#define DEBUG_TYPE "instcombine"
-/// DecomposeSimpleLinearExpr - Analyze 'Val', seeing if it is a simple linear
-/// expression. If so, decompose it, returning some value X, such that Val is
+/// Analyze 'Val', seeing if it is a simple linear expression.
+/// If so, decompose it, returning some value X, such that Val is
/// X*Scale+Offset.
///
-static Value *DecomposeSimpleLinearExpr(Value *Val, unsigned &Scale,
+static Value *decomposeSimpleLinearExpr(Value *Val, unsigned &Scale,
uint64_t &Offset) {
if (ConstantInt *CI = dyn_cast<ConstantInt>(Val)) {
Offset = CI->getZExtValue();
// where C1 is divisible by C2.
unsigned SubScale;
Value *SubVal =
- DecomposeSimpleLinearExpr(I->getOperand(0), SubScale, Offset);
+ decomposeSimpleLinearExpr(I->getOperand(0), SubScale, Offset);
Offset += RHS->getZExtValue();
Scale = SubScale;
return SubVal;
return Val;
}
-/// PromoteCastOfAllocation - If we find a cast of an allocation instruction,
-/// try to eliminate the cast by moving the type information into the alloc.
+/// If we find a cast of an allocation instruction, try to eliminate the cast by
+/// moving the type information into the alloc.
Instruction *InstCombiner::PromoteCastOfAllocation(BitCastInst &CI,
AllocaInst &AI) {
PointerType *PTy = cast<PointerType>(CI.getType());
BuilderTy AllocaBuilder(*Builder);
- AllocaBuilder.SetInsertPoint(AI.getParent(), &AI);
+ AllocaBuilder.SetInsertPoint(&AI);
// Get the type really allocated and the type casted to.
Type *AllocElTy = AI.getAllocatedType();
unsigned ArraySizeScale;
uint64_t ArrayOffset;
Value *NumElements = // See if the array size is a decomposable linear expr.
- DecomposeSimpleLinearExpr(AI.getOperand(0), ArraySizeScale, ArrayOffset);
+ decomposeSimpleLinearExpr(AI.getOperand(0), ArraySizeScale, ArrayOffset);
// If we can now satisfy the modulus, by using a non-1 scale, we really can
// do the xform.
return ReplaceInstUsesWith(CI, New);
}
-/// EvaluateInDifferentType - Given an expression that
-/// CanEvaluateTruncated or CanEvaluateSExtd returns true for, actually
-/// insert the code to evaluate the expression.
+/// Given an expression that CanEvaluateTruncated or CanEvaluateSExtd returns
+/// true for, actually insert the code to evaluate the expression.
Value *InstCombiner::EvaluateInDifferentType(Value *V, Type *Ty,
bool isSigned) {
if (Constant *C = dyn_cast<Constant>(V)) {
return Instruction::CastOps(Res);
}
-/// ShouldOptimizeCast - Return true if the cast from "V to Ty" actually
-/// results in any code being generated and is interesting to optimize out. If
-/// the cast can be eliminated by some other simple transformation, we prefer
+/// Return true if the cast from "V to Ty" actually results in any code being
+/// generated and is interesting to optimize out.
+/// If the cast can be eliminated by some other simple transformation, we prefer
/// to do the simplification first.
bool InstCombiner::ShouldOptimizeCast(Instruction::CastOps opc, const Value *V,
Type *Ty) {
return nullptr;
}
-/// CanEvaluateTruncated - Return true if we can evaluate the specified
-/// expression tree as type Ty instead of its larger type, and arrive with the
-/// same value. This is used by code that tries to eliminate truncates.
+/// Return true if we can evaluate the specified expression tree as type Ty
+/// instead of its larger type, and arrive with the same value.
+/// This is used by code that tries to eliminate truncates.
///
/// Ty will always be a type smaller than V. We should return true if trunc(V)
/// can be computed by computing V in the smaller type. If V is an instruction,
///
/// This function works on both vectors and scalars.
///
-static bool CanEvaluateTruncated(Value *V, Type *Ty, InstCombiner &IC,
+static bool canEvaluateTruncated(Value *V, Type *Ty, InstCombiner &IC,
Instruction *CxtI) {
// We can always evaluate constants in another type.
if (isa<Constant>(V))
case Instruction::Or:
case Instruction::Xor:
// These operators can all arbitrarily be extended or truncated.
