[amdgpu] Handle the case where there is no scavenged register.

[hliao]

Summary

• When an unconditional branch is expanded into an indirect branch, if there is no scavenged register, an SGPR pair needs spilling to enable the destination PC calculation. In addition, before jumping into the destination, that clobbered SGPR pair need restoring.
• As SGPR cannot be spilled to or restored from memory directly, the spilling/restoring of that SGPR pair reuses the regular SGPR spilling support but without spilling it into memory. As that spilling and restoring points are fully controlled, we only need to spill that SGPR into the temporary VGPR, which needs spilling into its emergency slot.
• The target-specific hook is revised to take additional restore block, where the restoring code is filled. After that, the relaxation will place that restore block directly before the destination block and insert an unconditional branch in any fall-through block into the destination block.

[hliao]

Rebase and kindly ping for review.

[hliao]

Rebase and kindly PING for review.

[hliao]

Rebase

[arsenm]

llvm/include/llvm/CodeGen/TargetInstrInfo.h

586–587

typo Optiionally

llvm/lib/CodeGen/BranchRelaxation.cpp

484–485

I'm pretty sure this is illegal, you can't have a branch to the entry block

llvm/test/CodeGen/AMDGPU/branch-relax-spill.ll

331

Where did this frame index come from?

[hliao]

Fix typos and remove dead code.

[hliao]

llvm/lib/CodeGen/BranchRelaxation.cpp

484–485

yeah, you are absolutely right!

llvm/test/CodeGen/AMDGPU/branch-relax-spill.ll

331

That's the scavenge frame index previously added in https://reviews.llvm.org/D96336. Here, we need to spill an SGPR into a VGPR, which needs spilling into a frame slow when no VGPR could be scavenged.

[hliao]

Rebase and kindly PING for review.

[hliao]

Kingly PING for review

[hliao]

Rebase and kingly PING for review.

[arsenm]

llvm/lib/Target/RISCV/RISCVInstrInfo.cpp

677–678

Should turn this into an assert

678

Can delete the return

llvm/test/CodeGen/AMDGPU/branch-relax-spill.ll

2

Can you switch this to an amdhsa triple? I want to be sure the use of the sgpr0_sgpr1 ordinarily used for the scratch buffer is tested. I think you would need to add a test variant that is a non-kernel function too

[hliao]

Revise following reviewers' comment.

[arsenm]

LGTM. Should still add a non-kernel case to the same test so that s[0:3] really is the SRD

[hliao]

Add a non-kernel function case.

[hliao]

llvm/test/CodeGen/AMDGPU/branch-relax-spill.ll

2

that none-kernel case is added. however, due to calling convention, v0 is reused for spilling SGPR and is always available for spilling SGPRs. We cannot test the no-scavenged register case. Do you have suggestions to fabricate the test case for that purpose?

[arsenm]

llvm/test/CodeGen/AMDGPU/branch-relax-spill.ll

2

It's not available for spilling if there's a call that clobbers VGPRs

[hliao]

Update non-kernel test case

• It's turned out that we need a uniform condition to prevent vcc being *really* used.

llvm/include/llvm/CodeGen/TargetInstrInfo.h

public:
   }
 
   /// \returns The block that branch instruction \p MI jumps to.
   virtual MachineBasicBlock *getBranchDestBlock(const MachineInstr &MI) const {
     llvm_unreachable("target did not implement");
   }
 
   /// Insert an unconditional indirect branch at the end of \p MBB to \p
-  /// NewDestBB.  \p BrOffset indicates the offset of \p NewDestBB relative to
+  /// NewDestBB. Optiionally, insert the clobbered register restoring in \p
+  /// RestoreBB. \p BrOffset indicates the offset of \p NewDestBB relative to
   /// the offset of the position to insert the new branch.
-  ///
-  /// \returns The number of bytes added to the block.
-  virtual unsigned insertIndirectBranch(MachineBasicBlock &MBB,
-                                        MachineBasicBlock &NewDestBB,
-                                        const DebugLoc &DL,
-                                        int64_t BrOffset = 0,
-                                        RegScavenger *RS = nullptr) const {
+  virtual void insertIndirectBranch(MachineBasicBlock &MBB,
+                                    MachineBasicBlock &RestoreBB,
+                                    const DebugLoc &DL, int64_t BrOffset = 0,
     llvm_unreachable("target did not implement");
   }
 
   /// Analyze the branching code at the end of MBB, returning
   /// true if it cannot be understood (e.g. it's a switch dispatch or isn't
   /// implemented for a target).  Upon success, this returns false and returns
   /// with the following information in various cases:
   ///

llvm/lib/CodeGen/BranchRelaxation.cpp

if (!MBB->empty()) {
 
     BranchBB->sortUniqueLiveIns();
     BranchBB->addSuccessor(DestBB);
     MBB->replaceSuccessor(DestBB, BranchBB);
   }
 
   DebugLoc DL = MI.getDebugLoc();
   MI.eraseFromParent();
-  BlockInfo[BranchBB->getNumber()].Size += TII->insertIndirectBranch(
-    *BranchBB, *DestBB, DL, DestOffset - SrcOffset, RS.get());
 
