Cleanup now that frame index scavenging via post-pass is working for ARM and Thumb2.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85406 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/ARM/ARMBaseRegisterInfo.cpp

@@ -40,11 +40,6 @@
 #include "llvm/Support/CommandLine.h"
 using namespace llvm;
 
-static cl::opt<bool>
-ScavengeFrameIndexVals("arm-virtual-frame-index-vals", cl::Hidden,
-          cl::init(true),
-          cl::desc("Resolve frame index values via scavenging in PEI"));
-
 static cl::opt<bool>
 ReuseFrameIndexVals("arm-reuse-frame-index-vals", cl::Hidden, cl::init(true),
           cl::desc("Reuse repeated frame index values"));
@@ -1022,7 +1017,7 @@ requiresRegisterScavenging(const MachineFunction &MF) const {
 
 bool ARMBaseRegisterInfo::
 requiresFrameIndexScavenging(const MachineFunction &MF) const {
-  return ScavengeFrameIndexVals;
+  return true;
 }
 
 // hasReservedCallFrame - Under normal circumstances, when a frame pointer is
@@ -1100,17 +1095,6 @@ eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
   MBB.erase(I);
 }
 
-/// findScratchRegister - Find a 'free' ARM register. If register scavenger
-/// is not being used, R12 is available. Otherwise, try for a call-clobbered
-/// register first and then a spilled callee-saved register if that fails.
-static
-unsigned findScratchRegister(RegScavenger *RS, const TargetRegisterClass *RC,
-                             ARMFunctionInfo *AFI) {
-  unsigned Reg = RS ? RS->FindUnusedReg(RC) : (unsigned) ARM::R12;
-  assert(!AFI->isThumb1OnlyFunction());
-  return Reg;
-}
-
 unsigned
 ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
                                          int SPAdj, int *Value,
@@ -1186,19 +1170,8 @@ ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
     // Must be addrmode4.
     MI.getOperand(i).ChangeToRegister(FrameReg, false, false, false);
   else {
-    if (!ScavengeFrameIndexVals) {
-      // Insert a set of r12 with the full address: r12 = sp + offset
-      // If the offset we have is too large to fit into the instruction, we need
-      // to form it with a series of ADDri's.  Do this by taking 8-bit chunks
-      // out of 'Offset'.
-      ScratchReg = findScratchRegister(RS, ARM::GPRRegisterClass, AFI);
-      if (ScratchReg == 0)
-        // No register is "free". Scavenge a register.
-        ScratchReg = RS->scavengeRegister(ARM::GPRRegisterClass, II, SPAdj);
-    } else {
-      ScratchReg = MF.getRegInfo().createVirtualRegister(ARM::GPRRegisterClass);
-      *Value = Offset;
-    }
+    ScratchReg = MF.getRegInfo().createVirtualRegister(ARM::GPRRegisterClass);
+    if (Value) *Value = Offset;
     if (!AFI->isThumbFunction())
       emitARMRegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg,
                               Offset, Pred, PredReg, TII);
@@ -1208,7 +1181,7 @@ ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
                              Offset, Pred, PredReg, TII);
     }
     MI.getOperand(i).ChangeToRegister(ScratchReg, false, false, true);
-    if (!ReuseFrameIndexVals || !ScavengeFrameIndexVals)
+    if (!ReuseFrameIndexVals)
       ScratchReg = 0;
   }
   return ScratchReg;

lib/Target/ARM/Thumb1RegisterInfo.cpp

@@ -76,18 +76,6 @@ Thumb1RegisterInfo::getPhysicalRegisterRegClass(unsigned Reg, EVT VT) const {
   return TargetRegisterInfo::getPhysicalRegisterRegClass(Reg, VT);
 }
 
-bool
-Thumb1RegisterInfo::requiresRegisterScavenging(const MachineFunction &MF) const {
-  return true;
-}
-
-bool
-Thumb1RegisterInfo::requiresFrameIndexScavenging(const MachineFunction &MF)
-  const {
-  return true;
-}
-
-
 bool Thumb1RegisterInfo::hasReservedCallFrame(MachineFunction &MF) const {
   const MachineFrameInfo *FFI = MF.getFrameInfo();
   unsigned CFSize = FFI->getMaxCallFrameSize();

lib/Target/ARM/Thumb1RegisterInfo.h

@@ -40,9 +40,6 @@ public:
   const TargetRegisterClass *
     getPhysicalRegisterRegClass(unsigned Reg, EVT VT = MVT::Other) const;
 
-  bool requiresRegisterScavenging(const MachineFunction &MF) const;
-  bool requiresFrameIndexScavenging(const MachineFunction &MF) const;
-
   bool hasReservedCallFrame(MachineFunction &MF) const;
 
   void eliminateCallFramePseudoInstr(MachineFunction &MF,

lib/Target/ARM/Thumb2RegisterInfo.cpp

@@ -60,8 +60,3 @@ void Thumb2RegisterInfo::emitLoadConstPool(MachineBasicBlock &MBB,
     .addReg(DestReg, getDefRegState(true), SubIdx)
     .addConstantPoolIndex(Idx).addImm((int64_t)ARMCC::AL).addReg(0);
 }
-
-bool Thumb2RegisterInfo::
-requiresRegisterScavenging(const MachineFunction &MF) const {
-  return true;
-}

lib/Target/ARM/Thumb2RegisterInfo.h

@@ -35,8 +35,6 @@ public:
                          unsigned DestReg, unsigned SubIdx, int Val,
                          ARMCC::CondCodes Pred = ARMCC::AL,
                          unsigned PredReg = 0) const;
-
-  bool requiresRegisterScavenging(const MachineFunction &MF) const;
 };
 }