This patch implements medium code model support for 64-bit PowerPC.

The default for 64-bit PowerPC is small code model, in which TOC entries
must be addressable using a 16-bit offset from the TOC pointer.  Additionally,
only TOC entries are addressed via the TOC pointer.

With medium code model, TOC entries and data sections can all be addressed
via the TOC pointer using a 32-bit offset.  Cooperation with the linker
allows 16-bit offsets to be used when these are sufficient, reducing the
number of extra instructions that need to be executed.  Medium code model
also does not generate explicit TOC entries in ".section toc" for variables
that are wholly internal to the compilation unit.

Consider a load of an external 4-byte integer.  With small code model, the
compiler generates:

	ld 3, .LC1@toc(2)
	lwz 4, 0(3)

	.section	.toc,"aw",@progbits
.LC1:
	.tc ei[TC],ei

With medium model, it instead generates:

	addis 3, 2, .LC1@toc@ha
	ld 3, .LC1@toc@l(3)
	lwz 4, 0(3)

	.section	.toc,"aw",@progbits
.LC1:
	.tc ei[TC],ei

Here .LC1@toc@ha is a relocation requesting the upper 16 bits of the
32-bit offset of ei's TOC entry from the TOC base pointer.  Similarly,
.LC1@toc@l is a relocation requesting the lower 16 bits.  Note that if
the linker determines that ei's TOC entry is within a 16-bit offset of
the TOC base pointer, it will replace the "addis" with a "nop", and
replace the "ld" with the identical "ld" instruction from the small
code model example.

Consider next a load of a function-scope static integer.  For small code
model, the compiler generates:

	ld 3, .LC1@toc(2)
	lwz 4, 0(3)

	.section	.toc,"aw",@progbits
.LC1:
	.tc test_fn_static.si[TC],test_fn_static.si
	.type	test_fn_static.si,@object
	.local	test_fn_static.si
	.comm	test_fn_static.si,4,4

For medium code model, the compiler generates:

	addis 3, 2, test_fn_static.si@toc@ha
	addi 3, 3, test_fn_static.si@toc@l
	lwz 4, 0(3)

	.type	test_fn_static.si,@object
	.local	test_fn_static.si
	.comm	test_fn_static.si,4,4

Again, the linker may replace the "addis" with a "nop", calculating only
a 16-bit offset when this is sufficient.

Note that it would be more efficient for the compiler to generate:

	addis 3, 2, test_fn_static.si@toc@ha
        lwz 4, test_fn_static.si@toc@l(3)

The current patch does not perform this optimization yet.  This will be
addressed as a peephole optimization in a later patch.

For the moment, the default code model for 64-bit PowerPC will remain the
small code model.  We plan to eventually change the default to medium code
model, which matches current upstream GCC behavior.  Note that the different
code models are ABI-compatible, so code compiled with different models will
be linked and execute correctly.

I've tested the regression suite and the application/benchmark test suite in
two ways:  Once with the patch as submitted here, and once with additional
logic to force medium code model as the default.  The tests all compile
cleanly, with one exception.  The mandel-2 application test fails due to an
unrelated ABI compatibility with passing complex numbers.  It just so happens
that small code model was incredibly lucky, in that temporary values in 
floating-point registers held the expected values needed by the external
library routine that was called incorrectly.  My current thought is to correct
the ABI problems with _Complex before making medium code model the default,
to avoid introducing this "regression."

Here are a few comments on how the patch works, since the selection code
can be difficult to follow:

The existing logic for small code model defines three pseudo-instructions:
LDtoc for most uses, LDtocJTI for jump table addresses, and LDtocCPT for
constant pool addresses.  These are expanded by SelectCodeCommon().  The
pseudo-instruction approach doesn't work for medium code model, because
we need to generate two instructions when we match the same pattern.
Instead, new logic in PPCDAGToDAGISel::Select() intercepts the TOC_ENTRY
node for medium code model, and generates an ADDIStocHA followed by either
a LDtocL or an ADDItocL.  These new node types correspond naturally to
the sequences described above.

The addis/ld sequence is generated for the following cases:
 * Jump table addresses
 * Function addresses
 * External global variables
 * Tentative definitions of global variables (common linkage)

The addis/addi sequence is generated for the following cases:
 * Constant pool entries
 * File-scope static global variables
 * Function-scope static variables

Expanding to the two-instruction sequences at select time exposes the
instructions to subsequent optimization, particularly scheduling.

