Eliminate the stack slot used to save the global base register.

 
The long branch pass (fixed in r160601) no longer uses the global base register
to compute addresses of branch destinations, so it is not necessary to reserve
a slot on the stack.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160703 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 12 insertions, 32 deletions

diff --git a/lib/Target/Mips/MipsISelDAGToDAG.cpp b/lib/Target/Mips/MipsISelDAGToDAG.cpp
index ea33b74a75..87a9efca74 100644
--- a/lib/Target/Mips/MipsISelDAGToDAG.cpp
+++ b/lib/Target/Mips/MipsISelDAGToDAG.cpp
@@ -117,28 +117,23 @@ private:
 void MipsDAGToDAGISel::InitGlobalBaseReg(MachineFunction &MF) {
   MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
 
-  if (((MF.getTarget().getRelocationModel() == Reloc::Static) ||
-       Subtarget.inMips16Mode()) && !MipsFI->globalBaseRegSet())
+  if (!MipsFI->globalBaseRegSet())
     return;
 
   MachineBasicBlock &MBB = MF.front();
   MachineBasicBlock::iterator I = MBB.begin();
   MachineRegisterInfo &RegInfo = MF.getRegInfo();
-  const MipsRegisterInfo *TargetRegInfo = TM.getRegisterInfo();
-  const MipsInstrInfo *MII = TM.getInstrInfo();
   const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
   DebugLoc DL = I != MBB.end() ? I->getDebugLoc() : DebugLoc();
   unsigned V0, V1, V2, GlobalBaseReg = MipsFI->getGlobalBaseReg();
-  int FI = 0;
+  const TargetRegisterClass *RC;
 
-  FI= MipsFI->initGlobalRegFI();
-
-  const TargetRegisterClass *RC = Subtarget.isABI_N64() ?
-    (const TargetRegisterClass*)&Mips::CPU64RegsRegClass :
-    (const TargetRegisterClass*)&Mips::CPURegsRegClass;
-
-  if (Subtarget.inMips16Mode())
-    RC=(const TargetRegisterClass*)&Mips::CPU16RegsRegClass;
+  if (Subtarget.isABI_N64())
+    RC = (const TargetRegisterClass*)&Mips::CPU64RegsRegClass;
+  else if (Subtarget.inMips16Mode())
+    RC = (const TargetRegisterClass*)&Mips::CPU16RegsRegClass;
+  else
+    RC = (const TargetRegisterClass*)&Mips::CPURegsRegClass;
 
   V0 = RegInfo.createVirtualRegister(RC);
   V1 = RegInfo.createVirtualRegister(RC);
@@ -158,23 +153,17 @@ void MipsDAGToDAGISel::InitGlobalBaseReg(MachineFunction &MF) {
       .addReg(Mips::T9_64);
     BuildMI(MBB, I, DL, TII.get(Mips::DADDiu), GlobalBaseReg).addReg(V1)
       .addGlobalAddress(FName, 0, MipsII::MO_GPOFF_LO);
-    MII->storeRegToStackSlot(MBB, I, GlobalBaseReg, false, FI, RC,
-                             TargetRegInfo);
     return;
   }
 
   if (Subtarget.inMips16Mode()) {
     BuildMI(MBB, I, DL, TII.get(Mips::LiRxImmX16), V0)
-        .addExternalSymbol("_gp_disp", MipsII::MO_ABS_HI);
-    BuildMI(MBB, I, DL, TII.get(Mips::AddiuRxPcImmX16),
-            V1)
-        .addExternalSymbol("_gp_disp", MipsII::MO_ABS_LO);
-    BuildMI(MBB, I, DL, TII.get(Mips::SllX16),
-            V2 ).addReg(V0).addImm(16);
+      .addExternalSymbol("_gp_disp", MipsII::MO_ABS_HI);
+    BuildMI(MBB, I, DL, TII.get(Mips::AddiuRxPcImmX16), V1)
+      .addExternalSymbol("_gp_disp", MipsII::MO_ABS_LO);
+    BuildMI(MBB, I, DL, TII.get(Mips::SllX16), V2).addReg(V0).addImm(16);
     BuildMI(MBB, I, DL, TII.get(Mips::AdduRxRyRz16), GlobalBaseReg)
       .addReg(V1).addReg(V2);
-
-
     return;
   }
 
@@ -203,19 +192,11 @@ void MipsDAGToDAGISel::InitGlobalBaseReg(MachineFunction &MF) {
     BuildMI(MBB, I, DL, TII.get(Mips::ADDu), V1).addReg(V0).addReg(Mips::T9);
     BuildMI(MBB, I, DL, TII.get(Mips::ADDiu), GlobalBaseReg).addReg(V1)
       .addGlobalAddress(FName, 0, MipsII::MO_GPOFF_LO);
-    MII->storeRegToStackSlot(MBB, I, GlobalBaseReg, false, FI, RC,
-                             TargetRegInfo);
     return;
   }
 
   assert(Subtarget.isABI_O32());
 
-
-  //if (Subtarget.inMips16Mode())
-  //  return; // no need to load GP. It can be calculated anywhere
-
-
-
   // For O32 ABI, the following instruction sequence is emitted to initialize
   // the global base register:
   //
@@ -237,7 +218,6 @@ void MipsDAGToDAGISel::InitGlobalBaseReg(MachineFunction &MF) {
   MBB.addLiveIn(Mips::V0);
   BuildMI(MBB, I, DL, TII.get(Mips::ADDu), GlobalBaseReg)
     .addReg(Mips::V0).addReg(Mips::T9);
-  MII->storeRegToStackSlot(MBB, I, GlobalBaseReg, false, FI, RC, TargetRegInfo);
 }
 
 bool MipsDAGToDAGISel::ReplaceUsesWithZeroReg(MachineRegisterInfo *MRI,