[llvm] 61f5ba5 - [SystemZ] Implement the packed stack layout

Jonas Paulsson via llvm-commits llvm-commits at lists.llvm.org
Thu Dec 12 10:27:51 PST 2019


Author: Jonas Paulsson
Date: 2019-12-12T10:26:03-08:00
New Revision: 61f5ba5c32fae2726d3ead5e7360c084720f4692

URL: https://github.com/llvm/llvm-project/commit/61f5ba5c32fae2726d3ead5e7360c084720f4692
DIFF: https://github.com/llvm/llvm-project/commit/61f5ba5c32fae2726d3ead5e7360c084720f4692.diff

LOG: [SystemZ]  Implement the packed stack layout

Any llvm function with the "packed-stack" attribute will be compiled to use
the packed stack layout which reuses unused parts of the incoming register
save area. This is needed for building the Linux kernel.

Review: Ulrich Weigand
https://reviews.llvm.org/D70821

Added: 
    llvm/test/CodeGen/SystemZ/frame-22.ll

Modified: 
    llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
    llvm/lib/Target/SystemZ/SystemZFrameLowering.h
    llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
    llvm/lib/Target/SystemZ/SystemZMachineFunctionInfo.h
    llvm/test/CodeGen/SystemZ/anyregcc-novec.ll
    llvm/test/CodeGen/SystemZ/frame-02.ll
    llvm/test/CodeGen/SystemZ/frame-03.ll
    llvm/test/CodeGen/SystemZ/frame-04.ll
    llvm/test/CodeGen/SystemZ/frame-19.ll
    llvm/test/CodeGen/SystemZ/frame-20.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp b/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
index 24b99e49fc67..3e2b376d3be6 100644
--- a/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
@@ -24,48 +24,146 @@ namespace {
 // The ABI-defined register save slots, relative to the CFA (i.e.
 // incoming stack pointer + SystemZMC::CallFrameSize).
 static const TargetFrameLowering::SpillSlot SpillOffsetTable[] = {
-  { SystemZ::R2D,  -SystemZMC::CallFrameSize + 0x10 },
-  { SystemZ::R3D,  -SystemZMC::CallFrameSize + 0x18 },
-  { SystemZ::R4D,  -SystemZMC::CallFrameSize + 0x20 },
-  { SystemZ::R5D,  -SystemZMC::CallFrameSize + 0x28 },
-  { SystemZ::R6D,  -SystemZMC::CallFrameSize + 0x30 },
-  { SystemZ::R7D,  -SystemZMC::CallFrameSize + 0x38 },
-  { SystemZ::R8D,  -SystemZMC::CallFrameSize + 0x40 },
-  { SystemZ::R9D,  -SystemZMC::CallFrameSize + 0x48 },
-  { SystemZ::R10D, -SystemZMC::CallFrameSize + 0x50 },
-  { SystemZ::R11D, -SystemZMC::CallFrameSize + 0x58 },
-  { SystemZ::R12D, -SystemZMC::CallFrameSize + 0x60 },
-  { SystemZ::R13D, -SystemZMC::CallFrameSize + 0x68 },
-  { SystemZ::R14D, -SystemZMC::CallFrameSize + 0x70 },
-  { SystemZ::R15D, -SystemZMC::CallFrameSize + 0x78 },
-  { SystemZ::F0D,  -SystemZMC::CallFrameSize + 0x80 },
-  { SystemZ::F2D,  -SystemZMC::CallFrameSize + 0x88 },
-  { SystemZ::F4D,  -SystemZMC::CallFrameSize + 0x90 },
-  { SystemZ::F6D,  -SystemZMC::CallFrameSize + 0x98 }
+  { SystemZ::R2D,  0x10 },
+  { SystemZ::R3D,  0x18 },
+  { SystemZ::R4D,  0x20 },
+  { SystemZ::R5D,  0x28 },
+  { SystemZ::R6D,  0x30 },
+  { SystemZ::R7D,  0x38 },
+  { SystemZ::R8D,  0x40 },
+  { SystemZ::R9D,  0x48 },
+  { SystemZ::R10D, 0x50 },
+  { SystemZ::R11D, 0x58 },
+  { SystemZ::R12D, 0x60 },
+  { SystemZ::R13D, 0x68 },
+  { SystemZ::R14D, 0x70 },
+  { SystemZ::R15D, 0x78 },
+  { SystemZ::F0D,  0x80 },
+  { SystemZ::F2D,  0x88 },
+  { SystemZ::F4D,  0x90 },
+  { SystemZ::F6D,  0x98 }
 };
 } // end anonymous namespace
 
 SystemZFrameLowering::SystemZFrameLowering()
     : TargetFrameLowering(TargetFrameLowering::StackGrowsDown, Align(8),
-                          -SystemZMC::CallFrameSize, Align(8),
-                          false /* StackRealignable */) {
+                          0, Align(8), false /* StackRealignable */),
+      RegSpillOffsets(0) {
   // Due to the SystemZ ABI, the DWARF CFA (Canonical Frame Address) is not
   // equal to the incoming stack pointer, but to incoming stack pointer plus
-  // 160.  The getOffsetOfLocalArea() returned value is interpreted as "the
-  // offset of the local area from the CFA".
+  // 160.  Instead of using a Local Area Offset, the Register save area will
+  // be occupied by fixed frame objects, and all offsets are actually
+  // relative to CFA.
 
   // Create a mapping from register number to save slot offset.
   // These offsets are relative to the start of the register save area.
   RegSpillOffsets.grow(SystemZ::NUM_TARGET_REGS);
   for (unsigned I = 0, E = array_lengthof(SpillOffsetTable); I != E; ++I)
-    RegSpillOffsets[SpillOffsetTable[I].Reg] =
-      SystemZMC::CallFrameSize + SpillOffsetTable[I].Offset;
+    RegSpillOffsets[SpillOffsetTable[I].Reg] = SpillOffsetTable[I].Offset;
 }
 
