//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "instcombine"
#include "llvm/Transforms/Scalar.h"
#include "InstCombine.h"
-#include "llvm/IntrinsicInst.h"
+#include "llvm-c/Initialization.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/Analysis/AssumptionTracker.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/MemoryBuiltins.h"
-#include "llvm/Target/TargetData.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/IR/CFG.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/GetElementPtrTypeIterator.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/PatternMatch.h"
+#include "llvm/IR/ValueHandle.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
#include "llvm/Target/TargetLibraryInfo.h"
#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/Support/CFG.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/GetElementPtrTypeIterator.h"
-#include "llvm/Support/PatternMatch.h"
-#include "llvm/Support/ValueHandle.h"
-#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/StringSwitch.h"
-#include "llvm-c/Initialization.h"
#include <algorithm>
#include <climits>
using namespace llvm;
using namespace llvm::PatternMatch;
+#define DEBUG_TYPE "instcombine"
+
STATISTIC(NumCombined , "Number of insts combined");
STATISTIC(NumConstProp, "Number of constant folds");
STATISTIC(NumDeadInst , "Number of dead inst eliminated");
STATISTIC(NumFactor , "Number of factorizations");
STATISTIC(NumReassoc , "Number of reassociations");
+static cl::opt<bool>
+ EnableUnsafeFPShrink("enable-double-float-shrink", cl::Hidden,
+ cl::init(false),
+ cl::desc("Enable unsafe double to float "
+ "shrinking for math lib calls"));
+
// Initialization Routines
void llvm::initializeInstCombine(PassRegistry &Registry) {
initializeInstCombinerPass(Registry);
char InstCombiner::ID = 0;
INITIALIZE_PASS_BEGIN(InstCombiner, "instcombine",
"Combine redundant instructions", false, false)
+INITIALIZE_PASS_DEPENDENCY(AssumptionTracker)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
INITIALIZE_PASS_END(InstCombiner, "instcombine",
"Combine redundant instructions", false, false)
void InstCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
+ AU.addRequired<AssumptionTracker>();
AU.addRequired<TargetLibraryInfo>();
}
Value *InstCombiner::EmitGEPOffset(User *GEP) {
- return llvm::EmitGEPOffset(Builder, *getTargetData(), GEP);
+ return llvm::EmitGEPOffset(Builder, *getDataLayout(), GEP);
}
/// ShouldChangeType - Return true if it is desirable to convert a computation
bool InstCombiner::ShouldChangeType(Type *From, Type *To) const {
assert(From->isIntegerTy() && To->isIntegerTy());
- // If we don't have TD, we don't know if the source/dest are legal.
- if (!TD) return false;
+ // If we don't have DL, we don't know if the source/dest are legal.
+ if (!DL) return false;
unsigned FromWidth = From->getPrimitiveSizeInBits();
unsigned ToWidth = To->getPrimitiveSizeInBits();
- bool FromLegal = TD->isLegalInteger(FromWidth);
- bool ToLegal = TD->isLegalInteger(ToWidth);
+ bool FromLegal = DL->isLegalInteger(FromWidth);
+ bool ToLegal = DL->isLegalInteger(ToWidth);
// If this is a legal integer from type, and the result would be an illegal
// type, don't do the transformation.
return !Overflow;
}
+/// Conservatively clears subclassOptionalData after a reassociation or
+/// commutation. We preserve fast-math flags when applicable as they can be
+/// preserved.
+static void ClearSubclassDataAfterReassociation(BinaryOperator &I) {
+ FPMathOperator *FPMO = dyn_cast<FPMathOperator>(&I);
+ if (!FPMO) {
+ I.clearSubclassOptionalData();
+ return;
+ }
+
+ FastMathFlags FMF = I.getFastMathFlags();
+ I.clearSubclassOptionalData();
+ I.setFastMathFlags(FMF);
+}
+
/// SimplifyAssociativeOrCommutative - This performs a few simplifications for
/// operators which are associative or commutative:
//
Value *C = I.getOperand(1);
// Does "B op C" simplify?
- if (Value *V = SimplifyBinOp(Opcode, B, C, TD)) {
+ if (Value *V = SimplifyBinOp(Opcode, B, C, DL)) {
// It simplifies to V. Form "A op V".
I.setOperand(0, A);
I.setOperand(1, V);
// Conservatively clear the optional flags, since they may not be
// preserved by the reassociation.
if (MaintainNoSignedWrap(I, B, C) &&
- (!Op0 || (isa<BinaryOperator>(Op0) && Op0->hasNoSignedWrap()))) {
+ (!Op0 || (isa<BinaryOperator>(Op0) && Op0->hasNoSignedWrap()))) {
// Note: this is only valid because SimplifyBinOp doesn't look at
// the operands to Op0.
I.clearSubclassOptionalData();
I.setHasNoSignedWrap(true);
} else {
- I.clearSubclassOptionalData();
+ ClearSubclassDataAfterReassociation(I);
}
Changed = true;
Value *C = Op1->getOperand(1);
// Does "A op B" simplify?
- if (Value *V = SimplifyBinOp(Opcode, A, B, TD)) {
+ if (Value *V = SimplifyBinOp(Opcode, A, B, DL)) {
// It simplifies to V. Form "V op C".
I.setOperand(0, V);
I.setOperand(1, C);
// Conservatively clear the optional flags, since they may not be
// preserved by the reassociation.