The rest of the processing occurs at assembly time, in
PPCAsmPrinter::EmitInstruction.  Each of the instructions is converted to
a "real" PowerPC instruction.  When a TOC entry needs to be created, this
is done here in the same manner as for the existing LDtoc, LDtocJTI, and
LDtocCPT pseudo-instructions (I factored out a new routine to handle this).

I had originally thought that if a TOC entry was needed for LDtocL or
ADDItocL, it would already have been generated for the previous ADDIStocHA.
However, at higher optimization levels, the ADDIStocHA may appear in a 
different block, which may be assembled textually following the block
containing the LDtocL or ADDItocL.  So it is necessary to include the
possibility of creating a new TOC entry for those two instructions.

Note that for LDtocL, we generate a new form of LD called LDrs.  This
allows specifying the @toc@l relocation for the offset field of the LD
instruction (i.e., the offset is replaced by a SymbolLo relocation).
When the peephole optimization described above is added, we will need
to do similar things for all immediate-form load and store operations.

The seven "mcm-n.ll" test cases are kept separate because otherwise the
intermingling of various TOC entries and so forth makes the tests fragile
and hard to understand.

The above assumes use of an external assembler.  For use of the
integrated assembler, new relocations are added and used by
PPCELFObjectWriter.  Testing is done with "mcm-obj.ll", which tests for
proper generation of the various relocations for the same sequences
tested with the external assembler.






git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168708 91177308-0d34-0410-b5e6-96231b3b80d8

8 files changed, 235 insertions, 10 deletions

diff --git a/lib/MC/MCExpr.cpp b/lib/MC/MCExpr.cpp
index de2f375aab..d601d4e94a 100644
--- a/lib/MC/MCExpr.cpp
+++ b/lib/MC/MCExpr.cpp
@@ -209,6 +209,8 @@ StringRef MCSymbolRefExpr::getVariantKindName(VariantKind Kind) {
   case VK_PPC_GAS_LO16: return "l";
   case VK_PPC_TPREL16_HA: return "tprel@ha";
   case VK_PPC_TPREL16_LO: return "tprel@l";
+  case VK_PPC_TOC16_HA: return "toc@ha";
+  case VK_PPC_TOC16_LO: return "toc@l";
   case VK_Mips_GPREL: return "GPREL";
   case VK_Mips_GOT_CALL: return "GOT_CALL";
   case VK_Mips_GOT16: return "GOT16";
diff --git a/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp b/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp
index dc93f7124a..0fc0dd9f7c 100644
--- a/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp
+++ b/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp
@@ -82,6 +82,9 @@ unsigned PPCELFObjectWriter::getRelocTypeInner(const MCValue &Target,
       case MCSymbolRefExpr::VK_None:
         Type = ELF::R_PPC_ADDR16_HA;
 	break;
+      case MCSymbolRefExpr::VK_PPC_TOC16_HA:
+        Type = ELF::R_PPC64_TOC16_HA;
+        break;
       }
       break;
     case PPC::fixup_ppc_lo16:
@@ -93,6 +96,9 @@ unsigned PPCELFObjectWriter::getRelocTypeInner(const MCValue &Target,
       case MCSymbolRefExpr::VK_None:
         Type = ELF::R_PPC_ADDR16_LO;
 	break;
+      case MCSymbolRefExpr::VK_PPC_TOC16_LO:
+        Type = ELF::R_PPC64_TOC16_LO;
+        break;
       }
       break;
     case PPC::fixup_ppc_lo14:
@@ -105,7 +111,15 @@ unsigned PPCELFObjectWriter::getRelocTypeInner(const MCValue &Target,
       Type = ELF::R_PPC64_TOC16;
       break;
     case PPC::fixup_ppc_toc16_ds:
-      Type = ELF::R_PPC64_TOC16_DS;
+      switch (Modifier) {
+      default: llvm_unreachable("Unsupported Modifier");
+      case MCSymbolRefExpr::VK_PPC_TOC_ENTRY:
+        Type = ELF::R_PPC64_TOC16_DS;
+	break;
+      case MCSymbolRefExpr::VK_PPC_TOC16_LO:
+        Type = ELF::R_PPC64_TOC16_LO_DS;
+        break;
+      }
       break;
     case FK_Data_8:
       switch (Modifier) {
diff --git a/lib/Target/PowerPC/PPCAsmPrinter.cpp b/lib/Target/PowerPC/PPCAsmPrinter.cpp
index 3900c8bab4..5430fbd523 100644
--- a/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ b/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -73,6 +73,7 @@ namespace {
       return "PowerPC Assembly Printer";
     }
 