+  // Create the optional restore block and, initially, place it at the end of
+  // function. That block will be placed later if it's used; otherwise, it will
+  // be erased.
+  MachineBasicBlock *RestoreBB = createNewBlockAfter(MF->back());
+
+  TII->insertIndirectBranch(*BranchBB, *DestBB, *RestoreBB, DL,
+                            DestOffset - SrcOffset, RS.get());
+
+  BlockInfo[BranchBB->getNumber()].Size = computeBlockSize(*BranchBB);
   adjustBlockOffsets(*MBB);
+
+  // If RestoreBB is required, try to place just before DestBB.
+  if (!RestoreBB->empty()) {
+    // TODO: For multiple far branches to the same destination, there are
+    // chances that some restore blocks could be shared if they clobber the
+    // same registers and share the same restore sequence. So far, those
+    // restore blocks are just duplicated for each far branch.
+    if (DestBB->isEntryBlock()) {
+      // If DestBB is the entry block, create a new empty entry block falling
+      // through into DestBB.
+      MachineBasicBlock *NewBB =
+          MF->CreateMachineBasicBlock(DestBB->getBasicBlock());
+      MF->push_front(NewBB);
+      BlockInfo.insert(BlockInfo.begin() + NewBB->getNumber(),
+                       BasicBlockInfo());
+      // So far, this new empty entry block has the correct blockinfo, i.e.
+      // both zero size and offset.
+      NewBB->addSuccessor(DestBB);
+      if (TRI->trackLivenessAfterRegAlloc(*MF))
+        computeAndAddLiveIns(LiveRegs, *NewBB);
+    }
+    assert(!DestBB->isEntryBlock());
+    MachineBasicBlock *PrevBB = &*std::prev(DestBB->getIterator());
+    if (auto *FT = PrevBB->getFallThrough()) {
+      assert(FT == DestBB);
+      TII->insertUnconditionalBranch(*PrevBB, DestBB, DebugLoc());
+      // Recalculate the block size.
+      BlockInfo[PrevBB->getNumber()].Size = computeBlockSize(*PrevBB);
+    }
+    // Now, RestoreBB could be placed directly before DestBB.
+    MF->splice(DestBB->getIterator(), RestoreBB->getIterator());
+    // Update successors and predecessors.
+    RestoreBB->addSuccessor(DestBB);
+    BranchBB->replaceSuccessor(DestBB, RestoreBB);
+    if (TRI->trackLivenessAfterRegAlloc(*MF))
+      computeAndAddLiveIns(LiveRegs, *RestoreBB);
+    // Compute the restore block size.
+    BlockInfo[RestoreBB->getNumber()].Size = computeBlockSize(*RestoreBB);
+    // Update the offset starting from the previous block.
+    adjustBlockOffsets(*PrevBB);
+  } else {
+    // Remove restore block if it's not required.
+    MF->erase(RestoreBB);
+  }
+
   return true;
 }
 
 bool BranchRelaxation::relaxBranchInstructions() {
   bool Changed = false;
 
   // Relaxing branches involves creating new basic blocks, so re-eval
   // end() for termination.

llvm/lib/Target/AMDGPU/SIInstrInfo.h

public:
   bool findCommutedOpIndices(MCInstrDesc Desc, unsigned & SrcOpIdx0,
    unsigned & SrcOpIdx1) const;
 
   bool isBranchOffsetInRange(unsigned BranchOpc,
                              int64_t BrOffset) const override;
 
   MachineBasicBlock *getBranchDestBlock(const MachineInstr &MI) const override;
 
-  unsigned insertIndirectBranch(MachineBasicBlock &MBB,
-                                MachineBasicBlock &NewDestBB,
-                                const DebugLoc &DL,
-                                int64_t BrOffset,
-                                RegScavenger *RS = nullptr) const override;
+  void insertIndirectBranch(MachineBasicBlock &MBB,
+                            MachineBasicBlock &RestoreBB, const DebugLoc &DL,
+                            int64_t BrOffset, RegScavenger *RS) const override;
 
   bool analyzeBranchImpl(MachineBasicBlock &MBB,
                          MachineBasicBlock::iterator I,
                          MachineBasicBlock *&TBB,
                          MachineBasicBlock *&FBB,
                          SmallVectorImpl<MachineOperand> &Cond,
                          bool AllowModify) const;
 

llvm/lib/Target/AMDGPU/SIInstrInfo.cpp

if (MI.getOpcode() == AMDGPU::S_SETPC_B64) {
     // This would be a difficult analysis to perform, but can always be legal so
     // there's no need to analyze it.
     return nullptr;
   }
 
   return MI.getOperand(0).getMBB();
 }
 
-unsigned SIInstrInfo::insertIndirectBranch(MachineBasicBlock &MBB,
-                                           MachineBasicBlock &DestBB,
-                                           const DebugLoc &DL,
-                                           int64_t BrOffset,
-                                           RegScavenger *RS) const {
+void SIInstrInfo::insertIndirectBranch(MachineBasicBlock &MBB,
+                                       MachineBasicBlock &RestoreBB,
+                                       const DebugLoc &DL, int64_t BrOffset,
   assert(RS && "RegScavenger required for long branching");
   assert(MBB.empty() &&
          "new block should be inserted for expanding unconditional branch");
   assert(MBB.pred_size() == 1);
+  assert(RestoreBB.empty() &&
+         "restore block should be inserted for restoring clobbered registers");
 
   MachineFunction *MF = MBB.getParent();
   MachineRegisterInfo &MRI = MF->getRegInfo();
 
   // FIXME: Virtual register workaround for RegScavenger not working with empty
   // blocks.
   Register PCReg = MRI.createVirtualRegister(&AMDGPU::SReg_64RegClass);
 
BuildMI(MBB, I, DL, get(AMDGPU::S_ADDC_U32))
       .addReg(PCReg, RegState::Define, AMDGPU::sub1)
       .addReg(PCReg, 0, AMDGPU::sub1)
       .addSym(OffsetHi, MO_FAR_BRANCH_OFFSET);
 
   // Insert the indirect branch after the other terminator.
   BuildMI(&MBB, DL, get(AMDGPU::S_SETPC_B64))
     .addReg(PCReg);
 
-  auto ComputeBlockSize = [](const TargetInstrInfo *TII,
-                             const MachineBasicBlock &MBB) {
-    unsigned Size = 0;
-    for (const MachineInstr &MI : MBB)
-      Size += TII->getInstSizeInBytes(MI);
-    return Size;
-  };
-
   // FIXME: If spilling is necessary, this will fail because this scavenger has
   // no emergency stack slots. It is non-trivial to spill in this situation,
   // because the restore code needs to be specially placed after the
   // jump. BranchRelaxation then needs to be made aware of the newly inserted
   // block.
   //
   // If a spill is needed for the pc register pair, we need to insert a spill
   // restore block right before the destination block, and insert a short branch
void SIInstrInfo::insertIndirectBranch(MachineBasicBlock &MBB,
   //  restore s[8:9]
   //  fallthrough dest_bb
   ///
   // dest_bb:
   //   buzz;
 
