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llvm / llvm / d5c2cca72463233df77a065f201db31b140eb44d / . / lib / CodeGen / SelectionDAG / TargetLowering.cpp
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//===-- TargetLowering.cpp - Implement the TargetLowering class -----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This implements the TargetLowering class.
//
//===----------------------------------------------------------------------===//
#include "llvm/Target/TargetLowering.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/CodeGen/CallingConvLower.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/KnownBits.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetSubtargetInfo.h"
#include <cctype>
using namespace llvm;
/// NOTE: The TargetMachine owns TLOF.
TargetLowering::TargetLowering(const TargetMachine &tm)
: TargetLoweringBase(tm) {}
const char *TargetLowering::getTargetNodeName(unsigned Opcode) const {
return nullptr;
}
bool TargetLowering::isPositionIndependent() const {
return getTargetMachine().isPositionIndependent();
}
/// Check whether a given call node is in tail position within its function. If
/// so, it sets Chain to the input chain of the tail call.
bool TargetLowering::isInTailCallPosition(SelectionDAG &DAG, SDNode *Node,
SDValue &Chain) const {
const Function *F = DAG.getMachineFunction().getFunction();
// Conservatively require the attributes of the call to match those of
// the return. Ignore noalias because it doesn't affect the call sequence.
AttributeList CallerAttrs = F->getAttributes();
if (AttrBuilder(CallerAttrs, AttributeList::ReturnIndex)
.removeAttribute(Attribute::NoAlias)
.hasAttributes())
return false;
// It's not safe to eliminate the sign / zero extension of the return value.
if (CallerAttrs.hasAttribute(AttributeList::ReturnIndex, Attribute::ZExt) ||
CallerAttrs.hasAttribute(AttributeList::ReturnIndex, Attribute::SExt))
return false;
// Check if the only use is a function return node.
return isUsedByReturnOnly(Node, Chain);
}
bool TargetLowering::parametersInCSRMatch(const MachineRegisterInfo &MRI,
const uint32_t *CallerPreservedMask,
const SmallVectorImpl<CCValAssign> &ArgLocs,
const SmallVectorImpl<SDValue> &OutVals) const {
for (unsigned I = 0, E = ArgLocs.size(); I != E; ++I) {
const CCValAssign &ArgLoc = ArgLocs[I];
if (!ArgLoc.isRegLoc())
continue;
unsigned Reg = ArgLoc.getLocReg();
// Only look at callee saved registers.
if (MachineOperand::clobbersPhysReg(CallerPreservedMask, Reg))
continue;
// Check that we pass the value used for the caller.
// (We look for a CopyFromReg reading a virtual register that is used
// for the function live-in value of register Reg)
SDValue Value = OutVals[I];
if (Value->getOpcode() != ISD::CopyFromReg)
return false;
unsigned ArgReg = cast<RegisterSDNode>(Value->getOperand(1))->getReg();
if (MRI.getLiveInPhysReg(ArgReg) != Reg)
return false;
}
return true;
}
/// \brief Set CallLoweringInfo attribute flags based on a call instruction
/// and called function attributes.
void TargetLoweringBase::ArgListEntry::setAttributes(ImmutableCallSite *CS,
unsigned ArgIdx) {
IsSExt = CS->paramHasAttr(ArgIdx, Attribute::SExt);
IsZExt = CS->paramHasAttr(ArgIdx, Attribute::ZExt);
IsInReg = CS->paramHasAttr(ArgIdx, Attribute::InReg);
IsSRet = CS->paramHasAttr(ArgIdx, Attribute::StructRet);
IsNest = CS->paramHasAttr(ArgIdx, Attribute::Nest);
IsByVal = CS->paramHasAttr(ArgIdx, Attribute::ByVal);
IsInAlloca = CS->paramHasAttr(ArgIdx, Attribute::InAlloca);
IsReturned = CS->paramHasAttr(ArgIdx, Attribute::Returned);
IsSwiftSelf = CS->paramHasAttr(ArgIdx, Attribute::SwiftSelf);
IsSwiftError = CS->paramHasAttr(ArgIdx, Attribute::SwiftError);
Alignment = CS->getParamAlignment(ArgIdx);
}
/// Generate a libcall taking the given operands as arguments and returning a
/// result of type RetVT.
std::pair<SDValue, SDValue>
TargetLowering::makeLibCall(SelectionDAG &DAG, RTLIB::Libcall LC, EVT RetVT,
ArrayRef<SDValue> Ops, bool isSigned,
const SDLoc &dl, bool doesNotReturn,
bool isReturnValueUsed) const {
TargetLowering::ArgListTy Args;
Args.reserve(Ops.size());
TargetLowering::ArgListEntry Entry;
for (SDValue Op : Ops) {
Entry.Node = Op;
Entry.Ty = Entry.Node.getValueType().getTypeForEVT(*DAG.getContext());
Entry.IsSExt = shouldSignExtendTypeInLibCall(Op.getValueType(), isSigned);
Entry.IsZExt = !shouldSignExtendTypeInLibCall(Op.getValueType(), isSigned);
Args.push_back(Entry);
}
if (LC == RTLIB::UNKNOWN_LIBCALL)
report_fatal_error("Unsupported library call operation!");
SDValue Callee = DAG.getExternalSymbol(getLibcallName(LC),
getPointerTy(DAG.getDataLayout()));
Type *RetTy = RetVT.getTypeForEVT(*DAG.getContext());
TargetLowering::CallLoweringInfo CLI(DAG);
bool signExtend = shouldSignExtendTypeInLibCall(RetVT, isSigned);
CLI.setDebugLoc(dl)
.setChain(DAG.getEntryNode())
.setLibCallee(getLibcallCallingConv(LC), RetTy, Callee, std::move(Args))
.setNoReturn(doesNotReturn)
.setDiscardResult(!isReturnValueUsed)
.setSExtResult(signExtend)
.setZExtResult(!signExtend);
return LowerCallTo(CLI);
}
/// Soften the operands of a comparison. This code is shared among BR_CC,
/// SELECT_CC, and SETCC handlers.
void TargetLowering::softenSetCCOperands(SelectionDAG &DAG, EVT VT,
SDValue &NewLHS, SDValue &NewRHS,
ISD::CondCode &CCCode,
const SDLoc &dl) const {
assert((VT == MVT::f32 || VT == MVT::f64 || VT == MVT::f128 || VT == MVT::ppcf128)
&& "Unsupported setcc type!");
// Expand into one or more soft-fp libcall(s).
RTLIB::Libcall LC1 = RTLIB::UNKNOWN_LIBCALL, LC2 = RTLIB::UNKNOWN_LIBCALL;
bool ShouldInvertCC = false;
switch (CCCode) {
case ISD::SETEQ:
case ISD::SETOEQ:
LC1 = (VT == MVT::f32) ? RTLIB::OEQ_F32 :
(VT == MVT::f64) ? RTLIB::OEQ_F64 :
(VT == MVT::f128) ? RTLIB::OEQ_F128 : RTLIB::OEQ_PPCF128;
break;
case ISD::SETNE:
case ISD::SETUNE:
LC1 = (VT == MVT::f32) ? RTLIB::UNE_F32 :
(VT == MVT::f64) ? RTLIB::UNE_F64 :
(VT == MVT::f128) ? RTLIB::UNE_F128 : RTLIB::UNE_PPCF128;
break;
case ISD::SETGE:
case ISD::SETOGE:
LC1 = (VT == MVT::f32) ? RTLIB::OGE_F32 :
(VT == MVT::f64) ? RTLIB::OGE_F64 :
(VT == MVT::f128) ? RTLIB::OGE_F128 : RTLIB::OGE_PPCF128;
break;
case ISD::SETLT:
case ISD::SETOLT:
LC1 = (VT == MVT::f32) ? RTLIB::OLT_F32 :
(VT == MVT::f64) ? RTLIB::OLT_F64 :
(VT == MVT::f128) ? RTLIB::OLT_F128 : RTLIB::OLT_PPCF128;
break;
case ISD::SETLE:
case ISD::SETOLE:
LC1 = (VT == MVT::f32) ? RTLIB::OLE_F32 :
(VT == MVT::f64) ? RTLIB::OLE_F64 :
(VT == MVT::f128) ? RTLIB::OLE_F128 : RTLIB::OLE_PPCF128;
break;
case ISD::SETGT:
case ISD::SETOGT:
LC1 = (VT == MVT::f32) ? RTLIB::OGT_F32 :
(VT == MVT::f64) ? RTLIB::OGT_F64 :
(VT == MVT::f128) ? RTLIB::OGT_F128 : RTLIB::OGT_PPCF128;
break;
case ISD::SETUO:
LC1 = (VT == MVT::f32) ? RTLIB::UO_F32 :
(VT == MVT::f64) ? RTLIB::UO_F64 :
(VT == MVT::f128) ? RTLIB::UO_F128 : RTLIB::UO_PPCF128;
break;
case ISD::SETO:
LC1 = (VT == MVT::f32) ? RTLIB::O_F32 :
(VT == MVT::f64) ? RTLIB::O_F64 :
(VT == MVT::f128) ? RTLIB::O_F128 : RTLIB::O_PPCF128;
break;
case ISD::SETONE:
// SETONE = SETOLT | SETOGT
LC1 = (VT == MVT::f32) ? RTLIB::OLT_F32 :
(VT == MVT::f64) ? RTLIB::OLT_F64 :
(VT == MVT::f128) ? RTLIB::OLT_F128 : RTLIB::OLT_PPCF128;
LC2 = (VT == MVT::f32) ? RTLIB::OGT_F32 :
(VT == MVT::f64) ? RTLIB::OGT_F64 :
(VT == MVT::f128) ? RTLIB::OGT_F128 : RTLIB::OGT_PPCF128;
break;
case ISD::SETUEQ:
LC1 = (VT == MVT::f32) ? RTLIB::UO_F32 :
(VT == MVT::f64) ? RTLIB::UO_F64 :
(VT == MVT::f128) ? RTLIB::UO_F128 : RTLIB::UO_PPCF128;
LC2 = (VT == MVT::f32) ? RTLIB::OEQ_F32 :
(VT == MVT::f64) ? RTLIB::OEQ_F64 :
(VT == MVT::f128) ? RTLIB::OEQ_F128 : RTLIB::OEQ_PPCF128;
break;
default:
// Invert CC for unordered comparisons
ShouldInvertCC = true;
switch (CCCode) {
case ISD::SETULT:
LC1 = (VT == MVT::f32) ? RTLIB::OGE_F32 :
(VT == MVT::f64) ? RTLIB::OGE_F64 :
(VT == MVT::f128) ? RTLIB::OGE_F128 : RTLIB::OGE_PPCF128;
break;
case ISD::SETULE:
LC1 = (VT == MVT::f32) ? RTLIB::OGT_F32 :
(VT == MVT::f64) ? RTLIB::OGT_F64 :
(VT == MVT::f128) ? RTLIB::OGT_F128 : RTLIB::OGT_PPCF128;
break;
case ISD::SETUGT:
LC1 = (VT == MVT::f32) ? RTLIB::OLE_F32 :
(VT == MVT::f64) ? RTLIB::OLE_F64 :
(VT == MVT::f128) ? RTLIB::OLE_F128 : RTLIB::OLE_PPCF128;
break;
case ISD::SETUGE:
LC1 = (VT == MVT::f32) ? RTLIB::OLT_F32 :
(VT == MVT::f64) ? RTLIB::OLT_F64 :
(VT == MVT::f128) ? RTLIB::OLT_F128 : RTLIB::OLT_PPCF128;
break;
default: llvm_unreachable("Do not know how to soften this setcc!");
}
}
// Use the target specific return value for comparions lib calls.
EVT RetVT = getCmpLibcallReturnType();
SDValue Ops[2] = {NewLHS, NewRHS};
NewLHS = makeLibCall(DAG, LC1, RetVT, Ops, false /*sign irrelevant*/,
dl).first;
NewRHS = DAG.getConstant(0, dl, RetVT);
CCCode = getCmpLibcallCC(LC1);
if (ShouldInvertCC)
CCCode = getSetCCInverse(CCCode, /*isInteger=*/true);
if (LC2 != RTLIB::UNKNOWN_LIBCALL) {
SDValue Tmp = DAG.getNode(
ISD::SETCC, dl,
getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), RetVT),
NewLHS, NewRHS, DAG.getCondCode(CCCode));
NewLHS = makeLibCall(DAG, LC2, RetVT, Ops, false/*sign irrelevant*/,
dl).first;
NewLHS = DAG.getNode(
ISD::SETCC, dl,
getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), RetVT),
NewLHS, NewRHS, DAG.getCondCode(getCmpLibcallCC(LC2)));
NewLHS = DAG.getNode(ISD::OR, dl, Tmp.getValueType(), Tmp, NewLHS);
NewRHS = SDValue();
}
}
/// Return the entry encoding for a jump table in the current function. The
/// returned value is a member of the MachineJumpTableInfo::JTEntryKind enum.
unsigned TargetLowering::getJumpTableEncoding() const {
// In non-pic modes, just use the address of a block.
if (!isPositionIndependent())
return MachineJumpTableInfo::EK_BlockAddress;
// In PIC mode, if the target supports a GPRel32 directive, use it.
if (getTargetMachine().getMCAsmInfo()->getGPRel32Directive() != nullptr)
return MachineJumpTableInfo::EK_GPRel32BlockAddress;
// Otherwise, use a label difference.
return MachineJumpTableInfo::EK_LabelDifference32;
}
SDValue TargetLowering::getPICJumpTableRelocBase(SDValue Table,
SelectionDAG &DAG) const {
// If our PIC model is GP relative, use the global offset table as the base.
unsigned JTEncoding = getJumpTableEncoding();
if ((JTEncoding == MachineJumpTableInfo::EK_GPRel64BlockAddress) ||
(JTEncoding == MachineJumpTableInfo::EK_GPRel32BlockAddress))
return DAG.getGLOBAL_OFFSET_TABLE(getPointerTy(DAG.getDataLayout()));
return Table;
}
/// This returns the relocation base for the given PIC jumptable, the same as
/// getPICJumpTableRelocBase, but as an MCExpr.
const MCExpr *
TargetLowering::getPICJumpTableRelocBaseExpr(const MachineFunction *MF,
unsigned JTI,MCContext &Ctx) const{
// The normal PIC reloc base is the label at the start of the jump table.
return MCSymbolRefExpr::create(MF->getJTISymbol(JTI, Ctx), Ctx);
}
bool
TargetLowering::isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const {
const TargetMachine &TM = getTargetMachine();
const GlobalValue *GV = GA->getGlobal();
// If the address is not even local to this DSO we will have to load it from
// a got and then add the offset.
if (!TM.shouldAssumeDSOLocal(*GV->getParent(), GV))
return false;
// If the code is position independent we will have to add a base register.
if (isPositionIndependent())
return false;
// Otherwise we can do it.
return true;
}
//===----------------------------------------------------------------------===//
// Optimization Methods
//===----------------------------------------------------------------------===//
/// If the specified instruction has a constant integer operand and there are
/// bits set in that constant that are not demanded, then clear those bits and
/// return true.
bool TargetLowering::ShrinkDemandedConstant(SDValue Op, const APInt &Demanded,
TargetLoweringOpt &TLO) const {
SelectionDAG &DAG = TLO.DAG;
SDLoc DL(Op);
unsigned Opcode = Op.getOpcode();
// Do target-specific constant optimization.
if (targetShrinkDemandedConstant(Op, Demanded, TLO))
return TLO.New.getNode();
// FIXME: ISD::SELECT, ISD::SELECT_CC
switch (Opcode) {
default:
break;
case ISD::XOR:
case ISD::AND:
case ISD::OR: {
auto *Op1C = dyn_cast<ConstantSDNode>(Op.getOperand(1));
if (!Op1C)
return false;
// If this is a 'not' op, don't touch it because that's a canonical form.
const APInt &C = Op1C->getAPIntValue();
if (Opcode == ISD::XOR && Demanded.isSubsetOf(C))
return false;
if (!C.isSubsetOf(Demanded)) {
EVT VT = Op.getValueType();
SDValue NewC = DAG.getConstant(Demanded & C, DL, VT);
SDValue NewOp = DAG.getNode(Opcode, DL, VT, Op.getOperand(0), NewC);
return TLO.CombineTo(Op, NewOp);
}
break;
}
}
return false;
}
/// Convert x+y to (VT)((SmallVT)x+(SmallVT)y) if the casts are free.
/// This uses isZExtFree and ZERO_EXTEND for the widening cast, but it could be
/// generalized for targets with other types of implicit widening casts.
bool TargetLowering::ShrinkDemandedOp(SDValue Op, unsigned BitWidth,
const APInt &Demanded,
TargetLoweringOpt &TLO) const {
assert(Op.getNumOperands() == 2 &&
"ShrinkDemandedOp only supports binary operators!");
assert(Op.getNode()->getNumValues() == 1 &&
"ShrinkDemandedOp only supports nodes with one result!");
SelectionDAG &DAG = TLO.DAG;
SDLoc dl(Op);
// Early return, as this function cannot handle vector types.
if (Op.getValueType().isVector())
return false;
// Don't do this if the node has another user, which may require the
// full value.
if (!Op.getNode()->hasOneUse())
return false;
// Search for the smallest integer type with free casts to and from
// Op's type. For expedience, just check power-of-2 integer types.
const TargetLowering &TLI = DAG.getTargetLoweringInfo();
unsigned DemandedSize = Demanded.getActiveBits();
unsigned SmallVTBits = DemandedSize;
if (!isPowerOf2_32(SmallVTBits))
SmallVTBits = NextPowerOf2(SmallVTBits);
for (; SmallVTBits < BitWidth; SmallVTBits = NextPowerOf2(SmallVTBits)) {
EVT SmallVT = EVT::getIntegerVT(*DAG.getContext(), SmallVTBits);
if (TLI.isTruncateFree(Op.getValueType(), SmallVT) &&
TLI.isZExtFree(SmallVT, Op.getValueType())) {
// We found a type with free casts.
SDValue X = DAG.getNode(
Op.getOpcode(), dl, SmallVT,
DAG.getNode(ISD::TRUNCATE, dl, SmallVT, Op.getOperand(0)),
DAG.getNode(ISD::TRUNCATE, dl, SmallVT, Op.getOperand(1)));
assert(DemandedSize <= SmallVTBits && "Narrowed below demanded bits?");
SDValue Z = DAG.getNode(ISD::ANY_EXTEND, dl, Op.getValueType(), X);
return TLO.CombineTo(Op, Z);
}
}
return false;
}
bool
TargetLowering::SimplifyDemandedBits(SDNode *User, unsigned OpIdx,
const APInt &Demanded,
DAGCombinerInfo &DCI,
TargetLoweringOpt &TLO) const {
SDValue Op = User->getOperand(OpIdx);
KnownBits Known;
if (!SimplifyDemandedBits(Op, Demanded, Known, TLO, 0, true))
return false;
// Old will not always be the same as Op. For example:
//
// Demanded = 0xffffff
// Op = i64 truncate (i32 and x, 0xffffff)
// In this case simplify demand bits will want to replace the 'and' node
// with the value 'x', which will give us:
// Old = i32 and x, 0xffffff
// New = x
if (TLO.Old.hasOneUse()) {
// For the one use case, we just commit the change.
DCI.CommitTargetLoweringOpt(TLO);
return true;
}
// If Old has more than one use then it must be Op, because the
// AssumeSingleUse flag is not propogated to recursive calls of
// SimplifyDemanded bits, so the only node with multiple use that
// it will attempt to combine will be Op.
assert(TLO.Old == Op);
SmallVector <SDValue, 4> NewOps;
for (unsigned i = 0, e = User->getNumOperands(); i != e; ++i) {
if (i == OpIdx) {
NewOps.push_back(TLO.New);
continue;
}
NewOps.push_back(User->getOperand(i));
}
User = TLO.DAG.UpdateNodeOperands(User, NewOps);
// Op has less users now, so we may be able to perform additional combines
// with it.
DCI.AddToWorklist(Op.getNode());
// User's operands have been updated, so we may be able to do new combines
// with it.
