diff --git a/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp b/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp index 0a29b4f79c7d0..16bbfd44ef8a9 100644 --- a/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp +++ b/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp @@ -70,49 +70,62 @@ void SystemZInstrInfo::splitMove(MachineBasicBlock::iterator MI, MachineBasicBlock *MBB = MI->getParent(); MachineFunction &MF = *MBB->getParent(); - // Get two load or store instructions. Use the original instruction for one - // of them (arbitrarily the second here) and create a clone for the other. - MachineInstr *EarlierMI = MF.CloneMachineInstr(&*MI); - MBB->insert(MI, EarlierMI); + // Get two load or store instructions. Use the original instruction for + // one of them and create a clone for the other. + MachineInstr *HighPartMI = MF.CloneMachineInstr(&*MI); + MachineInstr *LowPartMI = &*MI; + MBB->insert(LowPartMI, HighPartMI); // Set up the two 64-bit registers and remember super reg and its flags. - MachineOperand &HighRegOp = EarlierMI->getOperand(0); - MachineOperand &LowRegOp = MI->getOperand(0); + MachineOperand &HighRegOp = HighPartMI->getOperand(0); + MachineOperand &LowRegOp = LowPartMI->getOperand(0); Register Reg128 = LowRegOp.getReg(); unsigned Reg128Killed = getKillRegState(LowRegOp.isKill()); unsigned Reg128Undef = getUndefRegState(LowRegOp.isUndef()); HighRegOp.setReg(RI.getSubReg(HighRegOp.getReg(), SystemZ::subreg_h64)); LowRegOp.setReg(RI.getSubReg(LowRegOp.getReg(), SystemZ::subreg_l64)); - if (MI->mayStore()) { - // Add implicit uses of the super register in case one of the subregs is - // undefined. We could track liveness and skip storing an undefined - // subreg, but this is hopefully rare (discovered with llvm-stress). - // If Reg128 was killed, set kill flag on MI. - unsigned Reg128UndefImpl = (Reg128Undef | RegState::Implicit); - MachineInstrBuilder(MF, EarlierMI).addReg(Reg128, Reg128UndefImpl); - MachineInstrBuilder(MF, MI).addReg(Reg128, (Reg128UndefImpl | Reg128Killed)); - } - // The address in the first (high) instruction is already correct. // Adjust the offset in the second (low) instruction. - MachineOperand &HighOffsetOp = EarlierMI->getOperand(2); - MachineOperand &LowOffsetOp = MI->getOperand(2); + MachineOperand &HighOffsetOp = HighPartMI->getOperand(2); + MachineOperand &LowOffsetOp = LowPartMI->getOperand(2); LowOffsetOp.setImm(LowOffsetOp.getImm() + 8); - // Clear the kill flags on the registers in the first instruction. - if (EarlierMI->getOperand(0).isReg() && EarlierMI->getOperand(0).isUse()) - EarlierMI->getOperand(0).setIsKill(false); - EarlierMI->getOperand(1).setIsKill(false); - EarlierMI->getOperand(3).setIsKill(false); - // Set the opcodes. unsigned HighOpcode = getOpcodeForOffset(NewOpcode, HighOffsetOp.getImm()); unsigned LowOpcode = getOpcodeForOffset(NewOpcode, LowOffsetOp.getImm()); assert(HighOpcode && LowOpcode && "Both offsets should be in range"); + HighPartMI->setDesc(get(HighOpcode)); + LowPartMI->setDesc(get(LowOpcode)); + + MachineInstr *FirstMI = HighPartMI; + if (MI->mayStore()) { + FirstMI->getOperand(0).setIsKill(false); + // Add implicit uses of the super register in case one of the subregs is + // undefined. We could track liveness and skip storing an undefined + // subreg, but this is hopefully rare (discovered with llvm-stress). + // If Reg128 was killed, set kill flag on MI. + unsigned Reg128UndefImpl = (Reg128Undef | RegState::Implicit); + MachineInstrBuilder(MF, HighPartMI).addReg(Reg128, Reg128UndefImpl); + MachineInstrBuilder(MF, LowPartMI).addReg(Reg128, (Reg128UndefImpl | Reg128Killed)); + } else { + // If HighPartMI clobbers any of the address registers, it needs to come + // after LowPartMI. + auto overlapsAddressReg = [&](Register Reg) -> bool { + return RI.regsOverlap(Reg, MI->getOperand(1).getReg()) || + RI.regsOverlap(Reg, MI->getOperand(3).getReg()); + }; + if (overlapsAddressReg(HighRegOp.getReg())) { + assert(!overlapsAddressReg(LowRegOp.getReg()) && + "Both loads clobber address!"); + MBB->splice(HighPartMI, MBB, LowPartMI); + FirstMI = LowPartMI; + } + } - EarlierMI->setDesc(get(HighOpcode)); - MI->setDesc(get(LowOpcode)); + // Clear the kill flags on the address registers in the first instruction. + FirstMI->getOperand(1).setIsKill(false); + FirstMI->getOperand(3).setIsKill(false); } // Split ADJDYNALLOC instruction MI. diff --git a/llvm/test/CodeGen/SystemZ/splitMove_addressReg.mir b/llvm/test/CodeGen/SystemZ/splitMove_addressReg.mir new file mode 100644 index 0000000000000..64ed2d8f2c00a --- /dev/null +++ b/llvm/test/CodeGen/SystemZ/splitMove_addressReg.mir @@ -0,0 +1,26 @@ +# RUN: llc -mtriple=s390x-linux-gnu -run-pass=postrapseudos \ +# RUN: %s -o - -verify-machineinstrs | FileCheck %s +# +# Test that a L128 reload do not overwrite an address register prematurely +# after being split into two LGs. + +--- | + target triple = "s390x-unknown-unknown" + + define void @fun() { + ret void + } + +... + +# CHECK: name: fun + +--- +name: 'fun' +body: | + bb.0: + liveins: $r4d, $r15d + $r4q = L128 $r15d, 14920, killed $r4d + Return + +...