   RS->enterBasicBlockEnd(MBB);
   Register Scav = RS->scavengeRegisterBackwards(
-    AMDGPU::SReg_64RegClass,
-    MachineBasicBlock::iterator(GetPC), false, 0);
+      AMDGPU::SReg_64RegClass, MachineBasicBlock::iterator(GetPC),
+      /* RestoreAfter */ false, 0, /* AllowSpill */ false);
+  if (Scav) {
+    RS->setRegUsed(Scav);
     MRI.replaceRegWith(PCReg, Scav);
     MRI.clearVirtRegs();
-  RS->setRegUsed(Scav);
+  } else {
+    // As SGPR needs VGPR to be spilled, we reuse the slot of temporary VGPR for
+    // SGPR spill.
+    const GCNSubtarget &ST = MF->getSubtarget<GCNSubtarget>();
+    const SIRegisterInfo *TRI = ST.getRegisterInfo();
+    TRI->spillEmergencySGPR(GetPC, RestoreBB, AMDGPU::SGPR0_SGPR1, RS);
+    MRI.replaceRegWith(PCReg, AMDGPU::SGPR0_SGPR1);
+    MRI.clearVirtRegs();
+  }
 
+  MCSymbol *DestLabel = Scav ? DestBB.getSymbol() : RestoreBB.getSymbol();
   // Now, the distance could be defined.
   auto *Offset = MCBinaryExpr::createSub(
-      MCSymbolRefExpr::create(DestBB.getSymbol(), MCCtx),
+      MCSymbolRefExpr::create(DestLabel, MCCtx),
       MCSymbolRefExpr::create(PostGetPCLabel, MCCtx), MCCtx);
   // Add offset assignments.
   auto *Mask = MCConstantExpr::create(0xFFFFFFFFULL, MCCtx);
   OffsetLo->setVariableValue(MCBinaryExpr::createAnd(Offset, Mask, MCCtx));
   auto *ShAmt = MCConstantExpr::create(32, MCCtx);
   OffsetHi->setVariableValue(MCBinaryExpr::createAShr(Offset, ShAmt, MCCtx));
-  return ComputeBlockSize(this, MBB);
+
+  return;
 }
 
 unsigned SIInstrInfo::getBranchOpcode(SIInstrInfo::BranchPredicate Cond) {
   switch (Cond) {
   case SIInstrInfo::SCC_TRUE:
     return AMDGPU::S_CBRANCH_SCC1;
   case SIInstrInfo::SCC_FALSE:
     return AMDGPU::S_CBRANCH_SCC0;

llvm/lib/Target/AMDGPU/SIRegisterInfo.h

bool spillSGPR(MachineBasicBlock::iterator MI,
                  LiveIntervals *LIS = nullptr,
                  bool OnlyToVGPR = false) const;
 
   bool restoreSGPR(MachineBasicBlock::iterator MI,
                    int FI, RegScavenger *RS,
                    LiveIntervals *LIS = nullptr,
                    bool OnlyToVGPR = false) const;
 
+  bool spillEmergencySGPR(MachineBasicBlock::iterator MI,
+                          MachineBasicBlock &RestoreMBB, Register SGPR,
+                          RegScavenger *RS) const;
+
   void eliminateFrameIndex(MachineBasicBlock::iterator MI, int SPAdj,
                            unsigned FIOperandNum,
                            RegScavenger *RS) const override;
 
   bool eliminateSGPRToVGPRSpillFrameIndex(MachineBasicBlock::iterator MI,
                                           int FI, RegScavenger *RS,
                                           LiveIntervals *LIS = nullptr) const;
 

llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp

struct SGPRSpillBuilder {
   bool TmpVGPRLive = false;
   // Scavenged SGPR to save EXEC.
   Register SavedExecReg = AMDGPU::NoRegister;
   // Stack index to write the SGPRs to.
   int Index;
   unsigned EltSize = 4;
 
   RegScavenger *RS;
-  MachineBasicBlock &MBB;
+  MachineBasicBlock *MBB;
   MachineFunction &MF;
   SIMachineFunctionInfo &MFI;
   const SIInstrInfo &TII;
   const SIRegisterInfo &TRI;
   bool IsWave32;
   Register ExecReg;
   unsigned MovOpc;
   unsigned NotOpc;
 
   SGPRSpillBuilder(const SIRegisterInfo &TRI, const SIInstrInfo &TII,
                    bool IsWave32, MachineBasicBlock::iterator MI, int Index,
                    RegScavenger *RS)
-      : SuperReg(MI->getOperand(0).getReg()), MI(MI),
-        IsKill(MI->getOperand(0).isKill()), DL(MI->getDebugLoc()), Index(Index),
-        RS(RS), MBB(*MI->getParent()), MF(*MBB.getParent()),
+      : SGPRSpillBuilder(TRI, TII, IsWave32, MI, MI->getOperand(0).getReg(),
+                         MI->getOperand(0).isKill(), Index, RS) {}
+
+  SGPRSpillBuilder(const SIRegisterInfo &TRI, const SIInstrInfo &TII,
+                   bool IsWave32, MachineBasicBlock::iterator MI, Register Reg,
+                   bool IsKill, int Index, RegScavenger *RS)
+      : SuperReg(Reg), MI(MI), IsKill(IsKill), DL(MI->getDebugLoc()),
+        Index(Index), RS(RS), MBB(MI->getParent()), MF(*MBB->getParent()),
         MFI(*MF.getInfo<SIMachineFunctionInfo>()), TII(TII), TRI(TRI),
         IsWave32(IsWave32) {
     const TargetRegisterClass *RC = TRI.getPhysRegClass(SuperReg);
     SplitParts = TRI.getRegSplitParts(RC, EltSize);
     NumSubRegs = SplitParts.empty() ? 1 : SplitParts.size();
 
