodeGen/SlotIndexes.h"
>  #include "llvm/CodeGen/TargetInstrInfo.h"
> +#include "llvm/CodeGen/TargetLowering.h"
>  #include "llvm/CodeGen/TargetOpcodes.h"
> +#include "llvm/CodeGen/TargetPassConfig.h"
>  #include "llvm/CodeGen/TargetRegisterInfo.h"
>  #include "llvm/CodeGen/TargetSubtargetInfo.h"
>  #include "llvm/Pass.h"
> @@ -252,11 +254,12 @@ void PHIElimination::LowerPHINode(Machin
>    // Insert a register to register copy at the top of the current block
> (but
>    // after any remaining phi nodes) which copies the new incoming register
>    // into the phi node destination.
> +  MachineInstr *PHICopy = nullptr;
>    const TargetInstrInfo *TII = MF.getSubtarget().getInstrInfo();
>    if (allPhiOperandsUndefined(*MPhi, *MRI))
>      // If all sources of a PHI node are implicit_def or undef uses, just
> emit an
>      // implicit_def instead of a copy.
> -    BuildMI(MBB, AfterPHIsIt, MPhi->getDebugLoc(),
> +    PHICopy = BuildMI(MBB, AfterPHIsIt, MPhi->getDebugLoc(),
>              TII->get(TargetOpcode::IMPLICIT_DEF), DestReg);
>    else {
>      // Can we reuse an earlier PHI node? This only happens for critical
> edges,
> @@ -273,15 +276,13 @@ void PHIElimination::LowerPHINode(Machin
>        const TargetRegisterClass *RC =
> MF.getRegInfo().getRegClass(DestReg);
>        entry = IncomingReg = MF.getRegInfo().createVirtualRegister(RC);
>      }
> -    BuildMI(MBB, AfterPHIsIt, MPhi->getDebugLoc(),
> -            TII->get(TargetOpcode::COPY), DestReg)
> -      .addReg(IncomingReg);
> +    // Give the target possiblity to handle special cases fallthrough
> otherwise
> +    PHICopy = TII->createPHIDestinationCopy(MBB, AfterPHIsIt,
> MPhi->getDebugLoc(),
> +                                  IncomingReg, DestReg);
>    }
>
>    // Update live variable information if there is any.
>    if (LV) {
> -    MachineInstr &PHICopy = *std::prev(AfterPHIsIt);
> -
>      if (IncomingReg) {
>        LiveVariables::VarInfo &VI = LV->getVarInfo(IncomingReg);
>
> @@ -302,7 +303,7 @@ void PHIElimination::LowerPHINode(Machin
>        // killed.  Note that because the value is defined in several
> places (once
>        // each for each incoming block), the "def" block and instruction
> fields
>        // for the VarInfo is not filled in.
> -      LV->addVirtualRegisterKilled(IncomingReg, PHICopy);
> +      LV->addVirtualRegisterKilled(IncomingReg, *PHICopy);
>      }
>
>      // Since we are going to be deleting the PHI node, if it is the last
> use of
> @@ -312,15 +313,14 @@ void PHIElimination::LowerPHINode(Machin
>
>      // If the result is dead, update LV.
>      if (isDead) {
> -      LV->addVirtualRegisterDead(DestReg, PHICopy);
> +      LV->addVirtualRegisterDead(DestReg, *PHICopy);
>        LV->removeVirtualRegisterDead(DestReg, *MPhi);
>      }
>    }
>
>    // Update LiveIntervals for the new copy or implicit def.
>    if (LIS) {
> -    SlotIndex DestCopyIndex =
> -        LIS->InsertMachineInstrInMaps(*std::prev(AfterPHIsIt));
> +    SlotIndex DestCopyIndex = LIS->InsertMachineInstrInMaps(*PHICopy);
>
>      SlotIndex MBBStartIndex = LIS->getMBBStartIdx(&MBB);
>      if (IncomingReg) {
> @@ -406,9 +406,9 @@ void PHIElimination::LowerPHINode(Machin
>            if (DefMI->isImplicitDef())
>              ImpDefs.insert(DefMI);
>        } else {
> -        NewSrcInstr = BuildMI(opBlock, InsertPos, MPhi->getDebugLoc(),
> -                            TII->get(TargetOpcode::COPY), IncomingReg)
> -                        .addReg(SrcReg, 0, SrcSubReg);
> +        NewSrcInstr =
> +            TII->createPHISourceCopy(opBlock, InsertPos,
> MPhi->getDebugLoc(),
> +                                     SrcReg, SrcSubReg, IncomingReg);
>        }
>      }
>
> @@ -457,7 +457,7 @@ void PHIElimination::LowerPHINode(Machin
>            }
>          } else {
>            // We just inserted this copy.
