Index: lib/Target/AMDGPU/SIInstrInfo.h =================================================================== --- lib/Target/AMDGPU/SIInstrInfo.h +++ lib/Target/AMDGPU/SIInstrInfo.h @@ -441,7 +441,7 @@ void LoadM0(MachineInstr *MoveRel, MachineBasicBlock::iterator I, unsigned SavReg, unsigned IndexReg) const; - void insertNOPs(MachineBasicBlock::iterator MI, int Count) const; + void insertWaitStates(MachineBasicBlock::iterator MI, int Count) const; /// \brief Returns the operand named \p Op. If \p MI does not have an /// operand named \c Op, this function returns nullptr. Index: lib/Target/AMDGPU/SIInstrInfo.cpp =================================================================== --- lib/Target/AMDGPU/SIInstrInfo.cpp +++ lib/Target/AMDGPU/SIInstrInfo.cpp @@ -742,8 +742,8 @@ return TmpReg; } -void SIInstrInfo::insertNOPs(MachineBasicBlock::iterator MI, - int Count) const { +void SIInstrInfo::insertWaitStates(MachineBasicBlock::iterator MI, + int Count) const { while (Count > 0) { int Arg; if (Count >= 8) Index: lib/Target/AMDGPU/SIRegisterInfo.cpp =================================================================== --- lib/Target/AMDGPU/SIRegisterInfo.cpp +++ lib/Target/AMDGPU/SIRegisterInfo.cpp @@ -331,16 +331,17 @@ // TODO: only do this when it is needed switch (MF->getSubtarget().getGeneration()) { case AMDGPUSubtarget::SOUTHERN_ISLANDS: - // "VALU writes SGPR" -> "SMRD reads that SGPR" needs "S_NOP 3" on SI - TII->insertNOPs(MI, 3); + // "VALU writes SGPR" -> "SMRD reads that SGPR" needs 4 wait states + // ("S_NOP 3") on SI + TII->insertWaitStates(MI, 4); break; case AMDGPUSubtarget::SEA_ISLANDS: break; default: // VOLCANIC_ISLANDS and later - // "VALU writes SGPR -> VMEM reads that SGPR" needs "S_NOP 4" on VI - // and later. This also applies to VALUs which write VCC, but we're - // unlikely to see VMEM use VCC. - TII->insertNOPs(MI, 4); + // "VALU writes SGPR -> VMEM reads that SGPR" needs 5 wait states + // ("S_NOP 4") on VI and later. This also applies to VALUs which write + // VCC, but we're unlikely to see VMEM use VCC. + TII->insertWaitStates(MI, 5); } MI->eraseFromParent();