In preparation for moving ARM's TargetRegisterInfo to the TargetMachine

merge Thumb1RegisterInfo and Thumb2RegisterInfo. This will enable
us to match the TargetMachine for our TargetRegisterInfo classes.

llvm-svn: 232117

12 files changed, 105 insertions, 146 deletions

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index aa225403b43..74e8512851e 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -1991,7 +1991,7 @@ ARMTargetLowering::IsEligibleForTailCallOptimization(SDValue Callee,
   if (isCalleeStructRet || isCallerStructRet)
     return false;
 
-  // FIXME: Completely disable sibcall for Thumb1 since Thumb1RegisterInfo::
+  // FIXME: Completely disable sibcall for Thumb1 since ThumbRegisterInfo::
   // emitEpilogue is not ready for them. Thumb tail calls also use t2B, as
   // the Thumb1 16-bit unconditional branch doesn't have sufficient relocation
   // support in the assembler and linker to be used. This would need to be
diff --git a/llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp b/llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
index a8d09818978..e3412e978b0 100644
--- a/llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
+++ b/llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
@@ -19,7 +19,7 @@
 #include "ARMMachineFunctionInfo.h"
 #include "ARMSubtarget.h"
 #include "MCTargetDesc/ARMAddressingModes.h"
-#include "Thumb1RegisterInfo.h"
+#include "ThumbRegisterInfo.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallPtrSet.h"
diff --git a/llvm/lib/Target/ARM/CMakeLists.txt b/llvm/lib/Target/ARM/CMakeLists.txt
index 2530640139a..0b6981979cf 100644
--- a/llvm/lib/Target/ARM/CMakeLists.txt
+++ b/llvm/lib/Target/ARM/CMakeLists.txt
@@ -40,10 +40,9 @@ add_llvm_target(ARMCodeGen
   MLxExpansionPass.cpp
   Thumb1FrameLowering.cpp
   Thumb1InstrInfo.cpp
-  Thumb1RegisterInfo.cpp
+  ThumbRegisterInfo.cpp
   Thumb2ITBlockPass.cpp
   Thumb2InstrInfo.cpp
-  Thumb2RegisterInfo.cpp
   Thumb2SizeReduction.cpp
   )
 
diff --git a/llvm/lib/Target/ARM/README-Thumb.txt b/llvm/lib/Target/ARM/README-Thumb.txt
index f4d9be3beb6..2d031d015f3 100644
--- a/llvm/lib/Target/ARM/README-Thumb.txt
+++ b/llvm/lib/Target/ARM/README-Thumb.txt
@@ -232,7 +232,7 @@ Make use of hi register variants of cmp: tCMPhir / tCMPZhir.
 //===---------------------------------------------------------------------===//
 
 Thumb1 immediate field sometimes keep pre-scaled values. See
-Thumb1RegisterInfo::eliminateFrameIndex. This is inconsistent from ARM and
+ThumbRegisterInfo::eliminateFrameIndex. This is inconsistent from ARM and
 Thumb2.
 
 //===---------------------------------------------------------------------===//
diff --git a/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp b/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp
index 825d359727b..c496cd7c759 100644
--- a/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp
+++ b/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp
@@ -41,7 +41,7 @@ static void
 emitSPUpdate(MachineBasicBlock &MBB,
              MachineBasicBlock::iterator &MBBI,
              const TargetInstrInfo &TII, DebugLoc dl,
-             const Thumb1RegisterInfo &MRI,
+             const ThumbRegisterInfo &MRI,
              int NumBytes, unsigned MIFlags = MachineInstr::NoFlags)  {
   emitThumbRegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes, TII,
                             MRI, MIFlags);
@@ -53,8 +53,8 @@ eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
                               MachineBasicBlock::iterator I) const {
   const Thumb1InstrInfo &TII =
       *static_cast<const Thumb1InstrInfo *>(STI.getInstrInfo());
-  const Thumb1RegisterInfo *RegInfo =
-      static_cast<const Thumb1RegisterInfo *>(STI.getRegisterInfo());
+  const ThumbRegisterInfo *RegInfo =
+      static_cast<const ThumbRegisterInfo *>(STI.getRegisterInfo());
   if (!hasReservedCallFrame(MF)) {
     // If we have alloca, convert as follows:
     // ADJCALLSTACKDOWN -> sub, sp, sp, amount
@@ -89,8 +89,8 @@ void Thumb1FrameLowering::emitPrologue(MachineFunction &MF) const {
   ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
   MachineModuleInfo &MMI = MF.getMMI();
   const MCRegisterInfo *MRI = MMI.getContext().getRegisterInfo();
-  const Thumb1RegisterInfo *RegInfo =
-      static_cast<const Thumb1RegisterInfo *>(STI.getRegisterInfo());
+  const ThumbRegisterInfo *RegInfo =
+      static_cast<const ThumbRegisterInfo *>(STI.getRegisterInfo());
   const Thumb1InstrInfo &TII =
       *static_cast<const Thumb1InstrInfo *>(STI.getInstrInfo());
 
