#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
-#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
using namespace llvm;
// Handle X86-64 rip-relative addresses. We check this before checking direct
// folding because RIP is preferable to non-RIP accesses.
- if (Subtarget->is64Bit() &&
+ if (Subtarget->is64Bit() && N.getOpcode() == X86ISD::WrapperRIP &&
// Under X86-64 non-small code model, GV (and friends) are 64-bits, so
// they cannot be folded into immediate fields.
// FIXME: This can be improved for kernel and other models?
- (M == CodeModel::Small || M == CodeModel::Kernel) &&
- // Base and index reg must be 0 in order to use %rip as base and lowering
- // must allow RIP.
- !AM.hasBaseOrIndexReg() && N.getOpcode() == X86ISD::WrapperRIP) {
+ (M == CodeModel::Small || M == CodeModel::Kernel)) {
+ // Base and index reg must be 0 in order to use %rip as base.
+ if (AM.hasBaseOrIndexReg())
+ return true;
if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(N0)) {
X86ISelAddressMode Backup = AM;
AM.GV = G->getGlobal();
}
// Handle the case when globals fit in our immediate field: This is true for
- // X86-32 always and X86-64 when in -static -mcmodel=small mode. In 64-bit
- // mode, this results in a non-RIP-relative computation.
+ // X86-32 always and X86-64 when in -mcmodel=small mode. In 64-bit
+ // mode, this only applies to a non-RIP-relative computation.
if (!Subtarget->is64Bit() ||
- ((M == CodeModel::Small || M == CodeModel::Kernel) &&
- TM.getRelocationModel() == Reloc::Static)) {
+ M == CodeModel::Small || M == CodeModel::Kernel) {
+ assert(N.getOpcode() != X86ISD::WrapperRIP &&
+ "RIP-relative addressing already handled");
if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(N0)) {
AM.GV = G->getGlobal();
AM.Disp += G->getOffset();
APInt MaskedHighBits = APInt::getHighBitsSet(X.getValueSizeInBits(),
MaskLZ);
APInt KnownZero, KnownOne;
- DAG.ComputeMaskedBits(X, MaskedHighBits, KnownZero, KnownOne);
+ DAG.ComputeMaskedBits(X, KnownZero, KnownOne);
if (MaskedHighBits != KnownZero) return true;
// We've identified a pattern that can be transformed into a single shift
return true;
}
+/// isLoadIncOrDecStore - Check whether or not the chain ending in StoreNode
+/// is suitable for doing the {load; increment or decrement; store} to modify
+/// transformation.
+static bool isLoadIncOrDecStore(StoreSDNode *StoreNode, unsigned Opc,
+ SDValue StoredVal, SelectionDAG *CurDAG,
+ LoadSDNode* &LoadNode, SDValue &InputChain) {
+
+ // is the value stored the result of a DEC or INC?
+ if (!(Opc == X86ISD::DEC || Opc == X86ISD::INC)) return false;
+
+ // is the stored value result 0 of the load?
+ if (StoredVal.getResNo() != 0) return false;
+
+ // are there other uses of the loaded value than the inc or dec?
+ if (!StoredVal.getNode()->hasNUsesOfValue(1, 0)) return false;
+
+ // is the store non-extending and non-indexed?
+ if (!ISD::isNormalStore(StoreNode) || StoreNode->isNonTemporal())
+ return false;
+
+ SDValue Load = StoredVal->getOperand(0);
+ // Is the stored value a non-extending and non-indexed load?
+ if (!ISD::isNormalLoad(Load.getNode())) return false;
+
+ // Return LoadNode by reference.
+ LoadNode = cast<LoadSDNode>(Load);
+ // is the size of the value one that we can handle? (i.e. 64, 32, 16, or 8)
+ EVT LdVT = LoadNode->getMemoryVT();
+ if (LdVT != MVT::i64 && LdVT != MVT::i32 && LdVT != MVT::i16 &&
+ LdVT != MVT::i8)
+ return false;
+
+ // Is store the only read of the loaded value?