- return CanEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI) &&
- CanEvaluateTruncated(I->getOperand(1), Ty, IC, CxtI);
+ return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI) &&
+ canEvaluateTruncated(I->getOperand(1), Ty, IC, CxtI);
case Instruction::UDiv:
case Instruction::URem: {
APInt Mask = APInt::getHighBitsSet(OrigBitWidth, OrigBitWidth-BitWidth);
if (IC.MaskedValueIsZero(I->getOperand(0), Mask, 0, CxtI) &&
IC.MaskedValueIsZero(I->getOperand(1), Mask, 0, CxtI)) {
- return CanEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI) &&
- CanEvaluateTruncated(I->getOperand(1), Ty, IC, CxtI);
+ return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI) &&
+ canEvaluateTruncated(I->getOperand(1), Ty, IC, CxtI);
}
}
break;
if (ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1))) {
uint32_t BitWidth = Ty->getScalarSizeInBits();
if (CI->getLimitedValue(BitWidth) < BitWidth)
- return CanEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI);
+ return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI);
}
break;
case Instruction::LShr:
if (IC.MaskedValueIsZero(I->getOperand(0),
APInt::getHighBitsSet(OrigBitWidth, OrigBitWidth-BitWidth), 0, CxtI) &&
CI->getLimitedValue(BitWidth) < BitWidth) {
- return CanEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI);
+ return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI);
}
}
break;
return true;
case Instruction::Select: {
SelectInst *SI = cast<SelectInst>(I);
- return CanEvaluateTruncated(SI->getTrueValue(), Ty, IC, CxtI) &&
- CanEvaluateTruncated(SI->getFalseValue(), Ty, IC, CxtI);
+ return canEvaluateTruncated(SI->getTrueValue(), Ty, IC, CxtI) &&
+ canEvaluateTruncated(SI->getFalseValue(), Ty, IC, CxtI);
}
case Instruction::PHI: {
// We can change a phi if we can change all operands. Note that we never
// instructions with a single use.
PHINode *PN = cast<PHINode>(I);
for (Value *IncValue : PN->incoming_values())
- if (!CanEvaluateTruncated(IncValue, Ty, IC, CxtI))
+ if (!canEvaluateTruncated(IncValue, Ty, IC, CxtI))
return false;
return true;
}
return false;
}
+/// Given a vector that is bitcast to an integer, optionally logically
+/// right-shifted, and truncated, convert it to an extractelement.
+/// Example (big endian):
+/// trunc (lshr (bitcast <4 x i32> %X to i128), 32) to i32
+/// --->
+/// extractelement <4 x i32> %X, 1
+static Instruction *foldVecTruncToExtElt(TruncInst &Trunc, InstCombiner &IC,
+ const DataLayout &DL) {
+ Value *TruncOp = Trunc.getOperand(0);
+ Type *DestType = Trunc.getType();
+ if (!TruncOp->hasOneUse() || !isa<IntegerType>(DestType))
+ return nullptr;
+
+ Value *VecInput = nullptr;
+ ConstantInt *ShiftVal = nullptr;
+ if (!match(TruncOp, m_CombineOr(m_BitCast(m_Value(VecInput)),
+ m_LShr(m_BitCast(m_Value(VecInput)),
+ m_ConstantInt(ShiftVal)))) ||
+ !isa<VectorType>(VecInput->getType()))
+ return nullptr;
+
+ VectorType *VecType = cast<VectorType>(VecInput->getType());
+ unsigned VecWidth = VecType->getPrimitiveSizeInBits();
+ unsigned DestWidth = DestType->getPrimitiveSizeInBits();
+ unsigned ShiftAmount = ShiftVal ? ShiftVal->getZExtValue() : 0;
+
+ if ((VecWidth % DestWidth != 0) || (ShiftAmount % DestWidth != 0))
+ return nullptr;
+
+ // If the element type of the vector doesn't match the result type,
+ // bitcast it to a vector type that we can extract from.
+ unsigned NumVecElts = VecWidth / DestWidth;
+ if (VecType->getElementType() != DestType) {
+ VecType = VectorType::get(DestType, NumVecElts);
+ VecInput = IC.Builder->CreateBitCast(VecInput, VecType, "bc");
+ }
+
+ unsigned Elt = ShiftAmount / DestWidth;
+ if (DL.isBigEndian())
+ Elt = NumVecElts - 1 - Elt;
+
+ return ExtractElementInst::Create(VecInput, IC.Builder->getInt32(Elt));
+}
+
Instruction *InstCombiner::visitTrunc(TruncInst &CI) {
if (Instruction *Result = commonCastTransforms(CI))
return Result;
+ // Test if the trunc is the user of a select which is part of a
+ // minimum or maximum operation. If so, don't do any more simplification.
+ // Even simplifying demanded bits can break the canonical form of a
+ // min/max.