@@ -327,8 +327,8 @@ void Thumb1FrameLowering::emitEpilogue(MachineFunction &MF,
   DebugLoc dl = MBBI->getDebugLoc();
   MachineFrameInfo *MFI = MF.getFrameInfo();
   ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
-  const Thumb1RegisterInfo *RegInfo =
-      static_cast<const Thumb1RegisterInfo *>(STI.getRegisterInfo());
+  const ThumbRegisterInfo *RegInfo =
+      static_cast<const ThumbRegisterInfo *>(STI.getRegisterInfo());
   const Thumb1InstrInfo &TII =
       *static_cast<const Thumb1InstrInfo *>(STI.getInstrInfo());
 
diff --git a/llvm/lib/Target/ARM/Thumb1FrameLowering.h b/llvm/lib/Target/ARM/Thumb1FrameLowering.h
index b785b2823da..cf932035b8d 100644
--- a/llvm/lib/Target/ARM/Thumb1FrameLowering.h
+++ b/llvm/lib/Target/ARM/Thumb1FrameLowering.h
@@ -16,7 +16,7 @@
 
 #include "ARMFrameLowering.h"
 #include "Thumb1InstrInfo.h"
-#include "Thumb1RegisterInfo.h"
+#include "ThumbRegisterInfo.h"
 #include "llvm/Target/TargetFrameLowering.h"
 
 namespace llvm {
diff --git a/llvm/lib/Target/ARM/Thumb1InstrInfo.h b/llvm/lib/Target/ARM/Thumb1InstrInfo.h
index 9fba76052a1..f3f493d8923 100644
--- a/llvm/lib/Target/ARM/Thumb1InstrInfo.h
+++ b/llvm/lib/Target/ARM/Thumb1InstrInfo.h
@@ -15,13 +15,13 @@
 #define LLVM_LIB_TARGET_ARM_THUMB1INSTRINFO_H
 
 #include "ARMBaseInstrInfo.h"
-#include "Thumb1RegisterInfo.h"
+#include "ThumbRegisterInfo.h"
 
 namespace llvm {
   class ARMSubtarget;
 
 class Thumb1InstrInfo : public ARMBaseInstrInfo {
-  Thumb1RegisterInfo RI;
+  ThumbRegisterInfo RI;
 public:
   explicit Thumb1InstrInfo(const ARMSubtarget &STI);
 
@@ -36,7 +36,7 @@ public:
   /// such, whenever a client has an instance of instruction info, it should
   /// always be able to get register info as well (through this method).
   ///
-  const Thumb1RegisterInfo &getRegisterInfo() const override { return RI; }
+  const ThumbRegisterInfo &getRegisterInfo() const override { return RI; }
 
   void copyPhysReg(MachineBasicBlock &MBB,
                    MachineBasicBlock::iterator I, DebugLoc DL,
diff --git a/llvm/lib/Target/ARM/Thumb2InstrInfo.h b/llvm/lib/Target/ARM/Thumb2InstrInfo.h
index 46a1f6d600a..916ab06ec30 100644
--- a/llvm/lib/Target/ARM/Thumb2InstrInfo.h
+++ b/llvm/lib/Target/ARM/Thumb2InstrInfo.h
@@ -15,14 +15,14 @@
 #define LLVM_LIB_TARGET_ARM_THUMB2INSTRINFO_H
 