+ if (!Load.hasOneUse())
+ return false;
+
+ // Is the address of the store the same as the load?
+ if (LoadNode->getBasePtr() != StoreNode->getBasePtr() ||
+ LoadNode->getOffset() != StoreNode->getOffset())
+ return false;
+
+ // Check if the chain is produced by the load or is a TokenFactor with
+ // the load output chain as an operand. Return InputChain by reference.
+ SDValue Chain = StoreNode->getChain();
+
+ bool ChainCheck = false;
+ if (Chain == Load.getValue(1)) {
+ ChainCheck = true;
+ InputChain = LoadNode->getChain();
+ } else if (Chain.getOpcode() == ISD::TokenFactor) {
+ SmallVector<SDValue, 4> ChainOps;
+ for (unsigned i = 0, e = Chain.getNumOperands(); i != e; ++i) {
+ SDValue Op = Chain.getOperand(i);
+ if (Op == Load.getValue(1)) {
+ ChainCheck = true;
+ continue;
+ }
+
+ // Make sure using Op as part of the chain would not cause a cycle here.
+ // In theory, we could check whether the chain node is a predecessor of
+ // the load. But that can be very expensive. Instead visit the uses and
+ // make sure they all have smaller node id than the load.
+ int LoadId = LoadNode->getNodeId();
+ for (SDNode::use_iterator UI = Op.getNode()->use_begin(),
+ UE = UI->use_end(); UI != UE; ++UI) {
+ if (UI.getUse().getResNo() != 0)
+ continue;
+ if (UI->getNodeId() > LoadId)
+ return false;
+ }
+
+ ChainOps.push_back(Op);
+ }
+
+ if (ChainCheck)
+ // Make a new TokenFactor with all the other input chains except
+ // for the load.
+ InputChain = CurDAG->getNode(ISD::TokenFactor, Chain.getDebugLoc(),
+ MVT::Other, &ChainOps[0], ChainOps.size());
+ }
+ if (!ChainCheck)
+ return false;
+
+ return true;
+}
+
+/// getFusedLdStOpcode - Get the appropriate X86 opcode for an in memory
+/// increment or decrement. Opc should be X86ISD::DEC or X86ISD::INC.
+static unsigned getFusedLdStOpcode(EVT &LdVT, unsigned Opc) {
+ if (Opc == X86ISD::DEC) {
+ if (LdVT == MVT::i64) return X86::DEC64m;
+ if (LdVT == MVT::i32) return X86::DEC32m;
+ if (LdVT == MVT::i16) return X86::DEC16m;
+ if (LdVT == MVT::i8) return X86::DEC8m;
+ } else {
+ assert(Opc == X86ISD::INC && "unrecognized opcode");
+ if (LdVT == MVT::i64) return X86::INC64m;
+ if (LdVT == MVT::i32) return X86::INC32m;
+ if (LdVT == MVT::i16) return X86::INC16m;
+ if (LdVT == MVT::i8) return X86::INC8m;
+ }
+ llvm_unreachable("unrecognized size for LdVT");
+}
+
SDNode *X86DAGToDAGISel::Select(SDNode *Node) {
EVT NVT = Node->getValueType(0);
unsigned Opc, MOpc;
}
SDValue InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, LoReg,
- N0, SDValue()).getValue(1);
+ N0, SDValue()).getValue(1);
if (foldedLoad) {
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, N1.getOperand(0),
// Copy the low half of the result, if it is needed.
if (!SDValue(Node, 0).use_empty()) {
SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
- LoReg, NVT, InFlag);
+ LoReg, NVT, InFlag);
InFlag = Result.getValue(2);
ReplaceUses(SDValue(Node, 0), Result);
DEBUG(dbgs() << "=> "; Result.getNode()->dump(CurDAG); dbgs() << '\n');
break;
}
case ISD::STORE: {
+ // Change a chain of {load; incr or dec; store} of the same value into
+ // a simple increment or decrement through memory of that value, if the
+ // uses of the modified value and its address are suitable.
