From fee76fac2f626baea2e5cc4b69fe3859a53680eb Mon Sep 17 00:00:00 2001
From: Venkatraman Govindaraju <venkatra@cs.wisc.edu>
Date: Tue, 30 Jul 2013 19:53:10 +0000
Subject: [PATCH] [Sparc] Rewrite MBB's live-in registers for leaf functions.
 Also, add register i7 as a live-in if current function's return address is
 taken.

This revision fixes PR16269.

llvm-svn: 187433
---
 llvm/lib/Target/Sparc/SparcFrameLowering.cpp | 11 +++++++++++
 llvm/lib/Target/Sparc/SparcISelLowering.cpp  | 16 +++++++++-------
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/llvm/lib/Target/Sparc/SparcFrameLowering.cpp b/llvm/lib/Target/Sparc/SparcFrameLowering.cpp
index 7e91bc3..536e466 100644
--- a/llvm/lib/Target/Sparc/SparcFrameLowering.cpp
+++ b/llvm/lib/Target/Sparc/SparcFrameLowering.cpp
@@ -188,6 +188,17 @@ void SparcFrameLowering::remapRegsForLeafProc(MachineFunction &MF) const {
     MRI.setPhysRegUnused(reg);
   }
 
+  // Rewrite MBB's Live-ins.
+  for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
+       MBB != E; ++MBB) {
+    for (unsigned reg = SP::I0; reg <= SP::I7; ++reg) {
+      if (!MBB->isLiveIn(reg))
+        continue;
+      MBB->removeLiveIn(reg);
+      MBB->addLiveIn(reg - SP::I0 + SP::O0);
+    }
+  }
+
   assert(verifyLeafProcRegUse(&MRI));
 #ifdef XDEBUG
   MF.verify(0, "After LeafProc Remapping");
diff --git a/llvm/lib/Target/Sparc/SparcISelLowering.cpp b/llvm/lib/Target/Sparc/SparcISelLowering.cpp
index 6ddfa8c..4b0fa67 100644
--- a/llvm/lib/Target/Sparc/SparcISelLowering.cpp
+++ b/llvm/lib/Target/Sparc/SparcISelLowering.cpp
@@ -1722,20 +1722,22 @@ static SDValue LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) {
   return FrameAddr;
 }
 
-static SDValue LowerRETURNADDR(SDValue Op, SelectionDAG &DAG) {
-  MachineFrameInfo *MFI = DAG.getMachineFunction().getFrameInfo();
+static SDValue LowerRETURNADDR(SDValue Op, SelectionDAG &DAG,
+                               const SparcTargetLowering &TLI) {
+  MachineFunction &MF = DAG.getMachineFunction();
+  MachineFrameInfo *MFI = MF.getFrameInfo();
   MFI->setReturnAddressIsTaken(true);
 
   EVT VT = Op.getValueType();
   SDLoc dl(Op);
-  unsigned RetReg = SP::I7;
-
   uint64_t depth = Op.getConstantOperandVal(0);
 
   SDValue RetAddr;
-  if (depth == 0)
+  if (depth == 0) {
+    unsigned RetReg = MF.addLiveIn(SP::I7,
+                                   TLI.getRegClassFor(TLI.getPointerTy()));
     RetAddr = DAG.getCopyFromReg(DAG.getEntryNode(), dl, RetReg, VT);
-  else {
+  } else {
     // Need frame address to find return address of the caller.
     MFI->setFrameAddressIsTaken(true);
 
@@ -1793,7 +1795,7 @@ LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   case ISD::FNEG:
   case ISD::FABS:               return LowerF64Op(Op, DAG);
 
-  case ISD::RETURNADDR:         return LowerRETURNADDR(Op, DAG);
+  case ISD::RETURNADDR:         return LowerRETURNADDR(Op, DAG, *this);
   case ISD::FRAMEADDR:          return LowerFRAMEADDR(Op, DAG);
   case ISD::GlobalTLSAddress:
     llvm_unreachable("TLS not implemented for Sparc.");
-- 
2.7.4