Use a command-line option to turn register scavenging on/off for PPC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47915 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 51 insertions, 39 deletions

diff --git a/lib/Target/PowerPC/PPCInstrInfo.cpp b/lib/Target/PowerPC/PPCInstrInfo.cpp
index afaf8da..d8f6015 100644
--- a/lib/Target/PowerPC/PPCInstrInfo.cpp
+++ b/lib/Target/PowerPC/PPCInstrInfo.cpp
@@ -19,8 +19,11 @@
 #include "PPCTargetMachine.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/Support/CommandLine.h"
 using namespace llvm;
 
+extern cl::opt<bool> EnablePPCRS;  // FIXME (64-bit): See PPCRegisterInfo.cpp.
+
 PPCInstrInfo::PPCInstrInfo(PPCTargetMachine &tm)
   : TargetInstrInfoImpl(PPCInsts, array_lengthof(PPCInsts)), TM(tm),
     RI(*TM.getSubtargetImpl(), *this) {}
@@ -320,8 +323,7 @@ void PPCInstrInfo::copyRegToReg(MachineBasicBlock &MBB,
 static bool StoreRegToStackSlot(const TargetInstrInfo &TII,
                                 unsigned SrcReg, bool isKill, int FrameIdx,
                                 const TargetRegisterClass *RC,
-                                SmallVectorImpl<MachineInstr*> &NewMIs,
-                                bool isPPC64/*FIXME (64-bit): Remove.*/) {
+                                SmallVectorImpl<MachineInstr*> &NewMIs) {
   if (RC == PPC::GPRCRegisterClass) {
     if (SrcReg != PPC::LR) {
       NewMIs.push_back(addFrameReference(BuildMI(TII.get(PPC::STW))
@@ -353,7 +355,7 @@ static bool StoreRegToStackSlot(const TargetInstrInfo &TII,
     NewMIs.push_back(addFrameReference(BuildMI(TII.get(PPC::STFS))
                                 .addReg(SrcReg, false, false, isKill), FrameIdx));
   } else if (RC == PPC::CRRCRegisterClass) {
-    if (!isPPC64) {             // FIXME (64-bit): Enable
+    if (EnablePPCRS) {  // FIXME (64-bit): Enable
       NewMIs.push_back(addFrameReference(BuildMI(TII.get(PPC::SPILL_CR))
                                          .addReg(SrcReg, false, false, isKill),
 					 FrameIdx));
@@ -402,8 +404,7 @@ PPCInstrInfo::storeRegToStackSlot(MachineBasicBlock &MBB,
                                   const TargetRegisterClass *RC) const {
   SmallVector<MachineInstr*, 4> NewMIs;
 
-  if (StoreRegToStackSlot(*this, SrcReg, isKill, FrameIdx, RC, NewMIs,
-                 TM.getSubtargetImpl()->isPPC64()/*FIXME (64-bit): Remove.*/)) {
+  if (StoreRegToStackSlot(*this, SrcReg, isKill, FrameIdx, RC, NewMIs)) {
     PPCFunctionInfo *FuncInfo = MBB.getParent()->getInfo<PPCFunctionInfo>();
     FuncInfo->setSpillsCR();
   }
@@ -418,8 +419,8 @@ void PPCInstrInfo::storeRegToAddr(MachineFunction &MF, unsigned SrcReg,
                                   const TargetRegisterClass *RC,
                                   SmallVectorImpl<MachineInstr*> &NewMIs) const{
   if (Addr[0].isFrameIndex()) {
-    if (StoreRegToStackSlot(*this, SrcReg, isKill, Addr[0].getIndex(), RC, NewMIs,
-                 TM.getSubtargetImpl()->isPPC64()/*FIXME (64-bit): Remove.*/)) {
+    if (StoreRegToStackSlot(*this, SrcReg, isKill, Addr[0].getIndex(),
+                            RC, NewMIs)) {
       PPCFunctionInfo *FuncInfo = MF.getInfo<PPCFunctionInfo>();
       FuncInfo->setSpillsCR();
     }
diff --git a/lib/Target/PowerPC/PPCRegisterInfo.cpp b/lib/Target/PowerPC/PPCRegisterInfo.cpp
index ecb0cf8..fd82767 100644
--- a/lib/Target/PowerPC/PPCRegisterInfo.cpp
+++ b/lib/Target/PowerPC/PPCRegisterInfo.cpp
@@ -42,10 +42,16 @@
 #include <cstdlib>
 using namespace llvm;
 
+// FIXME (64-bit): Eventually enable by default.
+cl::opt<bool> EnablePPCRS("enable-ppc-regscavenger",
+			  cl::init(false),
+			  cl::desc("enable PPC register scavenger"),
+			  cl::Hidden);
+
 // FIXME (64-bit): Should be inlined.
 bool
 PPCRegisterInfo::requiresRegisterScavenging(const MachineFunction &) const {
-  return !Subtarget.isPPC64();
+  return EnablePPCRS;
 }
 
 /// getRegisterNumbering - Given the enum value for some register, e.g.
@@ -310,7 +316,8 @@ BitVector PPCRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
     Reserved.set(PPC::R13);
     Reserved.set(PPC::R31);
 