     if (IsWave32) {
       ExecReg = AMDGPU::EXEC_LO;
void prepare() {
     RS->setRegUsed(SuperReg);
     SavedExecReg = RS->scavengeRegister(&RC, MI, 0, false);
 
     int64_t VGPRLanes = getPerVGPRData().VGPRLanes;
 
     if (SavedExecReg) {
       RS->setRegUsed(SavedExecReg);
       // Set exec to needed lanes
-      BuildMI(MBB, MI, DL, TII.get(MovOpc), SavedExecReg).addReg(ExecReg);
-      auto I = BuildMI(MBB, MI, DL, TII.get(MovOpc), ExecReg).addImm(VGPRLanes);
+      BuildMI(*MBB, MI, DL, TII.get(MovOpc), SavedExecReg).addReg(ExecReg);
+      auto I =
+          BuildMI(*MBB, MI, DL, TII.get(MovOpc), ExecReg).addImm(VGPRLanes);
       if (!TmpVGPRLive)
         I.addReg(TmpVGPR, RegState::ImplicitDefine);
       // Spill needed lanes
       TRI.buildVGPRSpillLoadStore(*this, TmpVGPRIndex, 0, /*IsLoad*/ false);
     } else {
       // Spill active lanes
       if (TmpVGPRLive)
         TRI.buildVGPRSpillLoadStore(*this, TmpVGPRIndex, 0, /*IsLoad*/ false,
                                     /*IsKill*/ false);
       // Spill inactive lanes
-      auto I = BuildMI(MBB, MI, DL, TII.get(NotOpc), ExecReg).addReg(ExecReg);
+      auto I = BuildMI(*MBB, MI, DL, TII.get(NotOpc), ExecReg).addReg(ExecReg);
       if (!TmpVGPRLive)
         I.addReg(TmpVGPR, RegState::ImplicitDefine);
       TRI.buildVGPRSpillLoadStore(*this, TmpVGPRIndex, 0, /*IsLoad*/ false);
     }
   }
 
   // Writes these instructions if an SGPR can be scavenged:
   // buffer_load_dword v1     ; Write scavenged VGPR to emergency slot
   // s_waitcnt vmcnt(0)       ; If a free VGPR was found
   // s_mov_b64 exec, s[6:7]   ; Save exec
   //
   // Writes these instructions if no SGPR can be scavenged:
   // buffer_load_dword v0     ; Restore inactive lanes
   // s_waitcnt vmcnt(0)       ; If a free VGPR was found
   // s_not_b64 exec, exec
   // buffer_load_dword v0     ; Only if no free VGPR was found
   void restore() {
     if (SavedExecReg) {
       // Restore used lanes
       TRI.buildVGPRSpillLoadStore(*this, TmpVGPRIndex, 0, /*IsLoad*/ true,
                                   /*IsKill*/ false);
       // Restore exec
-      auto I = BuildMI(MBB, MI, DL, TII.get(MovOpc), ExecReg)
+      auto I = BuildMI(*MBB, MI, DL, TII.get(MovOpc), ExecReg)
                    .addReg(SavedExecReg, RegState::Kill);
       // Add an implicit use of the load so it is not dead.
       // FIXME This inserts an unnecessary waitcnt
       if (!TmpVGPRLive) {
         I.addReg(TmpVGPR, RegState::ImplicitKill);
       }
     } else {
       // Restore inactive lanes
       TRI.buildVGPRSpillLoadStore(*this, TmpVGPRIndex, 0, /*IsLoad*/ true,
                                   /*IsKill*/ false);
-      auto I = BuildMI(MBB, MI, DL, TII.get(NotOpc), ExecReg).addReg(ExecReg);
+      auto I = BuildMI(*MBB, MI, DL, TII.get(NotOpc), ExecReg).addReg(ExecReg);
       if (!TmpVGPRLive) {
         I.addReg(TmpVGPR, RegState::ImplicitKill);
       }
       // Restore active lanes
       if (TmpVGPRLive)
         TRI.buildVGPRSpillLoadStore(*this, TmpVGPRIndex, 0, /*IsLoad*/ true);
     }
   }
void readWriteTmpVGPR(unsigned Offset, bool IsLoad) {
     if (SavedExecReg) {
       // Spill needed lanes
       TRI.buildVGPRSpillLoadStore(*this, Index, Offset, IsLoad);
     } else {
       // Spill active lanes
       TRI.buildVGPRSpillLoadStore(*this, Index, Offset, IsLoad,
                                   /*IsKill*/ false);
       // Spill inactive lanes
-      BuildMI(MBB, MI, DL, TII.get(NotOpc), ExecReg).addReg(ExecReg);
+      BuildMI(*MBB, MI, DL, TII.get(NotOpc), ExecReg).addReg(ExecReg);
       TRI.buildVGPRSpillLoadStore(*this, Index, Offset, IsLoad);
-      BuildMI(MBB, MI, DL, TII.get(NotOpc), ExecReg).addReg(ExecReg);
+      BuildMI(*MBB, MI, DL, TII.get(NotOpc), ExecReg).addReg(ExecReg);
     }
   }
+
+  void setMI(MachineBasicBlock *NewMBB, MachineBasicBlock::iterator NewMI) {
+    assert(MBB->getParent() == &MF);
+    MI = NewMI;
+    MBB = NewMBB;
+  }
 };
 