DCI.AddToWorklist(User);
return true;
}
bool TargetLowering::SimplifyDemandedBits(SDValue Op, const APInt &DemandedMask,
DAGCombinerInfo &DCI) const {
SelectionDAG &DAG = DCI.DAG;
TargetLoweringOpt TLO(DAG, !DCI.isBeforeLegalize(),
!DCI.isBeforeLegalizeOps());
KnownBits Known;
bool Simplified = SimplifyDemandedBits(Op, DemandedMask, Known, TLO);
if (Simplified)
DCI.CommitTargetLoweringOpt(TLO);
return Simplified;
}
/// Look at Op. At this point, we know that only the DemandedMask bits of the
/// result of Op are ever used downstream. If we can use this information to
/// simplify Op, create a new simplified DAG node and return true, returning the
/// original and new nodes in Old and New. Otherwise, analyze the expression and
/// return a mask of Known bits for the expression (used to simplify the
/// caller). The Known bits may only be accurate for those bits in the
/// DemandedMask.
bool TargetLowering::SimplifyDemandedBits(SDValue Op,
const APInt &DemandedMask,
KnownBits &Known,
TargetLoweringOpt &TLO,
unsigned Depth,
bool AssumeSingleUse) const {
unsigned BitWidth = DemandedMask.getBitWidth();
assert(Op.getScalarValueSizeInBits() == BitWidth &&
"Mask size mismatches value type size!");
APInt NewMask = DemandedMask;
SDLoc dl(Op);
auto &DL = TLO.DAG.getDataLayout();
// Don't know anything.
Known = KnownBits(BitWidth);
if (Op.getOpcode() == ISD::Constant) {
// We know all of the bits for a constant!
Known.One = cast<ConstantSDNode>(Op)->getAPIntValue();
Known.Zero = ~Known.One;
return false;
}
// Other users may use these bits.
if (!Op.getNode()->hasOneUse() && !AssumeSingleUse) {
if (Depth != 0) {
// If not at the root, Just compute the Known bits to
// simplify things downstream.
TLO.DAG.computeKnownBits(Op, Known, Depth);
return false;
}
// If this is the root being simplified, allow it to have multiple uses,
// just set the NewMask to all bits.
NewMask = APInt::getAllOnesValue(BitWidth);
} else if (DemandedMask == 0) {
// Not demanding any bits from Op.
if (!Op.isUndef())
return TLO.CombineTo(Op, TLO.DAG.getUNDEF(Op.getValueType()));
return false;
} else if (Depth == 6) { // Limit search depth.
return false;
}
KnownBits Known2, KnownOut;
switch (Op.getOpcode()) {
case ISD::BUILD_VECTOR:
// Collect the known bits that are shared by every constant vector element.
Known.Zero.setAllBits(); Known.One.setAllBits();
for (SDValue SrcOp : Op->ops()) {
if (!isa<ConstantSDNode>(SrcOp)) {
// We can only handle all constant values - bail out with no known bits.
Known = KnownBits(BitWidth);
return false;
}
Known2.One = cast<ConstantSDNode>(SrcOp)->getAPIntValue();
Known2.Zero = ~Known2.One;
// BUILD_VECTOR can implicitly truncate sources, we must handle this.
if (Known2.One.getBitWidth() != BitWidth) {
assert(Known2.getBitWidth() > BitWidth &&
"Expected BUILD_VECTOR implicit truncation");
Known2 = Known2.trunc(BitWidth);
}
// Known bits are the values that are shared by every element.
// TODO: support per-element known bits.
Known.One &= Known2.One;
Known.Zero &= Known2.Zero;
}
return false; // Don't fall through, will infinitely loop.
case ISD::AND:
// If the RHS is a constant, check to see if the LHS would be zero without
// using the bits from the RHS. Below, we use knowledge about the RHS to
// simplify the LHS, here we're using information from the LHS to simplify
// the RHS.
if (ConstantSDNode *RHSC = isConstOrConstSplat(Op.getOperand(1))) {
SDValue Op0 = Op.getOperand(0);
KnownBits LHSKnown;
// Do not increment Depth here; that can cause an infinite loop.
TLO.DAG.computeKnownBits(Op0, LHSKnown, Depth);
// If the LHS already has zeros where RHSC does, this and is dead.
if ((LHSKnown.Zero & NewMask) == (~RHSC->getAPIntValue() & NewMask))
return TLO.CombineTo(Op, Op0);
// If any of the set bits in the RHS are known zero on the LHS, shrink
// the constant.
if (ShrinkDemandedConstant(Op, ~LHSKnown.Zero & NewMask, TLO))
return true;
// Bitwise-not (xor X, -1) is a special case: we don't usually shrink its
// constant, but if this 'and' is only clearing bits that were just set by
// the xor, then this 'and' can be eliminated by shrinking the mask of
// the xor. For example, for a 32-bit X:
// and (xor (srl X, 31), -1), 1 --> xor (srl X, 31), 1
if (isBitwiseNot(Op0) && Op0.hasOneUse() &&
LHSKnown.One == ~RHSC->getAPIntValue()) {
SDValue Xor = TLO.DAG.getNode(ISD::XOR, dl, Op.getValueType(),
Op0.getOperand(0), Op.getOperand(1));
return TLO.CombineTo(Op, Xor);
}
}
if (SimplifyDemandedBits(Op.getOperand(1), NewMask, Known, TLO, Depth+1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
if (SimplifyDemandedBits(Op.getOperand(0), ~Known.Zero & NewMask,
Known2, TLO, Depth+1))
return true;
assert(!Known2.hasConflict() && "Bits known to be one AND zero?");
// If all of the demanded bits are known one on one side, return the other.
// These bits cannot contribute to the result of the 'and'.
if (NewMask.isSubsetOf(Known2.Zero | Known.One))
return TLO.CombineTo(Op, Op.getOperand(0));
if (NewMask.isSubsetOf(Known.Zero | Known2.One))
return TLO.CombineTo(Op, Op.getOperand(1));
// If all of the demanded bits in the inputs are known zeros, return zero.
if (NewMask.isSubsetOf(Known.Zero | Known2.Zero))
return TLO.CombineTo(Op, TLO.DAG.getConstant(0, dl, Op.getValueType()));
// If the RHS is a constant, see if we can simplify it.
if (ShrinkDemandedConstant(Op, ~Known2.Zero & NewMask, TLO))
return true;
// If the operation can be done in a smaller type, do so.
if (ShrinkDemandedOp(Op, BitWidth, NewMask, TLO))
return true;
// Output known-1 bits are only known if set in both the LHS & RHS.
Known.One &= Known2.One;
// Output known-0 are known to be clear if zero in either the LHS | RHS.
Known.Zero |= Known2.Zero;
break;
case ISD::OR:
if (SimplifyDemandedBits(Op.getOperand(1), NewMask, Known, TLO, Depth+1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
if (SimplifyDemandedBits(Op.getOperand(0), ~Known.One & NewMask,
Known2, TLO, Depth+1))
return true;
assert(!Known2.hasConflict() && "Bits known to be one AND zero?");
// If all of the demanded bits are known zero on one side, return the other.
// These bits cannot contribute to the result of the 'or'.
if (NewMask.isSubsetOf(Known2.One | Known.Zero))
return TLO.CombineTo(Op, Op.getOperand(0));
if (NewMask.isSubsetOf(Known.One | Known2.Zero))
return TLO.CombineTo(Op, Op.getOperand(1));
// If the RHS is a constant, see if we can simplify it.
if (ShrinkDemandedConstant(Op, NewMask, TLO))
return true;
// If the operation can be done in a smaller type, do so.
if (ShrinkDemandedOp(Op, BitWidth, NewMask, TLO))
return true;
// Output known-0 bits are only known if clear in both the LHS & RHS.
Known.Zero &= Known2.Zero;
// Output known-1 are known to be set if set in either the LHS | RHS.
Known.One |= Known2.One;
break;
case ISD::XOR: {
if (SimplifyDemandedBits(Op.getOperand(1), NewMask, Known, TLO, Depth+1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
if (SimplifyDemandedBits(Op.getOperand(0), NewMask, Known2, TLO, Depth+1))
return true;
assert(!Known2.hasConflict() && "Bits known to be one AND zero?");
// If all of the demanded bits are known zero on one side, return the other.
// These bits cannot contribute to the result of the 'xor'.
if (NewMask.isSubsetOf(Known.Zero))
return TLO.CombineTo(Op, Op.getOperand(0));
if (NewMask.isSubsetOf(Known2.Zero))
return TLO.CombineTo(Op, Op.getOperand(1));
// If the operation can be done in a smaller type, do so.
if (ShrinkDemandedOp(Op, BitWidth, NewMask, TLO))
return true;
// If all of the unknown bits are known to be zero on one side or the other
// (but not both) turn this into an *inclusive* or.
// e.g. (A & C1)^(B & C2) -> (A & C1)|(B & C2) iff C1&C2 == 0
if ((NewMask & ~Known.Zero & ~Known2.Zero) == 0)
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::OR, dl, Op.getValueType(),
Op.getOperand(0),
Op.getOperand(1)));
// Output known-0 bits are known if clear or set in both the LHS & RHS.
KnownOut.Zero = (Known.Zero & Known2.Zero) | (Known.One & Known2.One);
// Output known-1 are known to be set if set in only one of the LHS, RHS.
KnownOut.One = (Known.Zero & Known2.One) | (Known.One & Known2.Zero);
// If all of the demanded bits on one side are known, and all of the set
// bits on that side are also known to be set on the other side, turn this
// into an AND, as we know the bits will be cleared.
// e.g. (X | C1) ^ C2 --> (X | C1) & ~C2 iff (C1&C2) == C2
// NB: it is okay if more bits are known than are requested
if (NewMask.isSubsetOf(Known.Zero|Known.One)) { // all known on one side
if (Known.One == Known2.One) { // set bits are the same on both sides
EVT VT = Op.getValueType();
SDValue ANDC = TLO.DAG.getConstant(~Known.One & NewMask, dl, VT);
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::AND, dl, VT,
Op.getOperand(0), ANDC));
}
}
// If the RHS is a constant, see if we can change it. Don't alter a -1
// constant because that's a 'not' op, and that is better for combining and
// codegen.
ConstantSDNode *C = isConstOrConstSplat(Op.getOperand(1));
if (C && !C->isAllOnesValue()) {
if (NewMask.isSubsetOf(C->getAPIntValue())) {
// We're flipping all demanded bits. Flip the undemanded bits too.
SDValue New = TLO.DAG.getNOT(dl, Op.getOperand(0), Op.getValueType());
return TLO.CombineTo(Op, New);
}
// If we can't turn this into a 'not', try to shrink the constant.
if (ShrinkDemandedConstant(Op, NewMask, TLO))
return true;
}
Known = std::move(KnownOut);
break;
}
case ISD::SELECT:
if (SimplifyDemandedBits(Op.getOperand(2), NewMask, Known, TLO, Depth+1))
return true;
if (SimplifyDemandedBits(Op.getOperand(1), NewMask, Known2, TLO, Depth+1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
assert(!Known2.hasConflict() && "Bits known to be one AND zero?");
// If the operands are constants, see if we can simplify them.
if (ShrinkDemandedConstant(Op, NewMask, TLO))
return true;
// Only known if known in both the LHS and RHS.
Known.One &= Known2.One;
Known.Zero &= Known2.Zero;
break;
case ISD::SELECT_CC:
if (SimplifyDemandedBits(Op.getOperand(3), NewMask, Known, TLO, Depth+1))
return true;
if (SimplifyDemandedBits(Op.getOperand(2), NewMask, Known2, TLO, Depth+1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
assert(!Known2.hasConflict() && "Bits known to be one AND zero?");
// If the operands are constants, see if we can simplify them.
if (ShrinkDemandedConstant(Op, NewMask, TLO))
return true;
// Only known if known in both the LHS and RHS.
Known.One &= Known2.One;
Known.Zero &= Known2.Zero;
break;
case ISD::SETCC: {
SDValue Op0 = Op.getOperand(0);
SDValue Op1 = Op.getOperand(1);
ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(2))->get();
// If (1) we only need the sign-bit, (2) the setcc operands are the same
// width as the setcc result, and (3) the result of a setcc conforms to 0 or
// -1, we may be able to bypass the setcc.
if (NewMask.isSignMask() && Op0.getScalarValueSizeInBits() == BitWidth &&
getBooleanContents(Op.getValueType()) ==
BooleanContent::ZeroOrNegativeOneBooleanContent) {
// If we're testing X < 0, then this compare isn't needed - just use X!
// FIXME: We're limiting to integer types here, but this should also work
// if we don't care about FP signed-zero. The use of SETLT with FP means
// that we don't care about NaNs.
if (CC == ISD::SETLT && Op1.getValueType().isInteger() &&
(isNullConstant(Op1) || ISD::isBuildVectorAllZeros(Op1.getNode())))
return TLO.CombineTo(Op, Op0);
// TODO: Should we check for other forms of sign-bit comparisons?
// Examples: X <= -1, X >= 0
}
if (getBooleanContents(Op0.getValueType()) ==
TargetLowering::ZeroOrOneBooleanContent &&
BitWidth > 1)
Known.Zero.setBitsFrom(1);
break;
}
case ISD::SHL:
if (ConstantSDNode *SA = isConstOrConstSplat(Op.getOperand(1))) {
SDValue InOp = Op.getOperand(0);
// If the shift count is an invalid immediate, don't do anything.
if (SA->getAPIntValue().uge(BitWidth))
break;
unsigned ShAmt = SA->getZExtValue();
// If this is ((X >>u C1) << ShAmt), see if we can simplify this into a
// single shift. We can do this if the bottom bits (which are shifted
// out) are never demanded.
if (InOp.getOpcode() == ISD::SRL) {
if (ConstantSDNode *SA2 = isConstOrConstSplat(InOp.getOperand(1))) {
if (ShAmt && (NewMask & APInt::getLowBitsSet(BitWidth, ShAmt)) == 0) {
if (SA2->getAPIntValue().ult(BitWidth)) {
unsigned C1 = SA2->getZExtValue();
unsigned Opc = ISD::SHL;
int Diff = ShAmt-C1;
if (Diff < 0) {
Diff = -Diff;
Opc = ISD::SRL;
}
SDValue NewSA =
TLO.DAG.getConstant(Diff, dl, Op.getOperand(1).getValueType());
EVT VT = Op.getValueType();
return TLO.CombineTo(Op, TLO.DAG.getNode(Opc, dl, VT,
InOp.getOperand(0),
NewSA));
}
}
}
}
if (SimplifyDemandedBits(InOp, NewMask.lshr(ShAmt), Known, TLO, Depth+1))
return true;
// Convert (shl (anyext x, c)) to (anyext (shl x, c)) if the high bits
// are not demanded. This will likely allow the anyext to be folded away.
if (InOp.getNode()->getOpcode() == ISD::ANY_EXTEND) {
SDValue InnerOp = InOp.getOperand(0);
EVT InnerVT = InnerOp.getValueType();
unsigned InnerBits = InnerVT.getScalarSizeInBits();
if (ShAmt < InnerBits && NewMask.getActiveBits() <= InnerBits &&
isTypeDesirableForOp(ISD::SHL, InnerVT)) {
EVT ShTy = getShiftAmountTy(InnerVT, DL);
if (!APInt(BitWidth, ShAmt).isIntN(ShTy.getSizeInBits()))
ShTy = InnerVT;
SDValue NarrowShl =
TLO.DAG.getNode(ISD::SHL, dl, InnerVT, InnerOp,
TLO.DAG.getConstant(ShAmt, dl, ShTy));
return
TLO.CombineTo(Op,
TLO.DAG.getNode(ISD::ANY_EXTEND, dl, Op.getValueType(),
NarrowShl));
}
// Repeat the SHL optimization above in cases where an extension
// intervenes: (shl (anyext (shr x, c1)), c2) to
// (shl (anyext x), c2-c1). This requires that the bottom c1 bits
// aren't demanded (as above) and that the shifted upper c1 bits of
// x aren't demanded.
if (InOp.hasOneUse() && InnerOp.getOpcode() == ISD::SRL &&
InnerOp.hasOneUse()) {
if (ConstantSDNode *SA2 = isConstOrConstSplat(InnerOp.getOperand(1))) {
unsigned InnerShAmt = SA2->getLimitedValue(InnerBits);
if (InnerShAmt < ShAmt &&
InnerShAmt < InnerBits &&
NewMask.getActiveBits() <= (InnerBits - InnerShAmt + ShAmt) &&
NewMask.countTrailingZeros() >= ShAmt) {
SDValue NewSA =
TLO.DAG.getConstant(ShAmt - InnerShAmt, dl,
Op.getOperand(1).getValueType());
EVT VT = Op.getValueType();
SDValue NewExt = TLO.DAG.getNode(ISD::ANY_EXTEND, dl, VT,
InnerOp.getOperand(0));
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SHL, dl, VT,
NewExt, NewSA));
}
}
}
}
Known.Zero <<= ShAmt;
Known.One <<= ShAmt;
// low bits known zero.
Known.Zero.setLowBits(ShAmt);
}
break;
case ISD::SRL:
if (ConstantSDNode *SA = isConstOrConstSplat(Op.getOperand(1))) {
SDValue InOp = Op.getOperand(0);
// If the shift count is an invalid immediate, don't do anything.
if (SA->getAPIntValue().uge(BitWidth))
break;
unsigned ShAmt = SA->getZExtValue();
APInt InDemandedMask = (NewMask << ShAmt);
// If the shift is exact, then it does demand the low bits (and knows that
// they are zero).
if (Op->getFlags().hasExact())
InDemandedMask.setLowBits(ShAmt);
// If this is ((X << C1) >>u ShAmt), see if we can simplify this into a
// single shift. We can do this if the top bits (which are shifted out)
// are never demanded.
if (InOp.getOpcode() == ISD::SHL) {
if (ConstantSDNode *SA2 = isConstOrConstSplat(InOp.getOperand(1))) {
if (ShAmt &&
(NewMask & APInt::getHighBitsSet(BitWidth, ShAmt)) == 0) {
if (SA2->getAPIntValue().ult(BitWidth)) {
unsigned C1 = SA2->getZExtValue();
unsigned Opc = ISD::SRL;
int Diff = ShAmt-C1;
if (Diff < 0) {
Diff = -Diff;
Opc = ISD::SHL;
}
SDValue NewSA =
TLO.DAG.getConstant(Diff, dl, Op.getOperand(1).getValueType());
EVT VT = Op.getValueType();
return TLO.CombineTo(Op, TLO.DAG.getNode(Opc, dl, VT,
InOp.getOperand(0),
NewSA));
}
}
}
}
// Compute the new bits that are at the top now.
if (SimplifyDemandedBits(InOp, InDemandedMask, Known, TLO, Depth+1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
Known.Zero.lshrInPlace(ShAmt);
Known.One.lshrInPlace(ShAmt);
Known.Zero.setHighBits(ShAmt); // High bits known zero.
}
break;
case ISD::SRA:
// If this is an arithmetic shift right and only the low-bit is set, we can
// always convert this into a logical shr, even if the shift amount is
// variable. The low bit of the shift cannot be an input sign bit unless
// the shift amount is >= the size of the datatype, which is undefined.
if (NewMask.isOneValue())
return TLO.CombineTo(Op,
TLO.DAG.getNode(ISD::SRL, dl, Op.getValueType(),
Op.getOperand(0), Op.getOperand(1)));
if (ConstantSDNode *SA = isConstOrConstSplat(Op.getOperand(1))) {
EVT VT = Op.getValueType();
// If the shift count is an invalid immediate, don't do anything.
if (SA->getAPIntValue().uge(BitWidth))
break;
unsigned ShAmt = SA->getZExtValue();
APInt InDemandedMask = (NewMask << ShAmt);
// If the shift is exact, then it does demand the low bits (and knows that
// they are zero).
if (Op->getFlags().hasExact())
InDemandedMask.setLowBits(ShAmt);
// If any of the demanded bits are produced by the sign extension, we also
// demand the input sign bit.
if (NewMask.countLeadingZeros() < ShAmt)
InDemandedMask.setSignBit();
if (SimplifyDemandedBits(Op.getOperand(0), InDemandedMask, Known, TLO,
Depth+1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
Known.Zero.lshrInPlace(ShAmt);
Known.One.lshrInPlace(ShAmt);
// If the input sign bit is known to be zero, or if none of the top bits
// are demanded, turn this into an unsigned shift right.
if (Known.Zero[BitWidth - ShAmt - 1] ||
NewMask.countLeadingZeros() >= ShAmt) {
SDNodeFlags Flags;
Flags.setExact(Op->getFlags().hasExact());
return TLO.CombineTo(Op,
TLO.DAG.getNode(ISD::SRL, dl, VT, Op.getOperand(0),
Op.getOperand(1), Flags));
}
int Log2 = NewMask.exactLogBase2();
if (Log2 >= 0) {
// The bit must come from the sign.
SDValue NewSA =
TLO.DAG.getConstant(BitWidth - 1 - Log2, dl,
Op.getOperand(1).getValueType());
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SRL, dl, VT,
Op.getOperand(0), NewSA));
}
if (Known.One[BitWidth - ShAmt - 1])
// New bits are known one.
