#include "InstCombine.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/InstructionSimplify.h"
-#include "llvm/Support/PatternMatch.h"
+#include "llvm/IR/PatternMatch.h"
using namespace llvm;
using namespace PatternMatch;
+#define DEBUG_TYPE "instcombine"
+
/// MatchSelectPattern - Pattern match integer [SU]MIN, [SU]MAX, and ABS idioms,
/// returning the kind and providing the out parameter results if we
/// successfully match.
static SelectPatternFlavor
MatchSelectPattern(Value *V, Value *&LHS, Value *&RHS) {
SelectInst *SI = dyn_cast<SelectInst>(V);
- if (SI == 0) return SPF_UNKNOWN;
+ if (!SI) return SPF_UNKNOWN;
ICmpInst *ICI = dyn_cast<ICmpInst>(SI->getCondition());
- if (ICI == 0) return SPF_UNKNOWN;
+ if (!ICI) return SPF_UNKNOWN;
LHS = ICI->getOperand(0);
RHS = ICI->getOperand(1);
if (TI->isCast()) {
Type *FIOpndTy = FI->getOperand(0)->getType();
if (TI->getOperand(0)->getType() != FIOpndTy)
- return 0;
+ return nullptr;
// The select condition may be a vector. We may only change the operand
// type if the vector width remains the same (and matches the condition).
Type *CondTy = SI.getCondition()->getType();
if (CondTy->isVectorTy() && (!FIOpndTy->isVectorTy() ||
CondTy->getVectorNumElements() != FIOpndTy->getVectorNumElements()))
- return 0;
+ return nullptr;
} else {
- return 0; // unknown unary op.
+ return nullptr; // unknown unary op.
}
// Fold this by inserting a select from the input values.
// Only handle binary operators here.
if (!isa<BinaryOperator>(TI))
- return 0;
+ return nullptr;
// Figure out if the operations have any operands in common.
Value *MatchOp, *OtherOpT, *OtherOpF;
OtherOpF = FI->getOperand(0);
MatchIsOpZero = false;
} else if (!TI->isCommutative()) {
- return 0;
+ return nullptr;
} else if (TI->getOperand(0) == FI->getOperand(1)) {
MatchOp = TI->getOperand(0);
OtherOpT = TI->getOperand(1);
OtherOpF = FI->getOperand(1);
MatchIsOpZero = true;
} else {
- return 0;
+ return nullptr;
}
// If we reach here, they do have operations in common.
}
}
- return 0;
+ return nullptr;
}
/// SimplifyWithOpReplaced - See if V simplifies when its operand Op is
Instruction *I = dyn_cast<Instruction>(V);
if (!I)
- return 0;
+ return nullptr;
// If this is a binary operator, try to simplify it with the replaced op.
if (BinaryOperator *B = dyn_cast<BinaryOperator>(I)) {
}
}
- return 0;
+ return nullptr;
+}
+
+/// foldSelectICmpAndOr - We want to turn:
+/// (select (icmp eq (and X, C1), 0), Y, (or Y, C2))
+/// into:
+/// (or (shl (and X, C1), C3), y)
+/// iff:
+/// C1 and C2 are both powers of 2
+/// where:
+/// C3 = Log(C2) - Log(C1)
+///
+/// This transform handles cases where:
+/// 1. The icmp predicate is inverted
+/// 2. The select operands are reversed
+/// 3. The magnitude of C2 and C1 are flipped
+static Value *foldSelectICmpAndOr(const SelectInst &SI, Value *TrueVal,
+ Value *FalseVal,
+ InstCombiner::BuilderTy *Builder) {
+ const ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition());
+ if (!IC || !IC->isEquality() || !SI.getType()->isIntegerTy())
+ return nullptr;
+
+ Value *CmpLHS = IC->getOperand(0);
+ Value *CmpRHS = IC->getOperand(1);
+
+ if (!match(CmpRHS, m_Zero()))
+ return nullptr;
+
+ Value *X;
+ const APInt *C1;
+ if (!match(CmpLHS, m_And(m_Value(X), m_Power2(C1))))
+ return nullptr;
+
+ const APInt *C2;
+ bool OrOnTrueVal = false;
+ bool OrOnFalseVal = match(FalseVal, m_Or(m_Specific(TrueVal), m_Power2(C2)));
