From cd7f02bb43ec07e0a2bd6d90177b353c94408586 Mon Sep 17 00:00:00 2001
From: Pete Cooper <peter_cooper@apple.com>
Date: Wed, 18 Jan 2012 04:16:16 +0000
Subject: [PATCH] Fix ISD::REG_SEQUENCE to accept physical registers and change
 TwoAddressInstructionPass to insert copies for any physical reg operands of
 the REG_SEQUENCE

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148377 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SelectionDAG/InstrEmitter.cpp | 19 ++++++++++++-------
 lib/CodeGen/TwoAddressInstructionPass.cpp | 21 ++++++++++++---------
 2 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/lib/CodeGen/SelectionDAG/InstrEmitter.cpp b/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
index cb6fd53db07..fbf6d77cd7a 100644
--- a/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
+++ b/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
@@ -574,14 +574,19 @@ void InstrEmitter::EmitRegSequence(SDNode *Node,
   for (unsigned i = 1; i != NumOps; ++i) {
     SDValue Op = Node->getOperand(i);
     if ((i & 1) == 0) {
-      unsigned SubIdx = cast<ConstantSDNode>(Op)->getZExtValue();
-      unsigned SubReg = getVR(Node->getOperand(i-1), VRBaseMap);
-      const TargetRegisterClass *TRC = MRI->getRegClass(SubReg);
-      const TargetRegisterClass *SRC =
+      RegisterSDNode *R = dyn_cast<RegisterSDNode>(Node->getOperand(i-1));
+      // Skip physical registers as they don't have a vreg to get and we'll
+      // insert copies for them in TwoAddressInstructionPass anyway.
+      if (!R || !TargetRegisterInfo::isPhysicalRegister(R->getReg())) {
+        unsigned SubIdx = cast<ConstantSDNode>(Op)->getZExtValue();
+        unsigned SubReg = getVR(Node->getOperand(i-1), VRBaseMap);
+        const TargetRegisterClass *TRC = MRI->getRegClass(SubReg);
+        const TargetRegisterClass *SRC =
         TRI->getMatchingSuperRegClass(RC, TRC, SubIdx);
-      if (SRC && SRC != RC) {
-        MRI->setRegClass(NewVReg, SRC);
-        RC = SRC;
+        if (SRC && SRC != RC) {
+          MRI->setRegClass(NewVReg, SRC);
+          RC = SRC;
+        }
       }
     }
     AddOperand(MI, Op, i+1, &II, VRBaseMap, /*IsDebug=*/false,
diff --git a/lib/CodeGen/TwoAddressInstructionPass.cpp b/lib/CodeGen/TwoAddressInstructionPass.cpp
index 6a63335cf80..dc6b3420ab1 100644
--- a/lib/CodeGen/TwoAddressInstructionPass.cpp
+++ b/lib/CodeGen/TwoAddressInstructionPass.cpp
@@ -1801,25 +1801,28 @@ bool TwoAddressInstructionPass::EliminateRegSequences() {
     for (unsigned i = 1, e = MI->getNumOperands(); i < e; i += 2) {
       unsigned SrcReg = MI->getOperand(i).getReg();
       unsigned SubIdx = MI->getOperand(i+1).getImm();
-      if (MI->getOperand(i).getSubReg() ||
-          TargetRegisterInfo::isPhysicalRegister(SrcReg)) {
-        DEBUG(dbgs() << "Illegal REG_SEQUENCE instruction:" << *MI);
-        llvm_unreachable(0);
+      // DefMI of NULL means the value does not have a vreg in this block
+      // i.e., its a physical register or a subreg.
+      // In either case we force a copy to be generated.
+      MachineInstr *DefMI = NULL;
+      if (!MI->getOperand(i).getSubReg() &&
+          !TargetRegisterInfo::isPhysicalRegister(SrcReg)) {
+        DefMI = MRI->getVRegDef(SrcReg);
       }
 
-      MachineInstr *DefMI = MRI->getVRegDef(SrcReg);
-      if (DefMI->isImplicitDef()) {
+      if (DefMI && DefMI->isImplicitDef()) {
         DefMI->eraseFromParent();
         continue;
       }
       IsImpDef = false;
 
       // Remember COPY sources. These might be candidate for coalescing.
-      if (DefMI->isCopy() && DefMI->getOperand(1).getSubReg())
+      if (DefMI && DefMI->isCopy() && DefMI->getOperand(1).getSubReg())
         RealSrcs.push_back(DefMI->getOperand(1).getReg());
 
       bool isKill = MI->getOperand(i).isKill();
-      if (!Seen.insert(SrcReg) || MI->getParent() != DefMI->getParent() ||
+      if (!DefMI || !Seen.insert(SrcReg) ||
+          MI->getParent() != DefMI->getParent() ||
           !isKill || HasOtherRegSequenceUses(SrcReg, MI, MRI) ||
           !TRI->getMatchingSuperRegClass(MRI->getRegClass(DstReg),
                                          MRI->getRegClass(SrcReg), SubIdx)) {
@@ -1854,7 +1857,7 @@ bool TwoAddressInstructionPass::EliminateRegSequences() {
             .addReg(DstReg, RegState::Define, SubIdx)
             .addReg(SrcReg, getKillRegState(isKill));
         MI->getOperand(i).setReg(0);
-        if (LV && isKill)
+        if (LV && isKill && !TargetRegisterInfo::isPhysicalRegister(SrcReg))
           LV->replaceKillInstruction(SrcReg, MI, CopyMI);
         DEBUG(dbgs() << "Inserted: " << *CopyMI);
       }