Implement a bunch more TargetSelectionDAGInfo infrastructure.

Move EmitTargetCodeForMemcpy, EmitTargetCodeForMemset, and
EmitTargetCodeForMemmove out of TargetLowering and into
SelectionDAGInfo to exercise this.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103481 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 223 insertions, 2 deletions

diff --git a/lib/Target/X86/X86SelectionDAGInfo.cpp b/lib/Target/X86/X86SelectionDAGInfo.cpp
index cd87b82..6297a27 100644
--- a/lib/Target/X86/X86SelectionDAGInfo.cpp
+++ b/lib/Target/X86/X86SelectionDAGInfo.cpp
@@ -12,11 +12,232 @@
 //===----------------------------------------------------------------------===//
 
 #define DEBUG_TYPE "x86-selectiondag-info"
-#include "X86SelectionDAGInfo.h"
+#include "X86TargetMachine.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/CodeGen/SelectionDAG.h"
 using namespace llvm;
 
-X86SelectionDAGInfo::X86SelectionDAGInfo() {
+X86SelectionDAGInfo::X86SelectionDAGInfo(const X86TargetMachine &TM) :
+  TargetSelectionDAGInfo(TM),
+  Subtarget(&TM.getSubtarget<X86Subtarget>()),
+  TLI(*TM.getTargetLowering()) {
 }
 
