1 files changed, 6 insertions, 20 deletions
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 10e19f92b4a63..c1ddb771e2faa 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -27781,11 +27781,16 @@ X86TargetLowering::EmitInstrWithCustomInserter(MachineInstr &MI,
         MI.getOpcode() == X86::RDFLAGS32 ? X86::PUSHF32 : X86::PUSHF64;
     unsigned Pop = MI.getOpcode() == X86::RDFLAGS32 ? X86::POP32r : X86::POP64r;
     MachineInstr *Push = BuildMI(*BB, MI, DL, TII->get(PushF));
-    // Permit reads of the FLAGS register without it being defined.
+    // Permit reads of the EFLAGS and DF registers without them being defined.
     // This intrinsic exists to read external processor state in flags, such as
     // the trap flag, interrupt flag, and direction flag, none of which are
     // modeled by the backend.
+    assert(Push->getOperand(2).getReg() == X86::EFLAGS &&
+           "Unexpected register in operand!");
     Push->getOperand(2).setIsUndef();
+    assert(Push->getOperand(3).getReg() == X86::DF &&
+           "Unexpected register in operand!");
+    Push->getOperand(3).setIsUndef();
     BuildMI(*BB, MI, DL, TII->get(Pop), MI.getOperand(0).getReg());
 
     MI.eraseFromParent(); // The pseudo is gone now.
@@ -37829,25 +37834,6 @@ bool X86TargetLowering::isTypeDesirableForOp(unsigned Opc, EVT VT) const {
   }
 }
 
-/// This function checks if any of the users of EFLAGS copies the EFLAGS. We
-/// know that the code that lowers COPY of EFLAGS has to use the stack, and if
-/// we don't adjust the stack we clobber the first frame index.
-/// See X86InstrInfo::copyPhysReg.
-static bool hasCopyImplyingStackAdjustment(const MachineFunction &MF) {
-  const MachineRegisterInfo &MRI = MF.getRegInfo();
-  return any_of(MRI.reg_instructions(X86::EFLAGS),
-                [](const MachineInstr &RI) { return RI.isCopy(); });
-}
-
-void X86TargetLowering::finalizeLowering(MachineFunction &MF) const {
-  if (hasCopyImplyingStackAdjustment(MF)) {
-    MachineFrameInfo &MFI = MF.getFrameInfo();
-    MFI.setHasCopyImplyingStackAdjustment(true);
-  }
-
-  TargetLoweringBase::finalizeLowering(MF);
-}
-
 /// This method query the target whether it is beneficial for dag combiner to
 /// promote the specified node. If true, it should return the desired promotion
 /// type by reference.