diff options
| -rw-r--r-- | llvm/lib/Target/X86/X86FrameLowering.cpp | 18 | ||||
| -rw-r--r-- | llvm/test/CodeGen/X86/no-prolog-kill.ll | 21 |
2 files changed, 36 insertions, 3 deletions
diff --git a/llvm/lib/Target/X86/X86FrameLowering.cpp b/llvm/lib/Target/X86/X86FrameLowering.cpp index ab219f680ba..10a15e1a375 100644 --- a/llvm/lib/Target/X86/X86FrameLowering.cpp +++ b/llvm/lib/Target/X86/X86FrameLowering.cpp @@ -1893,17 +1893,29 @@ bool X86FrameLowering::spillCalleeSavedRegisters( if (!X86::GR64RegClass.contains(Reg) && !X86::GR32RegClass.contains(Reg)) continue; - bool isLiveIn = MF.getRegInfo().isLiveIn(Reg); + const MachineRegisterInfo &MRI = MF.getRegInfo(); + bool isLiveIn = MRI.isLiveIn(Reg); if (!isLiveIn) MBB.addLiveIn(Reg); + // Decide whether we can add a kill flag to the use. + bool CanKill = !isLiveIn; + // Check if any subregister is live-in + if (CanKill) { + for (MCRegAliasIterator AReg(Reg, TRI, false); AReg.isValid(); ++AReg) { + if (MRI.isLiveIn(*AReg)) { + CanKill = false; + break; + } + } + } + // Do not set a kill flag on values that are also marked as live-in. This // happens with the @llvm-returnaddress intrinsic and with arguments // passed in callee saved registers. // Omitting the kill flags is conservatively correct even if the live-in // is not used after all. - bool isKill = !isLiveIn; - BuildMI(MBB, MI, DL, TII.get(Opc)).addReg(Reg, getKillRegState(isKill)) + BuildMI(MBB, MI, DL, TII.get(Opc)).addReg(Reg, getKillRegState(CanKill)) .setMIFlag(MachineInstr::FrameSetup); } diff --git a/llvm/test/CodeGen/X86/no-prolog-kill.ll b/llvm/test/CodeGen/X86/no-prolog-kill.ll new file mode 100644 index 00000000000..f625f315bb7 --- /dev/null +++ b/llvm/test/CodeGen/X86/no-prolog-kill.ll @@ -0,0 +1,21 @@ +; RUN: llc -verify-machineinstrs -o - %s | FileCheck %s +target triple = "x86_64--" + +; This function gets a AL live-in and at same time saves+restores RAX. We must +; not add a kill flag to the "PUSHQ %rax" or the machine verifier will complain. +; CHECK-LABEL: test: +; CHECK: pushq %rax +; CHECK: testb %al, %al +; CHECK: je .LBB +define void @test(i64 %a, i8* %b, ...) { +entry: + %bar = alloca i8 + call void @llvm.va_start(i8* %bar) + call void @llvm.eh.unwind.init() + call void @llvm.eh.return.i64(i64 %a, i8* %b) + unreachable +} + +declare void @llvm.eh.return.i64(i64, i8*) +declare void @llvm.eh.unwind.init() +declare void @llvm.va_start(i8*) |