-const TargetFrameLowering::SpillSlot *
-SystemZFrameLowering::getCalleeSavedSpillSlots(unsigned &NumEntries) const {
-  NumEntries = array_lengthof(SpillOffsetTable);
-  return SpillOffsetTable;
+static bool usePackedStack(MachineFunction &MF) {
+  bool HasPackedStackAttr = MF.getFunction().hasFnAttribute("packed-stack");
+  bool IsVarArg = MF.getFunction().isVarArg();
+  bool CallConv = MF.getFunction().getCallingConv() != CallingConv::GHC;
+  bool BackChain = MF.getFunction().hasFnAttribute("backchain");
+  bool FramAddressTaken = MF.getFrameInfo().isFrameAddressTaken();
+  return HasPackedStackAttr && !IsVarArg && CallConv && !BackChain &&
+         !FramAddressTaken;
+}
+
+bool SystemZFrameLowering::
+assignCalleeSavedSpillSlots(MachineFunction &MF,
+                            const TargetRegisterInfo *TRI,
+                            std::vector<CalleeSavedInfo> &CSI) const {
+  SystemZMachineFunctionInfo *ZFI = MF.getInfo<SystemZMachineFunctionInfo>();
+  MachineFrameInfo &MFFrame = MF.getFrameInfo();
+  bool IsVarArg = MF.getFunction().isVarArg();
+  if (CSI.empty())
+    return true; // Early exit if no callee saved registers are modified!
+
+  unsigned LowGPR = 0;
+  unsigned HighGPR = SystemZ::R15D;
+  int StartSPOffset = SystemZMC::CallFrameSize;
+  int CurrOffset;
+  if (!usePackedStack(MF)) {
+    for (auto &CS : CSI) {
+      unsigned Reg = CS.getReg();
+      int Offset = RegSpillOffsets[Reg];
+      if (Offset) {
+        if (SystemZ::GR64BitRegClass.contains(Reg) && StartSPOffset > Offset) {
+          LowGPR = Reg;
+          StartSPOffset = Offset;
+        }
+        Offset -= SystemZMC::CallFrameSize;
+        int FrameIdx = MFFrame.CreateFixedSpillStackObject(8, Offset);
+        CS.setFrameIdx(FrameIdx);
+      } else
+        CS.setFrameIdx(INT32_MAX);
+    }
+
+    // Save the range of call-saved registers, for use by the
+    // prologue/epilogue inserters.
+    ZFI->setRestoreGPRRegs(LowGPR, HighGPR, StartSPOffset);
+    if (IsVarArg) {
+      // Also save the GPR varargs, if any.  R6D is call-saved, so would
+      // already be included, but we also need to handle the call-clobbered
+      // argument registers.
+      unsigned FirstGPR = ZFI->getVarArgsFirstGPR();
+      if (FirstGPR < SystemZ::NumArgGPRs) {
+        unsigned Reg = SystemZ::ArgGPRs[FirstGPR];
+        int Offset = RegSpillOffsets[Reg];
+        if (StartSPOffset > Offset) {
+          LowGPR = Reg; StartSPOffset = Offset;
+        }
+      }
+    }
+    ZFI->setSpillGPRRegs(LowGPR, HighGPR, StartSPOffset);
+
+    CurrOffset = -SystemZMC::CallFrameSize;
+  } else {
+    // Packed stack: put all the GPRs at the top of the Register save area.
+    uint32_t LowGR64Num = UINT32_MAX;
+    for (auto &CS : CSI) {
+      unsigned Reg = CS.getReg();
+      if (SystemZ::GR64BitRegClass.contains(Reg)) {
+        unsigned GR64Num = SystemZMC::getFirstReg(Reg);
+        int Offset = -8 * (15 - GR64Num + 1);
+        if (LowGR64Num > GR64Num) {
+          LowGR64Num = GR64Num;
+          StartSPOffset = SystemZMC::CallFrameSize + Offset;
+        }
+        int FrameIdx = MFFrame.CreateFixedSpillStackObject(8, Offset);
+        CS.setFrameIdx(FrameIdx);
+      } else
+        CS.setFrameIdx(INT32_MAX);
+    }
+    if (LowGR64Num < UINT32_MAX)
+      LowGPR = SystemZMC::GR64Regs[LowGR64Num];
+
+    // Save the range of call-saved registers, for use by the
+    // prologue/epilogue inserters.
+    ZFI->setRestoreGPRRegs(LowGPR, HighGPR, StartSPOffset);
+    ZFI->setSpillGPRRegs(LowGPR, HighGPR, StartSPOffset);
+
+    CurrOffset = LowGPR ? -(SystemZMC::CallFrameSize - StartSPOffset) : 0;
+  }
+
+  // Create fixed stack objects for the remaining registers.
+  for (auto &CS : CSI) {
+    if (CS.getFrameIdx() != INT32_MAX)
+      continue;
+    unsigned Reg = CS.getReg();
+    const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
+    unsigned Size = TRI->getSpillSize(*RC);
+    CurrOffset -= Size;
+    assert(CurrOffset % 8 == 0 &&
+           "8-byte alignment required for for all register save slots");
+    int FrameIdx = MFFrame.CreateFixedSpillStackObject(Size, CurrOffset);
+    CS.setFrameIdx(FrameIdx);
+  }
+
+  return true;
 }
 
 void SystemZFrameLowering::determineCalleeSaves(MachineFunction &MF,
@@ -148,53 +246,21 @@ spillCalleeSavedRegisters(MachineBasicBlock &MBB,
   bool IsVarArg = MF.getFunction().isVarArg();
   DebugLoc DL;
 
-  // Scan the call-saved GPRs and find the bounds of the register spill area.
-  unsigned LowGPR = 0;
-  unsigned HighGPR = SystemZ::R15D;
-  unsigned StartOffset = -1U;
-  for (unsigned I = 0, E = CSI.size(); I != E; ++I) {
-    unsigned Reg = CSI[I].getReg();
-    if (SystemZ::GR64BitRegClass.contains(Reg)) {
-      unsigned Offset = RegSpillOffsets[Reg];
-      assert(Offset && "Unexpected GPR save");
-      if (StartOffset > Offset) {
-        LowGPR = Reg;
-        StartOffset = Offset;
-      }
-    }
-  }
-
-  // Save the range of call-saved registers, for use by the epilogue inserter.
-  ZFI->setLowSavedGPR(LowGPR);
-  ZFI->setHighSavedGPR(HighGPR);
-
-  // Include the GPR varargs, if any.  R6D is call-saved, so would
-  // be included by the loop above, but we also need to handle the
-  // call-clobbered argument registers.
-  if (IsVarArg) {
-    unsigned FirstGPR = ZFI->getVarArgsFirstGPR();
-    if (FirstGPR < SystemZ::NumArgGPRs) {
-      unsigned Reg = SystemZ::ArgGPRs[FirstGPR];
-      unsigned Offset = RegSpillOffsets[Reg];
-      if (StartOffset > Offset) {
-        LowGPR = Reg; StartOffset = Offset;
-      }
-    }
-  }
-
   // Save GPRs
-  if (LowGPR) {
-    assert(LowGPR != HighGPR && "Should be saving %r15 and something else");
+  SystemZ::GPRRegs SpillGPRs = ZFI->getSpillGPRRegs();
+  if (SpillGPRs.LowGPR) {
+    assert(SpillGPRs.LowGPR != SpillGPRs.HighGPR &&
+           "Should be saving %r15 and something else");
 
     // Build an STMG instruction.
     MachineInstrBuilder MIB = BuildMI(MBB, MBBI, DL, TII->get(SystemZ::STMG));
 
     // Add the explicit register operands.
-    addSavedGPR(MBB, MIB, LowGPR, false);
-    addSavedGPR(MBB, MIB, HighGPR, false);
+    addSavedGPR(MBB, MIB, SpillGPRs.LowGPR, false);
+    addSavedGPR(MBB, MIB, SpillGPRs.HighGPR, false);
 
     // Add the address.
-    MIB.addReg(SystemZ::R15D).addImm(StartOffset);
+    MIB.addReg(SystemZ::R15D).addImm(SpillGPRs.GPROffset);
 
     // Make sure all call-saved GPRs are included as operands and are
     // marked as live on entry.
@@ -255,30 +321,29 @@ restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
 
   // Restore call-saved GPRs (but not call-clobbered varargs, which at
   // this point might hold return values).
-  unsigned LowGPR = ZFI->getLowSavedGPR();
-  unsigned HighGPR = ZFI->getHighSavedGPR();
-  unsigned StartOffset = RegSpillOffsets[LowGPR];
-  if (LowGPR) {
+  SystemZ::GPRRegs RestoreGPRs = ZFI->getRestoreGPRRegs();
+  if (RestoreGPRs.LowGPR) {
     // If we saved any of %r2-%r5 as varargs, we should also be saving
     // and restoring %r6.  If we're saving %r6 or above, we should be
     // restoring it too.
-    assert(LowGPR != HighGPR && "Should be loading %r15 and something else");
+    assert(RestoreGPRs.LowGPR != RestoreGPRs.HighGPR &&
+           "Should be loading %r15 and something else");
 
     // Build an LMG instruction.
     MachineInstrBuilder MIB = BuildMI(MBB, MBBI, DL, TII->get(SystemZ::LMG));
 
     // Add the explicit register operands.
-    MIB.addReg(LowGPR, RegState::Define);
-    MIB.addReg(HighGPR, RegState::Define);
+    MIB.addReg(RestoreGPRs.LowGPR, RegState::Define);
+    MIB.addReg(RestoreGPRs.HighGPR, RegState::Define);
 
     // Add the address.
     MIB.addReg(HasFP ? SystemZ::R11D : SystemZ::R15D);
-    MIB.addImm(StartOffset);
+    MIB.addImm(RestoreGPRs.GPROffset);
 
     // Do a second scan adding regs as being defined by instruction
     for (unsigned I = 0, E = CSI.size(); I != E; ++I) {
       unsigned Reg = CSI[I].getReg();
-      if (Reg != LowGPR && Reg != HighGPR &&
+      if (Reg != RestoreGPRs.LowGPR && Reg != RestoreGPRs.HighGPR &&
           SystemZ::GR64BitRegClass.contains(Reg))
         MIB.addReg(Reg, RegState::ImplicitDefine);
     }
@@ -291,16 +356,20 @@ void SystemZFrameLowering::
 processFunctionBeforeFrameFinalized(MachineFunction &MF,
                                     RegScavenger *RS) const {
   MachineFrameInfo &MFFrame = MF.getFrameInfo();
+
+  if (!usePackedStack(MF))
+    // Always create the full incoming register save area.
+    getOrCreateFramePointerSaveIndex(MF);
+
   // Get the size of our stack frame to be allocated ...
   uint64_t StackSize = (MFFrame.estimateStackSize(MF) +
                         SystemZMC::CallFrameSize);
   // ... and the maximum offset we may need to reach into the
   // caller's frame to access the save area or stack arguments.
-  int64_t MaxArgOffset = SystemZMC::CallFrameSize;
+  int64_t MaxArgOffset = 0;
   for (int I = MFFrame.getObjectIndexBegin(); I != 0; ++I)
     if (MFFrame.getObjectOffset(I) >= 0) {
-      int64_t ArgOffset = SystemZMC::CallFrameSize +
-                          MFFrame.getObjectOffset(I) +
+      int64_t ArgOffset = MFFrame.getObjectOffset(I) +
                           MFFrame.getObjectSize(I);
       MaxArgOffset = std::max(MaxArgOffset, ArgOffset);
     }
@@ -382,7 +451,7 @@ void SystemZFrameLowering::emitPrologue(MachineFunction &MF,
   // The current offset of the stack pointer from the CFA.
   int64_t SPOffsetFromCFA = -SystemZMC::CFAOffsetFromInitialSP;
 