 #include "ARMBaseInstrInfo.h"
-#include "Thumb2RegisterInfo.h"
+#include "ThumbRegisterInfo.h"
 
 namespace llvm {
 class ARMSubtarget;
 class ScheduleHazardRecognizer;
 
 class Thumb2InstrInfo : public ARMBaseInstrInfo {
-  Thumb2RegisterInfo RI;
+  ThumbRegisterInfo RI;
 public:
   explicit Thumb2InstrInfo(const ARMSubtarget &STI);
 
@@ -60,7 +60,7 @@ public:
   /// such, whenever a client has an instance of instruction info, it should
   /// always be able to get register info as well (through this method).
   ///
-  const Thumb2RegisterInfo &getRegisterInfo() const override { return RI; }
+  const ThumbRegisterInfo &getRegisterInfo() const override { return RI; }
 
 private:
   void expandLoadStackGuard(MachineBasicBlock::iterator MI,
diff --git a/llvm/lib/Target/ARM/Thumb2RegisterInfo.cpp b/llvm/lib/Target/ARM/Thumb2RegisterInfo.cpp
deleted file mode 100644
index e7cab6fb880..00000000000
--- a/llvm/lib/Target/ARM/Thumb2RegisterInfo.cpp
+++ /dev/null
@@ -1,51 +0,0 @@
-//===-- Thumb2RegisterInfo.cpp - Thumb-2 Register Information -------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file contains the Thumb-2 implementation of the TargetRegisterInfo
-// class.
-//
-//===----------------------------------------------------------------------===//
-
-#include "Thumb2RegisterInfo.h"
-#include "ARM.h"
-#include "ARMSubtarget.h"
-#include "llvm/CodeGen/MachineConstantPool.h"
-#include "llvm/CodeGen/MachineFunction.h"
-#include "llvm/CodeGen/MachineInstrBuilder.h"
-#include "llvm/IR/Constants.h"
-#include "llvm/IR/DerivedTypes.h"
-#include "llvm/IR/Function.h"
-#include "llvm/Target/TargetInstrInfo.h"
-#include "llvm/Target/TargetMachine.h"
-using namespace llvm;
-
-Thumb2RegisterInfo::Thumb2RegisterInfo() : ARMBaseRegisterInfo() {}
-
-/// emitLoadConstPool - Emits a load from constpool to materialize the
-/// specified immediate.
-void
-Thumb2RegisterInfo::emitLoadConstPool(MachineBasicBlock &MBB,
-                                      MachineBasicBlock::iterator &MBBI,
-                                      DebugLoc dl,
-                                      unsigned DestReg, unsigned SubIdx,
-                                      int Val,
-                                      ARMCC::CondCodes Pred, unsigned PredReg,
-                                      unsigned MIFlags) const {
-  MachineFunction &MF = *MBB.getParent();
-  const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
-  MachineConstantPool *ConstantPool = MF.getConstantPool();
-  const Constant *C = ConstantInt::get(
-           Type::getInt32Ty(MBB.getParent()->getFunction()->getContext()), Val);
-  unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
-
-  BuildMI(MBB, MBBI, dl, TII.get(ARM::t2LDRpci))
-    .addReg(DestReg, getDefRegState(true), SubIdx)
-    .addConstantPoolIndex(Idx).addImm((int64_t)ARMCC::AL).addReg(0)
-    .setMIFlags(MIFlags);
-}
diff --git a/llvm/lib/Target/ARM/Thumb2RegisterInfo.h b/llvm/lib/Target/ARM/Thumb2RegisterInfo.h
deleted file mode 100644
index c5279a98f0f..00000000000
--- a/llvm/lib/Target/ARM/Thumb2RegisterInfo.h
+++ /dev/null
@@ -1,38 +0,0 @@
-//===- Thumb2RegisterInfo.h - Thumb-2 Register Information Impl -*- C++ -*-===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file contains the Thumb-2 implementation of the TargetRegisterInfo
-// class.
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLVM_LIB_TARGET_ARM_THUMB2REGISTERINFO_H
-#define LLVM_LIB_TARGET_ARM_THUMB2REGISTERINFO_H
-
-#include "ARMBaseRegisterInfo.h"
-
-namespace llvm {
-
-class ARMSubtarget;
-
-struct Thumb2RegisterInfo : public ARMBaseRegisterInfo {
-public:
-  Thumb2RegisterInfo();
-
-  /// emitLoadConstPool - Emits a load from constpool to materialize the
-  /// specified immediate.
-  void
-  emitLoadConstPool(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
-                    DebugLoc dl, unsigned DestReg, unsigned SubIdx, int Val,
-                    ARMCC::CondCodes Pred = ARMCC::AL, unsigned PredReg = 0,
-                    unsigned MIFlags = MachineInstr::NoFlags) const override;
-};
-}
-
-#endif
diff --git a/llvm/lib/Target/ARM/Thumb1RegisterInfo.cpp b/llvm/lib/Target/ARM/ThumbRegisterInfo.cpp
index 9725e19e1d0..e70b6172b46 100644
--- a/llvm/lib/Target/ARM/Thumb1RegisterInfo.cpp
+++ b/llvm/lib/Target/ARM/ThumbRegisterInfo.cpp
@@ -1,4 +1,4 @@
-//===-- Thumb1RegisterInfo.cpp - Thumb-1 Register Information -------------===//
+//===-- ThumbRegisterInfo.cpp - Thumb-1 Register Information -------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -12,7 +12,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "Thumb1RegisterInfo.h"
+#include "ThumbRegisterInfo.h"
 #include "ARMBaseInstrInfo.h"
 #include "ARMMachineFunctionInfo.h"
 #include "ARMSubtarget.h"
@@ -38,32 +38,33 @@ extern cl::opt<bool> ReuseFrameIndexVals;
 