 } // namespace llvm
 
 SIRegisterInfo::SIRegisterInfo(const GCNSubtarget &ST)
     : AMDGPUGenRegisterInfo(AMDGPU::PC_REG, ST.getAMDGPUDwarfFlavour()), ST(ST),
       SpillSGPRToVGPR(EnableSpillSGPRToVGPR), isWave32(ST.isWave32()) {
 
void SIRegisterInfo::buildVGPRSpillLoadStore(SGPRSpillBuilder &SB, int Index,
   MachinePointerInfo PtrInfo = MachinePointerInfo::getFixedStack(SB.MF, Index);
   MachineMemOperand *MMO = SB.MF.getMachineMemOperand(
       PtrInfo, IsLoad ? MachineMemOperand::MOLoad : MachineMemOperand::MOStore,
       SB.EltSize, Alignment);
 
   if (IsLoad) {
     unsigned Opc = ST.enableFlatScratch() ? AMDGPU::SCRATCH_LOAD_DWORD_SADDR
                                           : AMDGPU::BUFFER_LOAD_DWORD_OFFSET;
-    buildSpillLoadStore(SB.MBB, SB.MI, Opc, Index, SB.TmpVGPR, false, FrameReg,
+    buildSpillLoadStore(*SB.MBB, SB.MI, Opc, Index, SB.TmpVGPR, false, FrameReg,
                         Offset * SB.EltSize, MMO, SB.RS);
   } else {
     unsigned Opc = ST.enableFlatScratch() ? AMDGPU::SCRATCH_STORE_DWORD_SADDR
                                           : AMDGPU::BUFFER_STORE_DWORD_OFFSET;
-    buildSpillLoadStore(SB.MBB, SB.MI, Opc, Index, SB.TmpVGPR, IsKill, FrameReg,
-                        Offset * SB.EltSize, MMO, SB.RS);
+    buildSpillLoadStore(*SB.MBB, SB.MI, Opc, Index, SB.TmpVGPR, IsKill,
+                        FrameReg, Offset * SB.EltSize, MMO, SB.RS);
     // This only ever adds one VGPR spill
     SB.MFI.addToSpilledVGPRs(1);
   }
 }
 
 bool SIRegisterInfo::spillSGPR(MachineBasicBlock::iterator MI,
                                int Index,
                                RegScavenger *RS,
for (unsigned i = 0, e = SB.NumSubRegs; i < e; ++i) {
               ? SB.SuperReg
               : Register(getSubReg(SB.SuperReg, SB.SplitParts[i]));
       SIMachineFunctionInfo::SpilledReg Spill = VGPRSpills[i];
 
       bool UseKill = SB.IsKill && i == SB.NumSubRegs - 1;
 
       // Mark the "old value of vgpr" input undef only if this is the first sgpr
       // spill to this specific vgpr in the first basic block.
-      auto MIB = BuildMI(SB.MBB, MI, SB.DL, SB.TII.get(AMDGPU::V_WRITELANE_B32),
-                         Spill.VGPR)
+      auto MIB = BuildMI(*SB.MBB, MI, SB.DL,
+                         SB.TII.get(AMDGPU::V_WRITELANE_B32), Spill.VGPR)
                      .addReg(SubReg, getKillRegState(UseKill))
                      .addImm(Spill.Lane)
                      .addReg(Spill.VGPR);
       if (LIS) {
         if (i == 0)
           LIS->ReplaceMachineInstrInMaps(*MI, *MIB);
         else
           LIS->InsertMachineInstrInMaps(*MIB);
for (unsigned Offset = 0; Offset < PVD.NumVGPRs; ++Offset) {
                     e = std::min((Offset + 1) * PVD.PerVGPR, SB.NumSubRegs);
            i < e; ++i) {
         Register SubReg =
             SB.NumSubRegs == 1
                 ? SB.SuperReg
                 : Register(getSubReg(SB.SuperReg, SB.SplitParts[i]));
 
         MachineInstrBuilder WriteLane =
-            BuildMI(SB.MBB, MI, SB.DL, SB.TII.get(AMDGPU::V_WRITELANE_B32),
+            BuildMI(*SB.MBB, MI, SB.DL, SB.TII.get(AMDGPU::V_WRITELANE_B32),
                     SB.TmpVGPR)
                 .addReg(SubReg, SubKillState)
                 .addImm(i % PVD.PerVGPR)
                 .addReg(SB.TmpVGPR, TmpVGPRFlags);
         TmpVGPRFlags = 0;
 
         if (LIS) {
           if (i == 0)
bool SIRegisterInfo::restoreSGPR(MachineBasicBlock::iterator MI,
   if (SpillToVGPR) {
     for (unsigned i = 0, e = SB.NumSubRegs; i < e; ++i) {
       Register SubReg =
           SB.NumSubRegs == 1
               ? SB.SuperReg
               : Register(getSubReg(SB.SuperReg, SB.SplitParts[i]));
 
       SIMachineFunctionInfo::SpilledReg Spill = VGPRSpills[i];
-      auto MIB =
-          BuildMI(SB.MBB, MI, SB.DL, SB.TII.get(AMDGPU::V_READLANE_B32), SubReg)
+      auto MIB = BuildMI(*SB.MBB, MI, SB.DL, SB.TII.get(AMDGPU::V_READLANE_B32),
+                         SubReg)
                      .addReg(Spill.VGPR)
                      .addImm(Spill.Lane);
       if (SB.NumSubRegs > 1 && i == 0)
         MIB.addReg(SB.SuperReg, RegState::ImplicitDefine);
       if (LIS) {
         if (i == e - 1)
           LIS->ReplaceMachineInstrInMaps(*MI, *MIB);
         else
           LIS->InsertMachineInstrInMaps(*MIB);
       }
for (unsigned Offset = 0; Offset < PVD.NumVGPRs; ++Offset) {
                     e = std::min((Offset + 1) * PVD.PerVGPR, SB.NumSubRegs);
            i < e; ++i) {
         Register SubReg =
             SB.NumSubRegs == 1
                 ? SB.SuperReg
                 : Register(getSubReg(SB.SuperReg, SB.SplitParts[i]));
 
         bool LastSubReg = (i + 1 == e);
-        auto MIB = BuildMI(SB.MBB, MI, SB.DL,
+        auto MIB = BuildMI(*SB.MBB, MI, SB.DL,
                            SB.TII.get(AMDGPU::V_READLANE_B32), SubReg)
                        .addReg(SB.TmpVGPR, getKillRegState(LastSubReg))
                        .addImm(i);
         if (SB.NumSubRegs > 1 && i == 0)
           MIB.addReg(SB.SuperReg, RegState::ImplicitDefine);
         if (LIS) {
           if (i == e - 1)
             LIS->ReplaceMachineInstrInMaps(*MI, *MIB);
bool SIRegisterInfo::restoreSGPR(MachineBasicBlock::iterator MI,
   MI->eraseFromParent();
 
