Index: llvm/lib/Target/AMDGPU/SIFormMemoryClauses.cpp =================================================================== --- llvm/lib/Target/AMDGPU/SIFormMemoryClauses.cpp +++ llvm/lib/Target/AMDGPU/SIFormMemoryClauses.cpp @@ -317,6 +317,7 @@ MF.getFunction(), "amdgpu-max-memory-clause", MaxClause); for (MachineBasicBlock &MBB : MF) { + GCNDownwardRPTracker RPT(*LIS); MachineBasicBlock::instr_iterator Next; for (auto I = MBB.instr_begin(), E = MBB.instr_end(); I != E; I = Next) { MachineInstr &MI = *I; @@ -327,12 +328,17 @@ if (!isValidClauseInst(MI, IsVMEM)) continue; - RegUse Defs, Uses; - GCNDownwardRPTracker RPT(*LIS); - RPT.reset(MI); + if (!RPT.getNext().isValid()) + RPT.reset(MI); + else // Advance the state to the current MI. + RPT.advance(MachineBasicBlock::const_iterator(MI)); - if (!processRegUses(MI, Defs, Uses, RPT)) + const GCNRPTracker::LiveRegSet LiveRegsCopy(RPT.getLiveRegs()); + RegUse Defs, Uses; + if (!processRegUses(MI, Defs, Uses, RPT)) { + RPT.reset(MI, &LiveRegsCopy); continue; + } unsigned Length = 1; for ( ; Next != E && Length < FuncMaxClause; ++Next) { @@ -347,8 +353,10 @@ ++Length; } - if (Length < 2) + if (Length < 2) { + RPT.reset(MI, &LiveRegsCopy); continue; + } Changed = true; MFI->limitOccupancy(LastRecordedOccupancy); @@ -356,6 +364,9 @@ auto B = BuildMI(MBB, I, DebugLoc(), TII->get(TargetOpcode::BUNDLE)); Ind->insertMachineInstrInMaps(*B); + // Restore the state after processing the bundle. + RPT.reset(*B, &LiveRegsCopy); + for (auto BI = I; BI != Next; ++BI) { BI->bundleWithPred(); Ind->removeSingleMachineInstrFromMaps(*BI);