 using namespace llvm;
 
-Thumb1RegisterInfo::Thumb1RegisterInfo() : ARMBaseRegisterInfo() {}
+ThumbRegisterInfo::ThumbRegisterInfo() : ARMBaseRegisterInfo() {}
 
 const TargetRegisterClass *
-Thumb1RegisterInfo::getLargestLegalSuperClass(const TargetRegisterClass *RC,
+ThumbRegisterInfo::getLargestLegalSuperClass(const TargetRegisterClass *RC,
                                               const MachineFunction &MF) const {
+  if (!MF.getSubtarget<ARMSubtarget>().isThumb1Only())
+    return ARMBaseRegisterInfo::getLargestLegalSuperClass(RC, MF);
+
   if (ARM::tGPRRegClass.hasSubClassEq(RC))
     return &ARM::tGPRRegClass;
   return ARMBaseRegisterInfo::getLargestLegalSuperClass(RC, MF);
 }
 
 const TargetRegisterClass *
-Thumb1RegisterInfo::getPointerRegClass(const MachineFunction &MF, unsigned Kind)
-                                                                         const {
+ThumbRegisterInfo::getPointerRegClass(const MachineFunction &MF,
+                                      unsigned Kind) const {
+  if (!MF.getSubtarget<ARMSubtarget>().isThumb1Only())
+    return ARMBaseRegisterInfo::getPointerRegClass(MF, Kind);
   return &ARM::tGPRRegClass;
 }
 
-/// emitLoadConstPool - Emits a load from constpool to materialize the
-/// specified immediate.
-void Thumb1RegisterInfo::emitLoadConstPool(
-    MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI, DebugLoc dl,
-    unsigned DestReg, unsigned SubIdx, int Val, ARMCC::CondCodes Pred,
-    unsigned PredReg, unsigned MIFlags) const {
-  assert((isARMLowRegister(DestReg) ||
-          isVirtualRegister(DestReg)) &&
-             "Thumb1 does not have ldr to high register");
-
+static void emitThumb1LoadConstPool(MachineBasicBlock &MBB,
+                                    MachineBasicBlock::iterator &MBBI,
+                                    DebugLoc dl, unsigned DestReg,
+                                    unsigned SubIdx, int Val,
+                                    ARMCC::CondCodes Pred, unsigned PredReg,
+                                    unsigned MIFlags) {
   MachineFunction &MF = *MBB.getParent();
   const ARMSubtarget &STI = MF.getSubtarget<ARMSubtarget>();
   const TargetInstrInfo &TII = *STI.getInstrInfo();
@@ -78,6 +79,42 @@ void Thumb1RegisterInfo::emitLoadConstPool(
     .setMIFlags(MIFlags);
 }
 