+    MCSymbol *lookUpOrCreateTOCEntry(MCSymbol *Sym);
 
     virtual void EmitInstruction(const MachineInstr *MI);
 
@@ -310,6 +311,25 @@ bool PPCAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
 }
 
 
+/// lookUpOrCreateTOCEntry -- Given a symbol, look up whether a TOC entry
+/// exists for it.  If not, create one.  Then return a symbol that references
+/// the TOC entry.
+MCSymbol *PPCAsmPrinter::lookUpOrCreateTOCEntry(MCSymbol *Sym) {
+
+  MCSymbol *&TOCEntry = TOC[Sym];
+
+  // To avoid name clash check if the name already exists.
+  while (TOCEntry == 0) {
+    if (OutContext.LookupSymbol(Twine(MAI->getPrivateGlobalPrefix()) +
+                                "C" + Twine(TOCLabelID++)) == 0) {
+      TOCEntry = GetTempSymbol("C", TOCLabelID);
+    }
+  }
+
+  return TOCEntry;
+}
+
+
 /// EmitInstruction -- Print out a single PowerPC MI in Darwin syntax to
 /// the current output stream.
 ///
@@ -379,14 +399,8 @@ void PPCAsmPrinter::EmitInstruction(const MachineInstr *MI) {
       MOSymbol = GetCPISymbol(MO.getIndex());
     else if (MO.isJTI())
       MOSymbol = GetJTISymbol(MO.getIndex());
-    MCSymbol *&TOCEntry = TOC[MOSymbol];
-    // To avoid name clash check if the name already exists.
-    while (TOCEntry == 0) {
-      if (OutContext.LookupSymbol(Twine(MAI->getPrivateGlobalPrefix()) +
-                                  "C" + Twine(TOCLabelID++)) == 0) {
-        TOCEntry = GetTempSymbol("C", TOCLabelID);
-      }
-    }
+
+    MCSymbol *TOCEntry = lookUpOrCreateTOCEntry(MOSymbol);
 
     const MCExpr *Exp =
       MCSymbolRefExpr::Create(TOCEntry, MCSymbolRefExpr::VK_PPC_TOC_ENTRY,
@@ -396,6 +410,109 @@ void PPCAsmPrinter::EmitInstruction(const MachineInstr *MI) {
     return;
   }
       