- I.clearSubclassOptionalData();
+ ClearSubclassDataAfterReassociation(I);
Changed = true;
++NumReassoc;
continue;
Value *C = I.getOperand(1);
// Does "C op A" simplify?
- if (Value *V = SimplifyBinOp(Opcode, C, A, TD)) {
+ if (Value *V = SimplifyBinOp(Opcode, C, A, DL)) {
// It simplifies to V. Form "V op B".
I.setOperand(0, V);
I.setOperand(1, B);
// Conservatively clear the optional flags, since they may not be
// preserved by the reassociation.
- I.clearSubclassOptionalData();
+ ClearSubclassDataAfterReassociation(I);
Changed = true;
++NumReassoc;
continue;
Value *C = Op1->getOperand(1);
// Does "C op A" simplify?
- if (Value *V = SimplifyBinOp(Opcode, C, A, TD)) {
+ if (Value *V = SimplifyBinOp(Opcode, C, A, DL)) {
// It simplifies to V. Form "B op V".
I.setOperand(0, B);
I.setOperand(1, V);
// Conservatively clear the optional flags, since they may not be
// preserved by the reassociation.
- I.clearSubclassOptionalData();
+ ClearSubclassDataAfterReassociation(I);
Changed = true;
++NumReassoc;
continue;
Constant *Folded = ConstantExpr::get(Opcode, C1, C2);
BinaryOperator *New = BinaryOperator::Create(Opcode, A, B);
+ if (isa<FPMathOperator>(New)) {
+ FastMathFlags Flags = I.getFastMathFlags();
+ Flags &= Op0->getFastMathFlags();
+ Flags &= Op1->getFastMathFlags();
+ New->setFastMathFlags(Flags);
+ }
InsertNewInstWith(New, I);
New->takeName(Op1);
I.setOperand(0, New);
I.setOperand(1, Folded);
// Conservatively clear the optional flags, since they may not be
// preserved by the reassociation.
- I.clearSubclassOptionalData();
+ ClearSubclassDataAfterReassociation(I);
Changed = true;
continue;
Instruction::BinaryOps ROp) {
if (Instruction::isCommutative(ROp))
return LeftDistributesOverRight(ROp, LOp);
+
+ switch (LOp) {
+ default:
+ return false;
+ // (X >> Z) & (Y >> Z) -> (X&Y) >> Z for all shifts.
+ // (X >> Z) | (Y >> Z) -> (X|Y) >> Z for all shifts.
+ // (X >> Z) ^ (Y >> Z) -> (X^Y) >> Z for all shifts.
+ case Instruction::And:
+ case Instruction::Or:
+ case Instruction::Xor:
+ switch (ROp) {
+ default:
+ return false;
+ case Instruction::Shl:
+ case Instruction::LShr:
+ case Instruction::AShr:
+ return true;
+ }
+ }
// TODO: It would be nice to handle division, aka "(X + Y)/Z = X/Z + Y/Z",
// but this requires knowing that the addition does not overflow and other
// such subtleties.
return false;
}
+/// This function returns identity value for given opcode, which can be used to
+/// factor patterns like (X * 2) + X ==> (X * 2) + (X * 1) ==> X * (2 + 1).
+static Value *getIdentityValue(Instruction::BinaryOps OpCode, Value *V) {
+ if (isa<Constant>(V))
+ return nullptr;
+
+ if (OpCode == Instruction::Mul)
+ return ConstantInt::get(V->getType(), 1);
+
+ // TODO: We can handle other cases e.g. Instruction::And, Instruction::Or etc.
+
+ return nullptr;
+}
+
+/// This function factors binary ops which can be combined using distributive
+/// laws. This function tries to transform 'Op' based TopLevelOpcode to enable
+/// factorization e.g for ADD(SHL(X , 2), MUL(X, 5)), When this function called
+/// with TopLevelOpcode == Instruction::Add and Op = SHL(X, 2), transforms
+/// SHL(X, 2) to MUL(X, 4) i.e. returns Instruction::Mul with LHS set to 'X' and
+/// RHS to 4.
+static Instruction::BinaryOps
+getBinOpsForFactorization(Instruction::BinaryOps TopLevelOpcode,
+ BinaryOperator *Op, Value *&LHS, Value *&RHS) {
+ if (!Op)
+ return Instruction::BinaryOpsEnd;
+
+ LHS = Op->getOperand(0);
+ RHS = Op->getOperand(1);
+
+ switch (TopLevelOpcode) {
+ default:
+ return Op->getOpcode();
+
+ case Instruction::Add:
+ case Instruction::Sub:
+ if (Op->getOpcode() == Instruction::Shl) {
+ if (Constant *CST = dyn_cast<Constant>(Op->getOperand(1))) {
+ // The multiplier is really 1 << CST.
+ RHS = ConstantExpr::getShl(ConstantInt::get(Op->getType(), 1), CST);
+ return Instruction::Mul;
+ }
+ }
+ return Op->getOpcode();
+ }
+
+ // TODO: We can add other conversions e.g. shr => div etc.
+}
+
+/// This tries to simplify binary operations by factorizing out common terms
+/// (e. g. "(A*B)+(A*C)" -> "A*(B+C)").
+static Value *tryFactorization(InstCombiner::BuilderTy *Builder,
+ const DataLayout *DL, BinaryOperator &I,
+ Instruction::BinaryOps InnerOpcode, Value *A,
+ Value *B, Value *C, Value *D) {
+
+ // If any of A, B, C, D are null, we can not factor I, return early.
+ // Checking A and C should be enough.