+ Value *LHS, *RHS;
+ if (SelectInst *SI = dyn_cast<SelectInst>(CI.getOperand(0)))
+ if (matchSelectPattern(SI, LHS, RHS).Flavor != SPF_UNKNOWN)
+ return nullptr;
+
// See if we can simplify any instructions used by the input whose sole
// purpose is to compute bits we don't care about.
if (SimplifyDemandedInstructionBits(CI))
// expression tree to something weird like i93 unless the source is also
// strange.
if ((DestTy->isVectorTy() || ShouldChangeType(SrcTy, DestTy)) &&
- CanEvaluateTruncated(Src, DestTy, *this, &CI)) {
+ canEvaluateTruncated(Src, DestTy, *this, &CI)) {
// If this cast is a truncate, evaluting in a different type always
// eliminates the cast, so it is always a win.
// Canonicalize trunc x to i1 -> (icmp ne (and x, 1), 0), likewise for vector.
if (DestTy->getScalarSizeInBits() == 1) {
- Constant *One = ConstantInt::get(Src->getType(), 1);
+ Constant *One = ConstantInt::get(SrcTy, 1);
Src = Builder->CreateAnd(Src, One);
Value *Zero = Constant::getNullValue(Src->getType());
return new ICmpInst(ICmpInst::ICMP_NE, Src, Zero);
// If the shift amount is larger than the size of A, then the result is
// known to be zero because all the input bits got shifted out.
if (Cst->getZExtValue() >= ASize)
- return ReplaceInstUsesWith(CI, Constant::getNullValue(CI.getType()));
+ return ReplaceInstUsesWith(CI, Constant::getNullValue(DestTy));
// Since we're doing an lshr and a zero extend, and know that the shift
// amount is smaller than ASize, it is always safe to do the shift in A's
// type, then zero extend or truncate to the result.
Value *Shift = Builder->CreateLShr(A, Cst->getZExtValue());
Shift->takeName(Src);
- return CastInst::CreateIntegerCast(Shift, CI.getType(), false);
+ return CastInst::CreateIntegerCast(Shift, DestTy, false);
+ }
+
+ // Transform trunc(lshr (sext A), Cst) to ashr A, Cst to eliminate type
+ // conversion.
+ // It works because bits coming from sign extension have the same value as
+ // the sign bit of the original value; performing ashr instead of lshr
+ // generates bits of the same value as the sign bit.
+ if (Src->hasOneUse() &&
+ match(Src, m_LShr(m_SExt(m_Value(A)), m_ConstantInt(Cst))) &&
+ cast<Instruction>(Src)->getOperand(0)->hasOneUse()) {
+ const unsigned ASize = A->getType()->getPrimitiveSizeInBits();
+ // This optimization can be only performed when zero bits generated by
+ // the original lshr aren't pulled into the value after truncation, so we
+ // can only shift by values smaller than the size of destination type (in
+ // bits).
+ if (Cst->getValue().ult(ASize)) {
+ Value *Shift = Builder->CreateAShr(A, Cst->getZExtValue());
+ Shift->takeName(Src);
+ return CastInst::CreateIntegerCast(Shift, CI.getType(), true);
+ }
}
// Transform "trunc (and X, cst)" -> "and (trunc X), cst" so long as the dest
// type isn't non-native.
- if (Src->hasOneUse() && isa<IntegerType>(Src->getType()) &&
- ShouldChangeType(Src->getType(), CI.getType()) &&
+ if (Src->hasOneUse() && isa<IntegerType>(SrcTy) &&
+ ShouldChangeType(SrcTy, DestTy) &&
match(Src, m_And(m_Value(A), m_ConstantInt(Cst)))) {
- Value *NewTrunc = Builder->CreateTrunc(A, CI.getType(), A->getName()+".tr");
+ Value *NewTrunc = Builder->CreateTrunc(A, DestTy, A->getName() + ".tr");
return BinaryOperator::CreateAnd(NewTrunc,
- ConstantExpr::getTrunc(Cst, CI.getType()));
+ ConstantExpr::getTrunc(Cst, DestTy));
}
+ if (Instruction *I = foldVecTruncToExtElt(CI, *this, DL))
+ return I;
+
return nullptr;
}
-/// transformZExtICmp - Transform (zext icmp) to bitwise / integer operations
-/// in order to eliminate the icmp.
+/// Transform (zext icmp) to bitwise / integer operations in order to eliminate
+/// the icmp.
Instruction *InstCombiner::transformZExtICmp(ICmpInst *ICI, Instruction &CI,
bool DoXform) {
// If we are just checking for a icmp eq of a single bit and zext'ing it
return nullptr;
}
-/// CanEvaluateZExtd - Determine if the specified value can be computed in the
-/// specified wider type and produce the same low bits. If not, return false.