+ if (!OrOnFalseVal)
+ OrOnTrueVal = match(TrueVal, m_Or(m_Specific(FalseVal), m_Power2(C2)));
+
+ if (!OrOnFalseVal && !OrOnTrueVal)
+ return nullptr;
+
+ Value *V = CmpLHS;
+ Value *Y = OrOnFalseVal ? TrueVal : FalseVal;
+
+ unsigned C1Log = C1->logBase2();
+ unsigned C2Log = C2->logBase2();
+ if (C2Log > C1Log) {
+ V = Builder->CreateZExtOrTrunc(V, Y->getType());
+ V = Builder->CreateShl(V, C2Log - C1Log);
+ } else if (C1Log > C2Log) {
+ V = Builder->CreateLShr(V, C1Log - C2Log);
+ V = Builder->CreateZExtOrTrunc(V, Y->getType());
+ } else
+ V = Builder->CreateZExtOrTrunc(V, Y->getType());
+
+ ICmpInst::Predicate Pred = IC->getPredicate();
+ if ((Pred == ICmpInst::ICMP_NE && OrOnFalseVal) ||
+ (Pred == ICmpInst::ICMP_EQ && OrOnTrueVal))
+ V = Builder->CreateXor(V, *C2);
+
+ return Builder->CreateOr(V, Y);
}
/// visitSelectInstWithICmp - Visit a SelectInst that has an
if (IntegerType *Ty = dyn_cast<IntegerType>(CmpLHS->getType())) {
if (TrueVal->getType() == Ty) {
if (ConstantInt *Cmp = dyn_cast<ConstantInt>(CmpRHS)) {
- ConstantInt *C1 = NULL, *C2 = NULL;
+ ConstantInt *C1 = nullptr, *C2 = nullptr;
if (Pred == ICmpInst::ICMP_SGT && Cmp->isAllOnesValue()) {
C1 = dyn_cast<ConstantInt>(TrueVal);
C2 = dyn_cast<ConstantInt>(FalseVal);
// arms of the select. See if substituting this value into the arm and
// simplifying the result yields the same value as the other arm.
if (Pred == ICmpInst::ICMP_EQ) {
- if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, TD, TLI) == TrueVal ||
- SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, TD, TLI) == TrueVal)
+ if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, DL, TLI) == TrueVal ||
+ SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, DL, TLI) == TrueVal)
return ReplaceInstUsesWith(SI, FalseVal);
- if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, TD, TLI) == FalseVal ||
- SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, TD, TLI) == FalseVal)
+ if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, DL, TLI) == FalseVal ||
+ SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, DL, TLI) == FalseVal)
return ReplaceInstUsesWith(SI, FalseVal);
} else if (Pred == ICmpInst::ICMP_NE) {
- if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, TD, TLI) == FalseVal ||
- SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, TD, TLI) == FalseVal)
+ if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, DL, TLI) == FalseVal ||
+ SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, DL, TLI) == FalseVal)
return ReplaceInstUsesWith(SI, TrueVal);
- if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, TD, TLI) == TrueVal ||
- SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, TD, TLI) == TrueVal)
+ if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, DL, TLI) == TrueVal ||
+ SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, DL, TLI) == TrueVal)
return ReplaceInstUsesWith(SI, TrueVal);
}
}
}
- return Changed ? &SI : 0;
+ if (Value *V = foldSelectICmpAndOr(SI, TrueVal, FalseVal, Builder))
+ return ReplaceInstUsesWith(SI, V);
+
+ return Changed ? &SI : nullptr;
}
// If the value is a non-instruction value like a constant or argument, it
// can always be mapped.
const Instruction *I = dyn_cast<Instruction>(V);
- if (I == 0) return true;
+ if (!I) return true;
// If V is a PHI node defined in the same block as the condition PHI, we can
// map the arguments.