+ if (!A || !C || !B || !D)
+ return nullptr;
+
+ Value *SimplifiedInst = nullptr;
+ Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
+ Instruction::BinaryOps TopLevelOpcode = I.getOpcode();
+
+ // Does "X op' Y" always equal "Y op' X"?
+ bool InnerCommutative = Instruction::isCommutative(InnerOpcode);
+
+ // Does "X op' (Y op Z)" always equal "(X op' Y) op (X op' Z)"?
+ if (LeftDistributesOverRight(InnerOpcode, TopLevelOpcode))
+ // Does the instruction have the form "(A op' B) op (A op' D)" or, in the
+ // commutative case, "(A op' B) op (C op' A)"?
+ if (A == C || (InnerCommutative && A == D)) {
+ if (A != C)
+ std::swap(C, D);
+ // Consider forming "A op' (B op D)".
+ // If "B op D" simplifies then it can be formed with no cost.
+ Value *V = SimplifyBinOp(TopLevelOpcode, B, D, DL);
+ // If "B op D" doesn't simplify then only go on if both of the existing
+ // operations "A op' B" and "C op' D" will be zapped as no longer used.
+ if (!V && LHS->hasOneUse() && RHS->hasOneUse())
+ V = Builder->CreateBinOp(TopLevelOpcode, B, D, RHS->getName());
+ if (V) {
+ SimplifiedInst = Builder->CreateBinOp(InnerOpcode, A, V);
+ }
+ }
+
+ // Does "(X op Y) op' Z" always equal "(X op' Z) op (Y op' Z)"?
+ if (!SimplifiedInst && RightDistributesOverLeft(TopLevelOpcode, InnerOpcode))
+ // Does the instruction have the form "(A op' B) op (C op' B)" or, in the
+ // commutative case, "(A op' B) op (B op' D)"?
+ if (B == D || (InnerCommutative && B == C)) {
+ if (B != D)
+ std::swap(C, D);
+ // Consider forming "(A op C) op' B".
+ // If "A op C" simplifies then it can be formed with no cost.
+ Value *V = SimplifyBinOp(TopLevelOpcode, A, C, DL);
+
+ // If "A op C" doesn't simplify then only go on if both of the existing
+ // operations "A op' B" and "C op' D" will be zapped as no longer used.
+ if (!V && LHS->hasOneUse() && RHS->hasOneUse())
+ V = Builder->CreateBinOp(TopLevelOpcode, A, C, LHS->getName());
+ if (V) {
+ SimplifiedInst = Builder->CreateBinOp(InnerOpcode, V, B);
+ }
+ }
+
+ if (SimplifiedInst) {
+ ++NumFactor;
+ SimplifiedInst->takeName(&I);
+
+ // Check if we can add NSW flag to SimplifiedInst. If so, set NSW flag.
+ // TODO: Check for NUW.
+ if (BinaryOperator *BO = dyn_cast<BinaryOperator>(SimplifiedInst)) {
+ if (isa<OverflowingBinaryOperator>(SimplifiedInst)) {
+ bool HasNSW = false;
+ if (isa<OverflowingBinaryOperator>(&I))
+ HasNSW = I.hasNoSignedWrap();
+
+ if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS))
+ if (isa<OverflowingBinaryOperator>(Op0))
+ HasNSW &= Op0->hasNoSignedWrap();
+
+ if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS))
+ if (isa<OverflowingBinaryOperator>(Op1))
+ HasNSW &= Op1->hasNoSignedWrap();
+ BO->setHasNoSignedWrap(HasNSW);
+ }
+ }
+ }
+ return SimplifiedInst;
+}
+
/// SimplifyUsingDistributiveLaws - This tries to simplify binary operations
/// which some other binary operation distributes over either by factorizing
/// out common terms (eg "(A*B)+(A*C)" -> "A*(B+C)") or expanding out if this
Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
- Instruction::BinaryOps TopLevelOpcode = I.getOpcode(); // op
// Factorization.
- if (Op0 && Op1 && Op0->getOpcode() == Op1->getOpcode()) {
- // The instruction has the form "(A op' B) op (C op' D)". Try to factorize
- // a common term.
- Value *A = Op0->getOperand(0), *B = Op0->getOperand(1);
- Value *C = Op1->getOperand(0), *D = Op1->getOperand(1);
- Instruction::BinaryOps InnerOpcode = Op0->getOpcode(); // op'
+ Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
+ auto TopLevelOpcode = I.getOpcode();
+ auto LHSOpcode = getBinOpsForFactorization(TopLevelOpcode, Op0, A, B);
+ auto RHSOpcode = getBinOpsForFactorization(TopLevelOpcode, Op1, C, D);
+
+ // The instruction has the form "(A op' B) op (C op' D)". Try to factorize
+ // a common term.
+ if (LHSOpcode == RHSOpcode) {
+ if (Value *V = tryFactorization(Builder, DL, I, LHSOpcode, A, B, C, D))
+ return V;
+ }
- // Does "X op' Y" always equal "Y op' X"?
- bool InnerCommutative = Instruction::isCommutative(InnerOpcode);
-
- // Does "X op' (Y op Z)" always equal "(X op' Y) op (X op' Z)"?
- if (LeftDistributesOverRight(InnerOpcode, TopLevelOpcode))
- // Does the instruction have the form "(A op' B) op (A op' D)" or, in the
- // commutative case, "(A op' B) op (C op' A)"?