+/// Determine if the specified value can be computed in the specified wider type
+/// and produce the same low bits. If not, return false.
///
/// If this function returns true, it can also return a non-zero number of bits
/// (in BitsToClear) which indicates that the value it computes is correct for
/// clear the top bits anyway, doing this has no extra cost.
///
/// This function works on both vectors and scalars.
-static bool CanEvaluateZExtd(Value *V, Type *Ty, unsigned &BitsToClear,
+static bool canEvaluateZExtd(Value *V, Type *Ty, unsigned &BitsToClear,
InstCombiner &IC, Instruction *CxtI) {
BitsToClear = 0;
if (isa<Constant>(V))
case Instruction::Add:
case Instruction::Sub:
case Instruction::Mul:
- if (!CanEvaluateZExtd(I->getOperand(0), Ty, BitsToClear, IC, CxtI) ||
- !CanEvaluateZExtd(I->getOperand(1), Ty, Tmp, IC, CxtI))
+ if (!canEvaluateZExtd(I->getOperand(0), Ty, BitsToClear, IC, CxtI) ||
+ !canEvaluateZExtd(I->getOperand(1), Ty, Tmp, IC, CxtI))
return false;
// These can all be promoted if neither operand has 'bits to clear'.
if (BitsToClear == 0 && Tmp == 0)
// We can promote shl(x, cst) if we can promote x. Since shl overwrites the
// upper bits we can reduce BitsToClear by the shift amount.
if (ConstantInt *Amt = dyn_cast<ConstantInt>(I->getOperand(1))) {
- if (!CanEvaluateZExtd(I->getOperand(0), Ty, BitsToClear, IC, CxtI))
+ if (!canEvaluateZExtd(I->getOperand(0), Ty, BitsToClear, IC, CxtI))
return false;
uint64_t ShiftAmt = Amt->getZExtValue();
BitsToClear = ShiftAmt < BitsToClear ? BitsToClear - ShiftAmt : 0;
// We can promote lshr(x, cst) if we can promote x. This requires the
// ultimate 'and' to clear out the high zero bits we're clearing out though.
if (ConstantInt *Amt = dyn_cast<ConstantInt>(I->getOperand(1))) {
- if (!CanEvaluateZExtd(I->getOperand(0), Ty, BitsToClear, IC, CxtI))
+ if (!canEvaluateZExtd(I->getOperand(0), Ty, BitsToClear, IC, CxtI))
return false;
BitsToClear += Amt->getZExtValue();
if (BitsToClear > V->getType()->getScalarSizeInBits())
// Cannot promote variable LSHR.
return false;
case Instruction::Select:
- if (!CanEvaluateZExtd(I->getOperand(1), Ty, Tmp, IC, CxtI) ||
- !CanEvaluateZExtd(I->getOperand(2), Ty, BitsToClear, IC, CxtI) ||
+ if (!canEvaluateZExtd(I->getOperand(1), Ty, Tmp, IC, CxtI) ||
+ !canEvaluateZExtd(I->getOperand(2), Ty, BitsToClear, IC, CxtI) ||
// TODO: If important, we could handle the case when the BitsToClear are
// known zero in the disagreeing side.
Tmp != BitsToClear)
// get into trouble with cyclic PHIs here because we only consider
// instructions with a single use.
PHINode *PN = cast<PHINode>(I);
- if (!CanEvaluateZExtd(PN->getIncomingValue(0), Ty, BitsToClear, IC, CxtI))
+ if (!canEvaluateZExtd(PN->getIncomingValue(0), Ty, BitsToClear, IC, CxtI))
return false;
for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i)
- if (!CanEvaluateZExtd(PN->getIncomingValue(i), Ty, Tmp, IC, CxtI) ||
+ if (!canEvaluateZExtd(PN->getIncomingValue(i), Ty, Tmp, IC, CxtI) ||
// TODO: If important, we could handle the case when the BitsToClear
// are known zero in the disagreeing input.
Tmp != BitsToClear)
// strange.
unsigned BitsToClear;
if ((DestTy->isVectorTy() || ShouldChangeType(SrcTy, DestTy)) &&
- CanEvaluateZExtd(Src, DestTy, BitsToClear, *this, &CI)) {
+ canEvaluateZExtd(Src, DestTy, BitsToClear, *this, &CI)) {
assert(BitsToClear < SrcTy->getScalarSizeInBits() &&
"Unreasonable BitsToClear");
// Okay, we can transform this! Insert the new expression now.
DEBUG(dbgs() << "ICE: EvaluateInDifferentType converting expression type"
- " to avoid zero extend: " << CI);
+ " to avoid zero extend: " << CI << '\n');
Value *Res = EvaluateInDifferentType(Src, DestTy, false);
assert(Res->getType() == DestTy);
return nullptr;
}
-/// transformSExtICmp - Transform (sext icmp) to bitwise / integer operations
-/// in order to eliminate the icmp.