Known.One.setHighBits(ShAmt);
}
break;
case ISD::SIGN_EXTEND_INREG: {
EVT ExVT = cast<VTSDNode>(Op.getOperand(1))->getVT();
unsigned ExVTBits = ExVT.getScalarSizeInBits();
// If we only care about the highest bit, don't bother shifting right.
if (NewMask.isSignMask()) {
SDValue InOp = Op.getOperand(0);
bool AlreadySignExtended =
TLO.DAG.ComputeNumSignBits(InOp) >= BitWidth-ExVTBits+1;
// However if the input is already sign extended we expect the sign
// extension to be dropped altogether later and do not simplify.
if (!AlreadySignExtended) {
// Compute the correct shift amount type, which must be getShiftAmountTy
// for scalar types after legalization.
EVT ShiftAmtTy = Op.getValueType();
if (TLO.LegalTypes() && !ShiftAmtTy.isVector())
ShiftAmtTy = getShiftAmountTy(ShiftAmtTy, DL);
SDValue ShiftAmt = TLO.DAG.getConstant(BitWidth - ExVTBits, dl,
ShiftAmtTy);
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SHL, dl,
Op.getValueType(), InOp,
ShiftAmt));
}
}
// If none of the extended bits are demanded, eliminate the sextinreg.
if (NewMask.getActiveBits() <= ExVTBits)
return TLO.CombineTo(Op, Op.getOperand(0));
APInt InputDemandedBits = NewMask.getLoBits(ExVTBits);
// Since the sign extended bits are demanded, we know that the sign
// bit is demanded.
InputDemandedBits.setBit(ExVTBits - 1);
if (SimplifyDemandedBits(Op.getOperand(0), InputDemandedBits,
Known, TLO, Depth+1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
// If the sign bit of the input is known set or clear, then we know the
// top bits of the result.
// If the input sign bit is known zero, convert this into a zero extension.
if (Known.Zero[ExVTBits - 1])
return TLO.CombineTo(Op, TLO.DAG.getZeroExtendInReg(
Op.getOperand(0), dl, ExVT.getScalarType()));
APInt Mask = APInt::getLowBitsSet(BitWidth, ExVTBits);
if (Known.One[ExVTBits - 1]) { // Input sign bit known set
Known.One.setBitsFrom(ExVTBits);
Known.Zero &= Mask;
} else { // Input sign bit unknown
Known.Zero &= Mask;
Known.One &= Mask;
}
break;
}
case ISD::BUILD_PAIR: {
EVT HalfVT = Op.getOperand(0).getValueType();
unsigned HalfBitWidth = HalfVT.getScalarSizeInBits();
APInt MaskLo = NewMask.getLoBits(HalfBitWidth).trunc(HalfBitWidth);
APInt MaskHi = NewMask.getHiBits(HalfBitWidth).trunc(HalfBitWidth);
KnownBits KnownLo, KnownHi;
if (SimplifyDemandedBits(Op.getOperand(0), MaskLo, KnownLo, TLO, Depth + 1))
return true;
if (SimplifyDemandedBits(Op.getOperand(1), MaskHi, KnownHi, TLO, Depth + 1))
return true;
Known.Zero = KnownLo.Zero.zext(BitWidth) |
KnownHi.Zero.zext(BitWidth).shl(HalfBitWidth);
Known.One = KnownLo.One.zext(BitWidth) |
KnownHi.One.zext(BitWidth).shl(HalfBitWidth);
break;
}
case ISD::ZERO_EXTEND: {
unsigned OperandBitWidth = Op.getOperand(0).getScalarValueSizeInBits();
// If none of the top bits are demanded, convert this into an any_extend.
if (NewMask.getActiveBits() <= OperandBitWidth)
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::ANY_EXTEND, dl,
Op.getValueType(),
Op.getOperand(0)));
APInt InMask = NewMask.trunc(OperandBitWidth);
if (SimplifyDemandedBits(Op.getOperand(0), InMask, Known, TLO, Depth+1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
Known = Known.zext(BitWidth);
Known.Zero.setBitsFrom(OperandBitWidth);
break;
}
case ISD::SIGN_EXTEND: {
unsigned InBits = Op.getOperand(0).getValueType().getScalarSizeInBits();
// If none of the top bits are demanded, convert this into an any_extend.
if (NewMask.getActiveBits() <= InBits)
return TLO.CombineTo(Op,TLO.DAG.getNode(ISD::ANY_EXTEND, dl,
Op.getValueType(),
Op.getOperand(0)));
// Since some of the sign extended bits are demanded, we know that the sign
// bit is demanded.
APInt InDemandedBits = NewMask.trunc(InBits);
InDemandedBits.setBit(InBits - 1);
if (SimplifyDemandedBits(Op.getOperand(0), InDemandedBits, Known, TLO,
Depth+1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
// If the sign bit is known one, the top bits match.
Known = Known.sext(BitWidth);
// If the sign bit is known zero, convert this to a zero extend.
if (Known.isNonNegative())
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::ZERO_EXTEND, dl,
Op.getValueType(),
Op.getOperand(0)));
break;
}
case ISD::ANY_EXTEND: {
unsigned OperandBitWidth = Op.getOperand(0).getScalarValueSizeInBits();
APInt InMask = NewMask.trunc(OperandBitWidth);
if (SimplifyDemandedBits(Op.getOperand(0), InMask, Known, TLO, Depth+1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
Known = Known.zext(BitWidth);
break;
}
case ISD::TRUNCATE: {
// Simplify the input, using demanded bit information, and compute the known
// zero/one bits live out.
unsigned OperandBitWidth = Op.getOperand(0).getScalarValueSizeInBits();
APInt TruncMask = NewMask.zext(OperandBitWidth);
if (SimplifyDemandedBits(Op.getOperand(0), TruncMask, Known, TLO, Depth+1))
return true;
Known = Known.trunc(BitWidth);
// If the input is only used by this truncate, see if we can shrink it based
// on the known demanded bits.
if (Op.getOperand(0).getNode()->hasOneUse()) {
SDValue In = Op.getOperand(0);
switch (In.getOpcode()) {
default: break;
case ISD::SRL:
// Shrink SRL by a constant if none of the high bits shifted in are
// demanded.
if (TLO.LegalTypes() &&
!isTypeDesirableForOp(ISD::SRL, Op.getValueType()))
// Do not turn (vt1 truncate (vt2 srl)) into (vt1 srl) if vt1 is
// undesirable.
break;
ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(In.getOperand(1));
if (!ShAmt)
break;
SDValue Shift = In.getOperand(1);
if (TLO.LegalTypes()) {
uint64_t ShVal = ShAmt->getZExtValue();
Shift = TLO.DAG.getConstant(ShVal, dl,
getShiftAmountTy(Op.getValueType(), DL));
}
if (ShAmt->getZExtValue() < BitWidth) {
APInt HighBits = APInt::getHighBitsSet(OperandBitWidth,
OperandBitWidth - BitWidth);
HighBits.lshrInPlace(ShAmt->getZExtValue());
HighBits = HighBits.trunc(BitWidth);
if (!(HighBits & NewMask)) {
// None of the shifted in bits are needed. Add a truncate of the
// shift input, then shift it.
SDValue NewTrunc = TLO.DAG.getNode(ISD::TRUNCATE, dl,
Op.getValueType(),
In.getOperand(0));
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SRL, dl,
Op.getValueType(),
NewTrunc,
Shift));
}
}
break;
}
}
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
break;
}
case ISD::AssertZext: {
// AssertZext demands all of the high bits, plus any of the low bits
// demanded by its users.
EVT VT = cast<VTSDNode>(Op.getOperand(1))->getVT();
APInt InMask = APInt::getLowBitsSet(BitWidth,
VT.getSizeInBits());
if (SimplifyDemandedBits(Op.getOperand(0), ~InMask | NewMask,
Known, TLO, Depth+1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
Known.Zero |= ~InMask;
break;
}
case ISD::BITCAST:
// If this is an FP->Int bitcast and if the sign bit is the only
// thing demanded, turn this into a FGETSIGN.
if (!TLO.LegalOperations() &&
!Op.getValueType().isVector() &&
!Op.getOperand(0).getValueType().isVector() &&
NewMask == APInt::getSignMask(Op.getValueSizeInBits()) &&
Op.getOperand(0).getValueType().isFloatingPoint()) {
bool OpVTLegal = isOperationLegalOrCustom(ISD::FGETSIGN, Op.getValueType());
bool i32Legal = isOperationLegalOrCustom(ISD::FGETSIGN, MVT::i32);
if ((OpVTLegal || i32Legal) && Op.getValueType().isSimple() &&
Op.getOperand(0).getValueType() != MVT::f128) {
// Cannot eliminate/lower SHL for f128 yet.
EVT Ty = OpVTLegal ? Op.getValueType() : MVT::i32;
// Make a FGETSIGN + SHL to move the sign bit into the appropriate
// place. We expect the SHL to be eliminated by other optimizations.
SDValue Sign = TLO.DAG.getNode(ISD::FGETSIGN, dl, Ty, Op.getOperand(0));
unsigned OpVTSizeInBits = Op.getValueSizeInBits();
if (!OpVTLegal && OpVTSizeInBits > 32)
Sign = TLO.DAG.getNode(ISD::ZERO_EXTEND, dl, Op.getValueType(), Sign);
unsigned ShVal = Op.getValueSizeInBits() - 1;
SDValue ShAmt = TLO.DAG.getConstant(ShVal, dl, Op.getValueType());
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SHL, dl,
Op.getValueType(),
Sign, ShAmt));
}
}
break;
case ISD::ADD:
case ISD::MUL:
case ISD::SUB: {
// Add, Sub, and Mul don't demand any bits in positions beyond that
// of the highest bit demanded of them.
APInt LoMask = APInt::getLowBitsSet(BitWidth,
BitWidth - NewMask.countLeadingZeros());
if (SimplifyDemandedBits(Op.getOperand(0), LoMask, Known2, TLO, Depth+1) ||
SimplifyDemandedBits(Op.getOperand(1), LoMask, Known2, TLO, Depth+1) ||
// See if the operation should be performed at a smaller bit width.
ShrinkDemandedOp(Op, BitWidth, NewMask, TLO)) {
SDNodeFlags Flags = Op.getNode()->getFlags();
if (Flags.hasNoSignedWrap() || Flags.hasNoUnsignedWrap()) {
// Disable the nsw and nuw flags. We can no longer guarantee that we
// won't wrap after simplification.
Flags.setNoSignedWrap(false);
Flags.setNoUnsignedWrap(false);
SDValue NewOp = TLO.DAG.getNode(Op.getOpcode(), dl, Op.getValueType(),
Op.getOperand(0), Op.getOperand(1),
Flags);
return TLO.CombineTo(Op, NewOp);
}
return true;
}
LLVM_FALLTHROUGH;
}
default:
// Just use computeKnownBits to compute output bits.
TLO.DAG.computeKnownBits(Op, Known, Depth);
break;
}
// If we know the value of all of the demanded bits, return this as a
// constant.
if (NewMask.isSubsetOf(Known.Zero|Known.One)) {
// Avoid folding to a constant if any OpaqueConstant is involved.
const SDNode *N = Op.getNode();
for (SDNodeIterator I = SDNodeIterator::begin(N),
E = SDNodeIterator::end(N); I != E; ++I) {
SDNode *Op = *I;
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op))
if (C->isOpaque())
return false;
}
return TLO.CombineTo(Op,
TLO.DAG.getConstant(Known.One, dl, Op.getValueType()));
}
return false;
}
/// Determine which of the bits specified in Mask are known to be either zero or
/// one and return them in the Known.
void TargetLowering::computeKnownBitsForTargetNode(const SDValue Op,
KnownBits &Known,
const APInt &DemandedElts,
const SelectionDAG &DAG,
unsigned Depth) const {
assert((Op.getOpcode() >= ISD::BUILTIN_OP_END ||
Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_W_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_VOID) &&
"Should use MaskedValueIsZero if you don't know whether Op"
" is a target node!");
Known.resetAll();
}
void TargetLowering::computeKnownBitsForFrameIndex(const SDValue Op,
KnownBits &Known,
const APInt &DemandedElts,
const SelectionDAG &DAG,
unsigned Depth) const {
assert(isa<FrameIndexSDNode>(Op) && "expected FrameIndex");
if (unsigned Align = DAG.InferPtrAlignment(Op)) {
// The low bits are known zero if the pointer is aligned.
Known.Zero.setLowBits(Log2_32(Align));
}
}
/// This method can be implemented by targets that want to expose additional
/// information about sign bits to the DAG Combiner.
unsigned TargetLowering::ComputeNumSignBitsForTargetNode(SDValue Op,
const APInt &,
const SelectionDAG &,
unsigned Depth) const {
assert((Op.getOpcode() >= ISD::BUILTIN_OP_END ||
Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_W_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_VOID) &&
"Should use ComputeNumSignBits if you don't know whether Op"
" is a target node!");
return 1;
}
// FIXME: Ideally, this would use ISD::isConstantSplatVector(), but that must
// work with truncating build vectors and vectors with elements of less than
// 8 bits.
bool TargetLowering::isConstTrueVal(const SDNode *N) const {
if (!N)
return false;
APInt CVal;
if (auto *CN = dyn_cast<ConstantSDNode>(N)) {
CVal = CN->getAPIntValue();
} else if (auto *BV = dyn_cast<BuildVectorSDNode>(N)) {
auto *CN = BV->getConstantSplatNode();
if (!CN)
return false;
// If this is a truncating build vector, truncate the splat value.
// Otherwise, we may fail to match the expected values below.
unsigned BVEltWidth = BV->getValueType(0).getScalarSizeInBits();
CVal = CN->getAPIntValue();
if (BVEltWidth < CVal.getBitWidth())
CVal = CVal.trunc(BVEltWidth);
} else {
return false;
}
switch (getBooleanContents(N->getValueType(0))) {
case UndefinedBooleanContent:
return CVal[0];
case ZeroOrOneBooleanContent:
return CVal.isOneValue();
case ZeroOrNegativeOneBooleanContent:
return CVal.isAllOnesValue();
}
llvm_unreachable("Invalid boolean contents");
}
SDValue TargetLowering::getConstTrueVal(SelectionDAG &DAG, EVT VT,
const SDLoc &DL) const {
unsigned ElementWidth = VT.getScalarSizeInBits();
APInt TrueInt =
getBooleanContents(VT) == TargetLowering::ZeroOrOneBooleanContent
? APInt(ElementWidth, 1)
: APInt::getAllOnesValue(ElementWidth);
return DAG.getConstant(TrueInt, DL, VT);
}
bool TargetLowering::isConstFalseVal(const SDNode *N) const {
if (!N)
return false;
const ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N);
if (!CN) {
const BuildVectorSDNode *BV = dyn_cast<BuildVectorSDNode>(N);
if (!BV)
return false;
// Only interested in constant splats, we don't care about undef
// elements in identifying boolean constants and getConstantSplatNode
// returns NULL if all ops are undef;
CN = BV->getConstantSplatNode();
if (!CN)
return false;
}
if (getBooleanContents(N->getValueType(0)) == UndefinedBooleanContent)
return !CN->getAPIntValue()[0];
return CN->isNullValue();
}
bool TargetLowering::isExtendedTrueVal(const ConstantSDNode *N, EVT VT,
bool SExt) const {
if (VT == MVT::i1)
return N->isOne();
TargetLowering::BooleanContent Cnt = getBooleanContents(VT);
switch (Cnt) {
case TargetLowering::ZeroOrOneBooleanContent:
// An extended value of 1 is always true, unless its original type is i1,
// in which case it will be sign extended to -1.
return (N->isOne() && !SExt) || (SExt && (N->getValueType(0) != MVT::i1));
case TargetLowering::UndefinedBooleanContent:
case TargetLowering::ZeroOrNegativeOneBooleanContent:
return N->isAllOnesValue() && SExt;
}
llvm_unreachable("Unexpected enumeration.");
}
/// This helper function of SimplifySetCC tries to optimize the comparison when
/// either operand of the SetCC node is a bitwise-and instruction.
SDValue TargetLowering::simplifySetCCWithAnd(EVT VT, SDValue N0, SDValue N1,
ISD::CondCode Cond,
DAGCombinerInfo &DCI,
const SDLoc &DL) const {
// Match these patterns in any of their permutations:
// (X & Y) == Y
// (X & Y) != Y
if (N1.getOpcode() == ISD::AND && N0.getOpcode() != ISD::AND)
std::swap(N0, N1);
EVT OpVT = N0.getValueType();
if (N0.getOpcode() != ISD::AND || !OpVT.isInteger() ||
(Cond != ISD::SETEQ && Cond != ISD::SETNE))
return SDValue();
SDValue X, Y;
if (N0.getOperand(0) == N1) {
X = N0.getOperand(1);
Y = N0.getOperand(0);
} else if (N0.getOperand(1) == N1) {
X = N0.getOperand(0);
Y = N0.getOperand(1);
} else {
return SDValue();
}
SelectionDAG &DAG = DCI.DAG;
SDValue Zero = DAG.getConstant(0, DL, OpVT);
if (DAG.isKnownToBeAPowerOfTwo(Y)) {
// Simplify X & Y == Y to X & Y != 0 if Y has exactly one bit set.
// Note that where Y is variable and is known to have at most one bit set
// (for example, if it is Z & 1) we cannot do this; the expressions are not
// equivalent when Y == 0.
Cond = ISD::getSetCCInverse(Cond, /*isInteger=*/true);
if (DCI.isBeforeLegalizeOps() ||
isCondCodeLegal(Cond, N0.getSimpleValueType()))
return DAG.getSetCC(DL, VT, N0, Zero, Cond);
} else if (N0.hasOneUse() && hasAndNotCompare(Y)) {
// If the target supports an 'and-not' or 'and-complement' logic operation,
// try to use that to make a comparison operation more efficient.
// But don't do this transform if the mask is a single bit because there are
// more efficient ways to deal with that case (for example, 'bt' on x86 or
// 'rlwinm' on PPC).
// Bail out if the compare operand that we want to turn into a zero is
// already a zero (otherwise, infinite loop).
auto *YConst = dyn_cast<ConstantSDNode>(Y);
if (YConst && YConst->isNullValue())
return SDValue();
// Transform this into: ~X & Y == 0.
SDValue NotX = DAG.getNOT(SDLoc(X), X, OpVT);
SDValue NewAnd = DAG.getNode(ISD::AND, SDLoc(N0), OpVT, NotX, Y);
return DAG.getSetCC(DL, VT, NewAnd, Zero, Cond);
}
return SDValue();
}
/// Try to simplify a setcc built with the specified operands and cc. If it is
/// unable to simplify it, return a null SDValue.
SDValue TargetLowering::SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
ISD::CondCode Cond, bool foldBooleans,
DAGCombinerInfo &DCI,
const SDLoc &dl) const {
SelectionDAG &DAG = DCI.DAG;
// These setcc operations always fold.
switch (Cond) {
default: break;
case ISD::SETFALSE:
case ISD::SETFALSE2: return DAG.getConstant(0, dl, VT);
case ISD::SETTRUE:
case ISD::SETTRUE2: {
TargetLowering::BooleanContent Cnt =
getBooleanContents(N0->getValueType(0));
return DAG.getConstant(
Cnt == TargetLowering::ZeroOrNegativeOneBooleanContent ? -1ULL : 1, dl,
VT);
}
}
// Ensure that the constant occurs on the RHS and fold constant comparisons.
