1 files changed, 4 insertions, 0 deletions

diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.cpp b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
index d9b8323f4ae1..11e1c4862b41 100644
--- a/lib/Target/ARM/ARMBaseRegisterInfo.cpp
+++ b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
@@ -590,6 +590,10 @@ ARMBaseRegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
       AFI->isThumb2Function())
     MF.getRegInfo().setPhysRegUsed(ARM::R4);
 
+  // Spill LR if Thumb1 function uses variable length argument lists.
+  if (AFI->isThumb1OnlyFunction() && AFI->getVarArgsRegSaveSize() > 0)
+    MF.getRegInfo().setPhysRegUsed(ARM::LR);
+
   // Don't spill FP if the frame can be eliminated. This is determined
   // by scanning the callee-save registers to see if any is used.
   const unsigned *CSRegs = getCalleeSavedRegs();