- if (A == C || (InnerCommutative && A == D)) {
- if (A != C)
- std::swap(C, D);
- // Consider forming "A op' (B op D)".
- // If "B op D" simplifies then it can be formed with no cost.
- Value *V = SimplifyBinOp(TopLevelOpcode, B, D, TD);
- // If "B op D" doesn't simplify then only go on if both of the existing
- // operations "A op' B" and "C op' D" will be zapped as no longer used.
- if (!V && Op0->hasOneUse() && Op1->hasOneUse())
- V = Builder->CreateBinOp(TopLevelOpcode, B, D, Op1->getName());
- if (V) {
- ++NumFactor;
- V = Builder->CreateBinOp(InnerOpcode, A, V);
- V->takeName(&I);
- return V;
- }
- }
+ // The instruction has the form "(A op' B) op (C)". Try to factorize common
+ // term.
+ if (Value *V = tryFactorization(Builder, DL, I, LHSOpcode, A, B, RHS,
+ getIdentityValue(LHSOpcode, RHS)))
+ return V;
- // Does "(X op Y) op' Z" always equal "(X op' Z) op (Y op' Z)"?
- if (RightDistributesOverLeft(TopLevelOpcode, InnerOpcode))
- // Does the instruction have the form "(A op' B) op (C op' B)" or, in the
- // commutative case, "(A op' B) op (B op' D)"?
- if (B == D || (InnerCommutative && B == C)) {
- if (B != D)
- std::swap(C, D);
- // Consider forming "(A op C) op' B".
- // If "A op C" simplifies then it can be formed with no cost.
- Value *V = SimplifyBinOp(TopLevelOpcode, A, C, TD);
- // If "A op C" doesn't simplify then only go on if both of the existing
- // operations "A op' B" and "C op' D" will be zapped as no longer used.
- if (!V && Op0->hasOneUse() && Op1->hasOneUse())
- V = Builder->CreateBinOp(TopLevelOpcode, A, C, Op0->getName());
- if (V) {
- ++NumFactor;
- V = Builder->CreateBinOp(InnerOpcode, V, B);
- V->takeName(&I);
- return V;
- }
- }
- }
+ // The instruction has the form "(B) op (C op' D)". Try to factorize common
+ // term.
+ if (Value *V = tryFactorization(Builder, DL, I, RHSOpcode, LHS,
+ getIdentityValue(RHSOpcode, LHS), C, D))
+ return V;
// Expansion.
if (Op0 && RightDistributesOverLeft(Op0->getOpcode(), TopLevelOpcode)) {
Instruction::BinaryOps InnerOpcode = Op0->getOpcode(); // op'
// Do "A op C" and "B op C" both simplify?
- if (Value *L = SimplifyBinOp(TopLevelOpcode, A, C, TD))
- if (Value *R = SimplifyBinOp(TopLevelOpcode, B, C, TD)) {
+ if (Value *L = SimplifyBinOp(TopLevelOpcode, A, C, DL))
+ if (Value *R = SimplifyBinOp(TopLevelOpcode, B, C, DL)) {
// They do! Return "L op' R".
++NumExpand;
// If "L op' R" equals "A op' B" then "L op' R" is just the LHS.
(Instruction::isCommutative(InnerOpcode) && L == B && R == A))
return Op0;
// Otherwise return "L op' R" if it simplifies.
- if (Value *V = SimplifyBinOp(InnerOpcode, L, R, TD))
+ if (Value *V = SimplifyBinOp(InnerOpcode, L, R, DL))
return V;
// Otherwise, create a new instruction.
C = Builder->CreateBinOp(InnerOpcode, L, R);
Instruction::BinaryOps InnerOpcode = Op1->getOpcode(); // op'
// Do "A op B" and "A op C" both simplify?
- if (Value *L = SimplifyBinOp(TopLevelOpcode, A, B, TD))
- if (Value *R = SimplifyBinOp(TopLevelOpcode, A, C, TD)) {
+ if (Value *L = SimplifyBinOp(TopLevelOpcode, A, B, DL))
+ if (Value *R = SimplifyBinOp(TopLevelOpcode, A, C, DL)) {
// They do! Return "L op' R".
++NumExpand;
// If "L op' R" equals "B op' C" then "L op' R" is just the RHS.
(Instruction::isCommutative(InnerOpcode) && L == C && R == B))
return Op1;
// Otherwise return "L op' R" if it simplifies.
- if (Value *V = SimplifyBinOp(InnerOpcode, L, R, TD))
+ if (Value *V = SimplifyBinOp(InnerOpcode, L, R, DL))
return V;
// Otherwise, create a new instruction.
A = Builder->CreateBinOp(InnerOpcode, L, R);
}
}
- return 0;
+ return nullptr;
}
// dyn_castNegVal - Given a 'sub' instruction, return the RHS of the instruction
if (C->getType()->getElementType()->isIntegerTy())
return ConstantExpr::getNeg(C);
- return 0;
+ return nullptr;
}
// dyn_castFNegVal - Given a 'fsub' instruction, return the RHS of the
// instruction if the LHS is a constant negative zero (which is the 'negate'
// form).