ISD::CondCode SwappedCC = ISD::getSetCCSwappedOperands(Cond);
if (isa<ConstantSDNode>(N0.getNode()) &&
(DCI.isBeforeLegalizeOps() ||
isCondCodeLegal(SwappedCC, N0.getSimpleValueType())))
return DAG.getSetCC(dl, VT, N1, N0, SwappedCC);
if (auto *N1C = dyn_cast<ConstantSDNode>(N1.getNode())) {
const APInt &C1 = N1C->getAPIntValue();
// If the LHS is '(srl (ctlz x), 5)', the RHS is 0/1, and this is an
// equality comparison, then we're just comparing whether X itself is
// zero.
if (N0.getOpcode() == ISD::SRL && (C1.isNullValue() || C1.isOneValue()) &&
N0.getOperand(0).getOpcode() == ISD::CTLZ &&
N0.getOperand(1).getOpcode() == ISD::Constant) {
const APInt &ShAmt
= cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue();
if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
ShAmt == Log2_32(N0.getValueSizeInBits())) {
if ((C1 == 0) == (Cond == ISD::SETEQ)) {
// (srl (ctlz x), 5) == 0 -> X != 0
// (srl (ctlz x), 5) != 1 -> X != 0
Cond = ISD::SETNE;
} else {
// (srl (ctlz x), 5) != 0 -> X == 0
// (srl (ctlz x), 5) == 1 -> X == 0
Cond = ISD::SETEQ;
}
SDValue Zero = DAG.getConstant(0, dl, N0.getValueType());
return DAG.getSetCC(dl, VT, N0.getOperand(0).getOperand(0),
Zero, Cond);
}
}
SDValue CTPOP = N0;
// Look through truncs that don't change the value of a ctpop.
if (N0.hasOneUse() && N0.getOpcode() == ISD::TRUNCATE)
CTPOP = N0.getOperand(0);
if (CTPOP.hasOneUse() && CTPOP.getOpcode() == ISD::CTPOP &&
(N0 == CTPOP ||
N0.getValueSizeInBits() > Log2_32_Ceil(CTPOP.getValueSizeInBits()))) {
EVT CTVT = CTPOP.getValueType();
SDValue CTOp = CTPOP.getOperand(0);
// (ctpop x) u< 2 -> (x & x-1) == 0
// (ctpop x) u> 1 -> (x & x-1) != 0
if ((Cond == ISD::SETULT && C1 == 2) || (Cond == ISD::SETUGT && C1 == 1)){
SDValue Sub = DAG.getNode(ISD::SUB, dl, CTVT, CTOp,
DAG.getConstant(1, dl, CTVT));
SDValue And = DAG.getNode(ISD::AND, dl, CTVT, CTOp, Sub);
ISD::CondCode CC = Cond == ISD::SETULT ? ISD::SETEQ : ISD::SETNE;
return DAG.getSetCC(dl, VT, And, DAG.getConstant(0, dl, CTVT), CC);
}
// TODO: (ctpop x) == 1 -> x && (x & x-1) == 0 iff ctpop is illegal.
}
// (zext x) == C --> x == (trunc C)
// (sext x) == C --> x == (trunc C)
if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
DCI.isBeforeLegalize() && N0->hasOneUse()) {
unsigned MinBits = N0.getValueSizeInBits();
SDValue PreExt;
bool Signed = false;
if (N0->getOpcode() == ISD::ZERO_EXTEND) {
// ZExt
MinBits = N0->getOperand(0).getValueSizeInBits();
PreExt = N0->getOperand(0);
} else if (N0->getOpcode() == ISD::AND) {
// DAGCombine turns costly ZExts into ANDs
if (auto *C = dyn_cast<ConstantSDNode>(N0->getOperand(1)))
if ((C->getAPIntValue()+1).isPowerOf2()) {
MinBits = C->getAPIntValue().countTrailingOnes();
PreExt = N0->getOperand(0);
}
} else if (N0->getOpcode() == ISD::SIGN_EXTEND) {
// SExt
MinBits = N0->getOperand(0).getValueSizeInBits();
PreExt = N0->getOperand(0);
Signed = true;
} else if (auto *LN0 = dyn_cast<LoadSDNode>(N0)) {
// ZEXTLOAD / SEXTLOAD
if (LN0->getExtensionType() == ISD::ZEXTLOAD) {
MinBits = LN0->getMemoryVT().getSizeInBits();
PreExt = N0;
} else if (LN0->getExtensionType() == ISD::SEXTLOAD) {
Signed = true;
MinBits = LN0->getMemoryVT().getSizeInBits();
PreExt = N0;
}
}
// Figure out how many bits we need to preserve this constant.
unsigned ReqdBits = Signed ?
C1.getBitWidth() - C1.getNumSignBits() + 1 :
C1.getActiveBits();
// Make sure we're not losing bits from the constant.
if (MinBits > 0 &&
MinBits < C1.getBitWidth() &&
MinBits >= ReqdBits) {
EVT MinVT = EVT::getIntegerVT(*DAG.getContext(), MinBits);
if (isTypeDesirableForOp(ISD::SETCC, MinVT)) {
// Will get folded away.
SDValue Trunc = DAG.getNode(ISD::TRUNCATE, dl, MinVT, PreExt);
if (MinBits == 1 && C1 == 1)
// Invert the condition.
return DAG.getSetCC(dl, VT, Trunc, DAG.getConstant(0, dl, MVT::i1),
Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
SDValue C = DAG.getConstant(C1.trunc(MinBits), dl, MinVT);
return DAG.getSetCC(dl, VT, Trunc, C, Cond);
}
// If truncating the setcc operands is not desirable, we can still
// simplify the expression in some cases:
// setcc ([sz]ext (setcc x, y, cc)), 0, setne) -> setcc (x, y, cc)
// setcc ([sz]ext (setcc x, y, cc)), 0, seteq) -> setcc (x, y, inv(cc))
// setcc (zext (setcc x, y, cc)), 1, setne) -> setcc (x, y, inv(cc))
// setcc (zext (setcc x, y, cc)), 1, seteq) -> setcc (x, y, cc)
// setcc (sext (setcc x, y, cc)), -1, setne) -> setcc (x, y, inv(cc))
// setcc (sext (setcc x, y, cc)), -1, seteq) -> setcc (x, y, cc)
SDValue TopSetCC = N0->getOperand(0);
unsigned N0Opc = N0->getOpcode();
bool SExt = (N0Opc == ISD::SIGN_EXTEND);
if (TopSetCC.getValueType() == MVT::i1 && VT == MVT::i1 &&
TopSetCC.getOpcode() == ISD::SETCC &&
(N0Opc == ISD::ZERO_EXTEND || N0Opc == ISD::SIGN_EXTEND) &&
(isConstFalseVal(N1C) ||
isExtendedTrueVal(N1C, N0->getValueType(0), SExt))) {
bool Inverse = (N1C->isNullValue() && Cond == ISD::SETEQ) ||
(!N1C->isNullValue() && Cond == ISD::SETNE);
if (!Inverse)
return TopSetCC;
ISD::CondCode InvCond = ISD::getSetCCInverse(
cast<CondCodeSDNode>(TopSetCC.getOperand(2))->get(),
TopSetCC.getOperand(0).getValueType().isInteger());
return DAG.getSetCC(dl, VT, TopSetCC.getOperand(0),
TopSetCC.getOperand(1),
InvCond);
}
}
}
// If the LHS is '(and load, const)', the RHS is 0, the test is for
// equality or unsigned, and all 1 bits of the const are in the same
// partial word, see if we can shorten the load.
if (DCI.isBeforeLegalize() &&
!ISD::isSignedIntSetCC(Cond) &&
N0.getOpcode() == ISD::AND && C1 == 0 &&
N0.getNode()->hasOneUse() &&
isa<LoadSDNode>(N0.getOperand(0)) &&
N0.getOperand(0).getNode()->hasOneUse() &&
isa<ConstantSDNode>(N0.getOperand(1))) {
LoadSDNode *Lod = cast<LoadSDNode>(N0.getOperand(0));
APInt bestMask;
unsigned bestWidth = 0, bestOffset = 0;
if (!Lod->isVolatile() && Lod->isUnindexed()) {
unsigned origWidth = N0.getValueSizeInBits();
unsigned maskWidth = origWidth;
// We can narrow (e.g.) 16-bit extending loads on 32-bit target to
// 8 bits, but have to be careful...
if (Lod->getExtensionType() != ISD::NON_EXTLOAD)
origWidth = Lod->getMemoryVT().getSizeInBits();
const APInt &Mask =
cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue();
for (unsigned width = origWidth / 2; width>=8; width /= 2) {
APInt newMask = APInt::getLowBitsSet(maskWidth, width);
for (unsigned offset=0; offset<origWidth/width; offset++) {
if (Mask.isSubsetOf(newMask)) {
if (DAG.getDataLayout().isLittleEndian())
bestOffset = (uint64_t)offset * (width/8);
else
bestOffset = (origWidth/width - offset - 1) * (width/8);
bestMask = Mask.lshr(offset * (width/8) * 8);
bestWidth = width;
break;
}
newMask <<= width;
}
}
}
if (bestWidth) {
EVT newVT = EVT::getIntegerVT(*DAG.getContext(), bestWidth);
if (newVT.isRound()) {
EVT PtrType = Lod->getOperand(1).getValueType();
SDValue Ptr = Lod->getBasePtr();
if (bestOffset != 0)
Ptr = DAG.getNode(ISD::ADD, dl, PtrType, Lod->getBasePtr(),
DAG.getConstant(bestOffset, dl, PtrType));
unsigned NewAlign = MinAlign(Lod->getAlignment(), bestOffset);
SDValue NewLoad = DAG.getLoad(
newVT, dl, Lod->getChain(), Ptr,
Lod->getPointerInfo().getWithOffset(bestOffset), NewAlign);
return DAG.getSetCC(dl, VT,
DAG.getNode(ISD::AND, dl, newVT, NewLoad,
DAG.getConstant(bestMask.trunc(bestWidth),
dl, newVT)),
DAG.getConstant(0LL, dl, newVT), Cond);
}
}
}
// If the LHS is a ZERO_EXTEND, perform the comparison on the input.
if (N0.getOpcode() == ISD::ZERO_EXTEND) {
unsigned InSize = N0.getOperand(0).getValueSizeInBits();
// If the comparison constant has bits in the upper part, the
// zero-extended value could never match.
if (C1.intersects(APInt::getHighBitsSet(C1.getBitWidth(),
C1.getBitWidth() - InSize))) {
switch (Cond) {
case ISD::SETUGT:
case ISD::SETUGE:
case ISD::SETEQ:
return DAG.getConstant(0, dl, VT);
case ISD::SETULT:
case ISD::SETULE:
case ISD::SETNE:
return DAG.getConstant(1, dl, VT);
case ISD::SETGT:
case ISD::SETGE:
// True if the sign bit of C1 is set.
return DAG.getConstant(C1.isNegative(), dl, VT);
case ISD::SETLT:
case ISD::SETLE:
// True if the sign bit of C1 isn't set.
return DAG.getConstant(C1.isNonNegative(), dl, VT);
default:
break;
}
}
// Otherwise, we can perform the comparison with the low bits.
switch (Cond) {
case ISD::SETEQ:
case ISD::SETNE:
case ISD::SETUGT:
case ISD::SETUGE:
case ISD::SETULT:
case ISD::SETULE: {
EVT newVT = N0.getOperand(0).getValueType();
if (DCI.isBeforeLegalizeOps() ||
(isOperationLegal(ISD::SETCC, newVT) &&
getCondCodeAction(Cond, newVT.getSimpleVT()) == Legal)) {
EVT NewSetCCVT =
getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), newVT);
SDValue NewConst = DAG.getConstant(C1.trunc(InSize), dl, newVT);
SDValue NewSetCC = DAG.getSetCC(dl, NewSetCCVT, N0.getOperand(0),
NewConst, Cond);
return DAG.getBoolExtOrTrunc(NewSetCC, dl, VT, N0.getValueType());
}
break;
}
default:
break; // todo, be more careful with signed comparisons
}
} else if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
(Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
EVT ExtSrcTy = cast<VTSDNode>(N0.getOperand(1))->getVT();
unsigned ExtSrcTyBits = ExtSrcTy.getSizeInBits();
EVT ExtDstTy = N0.getValueType();
unsigned ExtDstTyBits = ExtDstTy.getSizeInBits();
// If the constant doesn't fit into the number of bits for the source of
// the sign extension, it is impossible for both sides to be equal.
if (C1.getMinSignedBits() > ExtSrcTyBits)
return DAG.getConstant(Cond == ISD::SETNE, dl, VT);
SDValue ZextOp;
EVT Op0Ty = N0.getOperand(0).getValueType();
if (Op0Ty == ExtSrcTy) {
ZextOp = N0.getOperand(0);
} else {
APInt Imm = APInt::getLowBitsSet(ExtDstTyBits, ExtSrcTyBits);
ZextOp = DAG.getNode(ISD::AND, dl, Op0Ty, N0.getOperand(0),
DAG.getConstant(Imm, dl, Op0Ty));
}
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(ZextOp.getNode());
// Otherwise, make this a use of a zext.
return DAG.getSetCC(dl, VT, ZextOp,
DAG.getConstant(C1 & APInt::getLowBitsSet(
ExtDstTyBits,
ExtSrcTyBits),
dl, ExtDstTy),
Cond);
} else if ((N1C->isNullValue() || N1C->isOne()) &&
(Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
// SETCC (SETCC), [0|1], [EQ|NE] -> SETCC
if (N0.getOpcode() == ISD::SETCC &&
isTypeLegal(VT) && VT.bitsLE(N0.getValueType())) {
bool TrueWhenTrue = (Cond == ISD::SETEQ) ^ (!N1C->isOne());
if (TrueWhenTrue)
return DAG.getNode(ISD::TRUNCATE, dl, VT, N0);
// Invert the condition.
ISD::CondCode CC = cast<CondCodeSDNode>(N0.getOperand(2))->get();
CC = ISD::getSetCCInverse(CC,
N0.getOperand(0).getValueType().isInteger());
if (DCI.isBeforeLegalizeOps() ||
isCondCodeLegal(CC, N0.getOperand(0).getSimpleValueType()))
return DAG.getSetCC(dl, VT, N0.getOperand(0), N0.getOperand(1), CC);
}
if ((N0.getOpcode() == ISD::XOR ||
(N0.getOpcode() == ISD::AND &&
N0.getOperand(0).getOpcode() == ISD::XOR &&
N0.getOperand(1) == N0.getOperand(0).getOperand(1))) &&
isa<ConstantSDNode>(N0.getOperand(1)) &&
cast<ConstantSDNode>(N0.getOperand(1))->isOne()) {
// If this is (X^1) == 0/1, swap the RHS and eliminate the xor. We
// can only do this if the top bits are known zero.
unsigned BitWidth = N0.getValueSizeInBits();
if (DAG.MaskedValueIsZero(N0,
APInt::getHighBitsSet(BitWidth,
BitWidth-1))) {
// Okay, get the un-inverted input value.
SDValue Val;
if (N0.getOpcode() == ISD::XOR) {
Val = N0.getOperand(0);
} else {
assert(N0.getOpcode() == ISD::AND &&
N0.getOperand(0).getOpcode() == ISD::XOR);
// ((X^1)&1)^1 -> X & 1
Val = DAG.getNode(ISD::AND, dl, N0.getValueType(),
N0.getOperand(0).getOperand(0),
N0.getOperand(1));
}
return DAG.getSetCC(dl, VT, Val, N1,
Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
}
} else if (N1C->isOne() &&
(VT == MVT::i1 ||
getBooleanContents(N0->getValueType(0)) ==
ZeroOrOneBooleanContent)) {
SDValue Op0 = N0;
if (Op0.getOpcode() == ISD::TRUNCATE)
Op0 = Op0.getOperand(0);
if ((Op0.getOpcode() == ISD::XOR) &&
Op0.getOperand(0).getOpcode() == ISD::SETCC &&
Op0.getOperand(1).getOpcode() == ISD::SETCC) {
// (xor (setcc), (setcc)) == / != 1 -> (setcc) != / == (setcc)
Cond = (Cond == ISD::SETEQ) ? ISD::SETNE : ISD::SETEQ;
return DAG.getSetCC(dl, VT, Op0.getOperand(0), Op0.getOperand(1),
Cond);
}
if (Op0.getOpcode() == ISD::AND &&
isa<ConstantSDNode>(Op0.getOperand(1)) &&
cast<ConstantSDNode>(Op0.getOperand(1))->isOne()) {
// If this is (X&1) == / != 1, normalize it to (X&1) != / == 0.
if (Op0.getValueType().bitsGT(VT))
Op0 = DAG.getNode(ISD::AND, dl, VT,
DAG.getNode(ISD::TRUNCATE, dl, VT, Op0.getOperand(0)),
DAG.getConstant(1, dl, VT));
else if (Op0.getValueType().bitsLT(VT))
Op0 = DAG.getNode(ISD::AND, dl, VT,
DAG.getNode(ISD::ANY_EXTEND, dl, VT, Op0.getOperand(0)),
DAG.getConstant(1, dl, VT));
return DAG.getSetCC(dl, VT, Op0,
DAG.getConstant(0, dl, Op0.getValueType()),
Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
}
if (Op0.getOpcode() == ISD::AssertZext &&
cast<VTSDNode>(Op0.getOperand(1))->getVT() == MVT::i1)
return DAG.getSetCC(dl, VT, Op0,
DAG.getConstant(0, dl, Op0.getValueType()),
Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
}
}
APInt MinVal, MaxVal;
unsigned OperandBitSize = N1C->getValueType(0).getSizeInBits();
if (ISD::isSignedIntSetCC(Cond)) {
MinVal = APInt::getSignedMinValue(OperandBitSize);
MaxVal = APInt::getSignedMaxValue(OperandBitSize);
} else {
MinVal = APInt::getMinValue(OperandBitSize);
MaxVal = APInt::getMaxValue(OperandBitSize);
}
// Canonicalize GE/LE comparisons to use GT/LT comparisons.
if (Cond == ISD::SETGE || Cond == ISD::SETUGE) {
// X >= MIN --> true
if (C1 == MinVal)
return DAG.getConstant(1, dl, VT);
// X >= C0 --> X > (C0 - 1)
APInt C = C1 - 1;
ISD::CondCode NewCC = (Cond == ISD::SETGE) ? ISD::SETGT : ISD::SETUGT;
if ((DCI.isBeforeLegalizeOps() ||
isCondCodeLegal(NewCC, VT.getSimpleVT())) &&
(!N1C->isOpaque() || (N1C->isOpaque() && C.getBitWidth() <= 64 &&
isLegalICmpImmediate(C.getSExtValue())))) {
return DAG.getSetCC(dl, VT, N0,
DAG.getConstant(C, dl, N1.getValueType()),
NewCC);
}
}
if (Cond == ISD::SETLE || Cond == ISD::SETULE) {
// X <= MAX --> true
if (C1 == MaxVal)
return DAG.getConstant(1, dl, VT);
// X <= C0 --> X < (C0 + 1)
APInt C = C1 + 1;
ISD::CondCode NewCC = (Cond == ISD::SETLE) ? ISD::SETLT : ISD::SETULT;
if ((DCI.isBeforeLegalizeOps() ||
isCondCodeLegal(NewCC, VT.getSimpleVT())) &&
(!N1C->isOpaque() || (N1C->isOpaque() && C.getBitWidth() <= 64 &&
isLegalICmpImmediate(C.getSExtValue())))) {
return DAG.getSetCC(dl, VT, N0,
DAG.getConstant(C, dl, N1.getValueType()),
NewCC);
}
}
if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal)
return DAG.getConstant(0, dl, VT); // X < MIN --> false
if ((Cond == ISD::SETGE || Cond == ISD::SETUGE) && C1 == MinVal)
return DAG.getConstant(1, dl, VT); // X >= MIN --> true
if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MaxVal)
return DAG.getConstant(0, dl, VT); // X > MAX --> false
if ((Cond == ISD::SETLE || Cond == ISD::SETULE) && C1 == MaxVal)
return DAG.getConstant(1, dl, VT); // X <= MAX --> true
// Canonicalize setgt X, Min --> setne X, Min
if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MinVal)
return DAG.getSetCC(dl, VT, N0, N1, ISD::SETNE);
// Canonicalize setlt X, Max --> setne X, Max
if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MaxVal)
return DAG.getSetCC(dl, VT, N0, N1, ISD::SETNE);
// If we have setult X, 1, turn it into seteq X, 0
if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal+1)
return DAG.getSetCC(dl, VT, N0,
DAG.getConstant(MinVal, dl, N0.getValueType()),
ISD::SETEQ);
// If we have setugt X, Max-1, turn it into seteq X, Max
if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MaxVal-1)
return DAG.getSetCC(dl, VT, N0,
DAG.getConstant(MaxVal, dl, N0.getValueType()),
ISD::SETEQ);
// If we have "setcc X, C0", check to see if we can shrink the immediate
// by changing cc.