-  if (ZFI->getLowSavedGPR()) {
+  if (ZFI->getSpillGPRRegs().LowGPR) {
     // Skip over the GPR saves.
     if (MBBI != MBB.end() && MBBI->getOpcode() == SystemZ::STMG)
       ++MBBI;
@@ -393,7 +462,8 @@ void SystemZFrameLowering::emitPrologue(MachineFunction &MF,
     for (auto &Save : CSI) {
       unsigned Reg = Save.getReg();
       if (SystemZ::GR64BitRegClass.contains(Reg)) {
-        int64_t Offset = SPOffsetFromCFA + RegSpillOffsets[Reg];
+        int FI = Save.getFrameIdx();
+        int64_t Offset = MFFrame.getObjectOffset(FI);
         unsigned CFIIndex = MF.addFrameInst(MCCFIInstruction::createOffset(
             nullptr, MRI->getDwarfRegNum(Reg, true), Offset));
         BuildMI(MBB, MBBI, DL, ZII->get(TargetOpcode::CFI_INSTRUCTION))
@@ -406,10 +476,19 @@ void SystemZFrameLowering::emitPrologue(MachineFunction &MF,
   // We need to allocate the ABI-defined 160-byte base area whenever
   // we allocate stack space for our own use and whenever we call another
   // function.
-  if (StackSize || MFFrame.hasVarSizedObjects() || MFFrame.hasCalls()) {
+  bool HasStackObject = false;
+  for (unsigned i = 0, e = MFFrame.getObjectIndexEnd(); i != e; ++i)
+    if (!MFFrame.isDeadObjectIndex(i)) {
+      HasStackObject = true;
+      break;
+    }
+  if (HasStackObject || MFFrame.hasCalls())
     StackSize += SystemZMC::CallFrameSize;
-    MFFrame.setStackSize(StackSize);
-  }
+  // Don't allocate the incoming reg save area.
+  StackSize = StackSize > SystemZMC::CallFrameSize
+                  ? StackSize - SystemZMC::CallFrameSize
+                  : 0;
+  MFFrame.setStackSize(StackSize);
 
   if (StackSize) {
     // Determine if we want to store a backchain.
@@ -434,7 +513,8 @@ void SystemZFrameLowering::emitPrologue(MachineFunction &MF,
 
     if (StoreBackchain)
       BuildMI(MBB, MBBI, DL, ZII->get(SystemZ::STG))
-        .addReg(SystemZ::R1D, RegState::Kill).addReg(SystemZ::R15D).addImm(0).addReg(0);
+        .addReg(SystemZ::R1D, RegState::Kill).addReg(SystemZ::R15D).addImm(0)
+        .addReg(0);
   }
 
   if (HasFP) {
@@ -510,7 +590,7 @@ void SystemZFrameLowering::emitEpilogue(MachineFunction &MF,
   assert(MBBI->isReturn() && "Can only insert epilogue into returning blocks");
 
   uint64_t StackSize = MFFrame.getStackSize();
-  if (ZFI->getLowSavedGPR()) {
+  if (ZFI->getRestoreGPRRegs().LowGPR) {
     --MBBI;
     unsigned Opcode = MBBI->getOpcode();
     if (Opcode != SystemZ::LMG)
@@ -555,6 +635,16 @@ SystemZFrameLowering::hasReservedCallFrame(const MachineFunction &MF) const {
   return true;
 }
 
+int SystemZFrameLowering::getFrameIndexReference(const MachineFunction &MF,
+                                                 int FI,
+                                                 unsigned &FrameReg) const {
+  // Our incoming SP is actually SystemZMC::CallFrameSize below the CFA, so
+  // add that 
diff erence here.
+  int64_t Offset =
+    TargetFrameLowering::getFrameIndexReference(MF, FI, FrameReg);
+  return Offset + SystemZMC::CallFrameSize;
+}
+
 MachineBasicBlock::iterator SystemZFrameLowering::
 eliminateCallFramePseudoInstr(MachineFunction &MF,
                               MachineBasicBlock &MBB,
@@ -571,3 +661,15 @@ eliminateCallFramePseudoInstr(MachineFunction &MF,
     llvm_unreachable("Unexpected call frame instruction");
   }
 }
+
+int SystemZFrameLowering::
+getOrCreateFramePointerSaveIndex(MachineFunction &MF) const {
+  SystemZMachineFunctionInfo *ZFI = MF.getInfo<SystemZMachineFunctionInfo>();
+  int FI = ZFI->getFramePointerSaveIndex();
+  if (!FI) {
+    MachineFrameInfo &MFFrame = MF.getFrameInfo();
+    FI = MFFrame.CreateFixedObject(8, -SystemZMC::CallFrameSize, false);
+    ZFI->setFramePointerSaveIndex(FI);
+  }
+  return FI;
+}

diff  --git a/llvm/lib/Target/SystemZ/SystemZFrameLowering.h b/llvm/lib/Target/SystemZ/SystemZFrameLowering.h
index 71ef3e4dc240..4189a92b8294 100644
--- a/llvm/lib/Target/SystemZ/SystemZFrameLowering.h
+++ b/llvm/lib/Target/SystemZ/SystemZFrameLowering.h
@@ -24,8 +24,10 @@ class SystemZFrameLowering : public TargetFrameLowering {
 
   // Override TargetFrameLowering.
   bool isFPCloseToIncomingSP() const override { return false; }
-  const SpillSlot *getCalleeSavedSpillSlots(unsigned &NumEntries) const
-    override;
+  bool
+  assignCalleeSavedSpillSlots(MachineFunction &MF,
+                              const TargetRegisterInfo *TRI,
+                              std::vector<CalleeSavedInfo> &CSI) const override;
   void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
                             RegScavenger *RS) const override;
   bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
@@ -43,6 +45,8 @@ class SystemZFrameLowering : public TargetFrameLowering {
   void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
   bool hasFP(const MachineFunction &MF) const override;
   bool hasReservedCallFrame(const MachineFunction &MF) const override;
+  int getFrameIndexReference(const MachineFunction &MF, int FI,
+                             unsigned &FrameReg) const override;
   MachineBasicBlock::iterator
   eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
                                 MachineBasicBlock::iterator MI) const override;
@@ -52,6 +56,9 @@ class SystemZFrameLowering : public TargetFrameLowering {
   unsigned getRegSpillOffset(unsigned Reg) const {
     return RegSpillOffsets[Reg];
   }
+
+  // Get or create the frame index of where the old frame pointer is stored.
+  int getOrCreateFramePointerSaveIndex(MachineFunction &MF) const;
 };
 } // end namespace llvm
 

diff  --git a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
index f0ec241c8f49..fa2102651ee4 100644
--- a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -1418,7 +1418,7 @@ SDValue SystemZTargetLowering::LowerFormalArguments(
 
     // ...and a similar frame index for the caller-allocated save area
     // that will be used to store the incoming registers.
-    int64_t RegSaveOffset = TFL->getOffsetOfLocalArea();
+    int64_t RegSaveOffset = -SystemZMC::CallFrameSize;
     unsigned RegSaveIndex = MFI.CreateFixedObject(1, RegSaveOffset, true);
     FuncInfo->setRegSaveFrameIndex(RegSaveIndex);
 
@@ -3203,14 +3203,10 @@ SDValue SystemZTargetLowering::lowerFRAMEADDR(SDValue Op,
   unsigned Depth = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
   EVT PtrVT = getPointerTy(DAG.getDataLayout());
 
