Add "Restored" flag to CalleeSavedInfo

The liveness-tracking code assumes that the registers that were saved
in the function's prolog are live outside of the function. Specifically,
that registers that were saved are also live-on-exit from the function.
This isn't always the case as illustrated by the LR register on ARM.

Differential Revision: https://reviews.llvm.org/D36160

llvm-svn: 310619

1 files changed, 2 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/LivePhysRegs.cpp b/llvm/lib/CodeGen/LivePhysRegs.cpp
index cde6ccd29df..870d8cc71c7 100644
--- a/llvm/lib/CodeGen/LivePhysRegs.cpp
+++ b/llvm/lib/CodeGen/LivePhysRegs.cpp
@@ -192,7 +192,8 @@ void LivePhysRegs::addLiveOutsNoPristines(const MachineBasicBlock &MBB) {
     const MachineFrameInfo &MFI = MF.getFrameInfo();
     if (MFI.isCalleeSavedInfoValid()) {
       for (const CalleeSavedInfo &Info : MFI.getCalleeSavedInfo())
-        addReg(Info.getReg());
+        if (Info.isRestored())
+          addReg(Info.getReg());
     }
   }
 }