+/// Transform (sext icmp) to bitwise / integer operations to eliminate the icmp.
Instruction *InstCombiner::transformSExtICmp(ICmpInst *ICI, Instruction &CI) {
Value *Op0 = ICI->getOperand(0), *Op1 = ICI->getOperand(1);
ICmpInst::Predicate Pred = ICI->getPredicate();
return nullptr;
}
-/// CanEvaluateSExtd - Return true if we can take the specified value
-/// and return it as type Ty without inserting any new casts and without
-/// changing the value of the common low bits. This is used by code that tries
-/// to promote integer operations to a wider types will allow us to eliminate
-/// the extension.
+/// Return true if we can take the specified value and return it as type Ty
+/// without inserting any new casts and without changing the value of the common
+/// low bits. This is used by code that tries to promote integer operations to
+/// a wider types will allow us to eliminate the extension.
///
/// This function works on both vectors and scalars.
///
-static bool CanEvaluateSExtd(Value *V, Type *Ty) {
+static bool canEvaluateSExtd(Value *V, Type *Ty) {
assert(V->getType()->getScalarSizeInBits() < Ty->getScalarSizeInBits() &&
"Can't sign extend type to a smaller type");
// If this is a constant, it can be trivially promoted.
case Instruction::Sub:
case Instruction::Mul:
// These operators can all arbitrarily be extended if their inputs can.
- return CanEvaluateSExtd(I->getOperand(0), Ty) &&
- CanEvaluateSExtd(I->getOperand(1), Ty);
+ return canEvaluateSExtd(I->getOperand(0), Ty) &&
+ canEvaluateSExtd(I->getOperand(1), Ty);
//case Instruction::Shl: TODO
//case Instruction::LShr: TODO
case Instruction::Select:
- return CanEvaluateSExtd(I->getOperand(1), Ty) &&
- CanEvaluateSExtd(I->getOperand(2), Ty);
+ return canEvaluateSExtd(I->getOperand(1), Ty) &&
+ canEvaluateSExtd(I->getOperand(2), Ty);
case Instruction::PHI: {
// We can change a phi if we can change all operands. Note that we never
// instructions with a single use.
PHINode *PN = cast<PHINode>(I);
for (Value *IncValue : PN->incoming_values())
- if (!CanEvaluateSExtd(IncValue, Ty)) return false;
+ if (!canEvaluateSExtd(IncValue, Ty)) return false;
return true;
}
default:
// expression tree to something weird like i93 unless the source is also
// strange.
if ((DestTy->isVectorTy() || ShouldChangeType(SrcTy, DestTy)) &&
- CanEvaluateSExtd(Src, DestTy)) {
+ canEvaluateSExtd(Src, DestTy)) {
// Okay, we can transform this! Insert the new expression now.
DEBUG(dbgs() << "ICE: EvaluateInDifferentType converting expression type"
- " to avoid sign extend: " << CI);
+ " to avoid sign extend: " << CI << '\n');
Value *Res = EvaluateInDifferentType(Src, DestTy, true);
assert(Res->getType() == DestTy);
}
-/// FitsInFPType - Return a Constant* for the specified FP constant if it fits
+/// Return a Constant* for the specified floating-point constant if it fits
/// in the specified FP type without changing its value.
-static Constant *FitsInFPType(ConstantFP *CFP, const fltSemantics &Sem) {
+static Constant *fitsInFPType(ConstantFP *CFP, const fltSemantics &Sem) {
bool losesInfo;
APFloat F = CFP->getValueAPF();
(void)F.convert(Sem, APFloat::rmNearestTiesToEven, &losesInfo);
return nullptr;
}
-/// LookThroughFPExtensions - If this is an fp extension instruction, look
+/// If this is a floating-point extension instruction, look
/// through it until we get the source value.
-static Value *LookThroughFPExtensions(Value *V) {
+static Value *lookThroughFPExtensions(Value *V) {
if (Instruction *I = dyn_cast<Instruction>(V))
if (I->getOpcode() == Instruction::FPExt)
- return LookThroughFPExtensions(I->getOperand(0));
+ return lookThroughFPExtensions(I->getOperand(0));
// If this value is a constant, return the constant in the smallest FP type
// that can accurately represent it. This allows us to turn
if (CFP->getType() == Type::getPPC_FP128Ty(V->getContext()))
return V; // No constant folding of this.
// See if the value can be truncated to half and then reextended.