-  // If the back chain frame index has not been allocated yet, do so.
-  SystemZMachineFunctionInfo *FI = MF.getInfo<SystemZMachineFunctionInfo>();
-  int BackChainIdx = FI->getFramePointerSaveIndex();
-  if (!BackChainIdx) {
-    // By definition, the frame address is the address of the back chain.
-    BackChainIdx = MFI.CreateFixedObject(8, -SystemZMC::CallFrameSize, false);
-    FI->setFramePointerSaveIndex(BackChainIdx);
-  }
+  // By definition, the frame address is the address of the back chain.
+  auto *TFL =
+      static_cast<const SystemZFrameLowering *>(Subtarget.getFrameLowering());
+  int BackChainIdx = TFL->getOrCreateFramePointerSaveIndex(MF);
   SDValue BackChain = DAG.getFrameIndex(BackChainIdx, PtrVT);
 
   // FIXME The frontend should detect this case.

diff  --git a/llvm/lib/Target/SystemZ/SystemZMachineFunctionInfo.h b/llvm/lib/Target/SystemZ/SystemZMachineFunctionInfo.h
index 9eec3f37bc28..d1f6511ceea3 100644
--- a/llvm/lib/Target/SystemZ/SystemZMachineFunctionInfo.h
+++ b/llvm/lib/Target/SystemZ/SystemZMachineFunctionInfo.h
@@ -13,10 +13,22 @@
 
 namespace llvm {
 
+namespace SystemZ {
+// A struct to hold the low and high GPR registers to be saved/restored as
+// well as the offset into the register save area of the low register.
+struct GPRRegs {
+  unsigned LowGPR;
+  unsigned HighGPR;
+  unsigned GPROffset;
+  GPRRegs() : LowGPR(0), HighGPR(0), GPROffset(0) {}
+  };
+}
+
 class SystemZMachineFunctionInfo : public MachineFunctionInfo {
   virtual void anchor();
-  unsigned LowSavedGPR;
-  unsigned HighSavedGPR;
+
+  SystemZ::GPRRegs SpillGPRRegs;
+  SystemZ::GPRRegs RestoreGPRRegs;
   unsigned VarArgsFirstGPR;
   unsigned VarArgsFirstFPR;
   unsigned VarArgsFrameIndex;
@@ -27,19 +39,29 @@ class SystemZMachineFunctionInfo : public MachineFunctionInfo {
 
 public:
   explicit SystemZMachineFunctionInfo(MachineFunction &MF)
-    : LowSavedGPR(0), HighSavedGPR(0), VarArgsFirstGPR(0), VarArgsFirstFPR(0),
-      VarArgsFrameIndex(0), RegSaveFrameIndex(0), FramePointerSaveIndex(0),
-      ManipulatesSP(false), NumLocalDynamics(0) {}
-
-  // Get and set the first call-saved GPR that should be saved and restored
-  // by this function.  This is 0 if no GPRs need to be saved or restored.
-  unsigned getLowSavedGPR() const { return LowSavedGPR; }
-  void setLowSavedGPR(unsigned Reg) { LowSavedGPR = Reg; }
-
-  // Get and set the last call-saved GPR that should be saved and restored
-  // by this function.
-  unsigned getHighSavedGPR() const { return HighSavedGPR; }
-  void setHighSavedGPR(unsigned Reg) { HighSavedGPR = Reg; }
+    : VarArgsFirstGPR(0), VarArgsFirstFPR(0), VarArgsFrameIndex(0),
+      RegSaveFrameIndex(0), FramePointerSaveIndex(0), ManipulatesSP(false),
+      NumLocalDynamics(0) {}
+
+  // Get and set the first and last call-saved GPR that should be saved by
+  // this function and the SP offset for the STMG.  These are 0 if no GPRs
+  // need to be saved or restored.
+  SystemZ::GPRRegs getSpillGPRRegs() const { return SpillGPRRegs; }
+  void setSpillGPRRegs(unsigned Low, unsigned High, unsigned Offs) {
+    SpillGPRRegs.LowGPR = Low;
+    SpillGPRRegs.HighGPR = High;
+    SpillGPRRegs.GPROffset = Offs;
+  }
+
+  // Get and set the first and last call-saved GPR that should be restored by
+  // this function and the SP offset for the LMG.  These are 0 if no GPRs
+  // need to be saved or restored.
+  SystemZ::GPRRegs getRestoreGPRRegs() const { return RestoreGPRRegs; }
+  void setRestoreGPRRegs(unsigned Low, unsigned High, unsigned Offs) {
+    RestoreGPRRegs.LowGPR = Low;
+    RestoreGPRRegs.HighGPR = High;
+    RestoreGPRRegs.GPROffset = Offs;
+  }
 
   // Get and set the number of fixed (as opposed to variable) arguments
   // that are passed in GPRs to this function.

diff  --git a/llvm/test/CodeGen/SystemZ/anyregcc-novec.ll b/llvm/test/CodeGen/SystemZ/anyregcc-novec.ll
index f7e2af917920..b37cd220ffeb 100644
--- a/llvm/test/CodeGen/SystemZ/anyregcc-novec.ll
+++ b/llvm/test/CodeGen/SystemZ/anyregcc-novec.ll
@@ -5,14 +5,14 @@ define anyregcc void @anyregcc1() {
 entry:
 ;CHECK-LABEL: anyregcc1
 ;CHECK: stmg %r2, %r15, 16(%r15)
-;CHECK: aghi %r15, -256
-;CHECK: std %f0, 384(%r15)
+;CHECK: aghi %r15, -96
+;CHECK: std %f0, 224(%r15)
 ;CHECK: std %f1,
-;CHECK: std %f2, 392(%r15)
+;CHECK: std %f2, 232(%r15)
 ;CHECK: std %f3,
-;CHECK: std %f4, 400(%r15)
+;CHECK: std %f4, 240(%r15)
 ;CHECK: std %f5,
-;CHECK: std %f6, 408(%r15)
+;CHECK: std %f6, 248(%r15)
 ;CHECK: std %f7,
 ;CHECK: std %f8,
 ;CHECK: std %f9,
@@ -26,10 +26,10 @@ entry:
 ;CHECK: .cfi_offset %f2, -24
 ;CHECK: .cfi_offset %f4, -16
 ;CHECK: .cfi_offset %f6, -8
-;CHECK: ld %f0, 384(%r15)
-;CHECK: ld %f2, 392(%r15)
-;CHECK: ld %f4, 400(%r15)
-;CHECK: ld %f6, 408(%r15)
+;CHECK: ld %f0, 224(%r15)
+;CHECK: ld %f2, 232(%r15)
+;CHECK: ld %f4, 240(%r15)
+;CHECK: ld %f6, 248(%r15)
   call void asm sideeffect "", "~{r0},~{r1},~{r2},~{r3},~{r4},~{r5},~{r6},~{r7},~{r8},~{r9},~{r10},~{r11},~{r12},~{r13},~{r14},~{f0},~{f1},~{f2},~{f3},~{f4},~{f5},~{f6},~{f7},~{f8},~{f9},~{f10},~{f11},~{f12},~{f13},~{f14},~{f15}"() nounwind
   ret void
 }

diff  --git a/llvm/test/CodeGen/SystemZ/frame-02.ll b/llvm/test/CodeGen/SystemZ/frame-02.ll
index 411a0826d849..d7160483b532 100644
--- a/llvm/test/CodeGen/SystemZ/frame-02.ll
+++ b/llvm/test/CodeGen/SystemZ/frame-02.ll
@@ -4,20 +4,20 @@
 