//
-Value *InstCombiner::dyn_castFNegVal(Value *V) const {
- if (BinaryOperator::isFNeg(V))
+Value *InstCombiner::dyn_castFNegVal(Value *V, bool IgnoreZeroSign) const {
+ if (BinaryOperator::isFNeg(V, IgnoreZeroSign))
return BinaryOperator::getFNegArgument(V);
// Constants can be considered to be negated values if they can be folded.
if (C->getType()->getElementType()->isFloatingPointTy())
return ConstantExpr::getFNeg(C);
- return 0;
+ return nullptr;
}
static Value *FoldOperationIntoSelectOperand(Instruction &I, Value *SO,
if (!ConstIsRHS)
std::swap(Op0, Op1);
- if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&I))
- return IC->Builder->CreateBinOp(BO->getOpcode(), Op0, Op1,
+ if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&I)) {
+ Value *RI = IC->Builder->CreateBinOp(BO->getOpcode(), Op0, Op1,
SO->getName()+".op");
+ Instruction *FPInst = dyn_cast<Instruction>(RI);
+ if (FPInst && isa<FPMathOperator>(FPInst))
+ FPInst->copyFastMathFlags(BO);
+ return RI;
+ }
if (ICmpInst *CI = dyn_cast<ICmpInst>(&I))
return IC->Builder->CreateICmp(CI->getPredicate(), Op0, Op1,
SO->getName()+".cmp");
// not have a second operand.
Instruction *InstCombiner::FoldOpIntoSelect(Instruction &Op, SelectInst *SI) {
// Don't modify shared select instructions
- if (!SI->hasOneUse()) return 0;
+ if (!SI->hasOneUse()) return nullptr;
Value *TV = SI->getOperand(1);
Value *FV = SI->getOperand(2);
if (isa<Constant>(TV) || isa<Constant>(FV)) {
// Bool selects with constant operands can be folded to logical ops.
- if (SI->getType()->isIntegerTy(1)) return 0;
+ if (SI->getType()->isIntegerTy(1)) return nullptr;
// If it's a bitcast involving vectors, make sure it has the same number of
// elements on both sides.
VectorType *SrcTy = dyn_cast<VectorType>(BC->getSrcTy());
// Verify that either both or neither are vectors.
- if ((SrcTy == NULL) != (DestTy == NULL)) return 0;
+ if ((SrcTy == nullptr) != (DestTy == nullptr)) return nullptr;
// If vectors, verify that they have the same number of elements.
if (SrcTy && SrcTy->getNumElements() != DestTy->getNumElements())
- return 0;
+ return nullptr;
}
Value *SelectTrueVal = FoldOperationIntoSelectOperand(Op, TV, this);
return SelectInst::Create(SI->getCondition(),
SelectTrueVal, SelectFalseVal);
}
- return 0;
+ return nullptr;
}
PHINode *PN = cast<PHINode>(I.getOperand(0));
unsigned NumPHIValues = PN->getNumIncomingValues();
if (NumPHIValues == 0)
- return 0;
+ return nullptr;
// We normally only transform phis with a single use. However, if a PHI has
// multiple uses and they are all the same operation, we can fold *all* of the
// uses into the PHI.
if (!PN->hasOneUse()) {
// Walk the use list for the instruction, comparing them to I.
- for (Value::use_iterator UI = PN->use_begin(), E = PN->use_end();
- UI != E; ++UI) {
- Instruction *User = cast<Instruction>(*UI);
- if (User != &I && !I.isIdenticalTo(User))
- return 0;
+ for (User *U : PN->users()) {
+ Instruction *UI = cast<Instruction>(U);
+ if (UI != &I && !I.isIdenticalTo(UI))
+ return nullptr;
}
// Otherwise, we can replace *all* users with the new PHI we form.
}
// remember the BB it is in. If there is more than one or if *it* is a PHI,
// bail out. We don't do arbitrary constant expressions here because moving
// their computation can be expensive without a cost model.
- BasicBlock *NonConstBB = 0;
+ BasicBlock *NonConstBB = nullptr;
for (unsigned i = 0; i != NumPHIValues; ++i) {
Value *InVal = PN->getIncomingValue(i);
if (isa<Constant>(InVal) && !isa<ConstantExpr>(InVal))
continue;
- if (isa<PHINode>(InVal)) return 0; // Itself a phi.
- if (NonConstBB) return 0; // More than one non-const value.
+ if (isa<PHINode>(InVal)) return nullptr; // Itself a phi.
+ if (NonConstBB) return nullptr; // More than one non-const value.
NonConstBB = PN->getIncomingBlock(i);
// insert a computation after it without breaking the edge.
if (InvokeInst *II = dyn_cast<InvokeInst>(InVal))
if (II->getParent() == NonConstBB)
- return 0;
+ return nullptr;
// If the incoming non-constant value is in I's block, we will remove one
// instruction, but insert another equivalent one, leading to infinite
// instcombine.
if (NonConstBB == I.getParent())
- return 0;
+ return nullptr;
}
// If there is exactly one non-constant value, we can insert a copy of the
// operation in that block. However, if this is a critical edge, we would be
// inserting the computation one some other paths (e.g. inside a loop). Only
// do this if the pred block is unconditionally branching into the phi block.
- if (NonConstBB != 0) {
+ if (NonConstBB != nullptr) {
BranchInst *BI = dyn_cast<BranchInst>(NonConstBB->getTerminator());
- if (!BI || !BI->isUnconditional()) return 0;
+ if (!BI || !BI->isUnconditional()) return nullptr;
}
// Okay, we can do the transformation: create the new PHI node.