// SETUGT X, SINTMAX -> SETLT X, 0
if (Cond == ISD::SETUGT &&
C1 == APInt::getSignedMaxValue(OperandBitSize))
return DAG.getSetCC(dl, VT, N0,
DAG.getConstant(0, dl, N1.getValueType()),
ISD::SETLT);
// SETULT X, SINTMIN -> SETGT X, -1
if (Cond == ISD::SETULT &&
C1 == APInt::getSignedMinValue(OperandBitSize)) {
SDValue ConstMinusOne =
DAG.getConstant(APInt::getAllOnesValue(OperandBitSize), dl,
N1.getValueType());
return DAG.getSetCC(dl, VT, N0, ConstMinusOne, ISD::SETGT);
}
// Fold bit comparisons when we can.
if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
(VT == N0.getValueType() ||
(isTypeLegal(VT) && VT.bitsLE(N0.getValueType()))) &&
N0.getOpcode() == ISD::AND) {
auto &DL = DAG.getDataLayout();
if (auto *AndRHS = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
EVT ShiftTy = DCI.isBeforeLegalize()
? getPointerTy(DL)
: getShiftAmountTy(N0.getValueType(), DL);
if (Cond == ISD::SETNE && C1 == 0) {// (X & 8) != 0 --> (X & 8) >> 3
// Perform the xform if the AND RHS is a single bit.
if (AndRHS->getAPIntValue().isPowerOf2()) {
return DAG.getNode(ISD::TRUNCATE, dl, VT,
DAG.getNode(ISD::SRL, dl, N0.getValueType(), N0,
DAG.getConstant(AndRHS->getAPIntValue().logBase2(), dl,
ShiftTy)));
}
} else if (Cond == ISD::SETEQ && C1 == AndRHS->getAPIntValue()) {
// (X & 8) == 8 --> (X & 8) >> 3
// Perform the xform if C1 is a single bit.
if (C1.isPowerOf2()) {
return DAG.getNode(ISD::TRUNCATE, dl, VT,
DAG.getNode(ISD::SRL, dl, N0.getValueType(), N0,
DAG.getConstant(C1.logBase2(), dl,
ShiftTy)));
}
}
}
}
if (C1.getMinSignedBits() <= 64 &&
!isLegalICmpImmediate(C1.getSExtValue())) {
// (X & -256) == 256 -> (X >> 8) == 1
if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
N0.getOpcode() == ISD::AND && N0.hasOneUse()) {
if (auto *AndRHS = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
const APInt &AndRHSC = AndRHS->getAPIntValue();
if ((-AndRHSC).isPowerOf2() && (AndRHSC & C1) == C1) {
unsigned ShiftBits = AndRHSC.countTrailingZeros();
auto &DL = DAG.getDataLayout();
EVT ShiftTy = DCI.isBeforeLegalize()
? getPointerTy(DL)
: getShiftAmountTy(N0.getValueType(), DL);
EVT CmpTy = N0.getValueType();
SDValue Shift = DAG.getNode(ISD::SRL, dl, CmpTy, N0.getOperand(0),
DAG.getConstant(ShiftBits, dl,
ShiftTy));
SDValue CmpRHS = DAG.getConstant(C1.lshr(ShiftBits), dl, CmpTy);
return DAG.getSetCC(dl, VT, Shift, CmpRHS, Cond);
}
}
} else if (Cond == ISD::SETULT || Cond == ISD::SETUGE ||
Cond == ISD::SETULE || Cond == ISD::SETUGT) {
bool AdjOne = (Cond == ISD::SETULE || Cond == ISD::SETUGT);
// X < 0x100000000 -> (X >> 32) < 1
// X >= 0x100000000 -> (X >> 32) >= 1
// X <= 0x0ffffffff -> (X >> 32) < 1
// X > 0x0ffffffff -> (X >> 32) >= 1
unsigned ShiftBits;
APInt NewC = C1;
ISD::CondCode NewCond = Cond;
if (AdjOne) {
ShiftBits = C1.countTrailingOnes();
NewC = NewC + 1;
NewCond = (Cond == ISD::SETULE) ? ISD::SETULT : ISD::SETUGE;
} else {
ShiftBits = C1.countTrailingZeros();
}
NewC.lshrInPlace(ShiftBits);
if (ShiftBits && NewC.getMinSignedBits() <= 64 &&
isLegalICmpImmediate(NewC.getSExtValue())) {
auto &DL = DAG.getDataLayout();
EVT ShiftTy = DCI.isBeforeLegalize()
? getPointerTy(DL)
: getShiftAmountTy(N0.getValueType(), DL);
EVT CmpTy = N0.getValueType();
SDValue Shift = DAG.getNode(ISD::SRL, dl, CmpTy, N0,
DAG.getConstant(ShiftBits, dl, ShiftTy));
SDValue CmpRHS = DAG.getConstant(NewC, dl, CmpTy);
return DAG.getSetCC(dl, VT, Shift, CmpRHS, NewCond);
}
}
}
}
if (isa<ConstantFPSDNode>(N0.getNode())) {
// Constant fold or commute setcc.
SDValue O = DAG.FoldSetCC(VT, N0, N1, Cond, dl);
if (O.getNode()) return O;
} else if (auto *CFP = dyn_cast<ConstantFPSDNode>(N1.getNode())) {
// If the RHS of an FP comparison is a constant, simplify it away in
// some cases.
if (CFP->getValueAPF().isNaN()) {
// If an operand is known to be a nan, we can fold it.
switch (ISD::getUnorderedFlavor(Cond)) {
default: llvm_unreachable("Unknown flavor!");
case 0: // Known false.
return DAG.getConstant(0, dl, VT);
case 1: // Known true.
return DAG.getConstant(1, dl, VT);
case 2: // Undefined.
return DAG.getUNDEF(VT);
}
}
// Otherwise, we know the RHS is not a NaN. Simplify the node to drop the
// constant if knowing that the operand is non-nan is enough. We prefer to
// have SETO(x,x) instead of SETO(x, 0.0) because this avoids having to
// materialize 0.0.
if (Cond == ISD::SETO || Cond == ISD::SETUO)
return DAG.getSetCC(dl, VT, N0, N0, Cond);
// setcc (fneg x), C -> setcc swap(pred) x, -C
if (N0.getOpcode() == ISD::FNEG) {
ISD::CondCode SwapCond = ISD::getSetCCSwappedOperands(Cond);
if (DCI.isBeforeLegalizeOps() ||
isCondCodeLegal(SwapCond, N0.getSimpleValueType())) {
SDValue NegN1 = DAG.getNode(ISD::FNEG, dl, N0.getValueType(), N1);
return DAG.getSetCC(dl, VT, N0.getOperand(0), NegN1, SwapCond);
}
}
// If the condition is not legal, see if we can find an equivalent one
// which is legal.
if (!isCondCodeLegal(Cond, N0.getSimpleValueType())) {
// If the comparison was an awkward floating-point == or != and one of
// the comparison operands is infinity or negative infinity, convert the
// condition to a less-awkward <= or >=.
if (CFP->getValueAPF().isInfinity()) {
if (CFP->getValueAPF().isNegative()) {
if (Cond == ISD::SETOEQ &&
isCondCodeLegal(ISD::SETOLE, N0.getSimpleValueType()))
return DAG.getSetCC(dl, VT, N0, N1, ISD::SETOLE);
if (Cond == ISD::SETUEQ &&
isCondCodeLegal(ISD::SETOLE, N0.getSimpleValueType()))
return DAG.getSetCC(dl, VT, N0, N1, ISD::SETULE);
if (Cond == ISD::SETUNE &&
isCondCodeLegal(ISD::SETUGT, N0.getSimpleValueType()))
return DAG.getSetCC(dl, VT, N0, N1, ISD::SETUGT);
if (Cond == ISD::SETONE &&
isCondCodeLegal(ISD::SETUGT, N0.getSimpleValueType()))
return DAG.getSetCC(dl, VT, N0, N1, ISD::SETOGT);
} else {
if (Cond == ISD::SETOEQ &&
isCondCodeLegal(ISD::SETOGE, N0.getSimpleValueType()))
return DAG.getSetCC(dl, VT, N0, N1, ISD::SETOGE);
if (Cond == ISD::SETUEQ &&
isCondCodeLegal(ISD::SETOGE, N0.getSimpleValueType()))
return DAG.getSetCC(dl, VT, N0, N1, ISD::SETUGE);
if (Cond == ISD::SETUNE &&
isCondCodeLegal(ISD::SETULT, N0.getSimpleValueType()))
return DAG.getSetCC(dl, VT, N0, N1, ISD::SETULT);
if (Cond == ISD::SETONE &&
isCondCodeLegal(ISD::SETULT, N0.getSimpleValueType()))
return DAG.getSetCC(dl, VT, N0, N1, ISD::SETOLT);
}
}
}
}
if (N0 == N1) {
// The sext(setcc()) => setcc() optimization relies on the appropriate
// constant being emitted.
uint64_t EqVal = 0;
switch (getBooleanContents(N0.getValueType())) {
case UndefinedBooleanContent:
case ZeroOrOneBooleanContent:
EqVal = ISD::isTrueWhenEqual(Cond);
break;
case ZeroOrNegativeOneBooleanContent:
EqVal = ISD::isTrueWhenEqual(Cond) ? -1 : 0;
break;
}
// We can always fold X == X for integer setcc's.
if (N0.getValueType().isInteger()) {
return DAG.getConstant(EqVal, dl, VT);
}
unsigned UOF = ISD::getUnorderedFlavor(Cond);
if (UOF == 2) // FP operators that are undefined on NaNs.
return DAG.getConstant(EqVal, dl, VT);
if (UOF == unsigned(ISD::isTrueWhenEqual(Cond)))
return DAG.getConstant(EqVal, dl, VT);
// Otherwise, we can't fold it. However, we can simplify it to SETUO/SETO
// if it is not already.
ISD::CondCode NewCond = UOF == 0 ? ISD::SETO : ISD::SETUO;
if (NewCond != Cond && (DCI.isBeforeLegalizeOps() ||
getCondCodeAction(NewCond, N0.getSimpleValueType()) == Legal))
return DAG.getSetCC(dl, VT, N0, N1, NewCond);
}
if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
N0.getValueType().isInteger()) {
if (N0.getOpcode() == ISD::ADD || N0.getOpcode() == ISD::SUB ||
N0.getOpcode() == ISD::XOR) {
// Simplify (X+Y) == (X+Z) --> Y == Z
if (N0.getOpcode() == N1.getOpcode()) {
if (N0.getOperand(0) == N1.getOperand(0))
return DAG.getSetCC(dl, VT, N0.getOperand(1), N1.getOperand(1), Cond);
if (N0.getOperand(1) == N1.getOperand(1))
return DAG.getSetCC(dl, VT, N0.getOperand(0), N1.getOperand(0), Cond);
if (isCommutativeBinOp(N0.getOpcode())) {
// If X op Y == Y op X, try other combinations.
if (N0.getOperand(0) == N1.getOperand(1))
return DAG.getSetCC(dl, VT, N0.getOperand(1), N1.getOperand(0),
Cond);
if (N0.getOperand(1) == N1.getOperand(0))
return DAG.getSetCC(dl, VT, N0.getOperand(0), N1.getOperand(1),
Cond);
}
}
// If RHS is a legal immediate value for a compare instruction, we need
// to be careful about increasing register pressure needlessly.
bool LegalRHSImm = false;
if (auto *RHSC = dyn_cast<ConstantSDNode>(N1)) {
if (auto *LHSR = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
// Turn (X+C1) == C2 --> X == C2-C1
if (N0.getOpcode() == ISD::ADD && N0.getNode()->hasOneUse()) {
return DAG.getSetCC(dl, VT, N0.getOperand(0),
DAG.getConstant(RHSC->getAPIntValue()-
LHSR->getAPIntValue(),
dl, N0.getValueType()), Cond);
}
// Turn (X^C1) == C2 into X == C1^C2 iff X&~C1 = 0.
if (N0.getOpcode() == ISD::XOR)
// If we know that all of the inverted bits are zero, don't bother
// performing the inversion.
if (DAG.MaskedValueIsZero(N0.getOperand(0), ~LHSR->getAPIntValue()))
return
DAG.getSetCC(dl, VT, N0.getOperand(0),
DAG.getConstant(LHSR->getAPIntValue() ^
RHSC->getAPIntValue(),
dl, N0.getValueType()),
Cond);
}
// Turn (C1-X) == C2 --> X == C1-C2
if (auto *SUBC = dyn_cast<ConstantSDNode>(N0.getOperand(0))) {
if (N0.getOpcode() == ISD::SUB && N0.getNode()->hasOneUse()) {
return
DAG.getSetCC(dl, VT, N0.getOperand(1),
DAG.getConstant(SUBC->getAPIntValue() -
RHSC->getAPIntValue(),
dl, N0.getValueType()),
Cond);
}
}
// Could RHSC fold directly into a compare?
if (RHSC->getValueType(0).getSizeInBits() <= 64)
LegalRHSImm = isLegalICmpImmediate(RHSC->getSExtValue());
}
// Simplify (X+Z) == X --> Z == 0
// Don't do this if X is an immediate that can fold into a cmp
// instruction and X+Z has other uses. It could be an induction variable
// chain, and the transform would increase register pressure.
if (!LegalRHSImm || N0.getNode()->hasOneUse()) {
if (N0.getOperand(0) == N1)
return DAG.getSetCC(dl, VT, N0.getOperand(1),
DAG.getConstant(0, dl, N0.getValueType()), Cond);
if (N0.getOperand(1) == N1) {
if (isCommutativeBinOp(N0.getOpcode()))
return DAG.getSetCC(dl, VT, N0.getOperand(0),
DAG.getConstant(0, dl, N0.getValueType()),
Cond);
if (N0.getNode()->hasOneUse()) {
assert(N0.getOpcode() == ISD::SUB && "Unexpected operation!");
auto &DL = DAG.getDataLayout();
// (Z-X) == X --> Z == X<<1
SDValue SH = DAG.getNode(
ISD::SHL, dl, N1.getValueType(), N1,
DAG.getConstant(1, dl,
getShiftAmountTy(N1.getValueType(), DL)));
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(SH.getNode());
return DAG.getSetCC(dl, VT, N0.getOperand(0), SH, Cond);
}
}
}
}
if (N1.getOpcode() == ISD::ADD || N1.getOpcode() == ISD::SUB ||
N1.getOpcode() == ISD::XOR) {
// Simplify X == (X+Z) --> Z == 0
if (N1.getOperand(0) == N0)
return DAG.getSetCC(dl, VT, N1.getOperand(1),
DAG.getConstant(0, dl, N1.getValueType()), Cond);
if (N1.getOperand(1) == N0) {
if (isCommutativeBinOp(N1.getOpcode()))
return DAG.getSetCC(dl, VT, N1.getOperand(0),
DAG.getConstant(0, dl, N1.getValueType()), Cond);
if (N1.getNode()->hasOneUse()) {
assert(N1.getOpcode() == ISD::SUB && "Unexpected operation!");
auto &DL = DAG.getDataLayout();
// X == (Z-X) --> X<<1 == Z
SDValue SH = DAG.getNode(
ISD::SHL, dl, N1.getValueType(), N0,
DAG.getConstant(1, dl, getShiftAmountTy(N0.getValueType(), DL)));
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(SH.getNode());
return DAG.getSetCC(dl, VT, SH, N1.getOperand(0), Cond);
}
}
}
if (SDValue V = simplifySetCCWithAnd(VT, N0, N1, Cond, DCI, dl))
return V;
}
// Fold away ALL boolean setcc's.
SDValue Temp;
if (N0.getValueType() == MVT::i1 && foldBooleans) {
switch (Cond) {
default: llvm_unreachable("Unknown integer setcc!");
case ISD::SETEQ: // X == Y -> ~(X^Y)
Temp = DAG.getNode(ISD::XOR, dl, MVT::i1, N0, N1);
N0 = DAG.getNOT(dl, Temp, MVT::i1);
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(Temp.getNode());
break;
case ISD::SETNE: // X != Y --> (X^Y)
N0 = DAG.getNode(ISD::XOR, dl, MVT::i1, N0, N1);
break;
case ISD::SETGT: // X >s Y --> X == 0 & Y == 1 --> ~X & Y
case ISD::SETULT: // X <u Y --> X == 0 & Y == 1 --> ~X & Y
Temp = DAG.getNOT(dl, N0, MVT::i1);
N0 = DAG.getNode(ISD::AND, dl, MVT::i1, N1, Temp);
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(Temp.getNode());
break;
case ISD::SETLT: // X <s Y --> X == 1 & Y == 0 --> ~Y & X
case ISD::SETUGT: // X >u Y --> X == 1 & Y == 0 --> ~Y & X
Temp = DAG.getNOT(dl, N1, MVT::i1);
N0 = DAG.getNode(ISD::AND, dl, MVT::i1, N0, Temp);
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(Temp.getNode());
break;
case ISD::SETULE: // X <=u Y --> X == 0 | Y == 1 --> ~X | Y
case ISD::SETGE: // X >=s Y --> X == 0 | Y == 1 --> ~X | Y
Temp = DAG.getNOT(dl, N0, MVT::i1);
N0 = DAG.getNode(ISD::OR, dl, MVT::i1, N1, Temp);
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(Temp.getNode());
break;
case ISD::SETUGE: // X >=u Y --> X == 1 | Y == 0 --> ~Y | X
case ISD::SETLE: // X <=s Y --> X == 1 | Y == 0 --> ~Y | X
Temp = DAG.getNOT(dl, N1, MVT::i1);
N0 = DAG.getNode(ISD::OR, dl, MVT::i1, N0, Temp);
break;
}
if (VT != MVT::i1) {
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(N0.getNode());
// FIXME: If running after legalize, we probably can't do this.
N0 = DAG.getNode(ISD::ZERO_EXTEND, dl, VT, N0);
}
return N0;
}
// Could not fold it.
return SDValue();
}
/// Returns true (and the GlobalValue and the offset) if the node is a
/// GlobalAddress + offset.
bool TargetLowering::isGAPlusOffset(SDNode *N, const GlobalValue *&GA,
int64_t &Offset) const {
if (auto *GASD = dyn_cast<GlobalAddressSDNode>(N)) {
GA = GASD->getGlobal();
Offset += GASD->getOffset();
return true;
}
if (N->getOpcode() == ISD::ADD) {
SDValue N1 = N->getOperand(0);
SDValue N2 = N->getOperand(1);
if (isGAPlusOffset(N1.getNode(), GA, Offset)) {
if (auto *V = dyn_cast<ConstantSDNode>(N2)) {
Offset += V->getSExtValue();
return true;
}
} else if (isGAPlusOffset(N2.getNode(), GA, Offset)) {
if (auto *V = dyn_cast<ConstantSDNode>(N1)) {
Offset += V->getSExtValue();
return true;
}
}
}
return false;
}
SDValue TargetLowering::PerformDAGCombine(SDNode *N,
DAGCombinerInfo &DCI) const {
// Default implementation: no optimization.
return SDValue();
}
//===----------------------------------------------------------------------===//
// Inline Assembler Implementation Methods
//===----------------------------------------------------------------------===//
TargetLowering::ConstraintType
TargetLowering::getConstraintType(StringRef Constraint) const {
unsigned S = Constraint.size();
if (S == 1) {
switch (Constraint[0]) {
default: break;
case 'r': return C_RegisterClass;
case 'm': // memory
case 'o': // offsetable
case 'V': // not offsetable
return C_Memory;
case 'i': // Simple Integer or Relocatable Constant
case 'n': // Simple Integer
case 'E': // Floating Point Constant
case 'F': // Floating Point Constant
case 's': // Relocatable Constant
case 'p': // Address.
case 'X': // Allow ANY value.
case 'I': // Target registers.
case 'J':
case 'K':
case 'L':
case 'M':
case 'N':
case 'O':
case 'P':
case '<':
case '>':
return C_Other;
}
}
if (S > 1 && Constraint[0] == '{' && Constraint[S-1] == '}') {
if (S == 8 && Constraint.substr(1, 6) == "memory") // "{memory}"
return C_Memory;
return C_Register;
}
return C_Unknown;
}
/// Try to replace an X constraint, which matches anything, with another that
/// has more specific requirements based on the type of the corresponding
/// operand.
const char *TargetLowering::LowerXConstraint(EVT ConstraintVT) const{
if (ConstraintVT.isInteger())
return "r";
if (ConstraintVT.isFloatingPoint())
return "f"; // works for many targets
return nullptr;
}
/// Lower the specified operand into the Ops vector.
/// If it is invalid, don't add anything to Ops.
void TargetLowering::LowerAsmOperandForConstraint(SDValue Op,
std::string &Constraint,
std::vector<SDValue> &Ops,
SelectionDAG &DAG) const {
if (Constraint.length() > 1) return;
char ConstraintLetter = Constraint[0];
switch (ConstraintLetter) {
default: break;
case 'X': // Allows any operand; labels (basic block) use this.
if (Op.getOpcode() == ISD::BasicBlock) {
Ops.push_back(Op);
return;
}
LLVM_FALLTHROUGH;
case 'i': // Simple Integer or Relocatable Constant
case 'n': // Simple Integer
case 's': { // Relocatable Constant
// These operands are interested in values of the form (GV+C), where C may
// be folded in as an offset of GV, or it may be explicitly added. Also, it
// is possible and fine if either GV or C are missing.
ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op);
GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(Op);
// If we have "(add GV, C)", pull out GV/C
if (Op.getOpcode() == ISD::ADD) {
C = dyn_cast<ConstantSDNode>(Op.getOperand(1));
GA = dyn_cast<GlobalAddressSDNode>(Op.getOperand(0));
if (!C || !GA) {
C = dyn_cast<ConstantSDNode>(Op.getOperand(0));
GA = dyn_cast<GlobalAddressSDNode>(Op.getOperand(1));
}
if (!C || !GA) {
C = nullptr;
GA = nullptr;
}
}
// If we find a valid operand, map to the TargetXXX version so that the
// value itself doesn't get selected.
if (GA) { // Either &GV or &GV+C
if (ConstraintLetter != 'n') {
int64_t Offs = GA->getOffset();
if (C) Offs += C->getZExtValue();
Ops.push_back(DAG.getTargetGlobalAddress(GA->getGlobal(),
C ? SDLoc(C) : SDLoc(),
Op.getValueType(), Offs));
}
return;
}
if (C) { // just C, no GV.
// Simple constants are not allowed for 's'.
if (ConstraintLetter != 's') {
// gcc prints these as sign extended. Sign extend value to 64 bits
// now; without this it would get ZExt'd later in
// ScheduleDAGSDNodes::EmitNode, which is very generic.
Ops.push_back(DAG.getTargetConstant(C->getSExtValue(),
SDLoc(C), MVT::i64));
}
return;
}
break;
}
}
}
std::pair<unsigned, const TargetRegisterClass *>
TargetLowering::getRegForInlineAsmConstraint(const TargetRegisterInfo *RI,
StringRef Constraint,
MVT VT) const {
if (Constraint.empty() || Constraint[0] != '{')
return std::make_pair(0u, static_cast<TargetRegisterClass*>(nullptr));
assert(*(Constraint.end()-1) == '}' && "Not a brace enclosed constraint?");
// Remove the braces from around the name.
StringRef RegName(Constraint.data()+1, Constraint.size()-2);
std::pair<unsigned, const TargetRegisterClass*> R =
std::make_pair(0u, static_cast<const TargetRegisterClass*>(nullptr));
// Figure out which register class contains this reg.
for (const TargetRegisterClass *RC : RI->regclasses()) {
// If none of the value types for this register class are valid, we
// can't use it. For example, 64-bit reg classes on 32-bit targets.
if (!isLegalRC(*RI, *RC))
continue;
for (TargetRegisterClass::iterator I = RC->begin(), E = RC->end();
I != E; ++I) {
if (RegName.equals_lower(RI->getRegAsmName(*I))) {
std::pair<unsigned, const TargetRegisterClass*> S =
std::make_pair(*I, RC);
// If this register class has the requested value type, return it,
// otherwise keep searching and return the first class found
// if no other is found which explicitly has the requested type.
if (RI->isTypeLegalForClass(*RC, VT))
return S;
if (!R.second)
R = S;
}
}
}
return R;
}
//===----------------------------------------------------------------------===//
// Constraint Selection.
/// Return true of this is an input operand that is a matching constraint like
/// "4".
bool TargetLowering::AsmOperandInfo::isMatchingInputConstraint() const {
assert(!ConstraintCode.empty() && "No known constraint!");
return isdigit(static_cast<unsigned char>(ConstraintCode[0]));
}
/// If this is an input matching constraint, this method returns the output
/// operand it matches.
unsigned TargetLowering::AsmOperandInfo::getMatchedOperand() const {
assert(!ConstraintCode.empty() && "No known constraint!");
return atoi(ConstraintCode.c_str());
}
/// Split up the constraint string from the inline assembly value into the
/// specific constraints and their prefixes, and also tie in the associated
/// operand values.
/// If this returns an empty vector, and if the constraint string itself
/// isn't empty, there was an error parsing.
TargetLowering::AsmOperandInfoVector
TargetLowering::ParseConstraints(const DataLayout &DL,
const TargetRegisterInfo *TRI,
ImmutableCallSite CS) const {
/// Information about all of the constraints.
AsmOperandInfoVector ConstraintOperands;
const InlineAsm *IA = cast<InlineAsm>(CS.getCalledValue());
unsigned maCount = 0; // Largest number of multiple alternative constraints.
// Do a prepass over the constraints, canonicalizing them, and building up the
// ConstraintOperands list.
unsigned ArgNo = 0; // ArgNo - The argument of the CallInst.
unsigned ResNo = 0; // ResNo - The result number of the next output.
for (InlineAsm::ConstraintInfo &CI : IA->ParseConstraints()) {
ConstraintOperands.emplace_back(std::move(CI));
AsmOperandInfo &OpInfo = ConstraintOperands.back();
// Update multiple alternative constraint count.
if (OpInfo.multipleAlternatives.size() > maCount)
maCount = OpInfo.multipleAlternatives.size();
OpInfo.ConstraintVT = MVT::Other;
// Compute the value type for each operand.
switch (OpInfo.Type) {
case InlineAsm::isOutput:
// Indirect outputs just consume an argument.
if (OpInfo.isIndirect) {
OpInfo.CallOperandVal = const_cast<Value *>(CS.getArgument(ArgNo++));
break;
}
// The return value of the call is this value. As such, there is no
// corresponding argument.
assert(!CS.getType()->isVoidTy() &&
"Bad inline asm!");
if (StructType *STy = dyn_cast<StructType>(CS.getType())) {
OpInfo.ConstraintVT =
getSimpleValueType(DL, STy->getElementType(ResNo));
} else {
assert(ResNo == 0 && "Asm only has one result!");
OpInfo.ConstraintVT = getSimpleValueType(DL, CS.getType());
}
++ResNo;
break;
case InlineAsm::isInput:
OpInfo.CallOperandVal = const_cast<Value *>(CS.getArgument(ArgNo++));
break;
case InlineAsm::isClobber:
// Nothing to do.
break;
}
if (OpInfo.CallOperandVal) {
llvm::Type *OpTy = OpInfo.CallOperandVal->getType();
if (OpInfo.isIndirect) {
llvm::PointerType *PtrTy = dyn_cast<PointerType>(OpTy);
if (!PtrTy)
report_fatal_error("Indirect operand for inline asm not a pointer!");
OpTy = PtrTy->getElementType();
}
// Look for vector wrapped in a struct. e.g. { <16 x i8> }.
if (StructType *STy = dyn_cast<StructType>(OpTy))
if (STy->getNumElements() == 1)
OpTy = STy->getElementType(0);
// If OpTy is not a single value, it may be a struct/union that we
// can tile with integers.
if (!OpTy->isSingleValueType() && OpTy->isSized()) {
unsigned BitSize = DL.getTypeSizeInBits(OpTy);
switch (BitSize) {
default: break;
case 1:
case 8:
case 16:
case 32:
case 64:
case 128:
OpInfo.ConstraintVT =
MVT::getVT(IntegerType::get(OpTy->getContext(), BitSize), true);
break;
}
} else if (PointerType *PT = dyn_cast<PointerType>(OpTy)) {
unsigned PtrSize = DL.getPointerSizeInBits(PT->getAddressSpace());
OpInfo.ConstraintVT = MVT::getIntegerVT(PtrSize);
} else {
OpInfo.ConstraintVT = MVT::getVT(OpTy, true);
}
}
}
// If we have multiple alternative constraints, select the best alternative.
if (!ConstraintOperands.empty()) {
if (maCount) {
unsigned bestMAIndex = 0;
int bestWeight = -1;
// weight: -1 = invalid match, and 0 = so-so match to 5 = good match.
int weight = -1;
unsigned maIndex;
// Compute the sums of the weights for each alternative, keeping track
// of the best (highest weight) one so far.
for (maIndex = 0; maIndex < maCount; ++maIndex) {
int weightSum = 0;
for (unsigned cIndex = 0, eIndex = ConstraintOperands.size();
cIndex != eIndex; ++cIndex) {
AsmOperandInfo& OpInfo = ConstraintOperands[cIndex];
if (OpInfo.Type == InlineAsm::isClobber)
continue;
// If this is an output operand with a matching input operand,
// look up the matching input. If their types mismatch, e.g. one
// is an integer, the other is floating point, or their sizes are
// different, flag it as an maCantMatch.
if (OpInfo.hasMatchingInput()) {
AsmOperandInfo &Input = ConstraintOperands[OpInfo.MatchingInput];
if (OpInfo.ConstraintVT != Input.ConstraintVT) {
if ((OpInfo.ConstraintVT.isInteger() !=
Input.ConstraintVT.isInteger()) ||
(OpInfo.ConstraintVT.getSizeInBits() !=
Input.ConstraintVT.getSizeInBits())) {
weightSum = -1; // Can't match.
break;
}
}
}
weight = getMultipleConstraintMatchWeight(OpInfo, maIndex);
if (weight == -1) {
weightSum = -1;
break;
}
weightSum += weight;
}
// Update best.
if (weightSum > bestWeight) {
bestWeight = weightSum;
bestMAIndex = maIndex;
}
}
// Now select chosen alternative in each constraint.
for (unsigned cIndex = 0, eIndex = ConstraintOperands.size();
cIndex != eIndex; ++cIndex) {
AsmOperandInfo& cInfo = ConstraintOperands[cIndex];
if (cInfo.Type == InlineAsm::isClobber)
continue;
cInfo.selectAlternative(bestMAIndex);
}
}
}
// Check and hook up tied operands, choose constraint code to use.
for (unsigned cIndex = 0, eIndex = ConstraintOperands.size();
cIndex != eIndex; ++cIndex) {
AsmOperandInfo& OpInfo = ConstraintOperands[cIndex];
// If this is an output operand with a matching input operand, look up the
// matching input. If their types mismatch, e.g. one is an integer, the
// other is floating point, or their sizes are different, flag it as an
// error.
if (OpInfo.hasMatchingInput()) {
AsmOperandInfo &Input = ConstraintOperands[OpInfo.MatchingInput];
if (OpInfo.ConstraintVT != Input.ConstraintVT) {
std::pair<unsigned, const TargetRegisterClass *> MatchRC =
getRegForInlineAsmConstraint(TRI, OpInfo.ConstraintCode,
OpInfo.ConstraintVT);
std::pair<unsigned, const TargetRegisterClass *> InputRC =
getRegForInlineAsmConstraint(TRI, Input.ConstraintCode,
Input.ConstraintVT);
if ((OpInfo.ConstraintVT.isInteger() !=
Input.ConstraintVT.isInteger()) ||
(MatchRC.second != InputRC.second)) {
report_fatal_error("Unsupported asm: input constraint"
" with a matching output constraint of"
" incompatible type!");
}
}
}
}
return ConstraintOperands;
}
/// Return an integer indicating how general CT is.
static unsigned getConstraintGenerality(TargetLowering::ConstraintType CT) {
switch (CT) {
case TargetLowering::C_Other:
case TargetLowering::C_Unknown:
return 0;
case TargetLowering::C_Register:
return 1;
case TargetLowering::C_RegisterClass:
return 2;
case TargetLowering::C_Memory:
return 3;
}
llvm_unreachable("Invalid constraint type");
}
/// Examine constraint type and operand type and determine a weight value.
/// This object must already have been set up with the operand type
/// and the current alternative constraint selected.
TargetLowering::ConstraintWeight
TargetLowering::getMultipleConstraintMatchWeight(
AsmOperandInfo &info, int maIndex) const {
InlineAsm::ConstraintCodeVector *rCodes;
if (maIndex >= (int)info.multipleAlternatives.size())
rCodes = &info.Codes;
else
rCodes = &info.multipleAlternatives[maIndex].Codes;
ConstraintWeight BestWeight = CW_Invalid;
// Loop over the options, keeping track of the most general one.
for (unsigned i = 0, e = rCodes->size(); i != e; ++i) {
ConstraintWeight weight =
getSingleConstraintMatchWeight(info, (*rCodes)[i].c_str());
if (weight > BestWeight)
BestWeight = weight;
}
return BestWeight;
}
/// Examine constraint type and operand type and determine a weight value.
/// This object must already have been set up with the operand type
/// and the current alternative constraint selected.
TargetLowering::ConstraintWeight
TargetLowering::getSingleConstraintMatchWeight(
AsmOperandInfo &info, const char *constraint) const {
ConstraintWeight weight = CW_Invalid;
Value *CallOperandVal = info.CallOperandVal;
// If we don't have a value, we can't do a match,
// but allow it at the lowest weight.
if (!CallOperandVal)
return CW_Default;
// Look at the constraint type.
switch (*constraint) {
case 'i': // immediate integer.
case 'n': // immediate integer with a known value.
if (isa<ConstantInt>(CallOperandVal))
weight = CW_Constant;
break;
case 's': // non-explicit intregal immediate.
if (isa<GlobalValue>(CallOperandVal))
weight = CW_Constant;
break;
case 'E': // immediate float if host format.
case 'F': // immediate float.
if (isa<ConstantFP>(CallOperandVal))
weight = CW_Constant;
break;
case '<': // memory operand with autodecrement.
case '>': // memory operand with autoincrement.
case 'm': // memory operand.
case 'o': // offsettable memory operand
case 'V': // non-offsettable memory operand
weight = CW_Memory;
break;
case 'r': // general register.
case 'g': // general register, memory operand or immediate integer.
// note: Clang converts "g" to "imr".
if (CallOperandVal->getType()->isIntegerTy())
weight = CW_Register;
break;
case 'X': // any operand.
default:
weight = CW_Default;
break;
}
return weight;
}
/// If there are multiple different constraints that we could pick for this
/// operand (e.g. "imr") try to pick the 'best' one.
/// This is somewhat tricky: constraints fall into four classes:
/// Other -> immediates and magic values
/// Register -> one specific register
/// RegisterClass -> a group of regs
/// Memory -> memory
/// Ideally, we would pick the most specific constraint possible: if we have
/// something that fits into a register, we would pick it. The problem here
/// is that if we have something that could either be in a register or in
/// memory that use of the register could cause selection of *other*
/// operands to fail: they might only succeed if we pick memory. Because of
/// this the heuristic we use is:
///
/// 1) If there is an 'other' constraint, and if the operand is valid for
/// that constraint, use it. This makes us take advantage of 'i'
/// constraints when available.
/// 2) Otherwise, pick the most general constraint present. This prefers
/// 'm' over 'r', for example.
///
static void ChooseConstraint(TargetLowering::AsmOperandInfo &OpInfo,
const TargetLowering &TLI,
SDValue Op, SelectionDAG *DAG) {
assert(OpInfo.Codes.size() > 1 && "Doesn't have multiple constraint options");
unsigned BestIdx = 0;
TargetLowering::ConstraintType BestType = TargetLowering::C_Unknown;
int BestGenerality = -1;
// Loop over the options, keeping track of the most general one.
for (unsigned i = 0, e = OpInfo.Codes.size(); i != e; ++i) {
TargetLowering::ConstraintType CType =
TLI.getConstraintType(OpInfo.Codes[i]);
// If this is an 'other' constraint, see if the operand is valid for it.
// For example, on X86 we might have an 'rI' constraint. If the operand
// is an integer in the range [0..31] we want to use I (saving a load
// of a register), otherwise we must use 'r'.
if (CType == TargetLowering::C_Other && Op.getNode()) {
assert(OpInfo.Codes[i].size() == 1 &&
"Unhandled multi-letter 'other' constraint");
std::vector<SDValue> ResultOps;
TLI.LowerAsmOperandForConstraint(Op, OpInfo.Codes[i],
ResultOps, *DAG);
if (!ResultOps.empty()) {
BestType = CType;
BestIdx = i;
break;
}
}
// Things with matching constraints can only be registers, per gcc
// documentation. This mainly affects "g" constraints.
if (CType == TargetLowering::C_Memory && OpInfo.hasMatchingInput())
continue;
// This constraint letter is more general than the previous one, use it.
int Generality = getConstraintGenerality(CType);
if (Generality > BestGenerality) {
BestType = CType;
BestIdx = i;
BestGenerality = Generality;
}
}
OpInfo.ConstraintCode = OpInfo.Codes[BestIdx];
OpInfo.ConstraintType = BestType;
}
/// Determines the constraint code and constraint type to use for the specific
/// AsmOperandInfo, setting OpInfo.ConstraintCode and OpInfo.ConstraintType.
void TargetLowering::ComputeConstraintToUse(AsmOperandInfo &OpInfo,
SDValue Op,
SelectionDAG *DAG) const {
assert(!OpInfo.Codes.empty() && "Must have at least one constraint");
// Single-letter constraints ('r') are very common.
if (OpInfo.Codes.size() == 1) {
OpInfo.ConstraintCode = OpInfo.Codes[0];
OpInfo.ConstraintType = getConstraintType(OpInfo.ConstraintCode);
} else {
ChooseConstraint(OpInfo, *this, Op, DAG);
}
// 'X' matches anything.
if (OpInfo.ConstraintCode == "X" && OpInfo.CallOperandVal) {
// Labels and constants are handled elsewhere ('X' is the only thing
// that matches labels). For Functions, the type here is the type of
// the result, which is not what we want to look at; leave them alone.
Value *v = OpInfo.CallOperandVal;
if (isa<BasicBlock>(v) || isa<ConstantInt>(v) || isa<Function>(v)) {
OpInfo.CallOperandVal = v;
return;
}
// Otherwise, try to resolve it to something we know about by looking at
// the actual operand type.
if (const char *Repl = LowerXConstraint(OpInfo.ConstraintVT)) {
OpInfo.ConstraintCode = Repl;
OpInfo.ConstraintType = getConstraintType(OpInfo.ConstraintCode);
}
}
}
/// \brief Given an exact SDIV by a constant, create a multiplication
/// with the multiplicative inverse of the constant.
static SDValue BuildExactSDIV(const TargetLowering &TLI, SDValue Op1, APInt d,
const SDLoc &dl, SelectionDAG &DAG,
std::vector<SDNode *> &Created) {
assert(d != 0 && "Division by zero!");
// Shift the value upfront if it is even, so the LSB is one.
unsigned ShAmt = d.countTrailingZeros();
if (ShAmt) {
// TODO: For UDIV use SRL instead of SRA.
SDValue Amt =
DAG.getConstant(ShAmt, dl, TLI.getShiftAmountTy(Op1.getValueType(),
DAG.getDataLayout()));
SDNodeFlags Flags;
Flags.setExact(true);
Op1 = DAG.getNode(ISD::SRA, dl, Op1.getValueType(), Op1, Amt, Flags);
Created.push_back(Op1.getNode());
d.ashrInPlace(ShAmt);
}
// Calculate the multiplicative inverse, using Newton's method.
APInt t, xn = d;
while ((t = d*xn) != 1)
xn *= APInt(d.getBitWidth(), 2) - t;
SDValue Op2 = DAG.getConstant(xn, dl, Op1.getValueType());
SDValue Mul = DAG.getNode(ISD::MUL, dl, Op1.getValueType(), Op1, Op2);
Created.push_back(Mul.getNode());
return Mul;
}
SDValue TargetLowering::BuildSDIVPow2(SDNode *N, const APInt &Divisor,
SelectionDAG &DAG,
std::vector<SDNode *> *Created) const {
AttributeList Attr = DAG.getMachineFunction().getFunction()->getAttributes();
const TargetLowering &TLI = DAG.getTargetLoweringInfo();
if (TLI.isIntDivCheap(N->getValueType(0), Attr))
return SDValue(N,0); // Lower SDIV as SDIV
return SDValue();
}
/// \brief Given an ISD::SDIV node expressing a divide by constant,
/// return a DAG expression to select that will generate the same value by
/// multiplying by a magic number.
/// Ref: "Hacker's Delight" or "The PowerPC Compiler Writer's Guide".
SDValue TargetLowering::BuildSDIV(SDNode *N, const APInt &Divisor,
SelectionDAG &DAG, bool IsAfterLegalization,
std::vector<SDNode *> *Created) const {
assert(Created && "No vector to hold sdiv ops.");
EVT VT = N->getValueType(0);
SDLoc dl(N);
// Check to see if we can do this.