 ; This function should require all FPRs, but no other spill slots.
 ; We need to save and restore 8 of the 16 FPRs, so the frame size
-; should be exactly 160 + 8 * 8 = 224.  The CFA offset is 160
-; (the caller-allocated part of the frame) + 224.
+; should be exactly 8 * 8 = 64.  The CFA offset is 160
+; (the caller-allocated part of the frame) + 64.
 define void @f1(float *%ptr) {
 ; CHECK-LABEL: f1:
-; CHECK: aghi %r15, -224
-; CHECK: .cfi_def_cfa_offset 384
-; CHECK: std %f8, 216(%r15)
-; CHECK: std %f9, 208(%r15)
-; CHECK: std %f10, 200(%r15)
-; CHECK: std %f11, 192(%r15)
-; CHECK: std %f12, 184(%r15)
-; CHECK: std %f13, 176(%r15)
-; CHECK: std %f14, 168(%r15)
-; CHECK: std %f15, 160(%r15)
+; CHECK: aghi %r15, -64
+; CHECK: .cfi_def_cfa_offset 224
+; CHECK: std %f8, 56(%r15)
+; CHECK: std %f9, 48(%r15)
+; CHECK: std %f10, 40(%r15)
+; CHECK: std %f11, 32(%r15)
+; CHECK: std %f12, 24(%r15)
+; CHECK: std %f13, 16(%r15)
+; CHECK: std %f14, 8(%r15)
+; CHECK: std %f15, 0(%r15)
 ; CHECK: .cfi_offset %f8, -168
 ; CHECK: .cfi_offset %f9, -176
 ; CHECK: .cfi_offset %f10, -184
@@ -27,15 +27,15 @@ define void @f1(float *%ptr) {
 ; CHECK: .cfi_offset %f14, -216
 ; CHECK: .cfi_offset %f15, -224
 ; ...main function body...
-; CHECK: ld %f8, 216(%r15)
-; CHECK: ld %f9, 208(%r15)
-; CHECK: ld %f10, 200(%r15)
-; CHECK: ld %f11, 192(%r15)
-; CHECK: ld %f12, 184(%r15)
-; CHECK: ld %f13, 176(%r15)
-; CHECK: ld %f14, 168(%r15)
-; CHECK: ld %f15, 160(%r15)
-; CHECK: aghi %r15, 224
+; CHECK: ld %f8, 56(%r15)
+; CHECK: ld %f9, 48(%r15)
+; CHECK: ld %f10, 40(%r15)
+; CHECK: ld %f11, 32(%r15)
+; CHECK: ld %f12, 24(%r15)
+; CHECK: ld %f13, 16(%r15)
+; CHECK: ld %f14, 8(%r15)
+; CHECK: ld %f15, 0(%r15)
+; CHECK: aghi %r15, 64
 ; CHECK: br %r14
   %l0 = load volatile float, float *%ptr
   %l1 = load volatile float, float *%ptr
@@ -92,15 +92,15 @@ define void @f1(float *%ptr) {
 ; so %f15 is the one that gets dropped.
 define void @f2(float *%ptr) {
 ; CHECK-LABEL: f2:
-; CHECK: aghi %r15, -216
-; CHECK: .cfi_def_cfa_offset 376
-; CHECK: std %f8, 208(%r15)
-; CHECK: std %f9, 200(%r15)
-; CHECK: std %f10, 192(%r15)
-; CHECK: std %f11, 184(%r15)
-; CHECK: std %f12, 176(%r15)
-; CHECK: std %f13, 168(%r15)
-; CHECK: std %f14, 160(%r15)
+; CHECK: aghi %r15, -56
+; CHECK: .cfi_def_cfa_offset 216
+; CHECK: std %f8, 48(%r15)
+; CHECK: std %f9, 40(%r15)
+; CHECK: std %f10, 32(%r15)
+; CHECK: std %f11, 24(%r15)
+; CHECK: std %f12, 16(%r15)
+; CHECK: std %f13, 8(%r15)
+; CHECK: std %f14, 0(%r15)
 ; CHECK: .cfi_offset %f8, -168
 ; CHECK: .cfi_offset %f9, -176
 ; CHECK: .cfi_offset %f10, -184
@@ -110,14 +110,14 @@ define void @f2(float *%ptr) {
 ; CHECK: .cfi_offset %f14, -216
 ; CHECK-NOT: %f15
 ; ...main function body...
-; CHECK: ld %f8, 208(%r15)
-; CHECK: ld %f9, 200(%r15)
-; CHECK: ld %f10, 192(%r15)
-; CHECK: ld %f11, 184(%r15)
-; CHECK: ld %f12, 176(%r15)
-; CHECK: ld %f13, 168(%r15)
-; CHECK: ld %f14, 160(%r15)
-; CHECK: aghi %r15, 216
+; CHECK: ld %f8, 48(%r15)
+; CHECK: ld %f9, 40(%r15)
+; CHECK: ld %f10, 32(%r15)
+; CHECK: ld %f11, 24(%r15)
+; CHECK: ld %f12, 16(%r15)
+; CHECK: ld %f13, 8(%r15)
+; CHECK: ld %f14, 0(%r15)
+; CHECK: aghi %r15, 56
 ; CHECK: br %r14
   %l0 = load volatile float, float *%ptr
   %l1 = load volatile float, float *%ptr
@@ -170,9 +170,9 @@ define void @f2(float *%ptr) {
 ; Like f1, but should require only one call-saved FPR.
 define void @f3(float *%ptr) {
 ; CHECK-LABEL: f3:
-; CHECK: aghi %r15, -168
-; CHECK: .cfi_def_cfa_offset 328
-; CHECK: std %f8, 160(%r15)
+; CHECK: aghi %r15, -8
+; CHECK: .cfi_def_cfa_offset 168
+; CHECK: std %f8, 0(%r15)
 ; CHECK: .cfi_offset %f8, -168
 ; CHECK-NOT: %f9
 ; CHECK-NOT: %f10
@@ -182,8 +182,8 @@ define void @f3(float *%ptr) {
 ; CHECK-NOT: %f14
 ; CHECK-NOT: %f15
 ; ...main function body...
-; CHECK: ld %f8, 160(%r15)
-; CHECK: aghi %r15, 168
+; CHECK: ld %f8, 0(%r15)
+; CHECK: aghi %r15, 8
 ; CHECK: br %r14
   %l0 = load volatile float, float *%ptr
   %l1 = load volatile float, float *%ptr

diff  --git a/llvm/test/CodeGen/SystemZ/frame-03.ll b/llvm/test/CodeGen/SystemZ/frame-03.ll
index 28826150e780..ce2e0244457d 100644
--- a/llvm/test/CodeGen/SystemZ/frame-03.ll
+++ b/llvm/test/CodeGen/SystemZ/frame-03.ll
@@ -6,20 +6,20 @@
 