- if (Value *V = FitsInFPType(CFP, APFloat::IEEEhalf))
+ if (Value *V = fitsInFPType(CFP, APFloat::IEEEhalf))
return V;
// See if the value can be truncated to float and then reextended.
- if (Value *V = FitsInFPType(CFP, APFloat::IEEEsingle))
+ if (Value *V = fitsInFPType(CFP, APFloat::IEEEsingle))
return V;
if (CFP->getType()->isDoubleTy())
return V; // Won't shrink.
- if (Value *V = FitsInFPType(CFP, APFloat::IEEEdouble))
+ if (Value *V = fitsInFPType(CFP, APFloat::IEEEdouble))
return V;
// Don't try to shrink to various long double types.
}
if (Instruction *I = commonCastTransforms(CI))
return I;
// If we have fptrunc(OpI (fpextend x), (fpextend y)), we would like to
- // simpilify this expression to avoid one or more of the trunc/extend
+ // simplify this expression to avoid one or more of the trunc/extend
// operations if we can do so without changing the numerical results.
//
// The exact manner in which the widths of the operands interact to limit
// is explained below in the various case statements.
BinaryOperator *OpI = dyn_cast<BinaryOperator>(CI.getOperand(0));
if (OpI && OpI->hasOneUse()) {
- Value *LHSOrig = LookThroughFPExtensions(OpI->getOperand(0));
- Value *RHSOrig = LookThroughFPExtensions(OpI->getOperand(1));
+ Value *LHSOrig = lookThroughFPExtensions(OpI->getOperand(0));
+ Value *RHSOrig = lookThroughFPExtensions(OpI->getOperand(1));
unsigned OpWidth = OpI->getType()->getFPMantissaWidth();
unsigned LHSWidth = LHSOrig->getType()->getFPMantissaWidth();
unsigned RHSWidth = RHSOrig->getType()->getFPMantissaWidth();
// (fptrunc (select cond, R1, Cst)) -->
// (select cond, (fptrunc R1), (fptrunc Cst))
+ //
+ // - but only if this isn't part of a min/max operation, else we'll
+ // ruin min/max canonical form which is to have the select and
+ // compare's operands be of the same type with no casts to look through.
+ Value *LHS, *RHS;
SelectInst *SI = dyn_cast<SelectInst>(CI.getOperand(0));
if (SI &&
(isa<ConstantFP>(SI->getOperand(1)) ||
- isa<ConstantFP>(SI->getOperand(2)))) {
+ isa<ConstantFP>(SI->getOperand(2))) &&
+ matchSelectPattern(SI, LHS, RHS).Flavor == SPF_UNKNOWN) {
Value *LHSTrunc = Builder->CreateFPTrunc(SI->getOperand(1),
CI.getType());
Value *RHSTrunc = Builder->CreateFPTrunc(SI->getOperand(2),
Value *InnerTrunc = Builder->CreateFPTrunc(II->getArgOperand(0),
CI.getType());
Type *IntrinsicType[] = { CI.getType() };
- Function *Overload =
- Intrinsic::getDeclaration(CI.getParent()->getParent()->getParent(),
- II->getIntrinsicID(), IntrinsicType);
+ Function *Overload = Intrinsic::getDeclaration(
+ CI.getModule(), II->getIntrinsicID(), IntrinsicType);
Value *Args[] = { InnerTrunc };
return CallInst::Create(Overload, Args, II->getName());
return CastInst::CreateIntegerCast(P, Ty, /*isSigned=*/false);
}
-/// OptimizeVectorResize - This input value (which is known to have vector type)
-/// is being zero extended or truncated to the specified vector type. Try to
-/// replace it with a shuffle (and vector/vector bitcast) if possible.
+/// This input value (which is known to have vector type) is being zero extended
+/// or truncated to the specified vector type.
+/// Try to replace it with a shuffle (and vector/vector bitcast) if possible.
///
/// The source and destination vector types may have different element types.
-static Instruction *OptimizeVectorResize(Value *InVal, VectorType *DestTy,
+static Instruction *optimizeVectorResize(Value *InVal, VectorType *DestTy,
InstCombiner &IC) {
// We can only do this optimization if the output is a multiple of the input
// element size, or the input is a multiple of the output element size.
return Value / Ty->getPrimitiveSizeInBits();
}
-/// CollectInsertionElements - V is a value which is inserted into a vector of
-/// VecEltTy. Look through the value to see if we can decompose it into
+/// V is a value which is inserted into a vector of VecEltTy.
+/// Look through the value to see if we can decompose it into
/// insertions into the vector. See the example in the comment for
/// OptimizeIntegerToVectorInsertions for the pattern this handles.
/// The type of V is always a non-zero multiple of VecEltTy's size.