+  case PPC::ADDIStocHA: {
+    // Transform %Xd = ADDIStocHA %X2, <ga:@sym>
+    LowerPPCMachineInstrToMCInst(MI, TmpInst, *this, Subtarget.isDarwin());
+
+    // Change the opcode to ADDIS8.  If the global address is external,
+    // has common linkage, is a function address, or is a jump table
+    // address, then generate a TOC entry and reference that.  Otherwise
+    // reference the symbol directly.
+    TmpInst.setOpcode(PPC::ADDIS8);
+    const MachineOperand &MO = MI->getOperand(2);
+    assert((MO.isGlobal() || MO.isCPI() || MO.isJTI()) &&
+           "Invalid operand for ADDIStocHA!");
+    MCSymbol *MOSymbol = 0;
+    bool IsExternal = false;
+    bool IsFunction = false;
+    bool IsCommon = false;
+
+    if (MO.isGlobal()) {
+      const GlobalValue *GValue = MO.getGlobal();
+      MOSymbol = Mang->getSymbol(GValue);
+      const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GValue);
+      IsExternal = GVar && !GVar->hasInitializer();
+      IsCommon = GVar && GValue->hasCommonLinkage();
+      IsFunction = !GVar;
+    } else if (MO.isCPI())
+      MOSymbol = GetCPISymbol(MO.getIndex());
+    else if (MO.isJTI())
+      MOSymbol = GetJTISymbol(MO.getIndex());
+
+    if (IsExternal || IsFunction || IsCommon || MO.isJTI())
+      MOSymbol = lookUpOrCreateTOCEntry(MOSymbol);
+
+    const MCExpr *Exp =
+      MCSymbolRefExpr::Create(MOSymbol, MCSymbolRefExpr::VK_PPC_TOC16_HA,
+                              OutContext);
+    TmpInst.getOperand(2) = MCOperand::CreateExpr(Exp);
+    OutStreamer.EmitInstruction(TmpInst);
+    return;
+  }
+  case PPC::LDtocL: {
+    // Transform %Xd = LDtocL <ga:@sym>, %Xs
+    LowerPPCMachineInstrToMCInst(MI, TmpInst, *this, Subtarget.isDarwin());
+
+    // Change the opcode to LDrs, which is a form of LD with the offset
+    // specified by a SymbolLo.  If the global address is external, has
+    // common linkage, or is a jump table address, then reference the
+    // associated TOC entry.  Otherwise reference the symbol directly.
+    TmpInst.setOpcode(PPC::LDrs);
+    const MachineOperand &MO = MI->getOperand(1);
+    assert((MO.isGlobal() || MO.isJTI()) && "Invalid operand for LDtocL!");
+    MCSymbol *MOSymbol = 0;
+
+    if (MO.isJTI())
+      MOSymbol = lookUpOrCreateTOCEntry(GetJTISymbol(MO.getIndex()));
+    else {
+      const GlobalValue *GValue = MO.getGlobal();
+      MOSymbol = Mang->getSymbol(GValue);
+      const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GValue);
+    
+      if (!GVar || !GVar->hasInitializer() || GValue->hasCommonLinkage())
+        MOSymbol = lookUpOrCreateTOCEntry(MOSymbol);
+    }
+
+    const MCExpr *Exp =
+      MCSymbolRefExpr::Create(MOSymbol, MCSymbolRefExpr::VK_PPC_TOC16_LO,
+                              OutContext);
+    TmpInst.getOperand(1) = MCOperand::CreateExpr(Exp);
+    OutStreamer.EmitInstruction(TmpInst);
+    return;
+  }
+  case PPC::ADDItocL: {
+    // Transform %Xd = ADDItocL %Xs, <ga:@sym>
+    LowerPPCMachineInstrToMCInst(MI, TmpInst, *this, Subtarget.isDarwin());
+
+    // Change the opcode to ADDI8L.  If the global address is external, then
+    // generate a TOC entry and reference that.  Otherwise reference the
+    // symbol directly.
+    TmpInst.setOpcode(PPC::ADDI8L);
+    const MachineOperand &MO = MI->getOperand(2);
+    assert((MO.isGlobal() || MO.isCPI()) && "Invalid operand for ADDItocL");
+    MCSymbol *MOSymbol = 0;
+    bool IsExternal = false;
+    bool IsFunction = false;
+
+    if (MO.isGlobal()) {
+      const GlobalValue *GValue = MO.getGlobal();
+      MOSymbol = Mang->getSymbol(GValue);
+      const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GValue);
+      IsExternal = GVar && !GVar->hasInitializer();
+      IsFunction = !GVar;
+    } else if (MO.isCPI())
+      MOSymbol = GetCPISymbol(MO.getIndex());
+
+    if (IsFunction || IsExternal)
+      MOSymbol = lookUpOrCreateTOCEntry(MOSymbol);
+
+    const MCExpr *Exp =
+      MCSymbolRefExpr::Create(MOSymbol, MCSymbolRefExpr::VK_PPC_TOC16_LO,
+                              OutContext);
+    TmpInst.getOperand(2) = MCOperand::CreateExpr(Exp);
+    OutStreamer.EmitInstruction(TmpInst);
+    return;
+  }
   case PPC::MFCRpseud:
   case PPC::MFCR8pseud:
     // Transform: %R3 = MFCRpseud %CR7
diff --git a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index 254fea67fc..ae8a9348fb 100644
--- a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -25,6 +25,7 @@
 #include "llvm/Constants.h"
 #include "llvm/Function.h"
 #include "llvm/GlobalValue.h"
+#include "llvm/GlobalVariable.h"
 #include "llvm/Intrinsics.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/MathExtras.h"
@@ -1268,6 +1269,48 @@ SDNode *PPCDAGToDAGISel::Select(SDNode *N) {
                                            Chain), 0);
     return CurDAG->SelectNodeTo(N, Reg, MVT::Other, Chain);
   }
+  case PPCISD::TOC_ENTRY: {
+    assert (PPCSubTarget.isPPC64() && "Only supported for 64-bit ABI");
+
+    // For medium code model, we generate two instructions as described
+    // below.  Otherwise we allow SelectCodeCommon to handle this, selecting
+    // one of LDtoc, LDtocJTI, and LDtocCPT.
+    if (TM.getCodeModel() != CodeModel::Medium)
+      break;
+
+    // The first source operand is a TargetGlobalAddress or a
+    // TargetJumpTable.  If it is an externally defined symbol, a symbol
+    // with common linkage, a function address, or a jump table address,
+    // we generate:
+    //   LDtocL(<ga:@sym>, ADDIStocHA(%X2, <ga:@sym>))
+    // Otherwise we generate:
+    //   ADDItocL(ADDIStocHA(%X2, <ga:@sym>), <ga:@sym>)
+    SDValue GA = N->getOperand(0);
+    SDValue TOCbase = N->getOperand(1);
+    SDNode *Tmp = CurDAG->getMachineNode(PPC::ADDIStocHA, dl, MVT::i64,
+                                        TOCbase, GA);
+
+    if (isa<JumpTableSDNode>(GA))
+      return CurDAG->getMachineNode(PPC::LDtocL, dl, MVT::i64, GA,
+                                    SDValue(Tmp, 0));
+
+    if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(GA)) {
+      const GlobalValue *GValue = G->getGlobal();
+      const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GValue);
+      assert((GVar || isa<Function>(GValue)) &&
+             "Unexpected global value subclass!");
+
+      // An external variable is one without an initializer.  For these,
+      // for variables with common linkage, and for Functions, generate
+      // the LDtocL form.
+      if (!GVar || !GVar->hasInitializer() || GValue->hasCommonLinkage())
+        return CurDAG->getMachineNode(PPC::LDtocL, dl, MVT::i64, GA,
+                                      SDValue(Tmp, 0));
+    }
+
+    return CurDAG->getMachineNode(PPC::ADDItocL, dl, MVT::i64,
+                                  SDValue(Tmp, 0), GA);
+  }
   }
 