+static void emitThumb2LoadConstPool(MachineBasicBlock &MBB,
+                                    MachineBasicBlock::iterator &MBBI,
+                                    DebugLoc dl, unsigned DestReg,
+                                    unsigned SubIdx, int Val,
+                                    ARMCC::CondCodes Pred, unsigned PredReg,
+                                    unsigned MIFlags) {
+  MachineFunction &MF = *MBB.getParent();
+  const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
+  MachineConstantPool *ConstantPool = MF.getConstantPool();
+  const Constant *C = ConstantInt::get(
+           Type::getInt32Ty(MBB.getParent()->getFunction()->getContext()), Val);
+  unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
+
+  BuildMI(MBB, MBBI, dl, TII.get(ARM::t2LDRpci))
+    .addReg(DestReg, getDefRegState(true), SubIdx)
+    .addConstantPoolIndex(Idx).addImm((int64_t)ARMCC::AL).addReg(0)
+    .setMIFlags(MIFlags);
+}
+
+/// emitLoadConstPool - Emits a load from constpool to materialize the
+/// specified immediate.
+void ThumbRegisterInfo::emitLoadConstPool(
+    MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI, DebugLoc dl,
+    unsigned DestReg, unsigned SubIdx, int Val, ARMCC::CondCodes Pred,
+    unsigned PredReg, unsigned MIFlags) const {
+  MachineFunction &MF = *MBB.getParent();
+  const ARMSubtarget &STI = MF.getSubtarget<ARMSubtarget>();
+  if (STI.isThumb1Only()) {
+    assert((isARMLowRegister(DestReg) || isVirtualRegister(DestReg)) &&
+           "Thumb1 does not have ldr to high register");
+    return emitThumb1LoadConstPool(MBB, MBBI, dl, DestReg, SubIdx, Val, Pred,
+                                   PredReg, MIFlags);
+  }
+  return emitThumb2LoadConstPool(MBB, MBBI, dl, DestReg, SubIdx, Val, Pred,
+                                 PredReg, MIFlags);
+}
 
 /// emitThumbRegPlusImmInReg - Emits a series of instructions to materialize
 /// a destreg = basereg + immediate in Thumb code. Materialize the immediate
@@ -312,12 +349,15 @@ static unsigned convertToNonSPOpcode(unsigned Opcode) {
   return Opcode;
 }
 
-bool Thumb1RegisterInfo::
-rewriteFrameIndex(MachineBasicBlock::iterator II, unsigned FrameRegIdx,
-                  unsigned FrameReg, int &Offset,
-                  const ARMBaseInstrInfo &TII) const {
+bool ThumbRegisterInfo::rewriteFrameIndex(MachineBasicBlock::iterator II,
+                                          unsigned FrameRegIdx,
+                                          unsigned FrameReg, int &Offset,
+                                          const ARMBaseInstrInfo &TII) const {
   MachineInstr &MI = *II;
   MachineBasicBlock &MBB = *MI.getParent();
+  const MachineFunction &MF = *MBB.getParent();
+  assert(MF.getSubtarget<ARMSubtarget>().isThumb1Only() &&
+         "This isn't needed for thumb2!");
   DebugLoc dl = MI.getDebugLoc();
   MachineInstrBuilder MIB(*MBB.getParent(), &MI);
   unsigned Opcode = MI.getOpcode();
@@ -381,10 +421,13 @@ rewriteFrameIndex(MachineBasicBlock::iterator II, unsigned FrameRegIdx,
   return Offset == 0;
 }
 
-void Thumb1RegisterInfo::resolveFrameIndex(MachineInstr &MI, unsigned BaseReg,
+void ThumbRegisterInfo::resolveFrameIndex(MachineInstr &MI, unsigned BaseReg,
                                            int64_t Offset) const {
   const MachineFunction &MF = *MI.getParent()->getParent();
   const ARMSubtarget &STI = MF.getSubtarget<ARMSubtarget>();
+  if (!STI.isThumb1Only())
+    return ARMBaseRegisterInfo::resolveFrameIndex(MI, BaseReg, Offset);
+
   const ARMBaseInstrInfo &TII = *STI.getInstrInfo();
   int Off = Offset; // ARM doesn't need the general 64-bit offsets
   unsigned i = 0;
@@ -400,18 +443,20 @@ void Thumb1RegisterInfo::resolveFrameIndex(MachineInstr &MI, unsigned BaseReg,
 