BasicBlock *ThisBB = PN->getIncomingBlock(i);
Value *TrueVInPred = TrueV->DoPHITranslation(PhiTransBB, ThisBB);
Value *FalseVInPred = FalseV->DoPHITranslation(PhiTransBB, ThisBB);
- Value *InV = 0;
- if (Constant *InC = dyn_cast<Constant>(PN->getIncomingValue(i)))
+ Value *InV = nullptr;
+ // Beware of ConstantExpr: it may eventually evaluate to getNullValue,
+ // even if currently isNullValue gives false.
+ Constant *InC = dyn_cast<Constant>(PN->getIncomingValue(i));
+ if (InC && !isa<ConstantExpr>(InC))
InV = InC->isNullValue() ? FalseVInPred : TrueVInPred;
else
InV = Builder->CreateSelect(PN->getIncomingValue(i),
} else if (CmpInst *CI = dyn_cast<CmpInst>(&I)) {
Constant *C = cast<Constant>(I.getOperand(1));
for (unsigned i = 0; i != NumPHIValues; ++i) {
- Value *InV = 0;
+ Value *InV = nullptr;
if (Constant *InC = dyn_cast<Constant>(PN->getIncomingValue(i)))
InV = ConstantExpr::getCompare(CI->getPredicate(), InC, C);
else if (isa<ICmpInst>(CI))
} else if (I.getNumOperands() == 2) {
Constant *C = cast<Constant>(I.getOperand(1));
for (unsigned i = 0; i != NumPHIValues; ++i) {
- Value *InV = 0;
+ Value *InV = nullptr;
if (Constant *InC = dyn_cast<Constant>(PN->getIncomingValue(i)))
InV = ConstantExpr::get(I.getOpcode(), InC, C);
else
}
}
- for (Value::use_iterator UI = PN->use_begin(), E = PN->use_end();
- UI != E; ) {
+ for (auto UI = PN->user_begin(), E = PN->user_end(); UI != E;) {
Instruction *User = cast<Instruction>(*UI++);
if (User == &I) continue;
ReplaceInstUsesWith(*User, NewPN);
return ReplaceInstUsesWith(I, NewPN);
}
-/// FindElementAtOffset - Given a type and a constant offset, determine whether
-/// or not there is a sequence of GEP indices into the type that will land us at
-/// the specified offset. If so, fill them into NewIndices and return the
-/// resultant element type, otherwise return null.
-Type *InstCombiner::FindElementAtOffset(Type *Ty, int64_t Offset,
- SmallVectorImpl<Value*> &NewIndices) {
- if (!TD) return 0;
- if (!Ty->isSized()) return 0;
+/// FindElementAtOffset - Given a pointer type and a constant offset, determine
+/// whether or not there is a sequence of GEP indices into the pointed type that
+/// will land us at the specified offset. If so, fill them into NewIndices and
+/// return the resultant element type, otherwise return null.
+Type *InstCombiner::FindElementAtOffset(Type *PtrTy, int64_t Offset,
+ SmallVectorImpl<Value*> &NewIndices) {
+ assert(PtrTy->isPtrOrPtrVectorTy());
+
+ if (!DL)
+ return nullptr;
+
+ Type *Ty = PtrTy->getPointerElementType();
+ if (!Ty->isSized())
+ return nullptr;
// Start with the index over the outer type. Note that the type size
// might be zero (even if the offset isn't zero) if the indexed type
// is something like [0 x {int, int}]
- Type *IntPtrTy = TD->getIntPtrType(Ty->getContext());
+ Type *IntPtrTy = DL->getIntPtrType(PtrTy);
int64_t FirstIdx = 0;
- if (int64_t TySize = TD->getTypeAllocSize(Ty)) {
+ if (int64_t TySize = DL->getTypeAllocSize(Ty)) {
FirstIdx = Offset/TySize;
Offset -= FirstIdx*TySize;
// Index into the types. If we fail, set OrigBase to null.
while (Offset) {
// Indexing into tail padding between struct/array elements.
- if (uint64_t(Offset*8) >= TD->getTypeSizeInBits(Ty))
- return 0;
+ if (uint64_t(Offset*8) >= DL->getTypeSizeInBits(Ty))
+ return nullptr;
if (StructType *STy = dyn_cast<StructType>(Ty)) {
- const StructLayout *SL = TD->getStructLayout(STy);
+ const StructLayout *SL = DL->getStructLayout(STy);
assert(Offset < (int64_t)SL->getSizeInBytes() &&
"Offset must stay within the indexed type");
Offset -= SL->getElementOffset(Elt);
Ty = STy->getElementType(Elt);
} else if (ArrayType *AT = dyn_cast<ArrayType>(Ty)) {
- uint64_t EltSize = TD->getTypeAllocSize(AT->getElementType());
+ uint64_t EltSize = DL->getTypeAllocSize(AT->getElementType());
assert(EltSize && "Cannot index into a zero-sized array");
NewIndices.push_back(ConstantInt::get(IntPtrTy,Offset/EltSize));
Offset %= EltSize;
Ty = AT->getElementType();
} else {
// Otherwise, we can't index into the middle of this atomic type, bail.
- return 0;
+ return nullptr;
}
}
return true;
}
+/// Descale - Return a value X such that Val = X * Scale, or null if none. If
+/// the multiplication is known not to overflow then NoSignedWrap is set.
+Value *InstCombiner::Descale(Value *Val, APInt Scale, bool &NoSignedWrap) {
+ assert(isa<IntegerType>(Val->getType()) && "Can only descale integers!");
+ assert(cast<IntegerType>(Val->getType())->getBitWidth() ==
+ Scale.getBitWidth() && "Scale not compatible with value!");
+
+ // If Val is zero or Scale is one then Val = Val * Scale.