   if (LIS)
     LIS->removeAllRegUnitsForPhysReg(SB.SuperReg);
 
   return true;
 }
 
+bool SIRegisterInfo::spillEmergencySGPR(MachineBasicBlock::iterator MI,
+                                        MachineBasicBlock &RestoreMBB,
+                                        Register SGPR, RegScavenger *RS) const {
+  SGPRSpillBuilder SB(*this, *ST.getInstrInfo(), isWave32, MI, SGPR, false, 0,
+                      RS);
+  SB.prepare();
+  // Generate the spill of SGPR to SB.TmpVGPR.
+  unsigned SubKillState = getKillRegState((SB.NumSubRegs == 1) && SB.IsKill);
+  auto PVD = SB.getPerVGPRData();
+  for (unsigned Offset = 0; Offset < PVD.NumVGPRs; ++Offset) {
+    unsigned TmpVGPRFlags = RegState::Undef;
+    // Write sub registers into the VGPR
+    for (unsigned i = Offset * PVD.PerVGPR,
+                  e = std::min((Offset + 1) * PVD.PerVGPR, SB.NumSubRegs);
+         i < e; ++i) {
+      Register SubReg =
+          SB.NumSubRegs == 1
+              ? SB.SuperReg
+              : Register(getSubReg(SB.SuperReg, SB.SplitParts[i]));
+
+      MachineInstrBuilder WriteLane =
+          BuildMI(*SB.MBB, MI, SB.DL, SB.TII.get(AMDGPU::V_WRITELANE_B32),
+                  SB.TmpVGPR)
+              .addReg(SubReg, SubKillState)
+              .addImm(i % PVD.PerVGPR)
+              .addReg(SB.TmpVGPR, TmpVGPRFlags);
+      TmpVGPRFlags = 0;
+      // There could be undef components of a spilled super register.
+      // TODO: Can we detect this and skip the spill?
+      if (SB.NumSubRegs > 1) {
+        // The last implicit use of the SB.SuperReg carries the "Kill" flag.
+        unsigned SuperKillState = 0;
+        if (i + 1 == SB.NumSubRegs)
+          SuperKillState |= getKillRegState(SB.IsKill);
+        WriteLane.addReg(SB.SuperReg, RegState::Implicit | SuperKillState);
+      }
+    }
+    // Don't need to write VGPR out.
+  }
+
+  // Restore clobbered registers in the specified restore block.
+  MI = RestoreMBB.end();
+  SB.setMI(&RestoreMBB, MI);
+  // Generate the restore of SGPR from SB.TmpVGPR.
+  for (unsigned Offset = 0; Offset < PVD.NumVGPRs; ++Offset) {
+    // Don't need to load VGPR in.
+    // Unpack lanes
+    for (unsigned i = Offset * PVD.PerVGPR,
+                  e = std::min((Offset + 1) * PVD.PerVGPR, SB.NumSubRegs);
+         i < e; ++i) {
+      Register SubReg =
+          SB.NumSubRegs == 1
+              ? SB.SuperReg
+              : Register(getSubReg(SB.SuperReg, SB.SplitParts[i]));
+      bool LastSubReg = (i + 1 == e);
+      auto MIB = BuildMI(*SB.MBB, MI, SB.DL, SB.TII.get(AMDGPU::V_READLANE_B32),
+                         SubReg)
+                     .addReg(SB.TmpVGPR, getKillRegState(LastSubReg))
+                     .addImm(i);
+      if (SB.NumSubRegs > 1 && i == 0)
+        MIB.addReg(SB.SuperReg, RegState::ImplicitDefine);
+    }
+  }
+  SB.restore();
+
+  SB.MFI.addToSpilledSGPRs(SB.NumSubRegs);
+  return false;
+}
+
 /// Special case of eliminateFrameIndex. Returns true if the SGPR was spilled to
 /// a VGPR and the stack slot can be safely eliminated when all other users are
 /// handled.
 bool SIRegisterInfo::eliminateSGPRToVGPRSpillFrameIndex(
   MachineBasicBlock::iterator MI,
   int FI,
   RegScavenger *RS,
   LiveIntervals *LIS) const {

llvm/lib/Target/AVR/AVRInstrInfo.h

public:
   bool
   reverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const override;
 
   MachineBasicBlock *getBranchDestBlock(const MachineInstr &MI) const override;
 
   bool isBranchOffsetInRange(unsigned BranchOpc,
                              int64_t BrOffset) const override;
 
-  unsigned insertIndirectBranch(MachineBasicBlock &MBB,
-                                MachineBasicBlock &NewDestBB,
-                                const DebugLoc &DL,
-                                int64_t BrOffset,
-                                RegScavenger *RS) const override;
+  void insertIndirectBranch(MachineBasicBlock &MBB,
+                            MachineBasicBlock &RestoreBB, const DebugLoc &DL,
+                            int64_t BrOffset, RegScavenger *RS) const override;
+
 private:
   const AVRRegisterInfo RI;
 };
 
 } // end namespace llvm
 
 #endif // LLVM_AVR_INSTR_INFO_H

llvm/lib/Target/AVR/AVRInstrInfo.cpp

bool AVRInstrInfo::isBranchOffsetInRange(unsigned BranchOp,
   case AVR::BRMIk:
   case AVR::BRPLk:
   case AVR::BRGEk:
   case AVR::BRLTk:
     return isIntN(7, BrOffset);
   }
 }
 