 /// saveScavengerRegister - Spill the register so it can be used by the
 /// register scavenger. Return true.
-bool
-Thumb1RegisterInfo::saveScavengerRegister(MachineBasicBlock &MBB,
-                                          MachineBasicBlock::iterator I,
-                                          MachineBasicBlock::iterator &UseMI,
-                                          const TargetRegisterClass *RC,
-                                          unsigned Reg) const {
+bool ThumbRegisterInfo::saveScavengerRegister(
+    MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
+    MachineBasicBlock::iterator &UseMI, const TargetRegisterClass *RC,
+    unsigned Reg) const {
+
+  const ARMSubtarget &STI = MBB.getParent()->getSubtarget<ARMSubtarget>();
+  if (!STI.isThumb1Only())
+    return ARMBaseRegisterInfo::saveScavengerRegister(MBB, I, UseMI, RC, Reg);
+
   // Thumb1 can't use the emergency spill slot on the stack because
   // ldr/str immediate offsets must be positive, and if we're referencing
   // off the frame pointer (if, for example, there are alloca() calls in
   // the function, the offset will be negative. Use R12 instead since that's
   // a call clobbered register that we know won't be used in Thumb1 mode.
-  const ARMSubtarget &STI = MBB.getParent()->getSubtarget<ARMSubtarget>();
   const TargetInstrInfo &TII = *STI.getInstrInfo();
   DebugLoc DL;
   AddDefaultPred(BuildMI(MBB, I, DL, TII.get(ARM::tMOVr))
@@ -450,15 +495,18 @@ Thumb1RegisterInfo::saveScavengerRegister(MachineBasicBlock &MBB,
   return true;
 }
 
-void
-Thumb1RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
-                                        int SPAdj, unsigned FIOperandNum,
-                                        RegScavenger *RS) const {
-  unsigned VReg = 0;
+void ThumbRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
+                                            int SPAdj, unsigned FIOperandNum,
+                                            RegScavenger *RS) const {
   MachineInstr &MI = *II;
   MachineBasicBlock &MBB = *MI.getParent();
   MachineFunction &MF = *MBB.getParent();
   const ARMSubtarget &STI = MF.getSubtarget<ARMSubtarget>();
+  if (!STI.isThumb1Only())
+    return ARMBaseRegisterInfo::eliminateFrameIndex(II, SPAdj, FIOperandNum,
+                                                    RS);
+
+  unsigned VReg = 0;
   const ARMBaseInstrInfo &TII = *STI.getInstrInfo();
   ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
   DebugLoc dl = MI.getDebugLoc();
diff --git a/llvm/lib/Target/ARM/Thumb1RegisterInfo.h b/llvm/lib/Target/ARM/ThumbRegisterInfo.h
index 3f99e24f2e6..23aaff37f40 100644
--- a/llvm/lib/Target/ARM/Thumb1RegisterInfo.h
+++ b/llvm/lib/Target/ARM/ThumbRegisterInfo.h
@@ -1,4 +1,4 @@
-//===- Thumb1RegisterInfo.h - Thumb-1 Register Information Impl -*- C++ -*-===//
+//===- ThumbRegisterInfo.h - Thumb Register Information Impl -*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -7,8 +7,9 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// This file contains the Thumb-1 implementation of the TargetRegisterInfo
-// class.
+// This file contains the Thumb implementation of the TargetRegisterInfo
+// class. With the exception of emitLoadConstPool Thumb2 tracks
+// ARMBaseRegisterInfo, Thumb1 overloads the functions below.
 //
 //===----------------------------------------------------------------------===//
 
@@ -22,9 +23,9 @@ namespace llvm {
   class ARMSubtarget;
   class ARMBaseInstrInfo;
 
-struct Thumb1RegisterInfo : public ARMBaseRegisterInfo {
+struct ThumbRegisterInfo : public ARMBaseRegisterInfo {
 public:
-  Thumb1RegisterInfo();
+  ThumbRegisterInfo();
 
   const TargetRegisterClass *
   getLargestLegalSuperClass(const TargetRegisterClass *RC,