   return SelectCode(N);
diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index 7d97450676..1c8524d3f9 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -575,6 +575,9 @@ const char *PPCTargetLowering::getTargetNodeName(unsigned Opcode) const {
   case PPCISD::TC_RETURN:       return "PPCISD::TC_RETURN";
   case PPCISD::CR6SET:          return "PPCISD::CR6SET";
   case PPCISD::CR6UNSET:        return "PPCISD::CR6UNSET";
+  case PPCISD::ADDIS_TOC_HA:    return "PPCISD::ADDIS_TOC_HA";
+  case PPCISD::LD_TOC_L:        return "PPCISD::LD_TOC_L";
+  case PPCISD::ADDI_TOC_L:      return "PPCISD::ADDI_TOC_L";
   }
 }
 
diff --git a/lib/Target/PowerPC/PPCISelLowering.h b/lib/Target/PowerPC/PPCISelLowering.h
index b3c7f9c28d..b187f856f3 100644
--- a/lib/Target/PowerPC/PPCISelLowering.h
+++ b/lib/Target/PowerPC/PPCISelLowering.h
@@ -191,7 +191,21 @@ namespace llvm {
       /// byte-swapping load instruction.  It loads "Type" bits, byte swaps it,
       /// then puts it in the bottom bits of the GPRC.  TYPE can be either i16
       /// or i32.
-      LBRX
+      LBRX,
+
+      /// G8RC = ADDIS_TOC_HA %X2, Symbol - For medium code model, produces
+      /// an ADDIS8 instruction that adds the TOC base register to sym@toc@ha.
+      ADDIS_TOC_HA,
+
+      /// G8RC = LD_TOC_L Symbol, G8RReg - For medium code model, produces a
+      /// LD instruction with base register G8RReg and offset sym@toc@l.
+      /// Preceded by an ADDIS_TOC_HA to form a full 32-bit offset.
+      LD_TOC_L,
+
+      /// G8RC = ADDI_TOC_L G8RReg, Symbol - For medium code model, produces
+      /// an ADDI8 instruction that adds G8RReg to sym@toc@l.
+      /// Preceded by an ADDIS_TOC_HA to form a full 32-bit offset.
+      ADDI_TOC_L
     };
   }
 