-unsigned AVRInstrInfo::insertIndirectBranch(MachineBasicBlock &MBB,
-                                            MachineBasicBlock &NewDestBB,
-                                            const DebugLoc &DL,
-                                            int64_t BrOffset,
-                                            RegScavenger *RS) const {
-    // This method inserts a *direct* branch (JMP), despite its name.
-    // LLVM calls this method to fixup unconditional branches; it never calls
-    // insertBranch or some hypothetical "insertDirectBranch".
-    // See lib/CodeGen/RegisterRelaxation.cpp for details.
-    // We end up here when a jump is too long for a RJMP instruction.
-    auto &MI = *BuildMI(&MBB, DL, get(AVR::JMPk)).addMBB(&NewDestBB);
+void AVRInstrInfo::insertIndirectBranch(MachineBasicBlock &MBB,
+                                        MachineBasicBlock &RestoreBB,
+                                        const DebugLoc &DL, int64_t BrOffset,
+  BuildMI(&MBB, DL, get(AVR::JMPk)).addMBB(&NewDestBB);
 
-    return getInstSizeInBytes(MI);
+  return;
 }
 
 } // end of namespace llvm
-

llvm/lib/Target/RISCV/RISCVInstrInfo.h

bool analyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
                      SmallVectorImpl<MachineOperand> &Cond,
                      bool AllowModify) const override;
 
   unsigned insertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
                         MachineBasicBlock *FBB, ArrayRef<MachineOperand> Cond,
                         const DebugLoc &dl,
                         int *BytesAdded = nullptr) const override;
 
-  unsigned insertIndirectBranch(MachineBasicBlock &MBB,
-                                MachineBasicBlock &NewDestBB,
-                                const DebugLoc &DL, int64_t BrOffset,
-                                RegScavenger *RS = nullptr) const override;
+  void insertIndirectBranch(MachineBasicBlock &MBB,
+                            MachineBasicBlock &RestoreBB, const DebugLoc &DL,
+                            int64_t BrOffset, RegScavenger *RS) const override;
 
   unsigned removeBranch(MachineBasicBlock &MBB,
                         int *BytesRemoved = nullptr) const override;
 
   bool
   reverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const override;
 
   MachineBasicBlock *getBranchDestBlock(const MachineInstr &MI) const override;

llvm/lib/Target/RISCV/RISCVInstrInfo.cpp

unsigned RISCVInstrInfo::insertBranch(
 
   // Two-way conditional branch.
   MachineInstr &MI = *BuildMI(&MBB, DL, get(RISCV::PseudoBR)).addMBB(FBB);
   if (BytesAdded)
     *BytesAdded += getInstSizeInBytes(MI);
   return 2;
 }
 
-unsigned RISCVInstrInfo::insertIndirectBranch(MachineBasicBlock &MBB,
-                                              MachineBasicBlock &DestBB,
-                                              const DebugLoc &DL,
-                                              int64_t BrOffset,
-                                              RegScavenger *RS) const {
+void RISCVInstrInfo::insertIndirectBranch(MachineBasicBlock &MBB,
+                                          MachineBasicBlock &RestoreBB,
+                                          const DebugLoc &DL, int64_t BrOffset,
   assert(RS && "RegScavenger required for long branching");
   assert(MBB.empty() &&
          "new block should be inserted for expanding unconditional branch");
   assert(MBB.pred_size() == 1);
 
   MachineFunction *MF = MBB.getParent();
   MachineRegisterInfo &MRI = MF->getRegInfo();
 
MachineInstr &MI = *BuildMI(MBB, II, DL, get(RISCV::PseudoJump))
                           .addMBB(&DestBB, RISCVII::MO_CALL);
 
   RS->enterBasicBlockEnd(MBB);
   unsigned Scav = RS->scavengeRegisterBackwards(RISCV::GPRRegClass,
                                                 MI.getIterator(), false, 0);
   MRI.replaceRegWith(ScratchReg, Scav);
   MRI.clearVirtRegs();
   RS->setRegUsed(Scav);
-  return 8;
+  // TODO: The case when there is no scavenged register needs special handling.
+  return;
 }
 
 bool RISCVInstrInfo::reverseBranchCondition(
     SmallVectorImpl<MachineOperand> &Cond) const {
   assert((Cond.size() == 3) && "Invalid branch condition!");
   Cond[0].setImm(getOppositeBranchOpcode(Cond[0].getImm()));
   return false;
 }

llvm/test/CodeGen/AMDGPU/branch-relax-spill.ll

-; RUN: not --crash llc -march=amdgcn -mcpu=tahiti -verify-machineinstrs  -amdgpu-s-branch-bits=4 < %s 2>&1 | FileCheck -check-prefix=FAIL %s
-
-; FIXME: This should be able to compile, but requires inserting an
-; extra block to restore the scavenged register.
-
-; FAIL: LLVM ERROR: Error while trying to spill SGPR0_SGPR1 from class SReg_64: Cannot scavenge register without an emergency spill slot!
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -march=amdgcn -mcpu=tahiti -verify-machineinstrs -amdgpu-s-branch-bits=5 -o - %s | FileCheck %s
 