return ReplaceInstUsesWith(Outer, C);
}
- // TODO: MIN(MIN(A, 23), 97)
- return 0;
+ if (SPF1 == SPF2) {
+ if (ConstantInt *CB = dyn_cast<ConstantInt>(B)) {
+ if (ConstantInt *CC = dyn_cast<ConstantInt>(C)) {
+ APInt ACB = CB->getValue();
+ APInt ACC = CC->getValue();
+
+ // MIN(MIN(A, 23), 97) -> MIN(A, 23)
+ // MAX(MAX(A, 97), 23) -> MAX(A, 97)
+ if ((SPF1 == SPF_UMIN && ACB.ule(ACC)) ||
+ (SPF1 == SPF_SMIN && ACB.sle(ACC)) ||
+ (SPF1 == SPF_UMAX && ACB.uge(ACC)) ||
+ (SPF1 == SPF_SMAX && ACB.sge(ACC)))
+ return ReplaceInstUsesWith(Outer, Inner);
+
+ // MIN(MIN(A, 97), 23) -> MIN(A, 23)
+ // MAX(MAX(A, 23), 97) -> MAX(A, 97)
+ if ((SPF1 == SPF_UMIN && ACB.ugt(ACC)) ||
+ (SPF1 == SPF_SMIN && ACB.sgt(ACC)) ||
+ (SPF1 == SPF_UMAX && ACB.ult(ACC)) ||
+ (SPF1 == SPF_SMAX && ACB.slt(ACC))) {
+ Outer.replaceUsesOfWith(Inner, A);
+ return &Outer;
+ }
+ }
+ }
+ }
+ return nullptr;
}
-
/// foldSelectICmpAnd - If one of the constants is zero (we know they can't
/// both be) and we have an icmp instruction with zero, and we have an 'and'
/// with the non-constant value and a power of two we can turn the select
ConstantInt *FalseVal,
InstCombiner::BuilderTy *Builder) {
const ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition());
- if (!IC || !IC->isEquality())
- return 0;
+ if (!IC || !IC->isEquality() || !SI.getType()->isIntegerTy())
+ return nullptr;
if (!match(IC->getOperand(1), m_Zero()))
- return 0;
+ return nullptr;
ConstantInt *AndRHS;
Value *LHS = IC->getOperand(0);
- if (LHS->getType() != SI.getType() ||
- !match(LHS, m_And(m_Value(), m_ConstantInt(AndRHS))))
- return 0;
+ if (!match(LHS, m_And(m_Value(), m_ConstantInt(AndRHS))))
+ return nullptr;
// If both select arms are non-zero see if we have a select of the form
// 'x ? 2^n + C : C'. Then we can offset both arms by C, use the logic
// for 'x ? 2^n : 0' and fix the thing up at the end.
- ConstantInt *Offset = 0;
+ ConstantInt *Offset = nullptr;
if (!TrueVal->isZero() && !FalseVal->isZero()) {
if ((TrueVal->getValue() - FalseVal->getValue()).isPowerOf2())
Offset = FalseVal;
else if ((FalseVal->getValue() - TrueVal->getValue()).isPowerOf2())
Offset = TrueVal;
else
- return 0;
+ return nullptr;
// Adjust TrueVal and FalseVal to the offset.
TrueVal = ConstantInt::get(Builder->getContext(),
if (!AndRHS->getValue().isPowerOf2() ||
(!TrueVal->getValue().isPowerOf2() &&
!FalseVal->getValue().isPowerOf2()))
- return 0;
+ return nullptr;
// Determine which shift is needed to transform result of the 'and' into the
// desired result.
unsigned ValZeros = ValC->getValue().logBase2();
unsigned AndZeros = AndRHS->getValue().logBase2();
- Value *V = LHS;
+ // If types don't match we can still convert the select by introducing a zext
+ // or a trunc of the 'and'. The trunc case requires that all of the truncated
+ // bits are zero, we can figure that out by looking at the 'and' mask.
+ if (AndZeros >= ValC->getBitWidth())
+ return nullptr;
+
+ Value *V = Builder->CreateZExtOrTrunc(LHS, SI.getType());
if (ValZeros > AndZeros)
V = Builder->CreateShl(V, ValZeros - AndZeros);
else if (ValZeros < AndZeros)
Value *TrueVal = SI.getTrueValue();
Value *FalseVal = SI.getFalseValue();
- if (Value *V = SimplifySelectInst(CondVal, TrueVal, FalseVal, TD))
+ if (Value *V = SimplifySelectInst(CondVal, TrueVal, FalseVal, DL))
return ReplaceInstUsesWith(SI, V);
if (SI.getType()->isIntegerTy(1)) {
// Change: A = select B, false, C --> A = and !B, C
Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName());
return BinaryOperator::CreateAnd(NotCond, FalseVal);
- } else if (ConstantInt *C = dyn_cast<ConstantInt>(FalseVal)) {
+ }
+ if (ConstantInt *C = dyn_cast<ConstantInt>(FalseVal)) {
if (C->getZExtValue() == false) {