> -          KillInst = std::prev(InsertPos);
> +          KillInst = NewSrcInstr;
>          }
>        }
>        assert(KillInst->readsRegister(SrcReg) && "Cannot find kill
> instruction");
>
> Modified: llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp?rev=371508&r1=371507&r2=371508&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp (original)
> +++ llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp Tue Sep 10 03:58:57 2019
> @@ -6410,3 +6410,31 @@ bool llvm::execMayBeModifiedBeforeAnyUse
>        return true;
>    }
>  }
> +
> +MachineInstr *SIInstrInfo::createPHIDestinationCopy(
> +    MachineBasicBlock &MBB, MachineBasicBlock::iterator LastPHIIt,
> +    const DebugLoc &DL, Register Src, Register Dst) const {
> +  auto Cur = MBB.begin();
> +  do {
> +    if (!Cur->isPHI() && Cur->readsRegister(Dst))
> +      return BuildMI(MBB, Cur, DL, get(TargetOpcode::COPY),
> Dst).addReg(Src);
> +    ++Cur;
> +  } while (Cur != MBB.end() && Cur != LastPHIIt);
> +
> +  return TargetInstrInfo::createPHIDestinationCopy(MBB, LastPHIIt, DL,
> Src,
> +                                                   Dst);
> +}
> +
> +MachineInstr *SIInstrInfo::createPHISourceCopy(
> +    MachineBasicBlock &MBB, MachineBasicBlock::iterator InsPt,
> +    const DebugLoc &DL, Register Src, Register SrcSubReg, Register Dst)
> const {
> +  if (InsPt != MBB.end() && InsPt->isPseudo() &&
> InsPt->definesRegister(Src)) {
> +    InsPt++;
> +    return BuildMI(MBB, InsPt, InsPt->getDebugLoc(),
> get(TargetOpcode::COPY),
> +                   Dst)
> +        .addReg(Src, 0, SrcSubReg)
> +        .addReg(AMDGPU::EXEC, RegState::Implicit);
> +  }
> +  return TargetInstrInfo::createPHISourceCopy(MBB, InsPt, DL, Src,
> SrcSubReg,
> +                                              Dst);
> +}
>
> Modified: llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.h?rev=371508&r1=371507&r2=371508&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.h (original)
> +++ llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.h Tue Sep 10 03:58:57 2019
> @@ -954,6 +954,17 @@ public:
>
>    bool isBasicBlockPrologue(const MachineInstr &MI) const override;
>
> +  MachineInstr *createPHIDestinationCopy(MachineBasicBlock &MBB,
> +                                         MachineBasicBlock::iterator
> InsPt,
> +                                         const DebugLoc &DL, Register Src,
> +                                         Register Dst) const override;
> +
> +  MachineInstr *createPHISourceCopy(MachineBasicBlock &MBB,
> +                                    MachineBasicBlock::iterator InsPt,
> +                                    const DebugLoc &DL, Register Src,
> +                                    Register SrcSubReg,
> +                                    Register Dst) const override;
> +
>    /// Return a partially built integer add instruction without carry.
>    /// Caller must add source operands.
>    /// For pre-GFX9 it will generate unused carry destination operand.
>
> Modified: llvm/trunk/lib/Target/AMDGPU/SILowerControlFlow.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/SILowerControlFlow.cpp?rev=371508&r1=371507&r2=371508&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Target/AMDGPU/SILowerControlFlow.cpp (original)
> +++ llvm/trunk/lib/Target/AMDGPU/SILowerControlFlow.cpp Tue Sep 10
> 03:58:57 2019
> @@ -400,13 +400,17 @@ void SILowerControlFlow::emitLoop(Machin
>
>  void SILowerControlFlow::emitEndCf(MachineInstr &MI) {
>    MachineBasicBlock &MBB = *MI.getParent();
> +  MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
> +  unsigned CFMask = MI.getOperand(0).getReg();
> +  MachineInstr *Def = MRI.getUniqueVRegDef(CFMask);
>    const DebugLoc &DL = MI.getDebugLoc();
>
> -  MachineBasicBlock::iterator InsPt = MBB.begin();
> -  MachineInstr *NewMI =
> -      BuildMI(MBB, InsPt, DL, TII->get(OrOpc), Exec)
> -          .addReg(Exec)
> -          .add(MI.getOperand(0));
> +  MachineBasicBlock::iterator InsPt =
> +      Def && Def->getParent() == &MBB ?