 ; This function should require all FPRs, but no other spill slots.
 ; We need to save and restore 8 of the 16 FPRs, so the frame size
-; should be exactly 160 + 8 * 8 = 224.  The CFA offset is 160
-; (the caller-allocated part of the frame) + 224.
+; should be exactly 8 * 8 = 64.  The CFA offset is 160
+; (the caller-allocated part of the frame) + 64.
 define void @f1(double *%ptr) {
 ; CHECK-LABEL: f1:
-; CHECK: aghi %r15, -224
-; CHECK: .cfi_def_cfa_offset 384
-; CHECK: std %f8, 216(%r15)
-; CHECK: std %f9, 208(%r15)
-; CHECK: std %f10, 200(%r15)
-; CHECK: std %f11, 192(%r15)
-; CHECK: std %f12, 184(%r15)
-; CHECK: std %f13, 176(%r15)
-; CHECK: std %f14, 168(%r15)
-; CHECK: std %f15, 160(%r15)
+; CHECK: aghi %r15, -64
+; CHECK: .cfi_def_cfa_offset 224
+; CHECK: std %f8, 56(%r15)
+; CHECK: std %f9, 48(%r15)
+; CHECK: std %f10, 40(%r15)
+; CHECK: std %f11, 32(%r15)
+; CHECK: std %f12, 24(%r15)
+; CHECK: std %f13, 16(%r15)
+; CHECK: std %f14, 8(%r15)
+; CHECK: std %f15, 0(%r15)
 ; CHECK: .cfi_offset %f8, -168
 ; CHECK: .cfi_offset %f9, -176
 ; CHECK: .cfi_offset %f10, -184
@@ -29,15 +29,15 @@ define void @f1(double *%ptr) {
 ; CHECK: .cfi_offset %f14, -216
 ; CHECK: .cfi_offset %f15, -224
 ; ...main function body...
-; CHECK: ld %f8, 216(%r15)
-; CHECK: ld %f9, 208(%r15)
-; CHECK: ld %f10, 200(%r15)
-; CHECK: ld %f11, 192(%r15)
-; CHECK: ld %f12, 184(%r15)
-; CHECK: ld %f13, 176(%r15)
-; CHECK: ld %f14, 168(%r15)
-; CHECK: ld %f15, 160(%r15)
-; CHECK: aghi %r15, 224
+; CHECK: ld %f8, 56(%r15)
+; CHECK: ld %f9, 48(%r15)
+; CHECK: ld %f10, 40(%r15)
+; CHECK: ld %f11, 32(%r15)
+; CHECK: ld %f12, 24(%r15)
+; CHECK: ld %f13, 16(%r15)
+; CHECK: ld %f14, 8(%r15)
+; CHECK: ld %f15, 0(%r15)
+; CHECK: aghi %r15, 64
 ; CHECK: br %r14
   %l0 = load volatile double, double *%ptr
   %l1 = load volatile double, double *%ptr
@@ -94,15 +94,15 @@ define void @f1(double *%ptr) {
 ; so %f15 is the one that gets dropped.
 define void @f2(double *%ptr) {
 ; CHECK-LABEL: f2:
-; CHECK: aghi %r15, -216
-; CHECK: .cfi_def_cfa_offset 376
-; CHECK: std %f8, 208(%r15)
-; CHECK: std %f9, 200(%r15)
-; CHECK: std %f10, 192(%r15)
-; CHECK: std %f11, 184(%r15)
-; CHECK: std %f12, 176(%r15)
-; CHECK: std %f13, 168(%r15)
-; CHECK: std %f14, 160(%r15)
+; CHECK: aghi %r15, -56
+; CHECK: .cfi_def_cfa_offset 216
+; CHECK: std %f8, 48(%r15)
+; CHECK: std %f9, 40(%r15)
+; CHECK: std %f10, 32(%r15)
+; CHECK: std %f11, 24(%r15)
+; CHECK: std %f12, 16(%r15)
+; CHECK: std %f13, 8(%r15)
+; CHECK: std %f14, 0(%r15)
 ; CHECK: .cfi_offset %f8, -168
 ; CHECK: .cfi_offset %f9, -176
 ; CHECK: .cfi_offset %f10, -184
@@ -112,14 +112,14 @@ define void @f2(double *%ptr) {
 ; CHECK: .cfi_offset %f14, -216
 ; CHECK-NOT: %f15
 ; ...main function body...
-; CHECK: ld %f8, 208(%r15)
-; CHECK: ld %f9, 200(%r15)
-; CHECK: ld %f10, 192(%r15)
-; CHECK: ld %f11, 184(%r15)
-; CHECK: ld %f12, 176(%r15)
-; CHECK: ld %f13, 168(%r15)
-; CHECK: ld %f14, 160(%r15)
-; CHECK: aghi %r15, 216
+; CHECK: ld %f8, 48(%r15)
+; CHECK: ld %f9, 40(%r15)
+; CHECK: ld %f10, 32(%r15)
+; CHECK: ld %f11, 24(%r15)
+; CHECK: ld %f12, 16(%r15)
+; CHECK: ld %f13, 8(%r15)
+; CHECK: ld %f14, 0(%r15)
+; CHECK: aghi %r15, 56
 ; CHECK: br %r14
   %l0 = load volatile double, double *%ptr
   %l1 = load volatile double, double *%ptr
@@ -172,9 +172,9 @@ define void @f2(double *%ptr) {
 ; Like f1, but should require only one call-saved FPR.
 define void @f3(double *%ptr) {
 ; CHECK-LABEL: f3:
-; CHECK: aghi %r15, -168
-; CHECK: .cfi_def_cfa_offset 328
-; CHECK: std %f8, 160(%r15)
+; CHECK: aghi %r15, -8
+; CHECK: .cfi_def_cfa_offset 168
+; CHECK: std %f8, 0(%r15)
 ; CHECK: .cfi_offset %f8, -168
 ; CHECK-NOT: %f9
 ; CHECK-NOT: %f10
@@ -184,8 +184,8 @@ define void @f3(double *%ptr) {
 ; CHECK-NOT: %f14
 ; CHECK-NOT: %f15
 ; ...main function body...
-; CHECK: ld %f8, 160(%r15)
-; CHECK: aghi %r15, 168
+; CHECK: ld %f8, 0(%r15)
+; CHECK: aghi %r15, 8
 ; CHECK: br %r14
   %l0 = load volatile double, double *%ptr
   %l1 = load volatile double, double *%ptr

diff  --git a/llvm/test/CodeGen/SystemZ/frame-04.ll b/llvm/test/CodeGen/SystemZ/frame-04.ll
index 5e1b29f570c8..ae9c53a7ddcf 100644
--- a/llvm/test/CodeGen/SystemZ/frame-04.ll
+++ b/llvm/test/CodeGen/SystemZ/frame-04.ll
@@ -5,20 +5,20 @@
 
 ; This function should require all FPRs, but no other spill slots.
 ; We need to save and restore 8 of the 16 FPRs, so the frame size
-; should be exactly 160 + 8 * 8 = 224.  The CFA offset is 160
-; (the caller-allocated part of the frame) + 224.
+; should be exactly 8 * 8 = 64.  The CFA offset is 160
+; (the caller-allocated part of the frame) + 64.
 define void @f1(fp128 *%ptr) {
 ; CHECK-LABEL: f1:
-; CHECK: aghi %r15, -224
-; CHECK: .cfi_def_cfa_offset 384
-; CHECK: std %f8, 216(%r15)
-; CHECK: std %f9, 208(%r15)
-; CHECK: std %f10, 200(%r15)
-; CHECK: std %f11, 192(%r15)
-; CHECK: std %f12, 184(%r15)
-; CHECK: std %f13, 176(%r15)
-; CHECK: std %f14, 168(%r15)
-; CHECK: std %f15, 160(%r15)
+; CHECK: aghi %r15, -64
+; CHECK: .cfi_def_cfa_offset 224
+; CHECK: std %f8, 56(%r15)
+; CHECK: std %f9, 48(%r15)
+; CHECK: std %f10, 40(%r15)
+; CHECK: std %f11, 32(%r15)
+; CHECK: std %f12, 24(%r15)
+; CHECK: std %f13, 16(%r15)
+; CHECK: std %f14, 8(%r15)
+; CHECK: std %f15, 0(%r15)
 ; CHECK: .cfi_offset %f8, -168
 ; CHECK: .cfi_offset %f9, -176
 ; CHECK: .cfi_offset %f10, -184
@@ -28,15 +28,15 @@ define void @f1(fp128 *%ptr) {
 ; CHECK: .cfi_offset %f14, -216
 ; CHECK: .cfi_offset %f15, -224
 ; ...main function body...
-; CHECK: ld %f8, 216(%r15)
-; CHECK: ld %f9, 208(%r15)
-; CHECK: ld %f10, 200(%r15)
-; CHECK: ld %f11, 192(%r15)
-; CHECK: ld %f12, 184(%r15)
-; CHECK: ld %f13, 176(%r15)
-; CHECK: ld %f14, 168(%r15)
-; CHECK: ld %f15, 160(%r15)
-; CHECK: aghi %r15, 224
+; CHECK: ld %f8, 56(%r15)
+; CHECK: ld %f9, 48(%r15)
+; CHECK: ld %f10, 40(%r15)
+; CHECK: ld %f11, 32(%r15)
+; CHECK: ld %f12, 24(%r15)
+; CHECK: ld %f13, 16(%r15)
+; CHECK: ld %f14, 8(%r15)
+; CHECK: ld %f15, 0(%r15)
+; CHECK: aghi %r15, 64
 ; CHECK: br %r14
   %l0 = load volatile fp128, fp128 *%ptr
   %l1 = load volatile fp128, fp128 *%ptr
@@ -69,14 +69,14 @@ define void @f1(fp128 *%ptr) {
 ; so %f13+%f15 is the pair that gets dropped.
 define void @f2(fp128 *%ptr) {
 ; CHECK-LABEL: f2:
-; CHECK: aghi %r15, -208
-; CHECK: .cfi_def_cfa_offset 368
-; CHECK: std %f8, 200(%r15)
-; CHECK: std %f9, 192(%r15)
-; CHECK: std %f10, 184(%r15)
-; CHECK: std %f11, 176(%r15)
-; CHECK: std %f12, 168(%r15)
-; CHECK: std %f14, 160(%r15)
+; CHECK: aghi %r15, -48
+; CHECK: .cfi_def_cfa_offset 208
+; CHECK: std %f8, 40(%r15)
+; CHECK: std %f9, 32(%r15)
+; CHECK: std %f10, 24(%r15)
+; CHECK: std %f11, 16(%r15)
+; CHECK: std %f12, 8(%r15)
+; CHECK: std %f14, 0(%r15)
 ; CHECK: .cfi_offset %f8, -168
 ; CHECK: .cfi_offset %f9, -176
 ; CHECK: .cfi_offset %f10, -184
@@ -86,13 +86,13 @@ define void @f2(fp128 *%ptr) {
 ; CHECK-NOT: %f13
 ; CHECK-NOT: %f15
 ; ...main function body...
-; CHECK: ld %f8, 200(%r15)
-; CHECK: ld %f9, 192(%r15)
-; CHECK: ld %f10, 184(%r15)
-; CHECK: ld %f11, 176(%r15)
-; CHECK: ld %f12, 168(%r15)
-; CHECK: ld %f14, 160(%r15)
-; CHECK: aghi %r15, 208
+; CHECK: ld %f8, 40(%r15)
+; CHECK: ld %f9, 32(%r15)
+; CHECK: ld %f10, 24(%r15)
+; CHECK: ld %f11, 16(%r15)
+; CHECK: ld %f12, 8(%r15)
+; CHECK: ld %f14, 0(%r15)
+; CHECK: aghi %r15, 48
 ; CHECK: br %r14
   %l0 = load volatile fp128, fp128 *%ptr
   %l1 = load volatile fp128, fp128 *%ptr
@@ -122,10 +122,10 @@ define void @f2(fp128 *%ptr) {
 ; numerical order so the pair should be %f8+%f10.
 define void @f3(fp128 *%ptr) {
 ; CHECK-LABEL: f3:
-; CHECK: aghi %r15, -176
-; CHECK: .cfi_def_cfa_offset 336
-; CHECK: std %f8, 168(%r15)
-; CHECK: std %f10, 160(%r15)
+; CHECK: aghi %r15, -16
+; CHECK: .cfi_def_cfa_offset 176
+; CHECK: std %f8, 8(%r15)
+; CHECK: std %f10, 0(%r15)
 ; CHECK: .cfi_offset %f8, -168
 ; CHECK: .cfi_offset %f10, -176
 ; CHECK-NOT: %f9
@@ -135,9 +135,9 @@ define void @f3(fp128 *%ptr) {
 ; CHECK-NOT: %f14
 ; CHECK-NOT: %f15
 ; ...main function body...
-; CHECK: ld %f8, 168(%r15)
-; CHECK: ld %f10, 160(%r15)
-; CHECK: aghi %r15, 176
+; CHECK: ld %f8, 8(%r15)
+; CHECK: ld %f10, 0(%r15)
+; CHECK: aghi %r15, 16
 ; CHECK: br %r14
   %l0 = load volatile fp128, fp128 *%ptr
   %l1 = load volatile fp128, fp128 *%ptr