// FIXME: We should be more aggressive here.
if (!isTypeLegal(VT))
return SDValue();
// If the sdiv has an 'exact' bit we can use a simpler lowering.
if (N->getFlags().hasExact())
return BuildExactSDIV(*this, N->getOperand(0), Divisor, dl, DAG, *Created);
APInt::ms magics = Divisor.magic();
// Multiply the numerator (operand 0) by the magic value
// FIXME: We should support doing a MUL in a wider type
SDValue Q;
if (IsAfterLegalization ? isOperationLegal(ISD::MULHS, VT) :
isOperationLegalOrCustom(ISD::MULHS, VT))
Q = DAG.getNode(ISD::MULHS, dl, VT, N->getOperand(0),
DAG.getConstant(magics.m, dl, VT));
else if (IsAfterLegalization ? isOperationLegal(ISD::SMUL_LOHI, VT) :
isOperationLegalOrCustom(ISD::SMUL_LOHI, VT))
Q = SDValue(DAG.getNode(ISD::SMUL_LOHI, dl, DAG.getVTList(VT, VT),
N->getOperand(0),
DAG.getConstant(magics.m, dl, VT)).getNode(), 1);
else
return SDValue(); // No mulhs or equvialent
// If d > 0 and m < 0, add the numerator
if (Divisor.isStrictlyPositive() && magics.m.isNegative()) {
Q = DAG.getNode(ISD::ADD, dl, VT, Q, N->getOperand(0));
Created->push_back(Q.getNode());
}
// If d < 0 and m > 0, subtract the numerator.
if (Divisor.isNegative() && magics.m.isStrictlyPositive()) {
Q = DAG.getNode(ISD::SUB, dl, VT, Q, N->getOperand(0));
Created->push_back(Q.getNode());
}
auto &DL = DAG.getDataLayout();
// Shift right algebraic if shift value is nonzero
if (magics.s > 0) {
Q = DAG.getNode(
ISD::SRA, dl, VT, Q,
DAG.getConstant(magics.s, dl, getShiftAmountTy(Q.getValueType(), DL)));
Created->push_back(Q.getNode());
}
// Extract the sign bit and add it to the quotient
SDValue T =
DAG.getNode(ISD::SRL, dl, VT, Q,
DAG.getConstant(VT.getScalarSizeInBits() - 1, dl,
getShiftAmountTy(Q.getValueType(), DL)));
Created->push_back(T.getNode());
return DAG.getNode(ISD::ADD, dl, VT, Q, T);
}
/// \brief Given an ISD::UDIV node expressing a divide by constant,
/// return a DAG expression to select that will generate the same value by
/// multiplying by a magic number.
/// Ref: "Hacker's Delight" or "The PowerPC Compiler Writer's Guide".
SDValue TargetLowering::BuildUDIV(SDNode *N, const APInt &Divisor,
SelectionDAG &DAG, bool IsAfterLegalization,
std::vector<SDNode *> *Created) const {
assert(Created && "No vector to hold udiv ops.");
EVT VT = N->getValueType(0);
SDLoc dl(N);
auto &DL = DAG.getDataLayout();
// Check to see if we can do this.
// FIXME: We should be more aggressive here.
if (!isTypeLegal(VT))
return SDValue();
// FIXME: We should use a narrower constant when the upper
// bits are known to be zero.
APInt::mu magics = Divisor.magicu();
SDValue Q = N->getOperand(0);
// If the divisor is even, we can avoid using the expensive fixup by shifting
// the divided value upfront.
if (magics.a != 0 && !Divisor[0]) {
unsigned Shift = Divisor.countTrailingZeros();
Q = DAG.getNode(
ISD::SRL, dl, VT, Q,
DAG.getConstant(Shift, dl, getShiftAmountTy(Q.getValueType(), DL)));
Created->push_back(Q.getNode());
// Get magic number for the shifted divisor.
magics = Divisor.lshr(Shift).magicu(Shift);
assert(magics.a == 0 && "Should use cheap fixup now");
}
// Multiply the numerator (operand 0) by the magic value
// FIXME: We should support doing a MUL in a wider type
if (IsAfterLegalization ? isOperationLegal(ISD::MULHU, VT) :
isOperationLegalOrCustom(ISD::MULHU, VT))
Q = DAG.getNode(ISD::MULHU, dl, VT, Q, DAG.getConstant(magics.m, dl, VT));
else if (IsAfterLegalization ? isOperationLegal(ISD::UMUL_LOHI, VT) :
isOperationLegalOrCustom(ISD::UMUL_LOHI, VT))
Q = SDValue(DAG.getNode(ISD::UMUL_LOHI, dl, DAG.getVTList(VT, VT), Q,
DAG.getConstant(magics.m, dl, VT)).getNode(), 1);
else
return SDValue(); // No mulhu or equivalent
Created->push_back(Q.getNode());
if (magics.a == 0) {
assert(magics.s < Divisor.getBitWidth() &&
"We shouldn't generate an undefined shift!");
return DAG.getNode(
ISD::SRL, dl, VT, Q,
DAG.getConstant(magics.s, dl, getShiftAmountTy(Q.getValueType(), DL)));
} else {
SDValue NPQ = DAG.getNode(ISD::SUB, dl, VT, N->getOperand(0), Q);
Created->push_back(NPQ.getNode());
NPQ = DAG.getNode(
ISD::SRL, dl, VT, NPQ,
DAG.getConstant(1, dl, getShiftAmountTy(NPQ.getValueType(), DL)));
Created->push_back(NPQ.getNode());
NPQ = DAG.getNode(ISD::ADD, dl, VT, NPQ, Q);
Created->push_back(NPQ.getNode());
return DAG.getNode(
ISD::SRL, dl, VT, NPQ,
DAG.getConstant(magics.s - 1, dl,
getShiftAmountTy(NPQ.getValueType(), DL)));
}
}
bool TargetLowering::
verifyReturnAddressArgumentIsConstant(SDValue Op, SelectionDAG &DAG) const {
if (!isa<ConstantSDNode>(Op.getOperand(0))) {
DAG.getContext()->emitError("argument to '__builtin_return_address' must "
"be a constant integer");
return true;
}
return false;
}
//===----------------------------------------------------------------------===//
// Legalization Utilities
//===----------------------------------------------------------------------===//
bool TargetLowering::expandMUL_LOHI(unsigned Opcode, EVT VT, SDLoc dl,
SDValue LHS, SDValue RHS,
SmallVectorImpl<SDValue> &Result,
EVT HiLoVT, SelectionDAG &DAG,
MulExpansionKind Kind, SDValue LL,
SDValue LH, SDValue RL, SDValue RH) const {
assert(Opcode == ISD::MUL || Opcode == ISD::UMUL_LOHI ||
Opcode == ISD::SMUL_LOHI);
bool HasMULHS = (Kind == MulExpansionKind::Always) ||
isOperationLegalOrCustom(ISD::MULHS, HiLoVT);
bool HasMULHU = (Kind == MulExpansionKind::Always) ||
isOperationLegalOrCustom(ISD::MULHU, HiLoVT);
bool HasSMUL_LOHI = (Kind == MulExpansionKind::Always) ||
isOperationLegalOrCustom(ISD::SMUL_LOHI, HiLoVT);
bool HasUMUL_LOHI = (Kind == MulExpansionKind::Always) ||
isOperationLegalOrCustom(ISD::UMUL_LOHI, HiLoVT);
if (!HasMULHU && !HasMULHS && !HasUMUL_LOHI && !HasSMUL_LOHI)
return false;
unsigned OuterBitSize = VT.getScalarSizeInBits();
unsigned InnerBitSize = HiLoVT.getScalarSizeInBits();
unsigned LHSSB = DAG.ComputeNumSignBits(LHS);
unsigned RHSSB = DAG.ComputeNumSignBits(RHS);
// LL, LH, RL, and RH must be either all NULL or all set to a value.
assert((LL.getNode() && LH.getNode() && RL.getNode() && RH.getNode()) ||
(!LL.getNode() && !LH.getNode() && !RL.getNode() && !RH.getNode()));
SDVTList VTs = DAG.getVTList(HiLoVT, HiLoVT);
auto MakeMUL_LOHI = [&](SDValue L, SDValue R, SDValue &Lo, SDValue &Hi,
bool Signed) -> bool {
if ((Signed && HasSMUL_LOHI) || (!Signed && HasUMUL_LOHI)) {
Lo = DAG.getNode(Signed ? ISD::SMUL_LOHI : ISD::UMUL_LOHI, dl, VTs, L, R);
Hi = SDValue(Lo.getNode(), 1);
return true;
}
if ((Signed && HasMULHS) || (!Signed && HasMULHU)) {
Lo = DAG.getNode(ISD::MUL, dl, HiLoVT, L, R);
Hi = DAG.getNode(Signed ? ISD::MULHS : ISD::MULHU, dl, HiLoVT, L, R);
return true;
}
return false;
};
SDValue Lo, Hi;
if (!LL.getNode() && !RL.getNode() &&
isOperationLegalOrCustom(ISD::TRUNCATE, HiLoVT)) {
LL = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, LHS);
RL = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, RHS);
}
if (!LL.getNode())
return false;
APInt HighMask = APInt::getHighBitsSet(OuterBitSize, InnerBitSize);
if (DAG.MaskedValueIsZero(LHS, HighMask) &&
DAG.MaskedValueIsZero(RHS, HighMask)) {
// The inputs are both zero-extended.
if (MakeMUL_LOHI(LL, RL, Lo, Hi, false)) {
Result.push_back(Lo);
Result.push_back(Hi);
if (Opcode != ISD::MUL) {
SDValue Zero = DAG.getConstant(0, dl, HiLoVT);
Result.push_back(Zero);
Result.push_back(Zero);
}
return true;
}
}
if (!VT.isVector() && Opcode == ISD::MUL && LHSSB > InnerBitSize &&
RHSSB > InnerBitSize) {
// The input values are both sign-extended.
// TODO non-MUL case?
if (MakeMUL_LOHI(LL, RL, Lo, Hi, true)) {
Result.push_back(Lo);
Result.push_back(Hi);
return true;
}
}
unsigned ShiftAmount = OuterBitSize - InnerBitSize;
EVT ShiftAmountTy = getShiftAmountTy(VT, DAG.getDataLayout());
if (APInt::getMaxValue(ShiftAmountTy.getSizeInBits()).ult(ShiftAmount)) {
// FIXME getShiftAmountTy does not always return a sensible result when VT
// is an illegal type, and so the type may be too small to fit the shift
// amount. Override it with i32. The shift will have to be legalized.
ShiftAmountTy = MVT::i32;
}
SDValue Shift = DAG.getConstant(ShiftAmount, dl, ShiftAmountTy);
if (!LH.getNode() && !RH.getNode() &&
isOperationLegalOrCustom(ISD::SRL, VT) &&
isOperationLegalOrCustom(ISD::TRUNCATE, HiLoVT)) {
LH = DAG.getNode(ISD::SRL, dl, VT, LHS, Shift);
LH = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, LH);
RH = DAG.getNode(ISD::SRL, dl, VT, RHS, Shift);
RH = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, RH);
}
if (!LH.getNode())
return false;
if (!MakeMUL_LOHI(LL, RL, Lo, Hi, false))
return false;
Result.push_back(Lo);
if (Opcode == ISD::MUL) {
RH = DAG.getNode(ISD::MUL, dl, HiLoVT, LL, RH);
LH = DAG.getNode(ISD::MUL, dl, HiLoVT, LH, RL);
Hi = DAG.getNode(ISD::ADD, dl, HiLoVT, Hi, RH);
Hi = DAG.getNode(ISD::ADD, dl, HiLoVT, Hi, LH);
Result.push_back(Hi);
return true;
}
// Compute the full width result.
auto Merge = [&](SDValue Lo, SDValue Hi) -> SDValue {
Lo = DAG.getNode(ISD::ZERO_EXTEND, dl, VT, Lo);
Hi = DAG.getNode(ISD::ZERO_EXTEND, dl, VT, Hi);
Hi = DAG.getNode(ISD::SHL, dl, VT, Hi, Shift);
return DAG.getNode(ISD::OR, dl, VT, Lo, Hi);
};
SDValue Next = DAG.getNode(ISD::ZERO_EXTEND, dl, VT, Hi);
if (!MakeMUL_LOHI(LL, RH, Lo, Hi, false))
return false;
// This is effectively the add part of a multiply-add of half-sized operands,
// so it cannot overflow.
Next = DAG.getNode(ISD::ADD, dl, VT, Next, Merge(Lo, Hi));
if (!MakeMUL_LOHI(LH, RL, Lo, Hi, false))
return false;
Next = DAG.getNode(ISD::ADDC, dl, DAG.getVTList(VT, MVT::Glue), Next,
Merge(Lo, Hi));
SDValue Carry = Next.getValue(1);
Result.push_back(DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, Next));
Next = DAG.getNode(ISD::SRL, dl, VT, Next, Shift);
if (!MakeMUL_LOHI(LH, RH, Lo, Hi, Opcode == ISD::SMUL_LOHI))
return false;
SDValue Zero = DAG.getConstant(0, dl, HiLoVT);
Hi = DAG.getNode(ISD::ADDE, dl, DAG.getVTList(HiLoVT, MVT::Glue), Hi, Zero,
Carry);
Next = DAG.getNode(ISD::ADD, dl, VT, Next, Merge(Lo, Hi));
if (Opcode == ISD::SMUL_LOHI) {
SDValue NextSub = DAG.getNode(ISD::SUB, dl, VT, Next,
DAG.getNode(ISD::ZERO_EXTEND, dl, VT, RL));
Next = DAG.getSelectCC(dl, LH, Zero, NextSub, Next, ISD::SETLT);
NextSub = DAG.getNode(ISD::SUB, dl, VT, Next,
DAG.getNode(ISD::ZERO_EXTEND, dl, VT, LL));
Next = DAG.getSelectCC(dl, RH, Zero, NextSub, Next, ISD::SETLT);
}
Result.push_back(DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, Next));
Next = DAG.getNode(ISD::SRL, dl, VT, Next, Shift);
Result.push_back(DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, Next));
return true;
}
bool TargetLowering::expandMUL(SDNode *N, SDValue &Lo, SDValue &Hi, EVT HiLoVT,
SelectionDAG &DAG, MulExpansionKind Kind,
SDValue LL, SDValue LH, SDValue RL,
SDValue RH) const {
SmallVector<SDValue, 2> Result;
bool Ok = expandMUL_LOHI(N->getOpcode(), N->getValueType(0), N,
N->getOperand(0), N->getOperand(1), Result, HiLoVT,
DAG, Kind, LL, LH, RL, RH);
if (Ok) {
assert(Result.size() == 2);
Lo = Result[0];
Hi = Result[1];
}
return Ok;
}
bool TargetLowering::expandFP_TO_SINT(SDNode *Node, SDValue &Result,
SelectionDAG &DAG) const {
EVT VT = Node->getOperand(0).getValueType();
EVT NVT = Node->getValueType(0);
SDLoc dl(SDValue(Node, 0));
// FIXME: Only f32 to i64 conversions are supported.
if (VT != MVT::f32 || NVT != MVT::i64)
return false;
// Expand f32 -> i64 conversion
// This algorithm comes from compiler-rt's implementation of fixsfdi:
// https://github.com/llvm-mirror/compiler-rt/blob/master/lib/builtins/fixsfdi.c
EVT IntVT = EVT::getIntegerVT(*DAG.getContext(),
VT.getSizeInBits());
SDValue ExponentMask = DAG.getConstant(0x7F800000, dl, IntVT);
SDValue ExponentLoBit = DAG.getConstant(23, dl, IntVT);
SDValue Bias = DAG.getConstant(127, dl, IntVT);
SDValue SignMask = DAG.getConstant(APInt::getSignMask(VT.getSizeInBits()), dl,
IntVT);
SDValue SignLowBit = DAG.getConstant(VT.getSizeInBits() - 1, dl, IntVT);
SDValue MantissaMask = DAG.getConstant(0x007FFFFF, dl, IntVT);
SDValue Bits = DAG.getNode(ISD::BITCAST, dl, IntVT, Node->getOperand(0));
auto &DL = DAG.getDataLayout();
SDValue ExponentBits = DAG.getNode(
ISD::SRL, dl, IntVT, DAG.getNode(ISD::AND, dl, IntVT, Bits, ExponentMask),
DAG.getZExtOrTrunc(ExponentLoBit, dl, getShiftAmountTy(IntVT, DL)));
SDValue Exponent = DAG.getNode(ISD::SUB, dl, IntVT, ExponentBits, Bias);
SDValue Sign = DAG.getNode(
ISD::SRA, dl, IntVT, DAG.getNode(ISD::AND, dl, IntVT, Bits, SignMask),
DAG.getZExtOrTrunc(SignLowBit, dl, getShiftAmountTy(IntVT, DL)));
Sign = DAG.getSExtOrTrunc(Sign, dl, NVT);
SDValue R = DAG.getNode(ISD::OR, dl, IntVT,
DAG.getNode(ISD::AND, dl, IntVT, Bits, MantissaMask),
DAG.getConstant(0x00800000, dl, IntVT));
R = DAG.getZExtOrTrunc(R, dl, NVT);
R = DAG.getSelectCC(
dl, Exponent, ExponentLoBit,
DAG.getNode(ISD::SHL, dl, NVT, R,
DAG.getZExtOrTrunc(
DAG.getNode(ISD::SUB, dl, IntVT, Exponent, ExponentLoBit),
dl, getShiftAmountTy(IntVT, DL))),
DAG.getNode(ISD::SRL, dl, NVT, R,
DAG.getZExtOrTrunc(
DAG.getNode(ISD::SUB, dl, IntVT, ExponentLoBit, Exponent),
dl, getShiftAmountTy(IntVT, DL))),
ISD::SETGT);
SDValue Ret = DAG.getNode(ISD::SUB, dl, NVT,
DAG.getNode(ISD::XOR, dl, NVT, R, Sign),
Sign);
Result = DAG.getSelectCC(dl, Exponent, DAG.getConstant(0, dl, IntVT),
DAG.getConstant(0, dl, NVT), Ret, ISD::SETLT);
return true;
}
SDValue TargetLowering::scalarizeVectorLoad(LoadSDNode *LD,
SelectionDAG &DAG) const {
SDLoc SL(LD);
SDValue Chain = LD->getChain();
SDValue BasePTR = LD->getBasePtr();
EVT SrcVT = LD->getMemoryVT();
ISD::LoadExtType ExtType = LD->getExtensionType();
unsigned NumElem = SrcVT.getVectorNumElements();
EVT SrcEltVT = SrcVT.getScalarType();
EVT DstEltVT = LD->getValueType(0).getScalarType();
unsigned Stride = SrcEltVT.getSizeInBits() / 8;
assert(SrcEltVT.isByteSized());
EVT PtrVT = BasePTR.getValueType();
SmallVector<SDValue, 8> Vals;
SmallVector<SDValue, 8> LoadChains;
for (unsigned Idx = 0; Idx < NumElem; ++Idx) {
SDValue ScalarLoad =
DAG.getExtLoad(ExtType, SL, DstEltVT, Chain, BasePTR,
LD->getPointerInfo().getWithOffset(Idx * Stride),
SrcEltVT, MinAlign(LD->getAlignment(), Idx * Stride),
LD->getMemOperand()->getFlags(), LD->getAAInfo());
BasePTR = DAG.getNode(ISD::ADD, SL, PtrVT, BasePTR,
DAG.getConstant(Stride, SL, PtrVT));
Vals.push_back(ScalarLoad.getValue(0));
LoadChains.push_back(ScalarLoad.getValue(1));
}
SDValue NewChain = DAG.getNode(ISD::TokenFactor, SL, MVT::Other, LoadChains);
SDValue Value = DAG.getBuildVector(LD->getValueType(0), SL, Vals);
return DAG.getMergeValues({ Value, NewChain }, SL);
}
// FIXME: This relies on each element having a byte size, otherwise the stride
// is 0 and just overwrites the same location. ExpandStore currently expects
// this broken behavior.
SDValue TargetLowering::scalarizeVectorStore(StoreSDNode *ST,
SelectionDAG &DAG) const {
SDLoc SL(ST);
SDValue Chain = ST->getChain();
SDValue BasePtr = ST->getBasePtr();
SDValue Value = ST->getValue();
EVT StVT = ST->getMemoryVT();
// The type of the data we want to save
EVT RegVT = Value.getValueType();
EVT RegSclVT = RegVT.getScalarType();
// The type of data as saved in memory.
EVT MemSclVT = StVT.getScalarType();
EVT PtrVT = BasePtr.getValueType();
// Store Stride in bytes
unsigned Stride = MemSclVT.getSizeInBits() / 8;
EVT IdxVT = getVectorIdxTy(DAG.getDataLayout());
unsigned NumElem = StVT.getVectorNumElements();
// Extract each of the elements from the original vector and save them into
// memory individually.
SmallVector<SDValue, 8> Stores;
for (unsigned Idx = 0; Idx < NumElem; ++Idx) {
SDValue Elt = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, SL, RegSclVT, Value,
DAG.getConstant(Idx, SL, IdxVT));
SDValue Ptr = DAG.getNode(ISD::ADD, SL, PtrVT, BasePtr,
DAG.getConstant(Idx * Stride, SL, PtrVT));
// This scalar TruncStore may be illegal, but we legalize it later.
