From eebaeff994a1a66e4ea4377f7a74b507521b62a4 Mon Sep 17 00:00:00 2001
From: cdevadas <cdevadas@amd.com>
Date: Mon, 24 Jun 2019 16:54:32 +0530
Subject: [PATCH] Fixing the liveset computation in the epilogue code.

---
 lib/Target/AMDGPU/SIFrameLowering.cpp | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/lib/Target/AMDGPU/SIFrameLowering.cpp b/lib/Target/AMDGPU/SIFrameLowering.cpp
index 11d41775421ac..7a10de4686bf2 100644
--- a/lib/Target/AMDGPU/SIFrameLowering.cpp
+++ b/lib/Target/AMDGPU/SIFrameLowering.cpp
@@ -681,7 +681,18 @@ void SIFrameLowering::emitEpilogue(MachineFunction &MF,
     if (ScratchExecCopy == AMDGPU::NoRegister) {
       // See emitPrologue
       LivePhysRegs LiveRegs(*ST.getRegisterInfo());
-      LiveRegs.addLiveIns(MBB);
+      LiveRegs.addLiveOuts(MBB);
+
+      // Step-backwards until the insertion point
+      // to get the live registers.
+      for (MachineInstr &MI : llvm::reverse(MBB)){
+        for (const MachineOperand &MO : MI.operands()) {
+          if (MO.isReg())
+            LiveRegs.addReg(MO.getReg());
+        }
+        if (MI == MBBI)
+          break;
+      }
 
       ScratchExecCopy
         = findScratchNonCalleeSaveRegister(MF, LiveRegs,