diff  --git a/llvm/test/CodeGen/SystemZ/frame-19.ll b/llvm/test/CodeGen/SystemZ/frame-19.ll
index 2a0693b9ac4c..c6a26600683f 100644
--- a/llvm/test/CodeGen/SystemZ/frame-19.ll
+++ b/llvm/test/CodeGen/SystemZ/frame-19.ll
@@ -96,10 +96,11 @@ define void @f1(<16 x i8> *%ptr) {
   ret void
 }
 
-; Like f1, but no 16-byte slot should be needed.
+; Like f1, but no 16-byte slot should be needed, and no outgoing reg save
+; area of 160 bytes.
 define void @f2(<16 x i8> *%ptr) {
 ; CHECK-LABEL: f2:
-; CHECK: aghi %r15, -224
+; CHECK: aghi %r15, -64
 ; CHECK-DAG: std %f8,
 ; CHECK-DAG: std %f9,
 ; CHECK-DAG: std %f10,
@@ -118,7 +119,7 @@ define void @f2(<16 x i8> *%ptr) {
 ; CHECK-DAG: ld %f13,
 ; CHECK-DAG: ld %f14,
 ; CHECK-DAG: ld %f15,
-; CHECK: aghi %r15, 224
+; CHECK: aghi %r15, 64
 ; CHECK: br %r14
   %v0 = load volatile <16 x i8>, <16 x i8> *%ptr
   %v1 = load volatile <16 x i8>, <16 x i8> *%ptr
@@ -190,7 +191,7 @@ define void @f2(<16 x i8> *%ptr) {
 ; Like f2, but only %f8 should be saved.
 define void @f3(<16 x i8> *%ptr) {
 ; CHECK-LABEL: f3:
-; CHECK: aghi %r15, -168
+; CHECK: aghi %r15, -8
 ; CHECK-DAG: std %f8,
 ; CHECK-NOT: vst {{.*}}(%r15)
 ; CHECK-NOT: vl {{.*}}(%r15)
@@ -202,7 +203,7 @@ define void @f3(<16 x i8> *%ptr) {
 ; CHECK-NOT: %v14
 ; CHECK-NOT: %v15
 ; CHECK-DAG: ld %f8,
-; CHECK: aghi %r15, 168
+; CHECK: aghi %r15, 8
 ; CHECK: br %r14
   %v0 = load volatile <16 x i8>, <16 x i8> *%ptr
   %v1 = load volatile <16 x i8>, <16 x i8> *%ptr

diff  --git a/llvm/test/CodeGen/SystemZ/frame-20.ll b/llvm/test/CodeGen/SystemZ/frame-20.ll
index 8d601c6f6d51..6653c8185b0a 100644
--- a/llvm/test/CodeGen/SystemZ/frame-20.ll
+++ b/llvm/test/CodeGen/SystemZ/frame-20.ll
@@ -5,20 +5,20 @@
 