 X86SelectionDAGInfo::~X86SelectionDAGInfo() {
 }
+
+SDValue
+X86SelectionDAGInfo::EmitTargetCodeForMemset(SelectionDAG &DAG, DebugLoc dl,
+                                             SDValue Chain,
+                                             SDValue Dst, SDValue Src,
+                                             SDValue Size, unsigned Align,
+                                             bool isVolatile,
+                                             const Value *DstSV,
+                                             uint64_t DstSVOff) const {
+  ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
+
+  // If not DWORD aligned or size is more than the threshold, call the library.
+  // The libc version is likely to be faster for these cases. It can use the
+  // address value and run time information about the CPU.
+  if ((Align & 3) != 0 ||
+      !ConstantSize ||
+      ConstantSize->getZExtValue() >
+        Subtarget->getMaxInlineSizeThreshold()) {
+    SDValue InFlag(0, 0);
+
+    // Check to see if there is a specialized entry-point for memory zeroing.
+    ConstantSDNode *V = dyn_cast<ConstantSDNode>(Src);
+
+    if (const char *bzeroEntry =  V &&
+        V->isNullValue() ? Subtarget->getBZeroEntry() : 0) {
+      EVT IntPtr = TLI.getPointerTy();
+      const Type *IntPtrTy = getTargetData()->getIntPtrType(*DAG.getContext());
+      TargetLowering::ArgListTy Args;
+      TargetLowering::ArgListEntry Entry;
+      Entry.Node = Dst;
+      Entry.Ty = IntPtrTy;
+      Args.push_back(Entry);
+      Entry.Node = Size;
+      Args.push_back(Entry);
+      std::pair<SDValue,SDValue> CallResult =
+        TLI.LowerCallTo(Chain, Type::getVoidTy(*DAG.getContext()),
+                        false, false, false, false,
+                        0, CallingConv::C, false, /*isReturnValueUsed=*/false,
+                        DAG.getExternalSymbol(bzeroEntry, IntPtr), Args,
+                        DAG, dl);
+      return CallResult.second;
+    }
+
+    // Otherwise have the target-independent code call memset.
+    return SDValue();
+  }
+
+  uint64_t SizeVal = ConstantSize->getZExtValue();
+  SDValue InFlag(0, 0);
+  EVT AVT;
+  SDValue Count;
+  ConstantSDNode *ValC = dyn_cast<ConstantSDNode>(Src);
+  unsigned BytesLeft = 0;
+  bool TwoRepStos = false;
+  if (ValC) {
+    unsigned ValReg;
+    uint64_t Val = ValC->getZExtValue() & 255;
+
+    // If the value is a constant, then we can potentially use larger sets.
+    switch (Align & 3) {
+    case 2:   // WORD aligned
+      AVT = MVT::i16;
+      ValReg = X86::AX;
+      Val = (Val << 8) | Val;
+      break;
+    case 0:  // DWORD aligned
+      AVT = MVT::i32;
+      ValReg = X86::EAX;
+      Val = (Val << 8)  | Val;
+      Val = (Val << 16) | Val;
+      if (Subtarget->is64Bit() && ((Align & 0x7) == 0)) {  // QWORD aligned
+        AVT = MVT::i64;
+        ValReg = X86::RAX;
+        Val = (Val << 32) | Val;
+      }
+      break;
+    default:  // Byte aligned
+      AVT = MVT::i8;
+      ValReg = X86::AL;
+      Count = DAG.getIntPtrConstant(SizeVal);
+      break;
+    }
+
+    if (AVT.bitsGT(MVT::i8)) {
+      unsigned UBytes = AVT.getSizeInBits() / 8;
+      Count = DAG.getIntPtrConstant(SizeVal / UBytes);
+      BytesLeft = SizeVal % UBytes;
+    }
+
+    Chain  = DAG.getCopyToReg(Chain, dl, ValReg, DAG.getConstant(Val, AVT),
+                              InFlag);
+    InFlag = Chain.getValue(1);
+  } else {
+    AVT = MVT::i8;
+    Count  = DAG.getIntPtrConstant(SizeVal);
+    Chain  = DAG.getCopyToReg(Chain, dl, X86::AL, Src, InFlag);
+    InFlag = Chain.getValue(1);
+  }
+
+  Chain  = DAG.getCopyToReg(Chain, dl, Subtarget->is64Bit() ? X86::RCX :
+                                                              X86::ECX,
+                            Count, InFlag);
+  InFlag = Chain.getValue(1);
+  Chain  = DAG.getCopyToReg(Chain, dl, Subtarget->is64Bit() ? X86::RDI :
+                                                              X86::EDI,
+                            Dst, InFlag);
+  InFlag = Chain.getValue(1);
+
+  SDVTList Tys = DAG.getVTList(MVT::Other, MVT::Flag);
+  SDValue Ops[] = { Chain, DAG.getValueType(AVT), InFlag };
+  Chain = DAG.getNode(X86ISD::REP_STOS, dl, Tys, Ops, array_lengthof(Ops));
+
+  if (TwoRepStos) {
+    InFlag = Chain.getValue(1);
+    Count  = Size;
+    EVT CVT = Count.getValueType();
+    SDValue Left = DAG.getNode(ISD::AND, dl, CVT, Count,
+                               DAG.getConstant((AVT == MVT::i64) ? 7 : 3, CVT));
+    Chain  = DAG.getCopyToReg(Chain, dl, (CVT == MVT::i64) ? X86::RCX :
+                                                             X86::ECX,
+                              Left, InFlag);
+    InFlag = Chain.getValue(1);
+    Tys = DAG.getVTList(MVT::Other, MVT::Flag);
+    SDValue Ops[] = { Chain, DAG.getValueType(MVT::i8), InFlag };
+    Chain = DAG.getNode(X86ISD::REP_STOS, dl, Tys, Ops, array_lengthof(Ops));
+  } else if (BytesLeft) {
+    // Handle the last 1 - 7 bytes.
+    unsigned Offset = SizeVal - BytesLeft;
+    EVT AddrVT = Dst.getValueType();
+    EVT SizeVT = Size.getValueType();
+
+    Chain = DAG.getMemset(Chain, dl,
+                          DAG.getNode(ISD::ADD, dl, AddrVT, Dst,
+                                      DAG.getConstant(Offset, AddrVT)),
+                          Src,
+                          DAG.getConstant(BytesLeft, SizeVT),
+                          Align, isVolatile, DstSV, DstSVOff + Offset);
+  }
+
+  // TODO: Use a Tokenfactor, as in memcpy, instead of a single chain.
+  return Chain;
+}
+
+SDValue
+X86SelectionDAGInfo::EmitTargetCodeForMemcpy(SelectionDAG &DAG, DebugLoc dl,
+                                        SDValue Chain, SDValue Dst, SDValue Src,
+                                        SDValue Size, unsigned Align,
+                                        bool isVolatile, bool AlwaysInline,
+                                        const Value *DstSV,
+                                        uint64_t DstSVOff,
+                                        const Value *SrcSV,
+                                        uint64_t SrcSVOff) const {
+  // This requires the copy size to be a constant, preferrably
+  // within a subtarget-specific limit.
+  ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
+  if (!ConstantSize)
+    return SDValue();
+  uint64_t SizeVal = ConstantSize->getZExtValue();
+  if (!AlwaysInline && SizeVal > Subtarget->getMaxInlineSizeThreshold())
+    return SDValue();
+
+  /// If not DWORD aligned, call the library.
+  if ((Align & 3) != 0)
+    return SDValue();
+
+  // DWORD aligned
+  EVT AVT = MVT::i32;
+  if (Subtarget->is64Bit() && ((Align & 0x7) == 0))  // QWORD aligned
+    AVT = MVT::i64;
+
+  unsigned UBytes = AVT.getSizeInBits() / 8;
+  unsigned CountVal = SizeVal / UBytes;
+  SDValue Count = DAG.getIntPtrConstant(CountVal);
+  unsigned BytesLeft = SizeVal % UBytes;
+
+  SDValue InFlag(0, 0);
+  Chain  = DAG.getCopyToReg(Chain, dl, Subtarget->is64Bit() ? X86::RCX :
+                                                              X86::ECX,
+                            Count, InFlag);
+  InFlag = Chain.getValue(1);
+  Chain  = DAG.getCopyToReg(Chain, dl, Subtarget->is64Bit() ? X86::RDI :
+                                                              X86::EDI,
+                            Dst, InFlag);
+  InFlag = Chain.getValue(1);
+  Chain  = DAG.getCopyToReg(Chain, dl, Subtarget->is64Bit() ? X86::RSI :
+                                                              X86::ESI,
+                            Src, InFlag);
+  InFlag = Chain.getValue(1);
+
+  SDVTList Tys = DAG.getVTList(MVT::Other, MVT::Flag);
+  SDValue Ops[] = { Chain, DAG.getValueType(AVT), InFlag };
+  SDValue RepMovs = DAG.getNode(X86ISD::REP_MOVS, dl, Tys, Ops,
+                                array_lengthof(Ops));
+
+  SmallVector<SDValue, 4> Results;
+  Results.push_back(RepMovs);
+  if (BytesLeft) {
+    // Handle the last 1 - 7 bytes.
+    unsigned Offset = SizeVal - BytesLeft;
+    EVT DstVT = Dst.getValueType();
+    EVT SrcVT = Src.getValueType();
+    EVT SizeVT = Size.getValueType();
+    Results.push_back(DAG.getMemcpy(Chain, dl,
+                                    DAG.getNode(ISD::ADD, dl, DstVT, Dst,
+                                                DAG.getConstant(Offset, DstVT)),
+                                    DAG.getNode(ISD::ADD, dl, SrcVT, Src,
+                                                DAG.getConstant(Offset, SrcVT)),
+                                    DAG.getConstant(BytesLeft, SizeVT),
+                                    Align, isVolatile, AlwaysInline,
+                                    DstSV, DstSVOff + Offset,
+                                    SrcSV, SrcSVOff + Offset));
+  }
+
+  return DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
+                     &Results[0], Results.size());
+}