 define amdgpu_kernel void @spill(i32 addrspace(1)* %arg, i32 %cnd) #0 {
+; CHECK-LABEL: spill:
+; CHECK:       ; %bb.0: ; %entry
+; CHECK-NEXT:    s_mov_b32 s96, SCRATCH_RSRC_DWORD0
+; CHECK-NEXT:    s_mov_b32 s97, SCRATCH_RSRC_DWORD1
+; CHECK-NEXT:    s_load_dword s44, s[0:1], 0xb
+; CHECK-NEXT:    s_mov_b32 s98, -1
+; CHECK-NEXT:    s_mov_b32 s99, 0xe8f000
+; CHECK-NEXT:    s_add_u32 s96, s96, s3
+; CHECK-NEXT:    s_addc_u32 s97, s97, 0
+; CHECK-NEXT:    s_waitcnt lgkmcnt(0)
+; CHECK-NEXT:    s_cmp_eq_u32 s44, 0
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s0, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s1, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s2, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s3, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s4, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s5, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s6, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s7, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s8, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s9, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s10, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s11, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s12, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s13, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s14, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s15, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s16, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s17, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s18, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s19, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s20, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s21, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s22, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s23, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s24, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s25, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s26, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s27, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s28, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s29, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s30, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s31, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s32, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s33, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s34, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s35, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s36, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s37, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s38, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s39, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s40, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s41, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s42, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s43, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s44, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s45, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s46, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s47, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s48, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s49, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s50, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s51, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s52, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s53, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s54, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s55, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s56, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s57, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s58, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s59, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s60, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s61, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s62, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s63, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s64, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s65, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s66, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s67, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s68, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s69, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s70, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s71, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s72, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s73, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s74, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s75, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s76, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s77, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s78, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s79, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s80, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s81, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s82, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s83, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s84, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s85, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s86, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s87, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s88, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s89, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s90, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s91, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s92, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s93, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s94, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s95, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s96, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s97, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s98, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s99, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s100, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 s101, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 vcc_lo, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    s_mov_b32 vcc_hi, 0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    s_cbranch_scc0 BB0_1
+; CHECK-NEXT:  BB0_3: ; %entry
+; CHECK-NEXT:    s_not_b64 exec, exec
+; CHECK-NEXT:    buffer_store_dword v0, off, s[96:99], 0
+; CHECK-NEXT:    v_writelane_b32 v0, s0, 0
+; CHECK-NEXT:    v_writelane_b32 v0, s1, 1
+; CHECK-NEXT:    s_getpc_b64 s[0:1]
+; CHECK-NEXT:  .Lpost_getpc0:
+; CHECK-NEXT:    s_add_u32 s0, s0, (BB0_4-.Lpost_getpc0)&4294967295
+; CHECK-NEXT:    s_addc_u32 s1, s1, (BB0_4-.Lpost_getpc0)>>32
+; CHECK-NEXT:    s_setpc_b64 s[0:1]
+; CHECK-NEXT:  BB0_1: ; %bb2
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    v_nop_e64
+; CHECK-NEXT:    v_nop_e64
+; CHECK-NEXT:    v_nop_e64
+; CHECK-NEXT:    v_nop_e64
+; CHECK-NEXT:    v_nop_e64
+; CHECK-NEXT:    v_nop_e64
+; CHECK-NEXT:    v_nop_e64
+; CHECK-NEXT:    v_nop_e64
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    s_branch BB0_2
+; CHECK-NEXT:  BB0_4: ; %bb3
+; CHECK-NEXT:    v_readlane_b32 s0, v0, 0
+; CHECK-NEXT:    v_readlane_b32 s1, v0, 1
+; CHECK-NEXT:    buffer_load_dword v0, off, s[96:99], 0
+; CHECK-NEXT:    s_not_b64 exec, exec
+; CHECK-NEXT:  BB0_2: ; %bb3
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s1
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s2
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s3
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s4
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s5
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s6
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s7
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s8
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s9
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s10
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s11
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s12
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s13
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s14
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s15
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s16
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s17
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s18
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s19
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s20
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s21
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s22
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s23
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s24
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s25
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s26
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s27
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s28
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s29
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s30
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s31
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s32
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s33
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s34
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s35
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s36
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s37
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s38
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s39
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s40
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s41
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s42
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s43
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s44
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s45
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s46
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s47
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s48
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s49
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s50
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s51
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s52
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s53
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s54
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s55
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s56
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s57
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s58
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s59
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s60
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s61
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s62
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s63
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s64
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s65
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s66
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s67
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s68
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s69
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s70
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s71
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s72
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s73
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s74
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s75
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s76
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s77
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s78
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s79
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s80
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s81
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s82
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s83
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s84
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s85
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s86
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s87
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s88
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s89
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s90
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s91
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s92
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s93
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s94
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s95
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s96
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s97
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s98
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s99
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s100
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use s101
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use vcc_lo
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; reg use vcc_hi
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    s_endpgm
 entry:
   %sgpr0 = tail call i32 asm sideeffect "s_mov_b32 s0, 0", "={s0}"() #0
   %sgpr1 = tail call i32 asm sideeffect "s_mov_b32 s1, 0", "={s1}"() #0
   %sgpr2 = tail call i32 asm sideeffect "s_mov_b32 s2, 0", "={s2}"() #0
   %sgpr3 = tail call i32 asm sideeffect "s_mov_b32 s3, 0", "={s3}"() #0
   %sgpr4 = tail call i32 asm sideeffect "s_mov_b32 s4, 0", "={s4}"() #0
   %sgpr5 = tail call i32 asm sideeffect "s_mov_b32 s5, 0", "={s5}"() #0
   %sgpr6 = tail call i32 asm sideeffect "s_mov_b32 s6, 0", "={s6}"() #0
entry:
   %sgpr99 = tail call i32 asm sideeffect "s_mov_b32 s99, 0", "={s99}"() #0
   %sgpr100 = tail call i32 asm sideeffect "s_mov_b32 s100, 0", "={s100}"() #0
   %sgpr101 = tail call i32 asm sideeffect "s_mov_b32 s101, 0", "={s101}"() #0
   %vcc_lo = tail call i32 asm sideeffect "s_mov_b32 $0, 0", "={vcc_lo}"() #0
   %vcc_hi = tail call i32 asm sideeffect "s_mov_b32 $0, 0", "={vcc_hi}"() #0
   %cmp = icmp eq i32 %cnd, 0
   br i1 %cmp, label %bb3, label %bb2 ; +8 dword branch
 
-bb2: ; 28 bytes
-  ; 24 byte asm
+bb2: ; 68 bytes
+  ; 64 byte asm
   call void asm sideeffect
    "v_nop_e64
     v_nop_e64
     v_nop_e64
+    v_nop_e64
+    v_nop_e64
+    v_nop_e64
+    v_nop_e64
     v_nop_e64",""() #0
   br label %bb3
 
 bb3:
   tail call void asm sideeffect "; reg use $0", "{s0}"(i32 %sgpr0) #0
   tail call void asm sideeffect "; reg use $0", "{s1}"(i32 %sgpr1) #0
   tail call void asm sideeffect "; reg use $0", "{s2}"(i32 %sgpr2) #0
   tail call void asm sideeffect "; reg use $0", "{s3}"(i32 %sgpr3) #0