diff --git a/llvm/lib/CodeGen/DeadMachineInstructionElim.cpp b/llvm/lib/CodeGen/DeadMachineInstructionElim.cpp index 64a0d2a3e5ef..4ae740e8f3f0 100644 --- a/llvm/lib/CodeGen/DeadMachineInstructionElim.cpp +++ b/llvm/lib/CodeGen/DeadMachineInstructionElim.cpp @@ -154,9 +154,24 @@ bool DeadMachineInstructionElimImpl::runImpl(MachineFunction &MF, return AnyChanges; } +SmallVector +getSimplifiableReservedRegs(const MachineRegisterInfo *MRI) { + BitVector ReservedRegs = MRI->getReservedRegs(); + SmallVector SimplifiableReservedRegs; + for (MCPhysReg PhysReg : ReservedRegs.set_bits()) { + if (MRI->canSimplifyPhysReg(PhysReg)) { + SimplifiableReservedRegs.push_back(PhysReg); + } + } + return SimplifiableReservedRegs; +} + bool DeadMachineInstructionElimImpl::eliminateDeadMI(MachineFunction &MF) { bool AnyChanges = false; + SmallVector SimplifiableReservedRegs = + getSimplifiableReservedRegs(MRI); + // Loop over all instructions in all blocks, from bottom to top, so that it's // more likely that chains of dependent but ultimately dead instructions will // be cleaned up. @@ -165,10 +180,8 @@ bool DeadMachineInstructionElimImpl::eliminateDeadMI(MachineFunction &MF) { // Reserved registers are considered always live, so consider them as // live-outs for MBB. Inside MBB, dead assignments can still be detected. - for (MCPhysReg PhysReg : MRI->getReservedRegs().set_bits()) { - if (MRI->canSimplifyPhysReg(PhysReg)) { - LivePhysRegs.addReg(PhysReg); - } + for (MCPhysReg PhysReg : SimplifiableReservedRegs) { + LivePhysRegs.addReg(PhysReg); } // Now scan the instructions and delete dead ones, tracking physreg @@ -187,6 +200,15 @@ bool DeadMachineInstructionElimImpl::eliminateDeadMI(MachineFunction &MF) { } LivePhysRegs.stepBackward(MI); + + // If the instruction is a call, ensure reserved registers are made live. + // This also ensures that reserved registers are preserved across call + // boundaries. + if (MI.isCall()) { + for (MCPhysReg PhysReg : SimplifiableReservedRegs) { + LivePhysRegs.addReg(PhysReg); + } + } } } diff --git a/llvm/test/CodeGen/AIE/aie2/live-reserved-regs-call.ll b/llvm/test/CodeGen/AIE/aie2/live-reserved-regs-call.ll index b7245818da49..5e37e33d74da 100644 --- a/llvm/test/CodeGen/AIE/aie2/live-reserved-regs-call.ll +++ b/llvm/test/CodeGen/AIE/aie2/live-reserved-regs-call.ll @@ -14,12 +14,12 @@ define void @caller1() { ; CHECK-LABEL: caller1: ; CHECK: .p2align 4 ; CHECK-NEXT: // %bb.0: // %entry -; CHECK-NEXT: nopb ; nopa ; nops ; jl #callee1; nopv -; CHECK-NEXT: nopx // Delay Slot 5 +; CHECK-NEXT: nopa ; nopb ; jl #callee1; nops +; CHECK-NEXT: nop // Delay Slot 5 ; CHECK-NEXT: paddb [sp], #32 // Delay Slot 4 ; CHECK-NEXT: st lr, [sp, #-32] // 4-byte Folded Spill Delay Slot 3 -; CHECK-NEXT: nop // Delay Slot 2 -; CHECK-NEXT: nop // Delay Slot 1 +; CHECK-NEXT: mov crSat, #1 // Delay Slot 2 +; CHECK-NEXT: mov crRnd, #12 // Delay Slot 1 ; CHECK-NEXT: lda lr, [sp, #-32] // 4-byte Folded Reload ; CHECK-NEXT: nop ; CHECK-NEXT: nop