-    Reserved.set(PPC::R0);      // FIXME (64-bit): Remove
+    if (!EnablePPCRS)
+      Reserved.set(PPC::R0);    // FIXME (64-bit): Remove
 
     Reserved.set(PPC::X0);
     Reserved.set(PPC::X1);
@@ -414,7 +421,7 @@ void PPCRegisterInfo::lowerDynamicAlloc(MachineBasicBlock::iterator II,
 
   // FIXME (64-bit): Use "findScratchRegister"
   unsigned Reg;
-  if (!LP64)
+  if (EnablePPCRS)
     Reg = findScratchRegister(II, RS, RC, SPAdj);
   else
     Reg = PPC::R0;
@@ -424,10 +431,15 @@ void PPCRegisterInfo::lowerDynamicAlloc(MachineBasicBlock::iterator II,
       .addReg(PPC::R31)
       .addImm(FrameSize);
   } else if (LP64) {
-    Reg = PPC::X0;              // FIXME (64-bit): Remove.
-    BuildMI(MBB, II, TII.get(PPC::LD), Reg)
-      .addImm(0)
-      .addReg(PPC::X1);
+    if (!EnablePPCRS)
+    if (EnablePPCRS) // FIXME (64-bit): Use "true" version.
+      BuildMI(MBB, II, TII.get(PPC::LD), Reg)
+	.addImm(0)
+	.addReg(PPC::X1);
+    else
+      BuildMI(MBB, II, TII.get(PPC::LD), PPC::X0)
+	.addImm(0)
+	.addReg(PPC::X1);
   } else {
     BuildMI(MBB, II, TII.get(PPC::LWZ), Reg)
       .addImm(0)
@@ -437,17 +449,16 @@ void PPCRegisterInfo::lowerDynamicAlloc(MachineBasicBlock::iterator II,
   // Grow the stack and update the stack pointer link, then determine the
   // address of new allocated space.
   if (LP64) {
-#if 0                           // FIXME (64-bit): Enable
-    BuildMI(MBB, II, TII.get(PPC::STDUX))
-      .addReg(Reg, false, false, true)
-      .addReg(PPC::X1)
-      .addReg(MI.getOperand(1).getReg());
-#else
-    BuildMI(MBB, II, TII.get(PPC::STDUX))
-      .addReg(PPC::X0, false, false, true)
-      .addReg(PPC::X1)
-      .addReg(MI.getOperand(1).getReg());
-#endif
+    if (EnablePPCRS) // FIXME (64-bit): Use "true" version.
+      BuildMI(MBB, II, TII.get(PPC::STDUX))
+	.addReg(Reg, false, false, true)
+	.addReg(PPC::X1)
+	.addReg(MI.getOperand(1).getReg());
+    else
+      BuildMI(MBB, II, TII.get(PPC::STDUX))
+	.addReg(PPC::X0, false, false, true)
+	.addReg(PPC::X1)
+	.addReg(MI.getOperand(1).getReg());
 
     if (!MI.getOperand(1).isKill())
       BuildMI(MBB, II, TII.get(PPC::ADDI8), MI.getOperand(0).getReg())
@@ -573,11 +584,11 @@ void PPCRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
   }
 
   // Special case for pseudo-op SPILL_CR.
-  if (!Subtarget.isPPC64())     // FIXME (64-bit): Remove.
-  if (OpC == PPC::SPILL_CR) {
-    lowerCRSpilling(II, FrameIndex, SPAdj, RS);
-    return;
-  }
+  if (EnablePPCRS)  // FIXME (64-bit): Enable by default
+    if (OpC == PPC::SPILL_CR) {
+      lowerCRSpilling(II, FrameIndex, SPAdj, RS);
+      return;
+    }
 
   // Replace the FrameIndex with base register with GPR1 (SP) or GPR31 (FP).
   MI.getOperand(FIOperandNo).ChangeToRegister(hasFP(MF) ? PPC::R31 : PPC::R1,
@@ -627,7 +638,7 @@ void PPCRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
 
   // FIXME (64-bit): Use "findScratchRegister".
   unsigned SReg;
-  if (!Subtarget.isPPC64())
+  if (EnablePPCRS)
     SReg = findScratchRegister(II, RS, &PPC::GPRCRegClass, SPAdj);
   else
     SReg = PPC::R0;
@@ -879,14 +890,14 @@ PPCRegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
   // FIXME: doesn't detect whether or not we need to spill vXX, which requires
   //        r0 for now.
 
-  if (!IsPPC64)                 // FIXME (64-bit): Enable.
-  if (needsFP(MF) || spillsCR(MF)) {
-    const TargetRegisterClass *GPRC = &PPC::GPRCRegClass;
-    const TargetRegisterClass *G8RC = &PPC::G8RCRegClass;
-    const TargetRegisterClass *RC = IsPPC64 ? G8RC : GPRC;
-    RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
-                                                       RC->getAlignment()));
-  }
+  if (EnablePPCRS)  // FIXME (64-bit): Enable.
+    if (needsFP(MF) || spillsCR(MF)) {
+      const TargetRegisterClass *GPRC = &PPC::GPRCRegClass;
+      const TargetRegisterClass *G8RC = &PPC::G8RCRegClass;
+      const TargetRegisterClass *RC = IsPPC64 ? G8RC : GPRC;
+      RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
+							 RC->getAlignment()));
+    }
 }
 
 void