// The DEC64m tablegen pattern is currently not able to match the case where
- // the EFLAGS on the original DEC are used.
- // we'll need to improve tablegen to allow flags to be transferred from a
+ // the EFLAGS on the original DEC are used. (This also applies to
+ // {INC,DEC}X{64,32,16,8}.)
+ // We'll need to improve tablegen to allow flags to be transferred from a
// node in the pattern to the result node. probably with a new keyword
// for example, we have this
// def DEC64m : RI<0xFF, MRM1m, (outs), (ins i64mem:$dst), "dec{q}\t$dst",
// def DEC64m : RI<0xFF, MRM1m, (outs), (ins i64mem:$dst), "dec{q}\t$dst",
// [(store (add (loadi64 addr:$dst), -1), addr:$dst),
// (transferrable EFLAGS)]>;
+
StoreSDNode *StoreNode = cast<StoreSDNode>(Node);
- SDValue Chain = StoreNode->getOperand(0);
SDValue StoredVal = StoreNode->getOperand(1);
- SDValue Address = StoreNode->getOperand(2);
- SDValue Undef = StoreNode->getOperand(3);
-
- if (StoreNode->getMemOperand()->getSize() != 8 ||
- Undef->getOpcode() != ISD::UNDEF ||
- Chain->getOpcode() != ISD::LOAD ||
- StoredVal->getOpcode() != X86ISD::DEC ||
- StoredVal.getResNo() != 0 ||
- !StoredVal.getNode()->hasNUsesOfValue(1, 0) ||
- !Chain.getNode()->hasNUsesOfValue(1, 0) ||
- StoredVal->getOperand(0).getNode() != Chain.getNode())
- break;
-
- //OPC_CheckPredicate, 1, // Predicate_nontemporalstore
- if (StoreNode->isNonTemporal())
- break;
+ unsigned Opc = StoredVal->getOpcode();
- LoadSDNode *LoadNode = cast<LoadSDNode>(Chain.getNode());
- if (LoadNode->getOperand(1) != Address ||
- LoadNode->getOperand(2) != Undef)
+ LoadSDNode *LoadNode = 0;
+ SDValue InputChain;
+ if (!isLoadIncOrDecStore(StoreNode, Opc, StoredVal, CurDAG,
+ LoadNode, InputChain))
break;
- if (!ISD::isNormalLoad(LoadNode))
- break;
-
- if (!ISD::isNormalStore(StoreNode))
- break;
-
- // check load chain has only one use (from the store)
- if (!Chain.hasOneUse())
- break;
-
- // Merge the input chains if they are not intra-pattern references.
- SDValue InputChain = LoadNode->getOperand(0);
-
SDValue Base, Scale, Index, Disp, Segment;
if (!SelectAddr(LoadNode, LoadNode->getBasePtr(),
Base, Scale, Index, Disp, Segment))
MemOp[0] = StoreNode->getMemOperand();
MemOp[1] = LoadNode->getMemOperand();
const SDValue Ops[] = { Base, Scale, Index, Disp, Segment, InputChain };
- MachineSDNode *Result = CurDAG->getMachineNode(X86::DEC64m,
+ EVT LdVT = LoadNode->getMemoryVT();
+ unsigned newOpc = getFusedLdStOpcode(LdVT, Opc);
+ MachineSDNode *Result = CurDAG->getMachineNode(newOpc,
Node->getDebugLoc(),
MVT::i32, MVT::Other, Ops,
array_lengthof(Ops));
/// X86-specific DAG, ready for instruction scheduling.
///
FunctionPass *llvm::createX86ISelDag(X86TargetMachine &TM,
- llvm::CodeGenOpt::Level OptLevel) {
+ CodeGenOpt::Level OptLevel) {
return new X86DAGToDAGISel(TM, OptLevel);
}
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