+ if (match(Val, m_Zero()) || Scale == 1) {
+ NoSignedWrap = true;
+ return Val;
+ }
+
+ // If Scale is zero then it does not divide Val.
+ if (Scale.isMinValue())
+ return nullptr;
+
+ // Look through chains of multiplications, searching for a constant that is
+ // divisible by Scale. For example, descaling X*(Y*(Z*4)) by a factor of 4
+ // will find the constant factor 4 and produce X*(Y*Z). Descaling X*(Y*8) by
+ // a factor of 4 will produce X*(Y*2). The principle of operation is to bore
+ // down from Val:
+ //
+ // Val = M1 * X || Analysis starts here and works down
+ // M1 = M2 * Y || Doesn't descend into terms with more
+ // M2 = Z * 4 \/ than one use
+ //
+ // Then to modify a term at the bottom:
+ //
+ // Val = M1 * X
+ // M1 = Z * Y || Replaced M2 with Z
+ //
+ // Then to work back up correcting nsw flags.
+
+ // Op - the term we are currently analyzing. Starts at Val then drills down.
+ // Replaced with its descaled value before exiting from the drill down loop.
+ Value *Op = Val;
+
+ // Parent - initially null, but after drilling down notes where Op came from.
+ // In the example above, Parent is (Val, 0) when Op is M1, because M1 is the
+ // 0'th operand of Val.
+ std::pair<Instruction*, unsigned> Parent;
+
+ // RequireNoSignedWrap - Set if the transform requires a descaling at deeper
+ // levels that doesn't overflow.
+ bool RequireNoSignedWrap = false;
+
+ // logScale - log base 2 of the scale. Negative if not a power of 2.
+ int32_t logScale = Scale.exactLogBase2();
+
+ for (;; Op = Parent.first->getOperand(Parent.second)) { // Drill down
+
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(Op)) {
+ // If Op is a constant divisible by Scale then descale to the quotient.
+ APInt Quotient(Scale), Remainder(Scale); // Init ensures right bitwidth.
+ APInt::sdivrem(CI->getValue(), Scale, Quotient, Remainder);
+ if (!Remainder.isMinValue())
+ // Not divisible by Scale.
+ return nullptr;
+ // Replace with the quotient in the parent.
+ Op = ConstantInt::get(CI->getType(), Quotient);
+ NoSignedWrap = true;
+ break;
+ }
+
+ if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Op)) {
+
+ if (BO->getOpcode() == Instruction::Mul) {
+ // Multiplication.
+ NoSignedWrap = BO->hasNoSignedWrap();
+ if (RequireNoSignedWrap && !NoSignedWrap)
+ return nullptr;
+
+ // There are three cases for multiplication: multiplication by exactly
+ // the scale, multiplication by a constant different to the scale, and
+ // multiplication by something else.
+ Value *LHS = BO->getOperand(0);
+ Value *RHS = BO->getOperand(1);
+
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
+ // Multiplication by a constant.
+ if (CI->getValue() == Scale) {
+ // Multiplication by exactly the scale, replace the multiplication
+ // by its left-hand side in the parent.
+ Op = LHS;
+ break;
+ }
+
+ // Otherwise drill down into the constant.
+ if (!Op->hasOneUse())
+ return nullptr;
+
+ Parent = std::make_pair(BO, 1);
+ continue;
+ }
+
+ // Multiplication by something else. Drill down into the left-hand side
+ // since that's where the reassociate pass puts the good stuff.
+ if (!Op->hasOneUse())
+ return nullptr;
+
+ Parent = std::make_pair(BO, 0);
+ continue;
+ }
+
+ if (logScale > 0 && BO->getOpcode() == Instruction::Shl &&
+ isa<ConstantInt>(BO->getOperand(1))) {
+ // Multiplication by a power of 2.
+ NoSignedWrap = BO->hasNoSignedWrap();
+ if (RequireNoSignedWrap && !NoSignedWrap)
+ return nullptr;
+
+ Value *LHS = BO->getOperand(0);
+ int32_t Amt = cast<ConstantInt>(BO->getOperand(1))->
+ getLimitedValue(Scale.getBitWidth());
+ // Op = LHS << Amt.
+
+ if (Amt == logScale) {
+ // Multiplication by exactly the scale, replace the multiplication
+ // by its left-hand side in the parent.
+ Op = LHS;
+ break;
+ }
+ if (Amt < logScale || !Op->hasOneUse())
+ return nullptr;
+
+ // Multiplication by more than the scale. Reduce the multiplying amount
+ // by the scale in the parent.
+ Parent = std::make_pair(BO, 1);
+ Op = ConstantInt::get(BO->getType(), Amt - logScale);
+ break;
+ }
+ }
+
+ if (!Op->hasOneUse())
+ return nullptr;
+
+ if (CastInst *Cast = dyn_cast<CastInst>(Op)) {
+ if (Cast->getOpcode() == Instruction::SExt) {
+ // Op is sign-extended from a smaller type, descale in the smaller type.
+ unsigned SmallSize = Cast->getSrcTy()->getPrimitiveSizeInBits();
+ APInt SmallScale = Scale.trunc(SmallSize);
+ // Suppose Op = sext X, and we descale X as Y * SmallScale. We want to
+ // descale Op as (sext Y) * Scale. In order to have
+ // sext (Y * SmallScale) = (sext Y) * Scale
+ // some conditions need to hold however: SmallScale must sign-extend to
+ // Scale and the multiplication Y * SmallScale should not overflow.