 ; This function should require all FPRs, but no other spill slots.
 ; We need to save and restore 8 of the 16 FPRs, so the frame size
-; should be exactly 160 + 8 * 8 = 224.  The CFA offset is 160
-; (the caller-allocated part of the frame) + 224.
+; should be exactly 8 * 8 = 64.  The CFA offset is 160
+; (the caller-allocated part of the frame) + 64.
 define void @f1(double *%ptr) {
 ; CHECK-LABEL: f1:
-; CHECK: aghi %r15, -224
-; CHECK: .cfi_def_cfa_offset 384
-; CHECK: std %f8, 216(%r15)
-; CHECK: std %f9, 208(%r15)
-; CHECK: std %f10, 200(%r15)
-; CHECK: std %f11, 192(%r15)
-; CHECK: std %f12, 184(%r15)
-; CHECK: std %f13, 176(%r15)
-; CHECK: std %f14, 168(%r15)
-; CHECK: std %f15, 160(%r15)
+; CHECK: aghi %r15, -64
+; CHECK: .cfi_def_cfa_offset 224
+; CHECK: std %f8, 56(%r15)
+; CHECK: std %f9, 48(%r15)
+; CHECK: std %f10, 40(%r15)
+; CHECK: std %f11, 32(%r15)
+; CHECK: std %f12, 24(%r15)
+; CHECK: std %f13, 16(%r15)
+; CHECK: std %f14, 8(%r15)
+; CHECK: std %f15, 0(%r15)
 ; CHECK: .cfi_offset %f8, -168
 ; CHECK: .cfi_offset %f9, -176
 ; CHECK: .cfi_offset %f10, -184
@@ -35,15 +35,15 @@ define void @f1(double *%ptr) {
 ; CHECK-DAG: vlrepg %v23, 0(%r2)
 ; CHECK-DAG: vlrepg %v24, 0(%r2)
 ; CHECK-DAG: vlrepg %v31, 0(%r2)
-; CHECK: ld %f8, 216(%r15)
-; CHECK: ld %f9, 208(%r15)
-; CHECK: ld %f10, 200(%r15)
-; CHECK: ld %f11, 192(%r15)
-; CHECK: ld %f12, 184(%r15)
-; CHECK: ld %f13, 176(%r15)
-; CHECK: ld %f14, 168(%r15)
-; CHECK: ld %f15, 160(%r15)
-; CHECK: aghi %r15, 224
+; CHECK: ld %f8, 56(%r15)
+; CHECK: ld %f9, 48(%r15)
+; CHECK: ld %f10, 40(%r15)
+; CHECK: ld %f11, 32(%r15)
+; CHECK: ld %f12, 24(%r15)
+; CHECK: ld %f13, 16(%r15)
+; CHECK: ld %f14, 8(%r15)
+; CHECK: ld %f15, 0(%r15)
+; CHECK: aghi %r15, 64
 ; CHECK: br %r14
   %l0 = load volatile double, double *%ptr
   %l1 = load volatile double, double *%ptr
@@ -148,15 +148,15 @@ define void @f1(double *%ptr) {
 ; so %f15 is the one that gets dropped.
 define void @f2(double *%ptr) {
 ; CHECK-LABEL: f2:
-; CHECK: aghi %r15, -216
-; CHECK: .cfi_def_cfa_offset 376
-; CHECK: std %f8, 208(%r15)
-; CHECK: std %f9, 200(%r15)
-; CHECK: std %f10, 192(%r15)
-; CHECK: std %f11, 184(%r15)
-; CHECK: std %f12, 176(%r15)
-; CHECK: std %f13, 168(%r15)
-; CHECK: std %f14, 160(%r15)
+; CHECK: aghi %r15, -56
+; CHECK: .cfi_def_cfa_offset 216
+; CHECK: std %f8, 48(%r15)
+; CHECK: std %f9, 40(%r15)
+; CHECK: std %f10, 32(%r15)
+; CHECK: std %f11, 24(%r15)
+; CHECK: std %f12, 16(%r15)
+; CHECK: std %f13, 8(%r15)
+; CHECK: std %f14, 0(%r15)
 ; CHECK: .cfi_offset %f8, -168
 ; CHECK: .cfi_offset %f9, -176
 ; CHECK: .cfi_offset %f10, -184
@@ -166,14 +166,14 @@ define void @f2(double *%ptr) {
 ; CHECK: .cfi_offset %f14, -216
 ; CHECK-NOT: %v15
 ; CHECK-NOT: %f15
-; CHECK: ld %f8, 208(%r15)
-; CHECK: ld %f9, 200(%r15)
-; CHECK: ld %f10, 192(%r15)
-; CHECK: ld %f11, 184(%r15)
-; CHECK: ld %f12, 176(%r15)
-; CHECK: ld %f13, 168(%r15)
-; CHECK: ld %f14, 160(%r15)
-; CHECK: aghi %r15, 216
+; CHECK: ld %f8, 48(%r15)
+; CHECK: ld %f9, 40(%r15)
+; CHECK: ld %f10, 32(%r15)
+; CHECK: ld %f11, 24(%r15)
+; CHECK: ld %f12, 16(%r15)
+; CHECK: ld %f13, 8(%r15)
+; CHECK: ld %f14, 0(%r15)
+; CHECK: aghi %r15, 56
 ; CHECK: br %r14
   %l0 = load volatile double, double *%ptr
   %l1 = load volatile double, double *%ptr
@@ -274,14 +274,14 @@ define void @f2(double *%ptr) {
 ; Like f1, but should require only one call-saved FPR.
 define void @f3(double *%ptr) {
 ; CHECK-LABEL: f3:
-; CHECK: aghi %r15, -168
-; CHECK: .cfi_def_cfa_offset 328
-; CHECK: std %f8, 160(%r15)
+; CHECK: aghi %r15, -8
+; CHECK: .cfi_def_cfa_offset 168
+; CHECK: std %f8, 0(%r15)
 ; CHECK: .cfi_offset %f8, -168
 ; CHECK-NOT: {{%[fv]9}}
 ; CHECK-NOT: {{%[fv]1[0-5]}}
-; CHECK: ld %f8, 160(%r15)
-; CHECK: aghi %r15, 168
+; CHECK: ld %f8, 0(%r15)
+; CHECK: aghi %r15, 8
 ; CHECK: br %r14
   %l0 = load volatile double, double *%ptr
   %l1 = load volatile double, double *%ptr

diff  --git a/llvm/test/CodeGen/SystemZ/frame-22.ll b/llvm/test/CodeGen/SystemZ/frame-22.ll
new file mode 100644
index 000000000000..fd4e3fec508a
--- /dev/null
+++ b/llvm/test/CodeGen/SystemZ/frame-22.ll
@@ -0,0 +1,87 @@
+; RUN: llc < %s -mtriple=s390x-linux-gnu | FileCheck %s
+;
+; Test the packed stack layout.
+
+; Test spill/restore of an FPR and a GPR.
+define void @f1() #0 {
+; CHECK-LABEL: f1:
+; CHECK: stmg %r12, %r15, 128(%r15)
+; CHECK-NEXT: .cfi_offset %r12, -32
+; CHECK-NEXT: .cfi_offset %r15, -8
+; CHECK-NEXT: std %f8, 120(%r15)          # 8-byte Folded Spill
+; CHECK-NEXT: .cfi_offset %f8, -40
+; CHECK-NEXT: #APP
+; CHECK-NEXT: #NO_APP
+; CHECK-NEXT: ld %f8, 120(%r15)          # 8-byte Folded Reload
+; CHECK-NEXT: lmg %r12, %r15, 128(%r15)
+; CHECK-NEXT: br %r14
+  call void asm sideeffect "", "~{f8},~{r12}"() nounwind
+  ret void
+}
+
+; Test spill/restore with anyregcc, including an FP argument register.
+define anyregcc void @f2() #0 {
+; CHECK-LABEL: f2:
+; CHECK: stmg %r3, %r15, 56(%r15)
+; CHECK-NEXT: .cfi_offset %r3, -104
+; CHECK-NEXT: .cfi_offset %r15, -8
+; CHECK-NEXT: std %f0, 48(%r15)          # 8-byte Folded Spill
+; CHECK-NEXT: std %f1, 40(%r15)          # 8-byte Folded Spill
+; CHECK-NEXT: .cfi_offset %f0, -112
+; CHECK-NEXT: .cfi_offset %f1, -120
+; CHECK-NEXT: #APP
+; CHECK-NEXT: #NO_APP
+; CHECK-NEXT: ld %f0, 48(%r15)          # 8-byte Folded Reload
+; CHECK-NEXT: ld %f1, 40(%r15)          # 8-byte Folded Reload
+; CHECK-NEXT: lmg %r3, %r15, 56(%r15)
+; CHECK-NEXT: br %r14
+  call void asm sideeffect "", "~{f0},~{f1},~{r3}"() nounwind
+  ret void
+}
+
+; Test spill/restore in local area with incoming stack arguments.
+define i64 @f3(i64 %a, i64 %b, i64 %c, i64 %d, i64 %e, i64 %f,
+               double %A, double %B, double %C, double %D, double %E) #0 {
+; CHECK-LABEL: f3:
+; CHECK: std %f8, 152(%r15)          # 8-byte Folded Spill
+; CHECK-NEXT: .cfi_offset %f8, -8
+; CHECK-NEXT: ld %f0, 168(%r15)
+; CHECK-NEXT: cgdbr %r2, 5, %f0
+; CHECK-NEXT: ag %r2, 160(%r15)
+; CHECK-NEXT: #APP
+; CHECK-NEXT: #NO_APP
+; CHECK-NEXT: ld %f8, 152(%r15)          # 8-byte Folded Reload
+; CHECK-NEXT: br %r14
+  call void asm sideeffect "", "~{f8}"() nounwind
+  %Ei = fptosi double %E to i64
+  %S = add i64 %f, %Ei
+  ret i64 %S
+}
+
+; Test spill/restore in local area with outgoing stack arguments.
+define i64 @f4() #0 {
+; CHECK-LABEL: f4:
+; CHECK: stmg    %r6, %r15, 80(%r15)
+; CHECK-NEXT: .cfi_offset %r6, -80
+; CHECK-NEXT: .cfi_offset %r14, -16
+; CHECK-NEXT: .cfi_offset %r15, -8
+; CHECK-NEXT: aghi    %r15, -104
+; CHECK-NEXT: .cfi_def_cfa_offset 264
+; CHECK-NEXT: std     %f8, 176(%r15)          # 8-byte Folded Spill
+; CHECK-NEXT: .cfi_offset %f8, -88
+; CHECK-NEXT: #APP
+; CHECK-NEXT: #NO_APP
+; CHECK-NEXT: llihh   %r0, 16404
+; CHECK-NEXT: stg     %r0, 168(%r15)
+; CHECK: mvghi   160(%r15), 6
+; CHECK-NEXT: brasl   %r14, f3 at PLT
+; CHECK-NEXT: ld      %f8, 176(%r15)          # 8-byte Folded Reload
+; CHECK-NEXT: lmg     %r6, %r15, 184(%r15)
+; CHECK-NEXT: br      %r14
+  call void asm sideeffect "", "~{f8}"() nounwind
+  %C = call i64 @f3 (i64 1, i64 2, i64 3, i64 4, i64 5, i64 6,
+                     double 1.0, double 2.0, double 3.0, double 4.0, double 5.0)
+  ret i64 %C
+}
+
+attributes #0 = { "packed-stack"="true" }


        


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