> std::next(MachineBasicBlock::iterator(Def))
> +                               : MBB.begin();
> +  MachineInstr *NewMI = BuildMI(MBB, InsPt, DL, TII->get(OrOpc), Exec)
> +                            .addReg(Exec)
> +                            .add(MI.getOperand(0));
>
>    if (LIS)
>      LIS->ReplaceMachineInstrInMaps(MI, *NewMI);
>
> Modified: llvm/trunk/test/CodeGen/AMDGPU/phi-elimination-assertion.mir
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AMDGPU/phi-elimination-assertion.mir?rev=371508&r1=371507&r2=371508&view=diff
>
> ==============================================================================
> --- llvm/trunk/test/CodeGen/AMDGPU/phi-elimination-assertion.mir (original)
> +++ llvm/trunk/test/CodeGen/AMDGPU/phi-elimination-assertion.mir Tue Sep
> 10 03:58:57 2019
> @@ -26,8 +26,8 @@ body:             |
>
>  # CHECK-LABEL: name:            foo
>  # CHECK:   bb.3:
> -# CHECK-NEXT:     %3:sreg_32_xm0 = COPY killed %4
>  # CHECK-NEXT:     dead %2:sreg_32_xm0 = IMPLICIT_DEF
> +# CHECK-NEXT:     %3:sreg_32_xm0 = COPY killed %4
>  # CHECK-NEXT:     S_NOP 0, implicit killed %3
>
>
>
> Added: llvm/trunk/test/CodeGen/AMDGPU/phi-elimination-end-cf.mir
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AMDGPU/phi-elimination-end-cf.mir?rev=371508&view=auto
>
> ==============================================================================
> --- llvm/trunk/test/CodeGen/AMDGPU/phi-elimination-end-cf.mir (added)
> +++ llvm/trunk/test/CodeGen/AMDGPU/phi-elimination-end-cf.mir Tue Sep 10
> 03:58:57 2019
> @@ -0,0 +1,54 @@
> +# RUN: llc -mtriple amdgcn -run-pass livevars -run-pass
> phi-node-elimination -o - %s | FileCheck %s
> +
> +# CHECK-LABEL:  phi-cf-test
> +# CHECK: bb.0:
> +# CHECK:     [[COND:%[0-9]+]]:sreg_64 = V_CMP_EQ_U32_e64
> +# CHECK:     [[IF_SOURCE0:%[0-9]+]]:sreg_64 = SI_IF [[COND]], %bb.1,
> implicit-def dead $exec, implicit-def dead $scc, implicit $exec
> +# CHECK:     [[IF_INPUT_REG:%[0-9]+]]:sreg_64 = COPY killed
> [[IF_SOURCE0]], implicit $exec
> +
> +# CHECK: bb.1:
> +# CHECK:     [[END_CF_ARG:%[0-9]+]]:sreg_64 = COPY killed [[IF_INPUT_REG]]
> +# CHECK:     SI_END_CF killed [[END_CF_ARG]], implicit-def dead $exec,
> implicit-def dead $scc, implicit $exec
> +
> +# CHECK: bb.2:
> +# CHECK:     [[IF_SOURCE1:%[0-9]+]]:sreg_64 = SI_IF [[COND]], %bb.1,
> implicit-def dead $exec, implicit-def dead $scc, implicit $exec
> +# CHECK:     [[IF_INPUT_REG]]:sreg_64 = COPY killed [[IF_SOURCE1]],
> implicit $exec
> +
> +
> +...
> +---
> +name:            phi-cf-test
> +tracksRegLiveness: true
> +body:             |
> +
> +  bb.0:
> +    successors: %bb.3(0x40000000), %bb.2(0x40000000)
> +    liveins: $vgpr0
> +
> +    %5:vgpr_32(s32) = COPY $vgpr0
> +    %0:sreg_64 = V_CMP_EQ_U32_e64 0, %5(s32), implicit $exec
> +    %18:vgpr_32 = V_MOV_B32_e32 0, implicit $exec
> +    %22:sreg_64 = SI_IF %0, %bb.2, implicit-def dead $exec, implicit-def
> dead $scc, implicit $exec
> +    S_BRANCH %bb.3
> +
> +  bb.2:
> +    successors: %bb.3(0x80000000)
> +
> +    %24:sreg_64 = PHI %20, %bb.3, %22, %bb.0
> +    %23:vgpr_32 = PHI %19, %bb.3, %18, %bb.0
> +    SI_END_CF %24, implicit-def dead $exec, implicit-def dead $scc,
> implicit $exec
> +    %3:vgpr_32, dead %10:sreg_64 = nsw V_ADD_I32_e64 1, %23, 0, implicit
> $exec
> +
> +  bb.3:
> +    successors: %bb.3(0x40000000), %bb.2(0x40000000)
> +
> +    %4:vgpr_32 = PHI %19, %bb.3, %3, %bb.2, %18, %bb.0
> +    %15:sreg_32_xm0 = S_MOV_B32 61440
> +    %16:sreg_32_xm0 = S_MOV_B32 -1
> +    %17:sreg_128 = REG_SEQUENCE undef %14:sreg_32_xm0, %subreg.sub0,
> undef %12:sreg_32_xm0, %subreg.sub1, %16, %subreg.sub2, %15, %subreg.sub3
> +    BUFFER_STORE_DWORD_OFFSET %4, %17, 0, 0, 0, 0, 0, 0, implicit $exec
> :: (volatile store 4 into `i32 addrspace(1)* undef`, addrspace 1)
> +    %19:vgpr_32 = COPY %4
> +    %20:sreg_64 = SI_IF %0, %bb.2, implicit-def dead $exec, implicit-def
> dead $scc, implicit $exec
> +    S_BRANCH %bb.3
> +
> +...
>
>
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