Fix PR14364.

This removes a const_cast hack from PPCRegisterInfo::hasReservedSpillSlot().
The proper place to save the frame index for the CR spill slot is in the
PPCFunctionInfo object, not the PPCRegisterInfo object.

No new test cases, as this just reimplements existing function.  Existing
tests such as test/CodeGen/PowerPC/crsave.ll are sufficient.

llvm-svn: 175998

lib/Target/PowerPC/PPCFrameLowering.cpp

@@ -786,7 +786,8 @@ PPCFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
   PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
   unsigned LR = RegInfo->getRARegister();
   FI->setMustSaveLR(MustSaveLR(MF, LR));
-  MF.getRegInfo().setPhysRegUnused(LR);
+  MachineRegisterInfo &MRI = MF.getRegInfo();
+  MRI.setPhysRegUnused(LR);
 
   //  Save R31 if necessary
   int FPSI = FI->getFramePointerSaveIndex();
@@ -811,6 +812,16 @@ PPCFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
     MFI->CreateFixedObject(-1 * TCSPDelta, TCSPDelta, true);
   }
 
+  // For 32-bit SVR4, allocate the nonvolatile CR spill slot iff the 
+  // function uses CR 2, 3, or 4.
+  if (!isPPC64 && !isDarwinABI && 
+      (MRI.isPhysRegUsed(PPC::CR2) ||
+       MRI.isPhysRegUsed(PPC::CR3) ||
+       MRI.isPhysRegUsed(PPC::CR4))) {
+    int FrameIdx = MFI->CreateFixedObject((uint64_t)4, (int64_t)-4, true);
+    FI->setCRSpillFrameIndex(FrameIdx);
+  }
+
   // Reserve a slot closest to SP or frame pointer if we have a dynalloc or
   // a large stack, which will require scavenging a register to materialize a
   // large offset.

lib/Target/PowerPC/PPCMachineFunctionInfo.h

@@ -71,6 +71,9 @@ class PPCFunctionInfo : public MachineFunctionInfo {
   /// register for parameter passing.
   unsigned VarArgsNumFPR;
 
+  /// CRSpillFrameIndex - FrameIndex for CR spill slot for 32-bit SVR4.
+  int CRSpillFrameIndex;
+
 public:
   explicit PPCFunctionInfo(MachineFunction &MF) 
     : FramePointerSaveIndex(0),
@@ -83,7 +86,8 @@ public:
       VarArgsFrameIndex(0),
       VarArgsStackOffset(0),
       VarArgsNumGPR(0),
-      VarArgsNumFPR(0) {}
+      VarArgsNumFPR(0),
+      CRSpillFrameIndex(0) {}
 
   int getFramePointerSaveIndex() const { return FramePointerSaveIndex; }
   void setFramePointerSaveIndex(int Idx) { FramePointerSaveIndex = Idx; }
@@ -125,6 +129,9 @@ public:
 
   unsigned getVarArgsNumFPR() const { return VarArgsNumFPR; }
   void setVarArgsNumFPR(unsigned Num) { VarArgsNumFPR = Num; }
+
+  int getCRSpillFrameIndex() const { return CRSpillFrameIndex; }
+  void setCRSpillFrameIndex(int idx) { CRSpillFrameIndex = idx; }
 };
 
 } // end of namespace llvm

lib/Target/PowerPC/PPCRegisterInfo.cpp

@@ -71,7 +71,7 @@ PPCRegisterInfo::PPCRegisterInfo(const PPCSubtarget &ST,
   : PPCGenRegisterInfo(ST.isPPC64() ? PPC::LR8 : PPC::LR,
                        ST.isPPC64() ? 0 : 1,
                        ST.isPPC64() ? 0 : 1),
-    Subtarget(ST), TII(tii), CRSpillFrameIdx(0) {
+    Subtarget(ST), TII(tii) {
   ImmToIdxMap[PPC::LD]   = PPC::LDX;    ImmToIdxMap[PPC::STD]  = PPC::STDX;
   ImmToIdxMap[PPC::LBZ]  = PPC::LBZX;   ImmToIdxMap[PPC::STB]  = PPC::STBX;
   ImmToIdxMap[PPC::LHZ]  = PPC::LHZX;   ImmToIdxMap[PPC::LHA]  = PPC::LHAX;
@@ -111,11 +111,6 @@ PPCRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
     return Subtarget.isPPC64() ? CSR_Darwin64_SaveList :
                                  CSR_Darwin32_SaveList;
 
-  // For 32-bit SVR4, also initialize the frame index associated with
-  // the CR spill slot.
-  if (!Subtarget.isPPC64())
-    CRSpillFrameIdx = 0;
-
   return Subtarget.isPPC64() ? CSR_SVR464_SaveList : CSR_SVR432_SaveList;
 }
 
@@ -450,19 +445,14 @@ PPCRegisterInfo::hasReservedSpillSlot(const MachineFunction &MF,
   // For the nonvolatile condition registers (CR2, CR3, CR4) in an SVR4
   // ABI, return true to prevent allocating an additional frame slot.
   // For 64-bit, the CR save area is at SP+8; the value of FrameIdx = 0
-  // is arbitrary and will be subsequently ignored.  For 32-bit, we must
-  // create exactly one stack slot and return its FrameIdx for all
-  // nonvolatiles.
+  // is arbitrary and will be subsequently ignored.  For 32-bit, we have
+  // previously created the stack slot if needed, so return its FrameIdx.
   if (Subtarget.isSVR4ABI() && PPC::CR2 <= Reg && Reg <= PPC::CR4) {
-    if (Subtarget.isPPC64()) {
+    if (Subtarget.isPPC64())
       FrameIdx = 0;
-    } else if (CRSpillFrameIdx) {
-      FrameIdx = CRSpillFrameIdx;
-    } else {
-      MachineFrameInfo *MFI = 
-        (const_cast<MachineFunction &>(MF)).getFrameInfo();
-      FrameIdx = MFI->CreateFixedObject((uint64_t)4, (int64_t)-4, true);
-      CRSpillFrameIdx = FrameIdx;
+    else {
+      const PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
+      FrameIdx = FI->getCRSpillFrameIndex();
     }
     return true;
   }

lib/Target/PowerPC/PPCRegisterInfo.h

@@ -30,7 +30,6 @@ class PPCRegisterInfo : public PPCGenRegisterInfo {
   std::map<unsigned, unsigned> ImmToIdxMap;
   const PPCSubtarget &Subtarget;
   const TargetInstrInfo &TII;
-  mutable int CRSpillFrameIdx;
 public:
   PPCRegisterInfo(const PPCSubtarget &SubTarget, const TargetInstrInfo &tii);