SDValue Store = DAG.getTruncStore(
Chain, SL, Elt, Ptr, ST->getPointerInfo().getWithOffset(Idx * Stride),
MemSclVT, MinAlign(ST->getAlignment(), Idx * Stride),
ST->getMemOperand()->getFlags(), ST->getAAInfo());
Stores.push_back(Store);
}
return DAG.getNode(ISD::TokenFactor, SL, MVT::Other, Stores);
}
std::pair<SDValue, SDValue>
TargetLowering::expandUnalignedLoad(LoadSDNode *LD, SelectionDAG &DAG) const {
assert(LD->getAddressingMode() == ISD::UNINDEXED &&
"unaligned indexed loads not implemented!");
SDValue Chain = LD->getChain();
SDValue Ptr = LD->getBasePtr();
EVT VT = LD->getValueType(0);
EVT LoadedVT = LD->getMemoryVT();
SDLoc dl(LD);
auto &MF = DAG.getMachineFunction();
if (VT.isFloatingPoint() || VT.isVector()) {
EVT intVT = EVT::getIntegerVT(*DAG.getContext(), LoadedVT.getSizeInBits());
if (isTypeLegal(intVT) && isTypeLegal(LoadedVT)) {
if (!isOperationLegalOrCustom(ISD::LOAD, intVT)) {
// Scalarize the load and let the individual components be handled.
SDValue Scalarized = scalarizeVectorLoad(LD, DAG);
return std::make_pair(Scalarized.getValue(0), Scalarized.getValue(1));
}
// Expand to a (misaligned) integer load of the same size,
// then bitconvert to floating point or vector.
SDValue newLoad = DAG.getLoad(intVT, dl, Chain, Ptr,
LD->getMemOperand());
SDValue Result = DAG.getNode(ISD::BITCAST, dl, LoadedVT, newLoad);
if (LoadedVT != VT)
Result = DAG.getNode(VT.isFloatingPoint() ? ISD::FP_EXTEND :
ISD::ANY_EXTEND, dl, VT, Result);
return std::make_pair(Result, newLoad.getValue(1));
}
// Copy the value to a (aligned) stack slot using (unaligned) integer
// loads and stores, then do a (aligned) load from the stack slot.
MVT RegVT = getRegisterType(*DAG.getContext(), intVT);
unsigned LoadedBytes = LoadedVT.getSizeInBits() / 8;
unsigned RegBytes = RegVT.getSizeInBits() / 8;
unsigned NumRegs = (LoadedBytes + RegBytes - 1) / RegBytes;
// Make sure the stack slot is also aligned for the register type.
SDValue StackBase = DAG.CreateStackTemporary(LoadedVT, RegVT);
auto FrameIndex = cast<FrameIndexSDNode>(StackBase.getNode())->getIndex();
SmallVector<SDValue, 8> Stores;
SDValue StackPtr = StackBase;
unsigned Offset = 0;
EVT PtrVT = Ptr.getValueType();
EVT StackPtrVT = StackPtr.getValueType();
SDValue PtrIncrement = DAG.getConstant(RegBytes, dl, PtrVT);
SDValue StackPtrIncrement = DAG.getConstant(RegBytes, dl, StackPtrVT);
// Do all but one copies using the full register width.
for (unsigned i = 1; i < NumRegs; i++) {
// Load one integer register's worth from the original location.
SDValue Load = DAG.getLoad(
RegVT, dl, Chain, Ptr, LD->getPointerInfo().getWithOffset(Offset),
MinAlign(LD->getAlignment(), Offset), LD->getMemOperand()->getFlags(),
LD->getAAInfo());
// Follow the load with a store to the stack slot. Remember the store.
Stores.push_back(DAG.getStore(
Load.getValue(1), dl, Load, StackPtr,
MachinePointerInfo::getFixedStack(MF, FrameIndex, Offset)));
// Increment the pointers.
Offset += RegBytes;
Ptr = DAG.getNode(ISD::ADD, dl, PtrVT, Ptr, PtrIncrement);
StackPtr = DAG.getNode(ISD::ADD, dl, StackPtrVT, StackPtr,
StackPtrIncrement);
}
// The last copy may be partial. Do an extending load.
EVT MemVT = EVT::getIntegerVT(*DAG.getContext(),
8 * (LoadedBytes - Offset));
SDValue Load =
DAG.getExtLoad(ISD::EXTLOAD, dl, RegVT, Chain, Ptr,
LD->getPointerInfo().getWithOffset(Offset), MemVT,
MinAlign(LD->getAlignment(), Offset),
LD->getMemOperand()->getFlags(), LD->getAAInfo());
// Follow the load with a store to the stack slot. Remember the store.
// On big-endian machines this requires a truncating store to ensure
// that the bits end up in the right place.
Stores.push_back(DAG.getTruncStore(
Load.getValue(1), dl, Load, StackPtr,
MachinePointerInfo::getFixedStack(MF, FrameIndex, Offset), MemVT));
// The order of the stores doesn't matter - say it with a TokenFactor.
SDValue TF = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Stores);
// Finally, perform the original load only redirected to the stack slot.
Load = DAG.getExtLoad(LD->getExtensionType(), dl, VT, TF, StackBase,
MachinePointerInfo::getFixedStack(MF, FrameIndex, 0),
LoadedVT);
// Callers expect a MERGE_VALUES node.
return std::make_pair(Load, TF);
}
assert(LoadedVT.isInteger() && !LoadedVT.isVector() &&
"Unaligned load of unsupported type.");
// Compute the new VT that is half the size of the old one. This is an
// integer MVT.
unsigned NumBits = LoadedVT.getSizeInBits();
EVT NewLoadedVT;
NewLoadedVT = EVT::getIntegerVT(*DAG.getContext(), NumBits/2);
NumBits >>= 1;
unsigned Alignment = LD->getAlignment();
unsigned IncrementSize = NumBits / 8;
ISD::LoadExtType HiExtType = LD->getExtensionType();
// If the original load is NON_EXTLOAD, the hi part load must be ZEXTLOAD.
if (HiExtType == ISD::NON_EXTLOAD)
HiExtType = ISD::ZEXTLOAD;
// Load the value in two parts
SDValue Lo, Hi;
if (DAG.getDataLayout().isLittleEndian()) {
Lo = DAG.getExtLoad(ISD::ZEXTLOAD, dl, VT, Chain, Ptr, LD->getPointerInfo(),
NewLoadedVT, Alignment, LD->getMemOperand()->getFlags(),
LD->getAAInfo());
Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
DAG.getConstant(IncrementSize, dl, Ptr.getValueType()));
Hi = DAG.getExtLoad(HiExtType, dl, VT, Chain, Ptr,
LD->getPointerInfo().getWithOffset(IncrementSize),
NewLoadedVT, MinAlign(Alignment, IncrementSize),
LD->getMemOperand()->getFlags(), LD->getAAInfo());
} else {
Hi = DAG.getExtLoad(HiExtType, dl, VT, Chain, Ptr, LD->getPointerInfo(),
NewLoadedVT, Alignment, LD->getMemOperand()->getFlags(),
LD->getAAInfo());
Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
DAG.getConstant(IncrementSize, dl, Ptr.getValueType()));
Lo = DAG.getExtLoad(ISD::ZEXTLOAD, dl, VT, Chain, Ptr,
LD->getPointerInfo().getWithOffset(IncrementSize),
NewLoadedVT, MinAlign(Alignment, IncrementSize),
LD->getMemOperand()->getFlags(), LD->getAAInfo());
}
// aggregate the two parts
SDValue ShiftAmount =
DAG.getConstant(NumBits, dl, getShiftAmountTy(Hi.getValueType(),
DAG.getDataLayout()));
SDValue Result = DAG.getNode(ISD::SHL, dl, VT, Hi, ShiftAmount);
Result = DAG.getNode(ISD::OR, dl, VT, Result, Lo);
SDValue TF = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Lo.getValue(1),
Hi.getValue(1));
return std::make_pair(Result, TF);
}
SDValue TargetLowering::expandUnalignedStore(StoreSDNode *ST,
SelectionDAG &DAG) const {
assert(ST->getAddressingMode() == ISD::UNINDEXED &&
"unaligned indexed stores not implemented!");
SDValue Chain = ST->getChain();
SDValue Ptr = ST->getBasePtr();
SDValue Val = ST->getValue();
EVT VT = Val.getValueType();
int Alignment = ST->getAlignment();
auto &MF = DAG.getMachineFunction();
SDLoc dl(ST);
if (ST->getMemoryVT().isFloatingPoint() ||
ST->getMemoryVT().isVector()) {
EVT intVT = EVT::getIntegerVT(*DAG.getContext(), VT.getSizeInBits());
if (isTypeLegal(intVT)) {
if (!isOperationLegalOrCustom(ISD::STORE, intVT)) {
// Scalarize the store and let the individual components be handled.
SDValue Result = scalarizeVectorStore(ST, DAG);
return Result;
}
// Expand to a bitconvert of the value to the integer type of the
// same size, then a (misaligned) int store.
// FIXME: Does not handle truncating floating point stores!
SDValue Result = DAG.getNode(ISD::BITCAST, dl, intVT, Val);
Result = DAG.getStore(Chain, dl, Result, Ptr, ST->getPointerInfo(),
Alignment, ST->getMemOperand()->getFlags());
return Result;
}
// Do a (aligned) store to a stack slot, then copy from the stack slot
// to the final destination using (unaligned) integer loads and stores.
EVT StoredVT = ST->getMemoryVT();
MVT RegVT =
getRegisterType(*DAG.getContext(),
EVT::getIntegerVT(*DAG.getContext(),
StoredVT.getSizeInBits()));
EVT PtrVT = Ptr.getValueType();
unsigned StoredBytes = StoredVT.getSizeInBits() / 8;
unsigned RegBytes = RegVT.getSizeInBits() / 8;
unsigned NumRegs = (StoredBytes + RegBytes - 1) / RegBytes;
// Make sure the stack slot is also aligned for the register type.
SDValue StackPtr = DAG.CreateStackTemporary(StoredVT, RegVT);
auto FrameIndex = cast<FrameIndexSDNode>(StackPtr.getNode())->getIndex();
// Perform the original store, only redirected to the stack slot.
SDValue Store = DAG.getTruncStore(
Chain, dl, Val, StackPtr,
MachinePointerInfo::getFixedStack(MF, FrameIndex, 0), StoredVT);
EVT StackPtrVT = StackPtr.getValueType();
SDValue PtrIncrement = DAG.getConstant(RegBytes, dl, PtrVT);
SDValue StackPtrIncrement = DAG.getConstant(RegBytes, dl, StackPtrVT);
SmallVector<SDValue, 8> Stores;
unsigned Offset = 0;
// Do all but one copies using the full register width.
for (unsigned i = 1; i < NumRegs; i++) {
// Load one integer register's worth from the stack slot.
SDValue Load = DAG.getLoad(
RegVT, dl, Store, StackPtr,
MachinePointerInfo::getFixedStack(MF, FrameIndex, Offset));
// Store it to the final location. Remember the store.
Stores.push_back(DAG.getStore(Load.getValue(1), dl, Load, Ptr,
ST->getPointerInfo().getWithOffset(Offset),
MinAlign(ST->getAlignment(), Offset),
ST->getMemOperand()->getFlags()));
// Increment the pointers.
Offset += RegBytes;
StackPtr = DAG.getNode(ISD::ADD, dl, StackPtrVT,
StackPtr, StackPtrIncrement);
Ptr = DAG.getNode(ISD::ADD, dl, PtrVT, Ptr, PtrIncrement);
}
// The last store may be partial. Do a truncating store. On big-endian
// machines this requires an extending load from the stack slot to ensure
// that the bits are in the right place.
EVT MemVT = EVT::getIntegerVT(*DAG.getContext(),
8 * (StoredBytes - Offset));
// Load from the stack slot.
SDValue Load = DAG.getExtLoad(
ISD::EXTLOAD, dl, RegVT, Store, StackPtr,
MachinePointerInfo::getFixedStack(MF, FrameIndex, Offset), MemVT);
Stores.push_back(
DAG.getTruncStore(Load.getValue(1), dl, Load, Ptr,
ST->getPointerInfo().getWithOffset(Offset), MemVT,
MinAlign(ST->getAlignment(), Offset),
ST->getMemOperand()->getFlags(), ST->getAAInfo()));
// The order of the stores doesn't matter - say it with a TokenFactor.
SDValue Result = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Stores);
return Result;
}
assert(ST->getMemoryVT().isInteger() &&
!ST->getMemoryVT().isVector() &&
"Unaligned store of unknown type.");
// Get the half-size VT
EVT NewStoredVT = ST->getMemoryVT().getHalfSizedIntegerVT(*DAG.getContext());
int NumBits = NewStoredVT.getSizeInBits();
int IncrementSize = NumBits / 8;
// Divide the stored value in two parts.
SDValue ShiftAmount =
DAG.getConstant(NumBits, dl, getShiftAmountTy(Val.getValueType(),
DAG.getDataLayout()));
SDValue Lo = Val;
SDValue Hi = DAG.getNode(ISD::SRL, dl, VT, Val, ShiftAmount);
// Store the two parts
SDValue Store1, Store2;
Store1 = DAG.getTruncStore(Chain, dl,
DAG.getDataLayout().isLittleEndian() ? Lo : Hi,
Ptr, ST->getPointerInfo(), NewStoredVT, Alignment,
ST->getMemOperand()->getFlags());
EVT PtrVT = Ptr.getValueType();
Ptr = DAG.getNode(ISD::ADD, dl, PtrVT, Ptr,
DAG.getConstant(IncrementSize, dl, PtrVT));
Alignment = MinAlign(Alignment, IncrementSize);
Store2 = DAG.getTruncStore(
Chain, dl, DAG.getDataLayout().isLittleEndian() ? Hi : Lo, Ptr,
ST->getPointerInfo().getWithOffset(IncrementSize), NewStoredVT, Alignment,
ST->getMemOperand()->getFlags(), ST->getAAInfo());
SDValue Result =
DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Store1, Store2);
return Result;
}
SDValue
TargetLowering::IncrementMemoryAddress(SDValue Addr, SDValue Mask,
const SDLoc &DL, EVT DataVT,
SelectionDAG &DAG,
bool IsCompressedMemory) const {
SDValue Increment;
EVT AddrVT = Addr.getValueType();
EVT MaskVT = Mask.getValueType();
assert(DataVT.getVectorNumElements() == MaskVT.getVectorNumElements() &&
"Incompatible types of Data and Mask");
if (IsCompressedMemory) {
// Incrementing the pointer according to number of '1's in the mask.
EVT MaskIntVT = EVT::getIntegerVT(*DAG.getContext(), MaskVT.getSizeInBits());
SDValue MaskInIntReg = DAG.getBitcast(MaskIntVT, Mask);
if (MaskIntVT.getSizeInBits() < 32) {
MaskInIntReg = DAG.getNode(ISD::ZERO_EXTEND, DL, MVT::i32, MaskInIntReg);
MaskIntVT = MVT::i32;
}
// Count '1's with POPCNT.
Increment = DAG.getNode(ISD::CTPOP, DL, MaskIntVT, MaskInIntReg);
Increment = DAG.getZExtOrTrunc(Increment, DL, AddrVT);
// Scale is an element size in bytes.
SDValue Scale = DAG.getConstant(DataVT.getScalarSizeInBits() / 8, DL,
AddrVT);
Increment = DAG.getNode(ISD::MUL, DL, AddrVT, Increment, Scale);
} else
Increment = DAG.getConstant(DataVT.getSizeInBits() / 8, DL, AddrVT);
return DAG.getNode(ISD::ADD, DL, AddrVT, Addr, Increment);
}
static SDValue clampDynamicVectorIndex(SelectionDAG &DAG,
SDValue Idx,
EVT VecVT,
const SDLoc &dl) {
if (isa<ConstantSDNode>(Idx))
return Idx;
EVT IdxVT = Idx.getValueType();
unsigned NElts = VecVT.getVectorNumElements();
if (isPowerOf2_32(NElts)) {
APInt Imm = APInt::getLowBitsSet(IdxVT.getSizeInBits(),
Log2_32(NElts));
return DAG.getNode(ISD::AND, dl, IdxVT, Idx,
DAG.getConstant(Imm, dl, IdxVT));
}
return DAG.getNode(ISD::UMIN, dl, IdxVT, Idx,
DAG.getConstant(NElts - 1, dl, IdxVT));
}
SDValue TargetLowering::getVectorElementPointer(SelectionDAG &DAG,
SDValue VecPtr, EVT VecVT,
SDValue Index) const {
SDLoc dl(Index);
// Make sure the index type is big enough to compute in.
Index = DAG.getZExtOrTrunc(Index, dl, getPointerTy(DAG.getDataLayout()));
EVT EltVT = VecVT.getVectorElementType();
// Calculate the element offset and add it to the pointer.
unsigned EltSize = EltVT.getSizeInBits() / 8; // FIXME: should be ABI size.
assert(EltSize * 8 == EltVT.getSizeInBits() &&
"Converting bits to bytes lost precision");
Index = clampDynamicVectorIndex(DAG, Index, VecVT, dl);
EVT IdxVT = Index.getValueType();
Index = DAG.getNode(ISD::MUL, dl, IdxVT, Index,
DAG.getConstant(EltSize, dl, IdxVT));
return DAG.getNode(ISD::ADD, dl, IdxVT, Index, VecPtr);
}
//===----------------------------------------------------------------------===//
// Implementation of Emulated TLS Model
//===----------------------------------------------------------------------===//
SDValue TargetLowering::LowerToTLSEmulatedModel(const GlobalAddressSDNode *GA,
SelectionDAG &DAG) const {
// Access to address of TLS varialbe xyz is lowered to a function call:
// __emutls_get_address( address of global variable named "__emutls_v.xyz" )
EVT PtrVT = getPointerTy(DAG.getDataLayout());
PointerType *VoidPtrType = Type::getInt8PtrTy(*DAG.getContext());
SDLoc dl(GA);
ArgListTy Args;
ArgListEntry Entry;
std::string NameString = ("__emutls_v." + GA->getGlobal()->getName()).str();
Module *VariableModule = const_cast<Module*>(GA->getGlobal()->getParent());
StringRef EmuTlsVarName(NameString);
GlobalVariable *EmuTlsVar = VariableModule->getNamedGlobal(EmuTlsVarName);
assert(EmuTlsVar && "Cannot find EmuTlsVar ");
Entry.Node = DAG.getGlobalAddress(EmuTlsVar, dl, PtrVT);
Entry.Ty = VoidPtrType;
Args.push_back(Entry);
SDValue EmuTlsGetAddr = DAG.getExternalSymbol("__emutls_get_address", PtrVT);
TargetLowering::CallLoweringInfo CLI(DAG);
CLI.setDebugLoc(dl).setChain(DAG.getEntryNode());
CLI.setLibCallee(CallingConv::C, VoidPtrType, EmuTlsGetAddr, std::move(Args));
std::pair<SDValue, SDValue> CallResult = LowerCallTo(CLI);
// TLSADDR will be codegen'ed as call. Inform MFI that function has calls.
// At last for X86 targets, maybe good for other targets too?
MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
MFI.setAdjustsStack(true); // Is this only for X86 target?
MFI.setHasCalls(true);
assert((GA->getOffset() == 0) &&
"Emulated TLS must have zero offset in GlobalAddressSDNode");
return CallResult.first;
}
SDValue TargetLowering::lowerCmpEqZeroToCtlzSrl(SDValue Op,
SelectionDAG &DAG) const {
assert((Op->getOpcode() == ISD::SETCC) && "Input has to be a SETCC node.");
if (!isCtlzFast())
return SDValue();
ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(2))->get();
SDLoc dl(Op);
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
if (C->isNullValue() && CC == ISD::SETEQ) {
EVT VT = Op.getOperand(0).getValueType();
SDValue Zext = Op.getOperand(0);
if (VT.bitsLT(MVT::i32)) {
VT = MVT::i32;
Zext = DAG.getNode(ISD::ZERO_EXTEND, dl, VT, Op.getOperand(0));
}
unsigned Log2b = Log2_32(VT.getSizeInBits());
SDValue Clz = DAG.getNode(ISD::CTLZ, dl, VT, Zext);
SDValue Scc = DAG.getNode(ISD::SRL, dl, VT, Clz,
DAG.getConstant(Log2b, dl, MVT::i32));
return DAG.getNode(ISD::TRUNCATE, dl, MVT::i32, Scc);
}
}
return SDValue();
}