// Change: A = select B, C, false --> A = and B, C
return BinaryOperator::CreateAnd(CondVal, TrueVal);
// select a, a, b -> a|b
if (CondVal == TrueVal)
return BinaryOperator::CreateOr(CondVal, FalseVal);
- else if (CondVal == FalseVal)
+ if (CondVal == FalseVal)
return BinaryOperator::CreateAnd(CondVal, TrueVal);
// select a, ~a, b -> (~a)&b
// select a, b, ~a -> (~a)|b
if (match(TrueVal, m_Not(m_Specific(CondVal))))
return BinaryOperator::CreateAnd(TrueVal, FalseVal);
- else if (match(FalseVal, m_Not(m_Specific(CondVal))))
+ if (match(FalseVal, m_Not(m_Specific(CondVal))))
return BinaryOperator::CreateOr(TrueVal, FalseVal);
}
if (Instruction *TI = dyn_cast<Instruction>(TrueVal))
if (Instruction *FI = dyn_cast<Instruction>(FalseVal))
if (TI->hasOneUse() && FI->hasOneUse()) {
- Instruction *AddOp = 0, *SubOp = 0;
+ Instruction *AddOp = nullptr, *SubOp = nullptr;
// Turn (select C, (op X, Y), (op X, Z)) -> (op X, (select C, Y, Z))
if (TI->getOpcode() == FI->getOpcode())
}
if (AddOp) {
- Value *OtherAddOp = 0;
+ Value *OtherAddOp = nullptr;
if (SubOp->getOperand(0) == AddOp->getOperand(0)) {
OtherAddOp = AddOp->getOperand(1);
} else if (SubOp->getOperand(0) == AddOp->getOperand(1)) {
Value *NegVal; // Compute -Z
if (SI.getType()->isFPOrFPVectorTy()) {
NegVal = Builder->CreateFNeg(SubOp->getOperand(1));
+ if (Instruction *NegInst = dyn_cast<Instruction>(NegVal)) {
+ FastMathFlags Flags = AddOp->getFastMathFlags();
+ Flags &= SubOp->getFastMathFlags();
+ NegInst->setFastMathFlags(Flags);
+ }
} else {
NegVal = Builder->CreateNeg(SubOp->getOperand(1));
}
Builder->CreateSelect(CondVal, NewTrueOp,
NewFalseOp, SI.getName() + ".p");
- if (SI.getType()->isFPOrFPVectorTy())
- return BinaryOperator::CreateFAdd(SubOp->getOperand(0), NewSel);
- else
+ if (SI.getType()->isFPOrFPVectorTy()) {
+ Instruction *RI =
+ BinaryOperator::CreateFAdd(SubOp->getOperand(0), NewSel);
+
+ FastMathFlags Flags = AddOp->getFastMathFlags();
+ Flags &= SubOp->getFastMathFlags();
+ RI->setFastMathFlags(Flags);
+ return RI;
+ } else
return BinaryOperator::CreateAdd(SubOp->getOperand(0), NewSel);
}
}
if (SelectInst *TrueSI = dyn_cast<SelectInst>(TrueVal)) {
if (TrueSI->getCondition() == CondVal) {
if (SI.getTrueValue() == TrueSI->getTrueValue())
- return 0;
+ return nullptr;
SI.setOperand(1, TrueSI->getTrueValue());
return &SI;
}
if (SelectInst *FalseSI = dyn_cast<SelectInst>(FalseVal)) {
if (FalseSI->getCondition() == CondVal) {
if (SI.getFalseValue() == FalseSI->getFalseValue())
- return 0;
+ return nullptr;
SI.setOperand(2, FalseSI->getFalseValue());
return &SI;
}
return &SI;
}
- if (VectorType *VecTy = dyn_cast<VectorType>(SI.getType())) {
+ if (VectorType* VecTy = dyn_cast<VectorType>(SI.getType())) {
unsigned VWidth = VecTy->getNumElements();
APInt UndefElts(VWidth, 0);
APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
return &SI;
}
- if (ConstantVector *CV = dyn_cast<ConstantVector>(CondVal)) {
- // Form a shufflevector instruction.
- SmallVector<Constant *, 8> Mask(VWidth);
- Type *Int32Ty = Type::getInt32Ty(CV->getContext());
- for (unsigned i = 0; i != VWidth; ++i) {
- Constant *Elem = cast<Constant>(CV->getOperand(i));
- if (ConstantInt *E = dyn_cast<ConstantInt>(Elem))
- Mask[i] = ConstantInt::get(Int32Ty, i + (E->isZero() ? VWidth : 0));
- else if (isa<UndefValue>(Elem))
- Mask[i] = UndefValue::get(Int32Ty);
- else
- return 0;
- }
- Constant *MaskVal = ConstantVector::get(Mask);
- Value *V = Builder->CreateShuffleVector(TrueVal, FalseVal, MaskVal);
- return ReplaceInstUsesWith(SI, V);
- }
-
if (isa<ConstantAggregateZero>(CondVal)) {
return ReplaceInstUsesWith(SI, FalseVal);
}
}
- return 0;
+ return nullptr;
}
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