///
/// This returns false if the pattern can't be matched or true if it can,
/// filling in Elements with the elements found here.
-static bool CollectInsertionElements(Value *V, unsigned Shift,
+static bool collectInsertionElements(Value *V, unsigned Shift,
SmallVectorImpl<Value *> &Elements,
Type *VecEltTy, bool isBigEndian) {
assert(isMultipleOfTypeSize(Shift, VecEltTy) &&
// If the constant is the size of a vector element, we just need to bitcast
// it to the right type so it gets properly inserted.
if (NumElts == 1)
- return CollectInsertionElements(ConstantExpr::getBitCast(C, VecEltTy),
+ return collectInsertionElements(ConstantExpr::getBitCast(C, VecEltTy),
Shift, Elements, VecEltTy, isBigEndian);
// Okay, this is a constant that covers multiple elements. Slice it up into
Constant *Piece = ConstantExpr::getLShr(C, ConstantInt::get(C->getType(),
ShiftI));
Piece = ConstantExpr::getTrunc(Piece, ElementIntTy);
- if (!CollectInsertionElements(Piece, ShiftI, Elements, VecEltTy,
+ if (!collectInsertionElements(Piece, ShiftI, Elements, VecEltTy,
isBigEndian))
return false;
}
switch (I->getOpcode()) {
default: return false; // Unhandled case.
case Instruction::BitCast:
- return CollectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
+ return collectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
isBigEndian);
case Instruction::ZExt:
if (!isMultipleOfTypeSize(
I->getOperand(0)->getType()->getPrimitiveSizeInBits(),
VecEltTy))
return false;
- return CollectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
+ return collectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
isBigEndian);
case Instruction::Or:
- return CollectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
+ return collectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
isBigEndian) &&
- CollectInsertionElements(I->getOperand(1), Shift, Elements, VecEltTy,
+ collectInsertionElements(I->getOperand(1), Shift, Elements, VecEltTy,
isBigEndian);
case Instruction::Shl: {
// Must be shifting by a constant that is a multiple of the element size.
if (!CI) return false;
Shift += CI->getZExtValue();
if (!isMultipleOfTypeSize(Shift, VecEltTy)) return false;
- return CollectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
+ return collectInsertionElements(I->getOperand(0), Shift, Elements, VecEltTy,
isBigEndian);
}
}
-/// OptimizeIntegerToVectorInsertions - If the input is an 'or' instruction, we
-/// may be doing shifts and ors to assemble the elements of the vector manually.
+/// If the input is an 'or' instruction, we may be doing shifts and ors to
+/// assemble the elements of the vector manually.
/// Try to rip the code out and replace it with insertelements. This is to
/// optimize code like this:
///
/// %tmp43 = bitcast i64 %ins35 to <2 x float>
///
/// Into two insertelements that do "buildvector{%inc, %inc5}".
-static Value *OptimizeIntegerToVectorInsertions(BitCastInst &CI,
+static Value *optimizeIntegerToVectorInsertions(BitCastInst &CI,
InstCombiner &IC) {
VectorType *DestVecTy = cast<VectorType>(CI.getType());
Value *IntInput = CI.getOperand(0);
SmallVector<Value*, 8> Elements(DestVecTy->getNumElements());
- if (!CollectInsertionElements(IntInput, 0, Elements,
+ if (!collectInsertionElements(IntInput, 0, Elements,
DestVecTy->getElementType(),
IC.getDataLayout().isBigEndian()))
return nullptr;
return Result;
}
-
-/// OptimizeIntToFloatBitCast - See if we can optimize an integer->float/double
-/// bitcast. The various long double bitcasts can't get in here.
-static Instruction *OptimizeIntToFloatBitCast(BitCastInst &CI, InstCombiner &IC,
+/// Canonicalize scalar bitcasts of extracted elements into a bitcast of the
+/// vector followed by extract element. The backend tends to handle bitcasts of
+/// vectors better than bitcasts of scalars because vector registers are
+/// usually not type-specific like scalar integer or scalar floating-point.
+static Instruction *canonicalizeBitCastExtElt(BitCastInst &BitCast,
+ InstCombiner &IC,
const DataLayout &DL) {
- Value *Src = CI.getOperand(0);
- Type *DestTy = CI.getType();
-
- // If this is a bitcast from int to float, check to see if the int is an
- // extraction from a vector.
- Value *VecInput = nullptr;
- // bitcast(trunc(bitcast(somevector)))
- if (match(Src, m_Trunc(m_BitCast(m_Value(VecInput)))) &&
- isa<VectorType>(VecInput->getType())) {
- VectorType *VecTy = cast<VectorType>(VecInput->getType());
- unsigned DestWidth = DestTy->getPrimitiveSizeInBits();
-
- if (VecTy->getPrimitiveSizeInBits() % DestWidth == 0) {
- // If the element type of the vector doesn't match the result type,
- // bitcast it to be a vector type we can extract from.