diff --git a/lib/Target/PowerPC/PPCInstr64Bit.td b/lib/Target/PowerPC/PPCInstr64Bit.td
index 9711452ec4..78844f5edd 100644
--- a/lib/Target/PowerPC/PPCInstr64Bit.td
+++ b/lib/Target/PowerPC/PPCInstr64Bit.td
@@ -32,6 +32,11 @@ def symbolLo64 : Operand<i64> {
 def tocentry : Operand<iPTR> {
   let MIOperandInfo = (ops i32imm:$imm);
 }
+def memrs : Operand<iPTR> {   // memri where the immediate is a symbolLo64
+  let PrintMethod = "printMemRegImm";
+  let EncoderMethod = "getMemRIXEncoding";
+  let MIOperandInfo = (ops symbolLo64:$off, ptr_rc:$reg);
+}
 
 //===----------------------------------------------------------------------===//
 // 64-bit transformation functions.
@@ -625,6 +630,12 @@ let canFoldAsLoad = 1, PPC970_Unit = 2 in {
 def LD   : DSForm_1<58, 0, (outs G8RC:$rD), (ins memrix:$src),
                     "ld $rD, $src", LdStLD,
                     [(set G8RC:$rD, (load ixaddr:$src))]>, isPPC64;
+def LDrs : DSForm_1<58, 0, (outs G8RC:$rD), (ins memrs:$src),
+                    "ld $rD, $src", LdStLD,
+                    []>, isPPC64;
+// The following three definitions are selected for small code model only.
+// Otherwise, we need to create two instructions to form a 32-bit offset,
+// so we have a custom matcher for TOC_ENTRY in PPCDAGToDAGIsel::Select().
 def LDtoc: Pseudo<(outs G8RC:$rD), (ins tocentry:$disp, G8RC:$reg),
                   "#LDtoc",
                   [(set G8RC:$rD,
@@ -671,6 +682,21 @@ def : Pat<(PPCload ixaddr:$src),
 def : Pat<(PPCload xaddr:$src),
           (LDX xaddr:$src)>;
 
+// Support for medium code model.
+def ADDIStocHA: Pseudo<(outs G8RC:$rD), (ins G8RC:$reg, tocentry:$disp),
+                       "#ADDIStocHA",
+                       [(set G8RC:$rD,
+                         (PPCaddisTocHA G8RC:$reg, tglobaladdr:$disp))]>,
+                       isPPC64;
+def LDtocL: Pseudo<(outs G8RC:$rD), (ins tocentry:$disp, G8RC:$reg),
+                   "#LDtocL",
+                   [(set G8RC:$rD,
+                     (PPCldTocL tglobaladdr:$disp, G8RC:$reg))]>, isPPC64;
+def ADDItocL: Pseudo<(outs G8RC:$rD), (ins G8RC:$reg, tocentry:$disp),
+                     "#ADDItocL",
+                     [(set G8RC:$rD,
+                       (PPCaddiTocL G8RC:$reg, tglobaladdr:$disp))]>, isPPC64;
+
 let PPC970_Unit = 2 in {
 // Truncating stores.                       
 def STB8 : DForm_1<38, (outs), (ins G8RC:$rS, memri:$src),
diff --git a/lib/Target/PowerPC/PPCInstrInfo.td b/lib/Target/PowerPC/PPCInstrInfo.td
index 6ee045a2c7..937ed0d90b 100644
--- a/lib/Target/PowerPC/PPCInstrInfo.td
+++ b/lib/Target/PowerPC/PPCInstrInfo.td
@@ -167,6 +167,12 @@ def PPClarx      : SDNode<"PPCISD::LARX", SDT_PPClarx,
 def PPCstcx      : SDNode<"PPCISD::STCX", SDT_PPCstcx,
                           [SDNPHasChain, SDNPMayStore]>;
 
+// Instructions to support medium code model
+def PPCaddisTocHA : SDNode<"PPCISD::ADDIS_TOC_HA", SDTIntBinOp, []>;
+def PPCldTocL     : SDNode<"PPCISD::LD_TOC_L", SDTIntBinOp, [SDNPMayLoad]>;
+def PPCaddiTocL   : SDNode<"PPCISD::ADDI_TOC_L", SDTIntBinOp, []>;
+
+
 // Instructions to support dynamic alloca.
 def SDTDynOp  : SDTypeProfile<1, 2, []>;
 def PPCdynalloc   : SDNode<"PPCISD::DYNALLOC", SDTDynOp, [SDNPHasChain]>;