- if (VecTy->getElementType() != DestTy) {
- VecTy = VectorType::get(DestTy,
- VecTy->getPrimitiveSizeInBits() / DestWidth);
- VecInput = IC.Builder->CreateBitCast(VecInput, VecTy);
- }
-
- unsigned Elt = 0;
- if (DL.isBigEndian())
- Elt = VecTy->getPrimitiveSizeInBits() / DestWidth - 1;
- return ExtractElementInst::Create(VecInput, IC.Builder->getInt32(Elt));
- }
- }
+ // TODO: Create and use a pattern matcher for ExtractElementInst.
+ auto *ExtElt = dyn_cast<ExtractElementInst>(BitCast.getOperand(0));
+ if (!ExtElt || !ExtElt->hasOneUse())
+ return nullptr;
- // bitcast(trunc(lshr(bitcast(somevector), cst))
- ConstantInt *ShAmt = nullptr;
- if (match(Src, m_Trunc(m_LShr(m_BitCast(m_Value(VecInput)),
- m_ConstantInt(ShAmt)))) &&
- isa<VectorType>(VecInput->getType())) {
- VectorType *VecTy = cast<VectorType>(VecInput->getType());
- unsigned DestWidth = DestTy->getPrimitiveSizeInBits();
- if (VecTy->getPrimitiveSizeInBits() % DestWidth == 0 &&
- ShAmt->getZExtValue() % DestWidth == 0) {
- // If the element type of the vector doesn't match the result type,
- // bitcast it to be a vector type we can extract from.
- if (VecTy->getElementType() != DestTy) {
- VecTy = VectorType::get(DestTy,
- VecTy->getPrimitiveSizeInBits() / DestWidth);
- VecInput = IC.Builder->CreateBitCast(VecInput, VecTy);
- }
+ // The bitcast must be to a vectorizable type, otherwise we can't make a new
+ // type to extract from.
+ Type *DestType = BitCast.getType();
+ if (!VectorType::isValidElementType(DestType))
+ return nullptr;
- unsigned Elt = ShAmt->getZExtValue() / DestWidth;
- if (DL.isBigEndian())
- Elt = VecTy->getPrimitiveSizeInBits() / DestWidth - 1 - Elt;
- return ExtractElementInst::Create(VecInput, IC.Builder->getInt32(Elt));
- }
- }
- return nullptr;
+ unsigned NumElts = ExtElt->getVectorOperandType()->getNumElements();
+ auto *NewVecType = VectorType::get(DestType, NumElts);
+ auto *NewBC = IC.Builder->CreateBitCast(ExtElt->getVectorOperand(),
+ NewVecType, "bc");
+ return ExtractElementInst::Create(NewBC, ExtElt->getIndexOperand());
}
Instruction *InstCombiner::visitBitCast(BitCastInst &CI) {
}
}
- // Try to optimize int -> float bitcasts.
- if ((DestTy->isFloatTy() || DestTy->isDoubleTy()) && isa<IntegerType>(SrcTy))
- if (Instruction *I = OptimizeIntToFloatBitCast(CI, *this, DL))
- return I;
-
if (VectorType *DestVTy = dyn_cast<VectorType>(DestTy)) {
if (DestVTy->getNumElements() == 1 && !SrcTy->isVectorTy()) {
Value *Elem = Builder->CreateBitCast(Src, DestVTy->getElementType());
CastInst *SrcCast = cast<CastInst>(Src);
if (BitCastInst *BCIn = dyn_cast<BitCastInst>(SrcCast->getOperand(0)))
if (isa<VectorType>(BCIn->getOperand(0)->getType()))
- if (Instruction *I = OptimizeVectorResize(BCIn->getOperand(0),
+ if (Instruction *I = optimizeVectorResize(BCIn->getOperand(0),
cast<VectorType>(DestTy), *this))
return I;
}
// If the input is an 'or' instruction, we may be doing shifts and ors to
// assemble the elements of the vector manually. Try to rip the code out
// and replace it with insertelements.
- if (Value *V = OptimizeIntegerToVectorInsertions(CI, *this))
+ if (Value *V = optimizeIntegerToVectorInsertions(CI, *this))
return ReplaceInstUsesWith(CI, V);
}
}
}
}
+ if (Instruction *I = canonicalizeBitCastExtElt(CI, *this, DL))
+ return I;
+
if (SrcTy->isPointerTy())
return commonPointerCastTransforms(CI);
return commonCastTransforms(CI);
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