+ if (SmallScale.sext(Scale.getBitWidth()) != Scale)
+ // SmallScale does not sign-extend to Scale.
+ return nullptr;
+ assert(SmallScale.exactLogBase2() == logScale);
+ // Require that Y * SmallScale must not overflow.
+ RequireNoSignedWrap = true;
+
+ // Drill down through the cast.
+ Parent = std::make_pair(Cast, 0);
+ Scale = SmallScale;
+ continue;
+ }
+
+ if (Cast->getOpcode() == Instruction::Trunc) {
+ // Op is truncated from a larger type, descale in the larger type.
+ // Suppose Op = trunc X, and we descale X as Y * sext Scale. Then
+ // trunc (Y * sext Scale) = (trunc Y) * Scale
+ // always holds. However (trunc Y) * Scale may overflow even if
+ // trunc (Y * sext Scale) does not, so nsw flags need to be cleared
+ // from this point up in the expression (see later).
+ if (RequireNoSignedWrap)
+ return nullptr;
+
+ // Drill down through the cast.
+ unsigned LargeSize = Cast->getSrcTy()->getPrimitiveSizeInBits();
+ Parent = std::make_pair(Cast, 0);
+ Scale = Scale.sext(LargeSize);
+ if (logScale + 1 == (int32_t)Cast->getType()->getPrimitiveSizeInBits())
+ logScale = -1;
+ assert(Scale.exactLogBase2() == logScale);
+ continue;
+ }
+ }
+
+ // Unsupported expression, bail out.
+ return nullptr;
+ }
+
+ // If Op is zero then Val = Op * Scale.
+ if (match(Op, m_Zero())) {
+ NoSignedWrap = true;
+ return Op;
+ }
+
+ // We know that we can successfully descale, so from here on we can safely
+ // modify the IR. Op holds the descaled version of the deepest term in the
+ // expression. NoSignedWrap is 'true' if multiplying Op by Scale is known
+ // not to overflow.
+
+ if (!Parent.first)
+ // The expression only had one term.
+ return Op;
+
+ // Rewrite the parent using the descaled version of its operand.
+ assert(Parent.first->hasOneUse() && "Drilled down when more than one use!");
+ assert(Op != Parent.first->getOperand(Parent.second) &&
+ "Descaling was a no-op?");
+ Parent.first->setOperand(Parent.second, Op);
+ Worklist.Add(Parent.first);
+
+ // Now work back up the expression correcting nsw flags. The logic is based
+ // on the following observation: if X * Y is known not to overflow as a signed
+ // multiplication, and Y is replaced by a value Z with smaller absolute value,
+ // then X * Z will not overflow as a signed multiplication either. As we work
+ // our way up, having NoSignedWrap 'true' means that the descaled value at the
+ // current level has strictly smaller absolute value than the original.
+ Instruction *Ancestor = Parent.first;
+ do {
+ if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Ancestor)) {
+ // If the multiplication wasn't nsw then we can't say anything about the
+ // value of the descaled multiplication, and we have to clear nsw flags
+ // from this point on up.
+ bool OpNoSignedWrap = BO->hasNoSignedWrap();
+ NoSignedWrap &= OpNoSignedWrap;
+ if (NoSignedWrap != OpNoSignedWrap) {
+ BO->setHasNoSignedWrap(NoSignedWrap);
+ Worklist.Add(Ancestor);
+ }
+ } else if (Ancestor->getOpcode() == Instruction::Trunc) {
+ // The fact that the descaled input to the trunc has smaller absolute
+ // value than the original input doesn't tell us anything useful about
+ // the absolute values of the truncations.
+ NoSignedWrap = false;
+ }
+ assert((Ancestor->getOpcode() != Instruction::SExt || NoSignedWrap) &&
+ "Failed to keep proper track of nsw flags while drilling down?");
+
+ if (Ancestor == Val)
+ // Got to the top, all done!
+ return Val;
+
+ // Move up one level in the expression.
+ assert(Ancestor->hasOneUse() && "Drilled down when more than one use!");
+ Ancestor = Ancestor->user_back();
+ } while (1);
+}
+
+/// \brief Creates node of binary operation with the same attributes as the
+/// specified one but with other operands.
+static Value *CreateBinOpAsGiven(BinaryOperator &Inst, Value *LHS, Value *RHS,
+ InstCombiner::BuilderTy *B) {
+ Value *BORes = B->CreateBinOp(Inst.getOpcode(), LHS, RHS);
+ if (BinaryOperator *NewBO = dyn_cast<BinaryOperator>(BORes)) {
+ if (isa<OverflowingBinaryOperator>(NewBO)) {
+ NewBO->setHasNoSignedWrap(Inst.hasNoSignedWrap());
+ NewBO->setHasNoUnsignedWrap(Inst.hasNoUnsignedWrap());
+ }
+ if (isa<PossiblyExactOperator>(NewBO))
+ NewBO->setIsExact(Inst.isExact());
+ }
+ return BORes;
+}
+
+/// \brief Makes transformation of binary operation specific for vector types.
+/// \param Inst Binary operator to transform.
+/// \return Pointer to node that must replace the original binary operator, or
+/// null pointer if no transformation was made.
+Value *InstCombiner::SimplifyVectorOp(BinaryOperator &Inst) {
+ if (!Inst.getType()->isVectorTy()) return nullptr;
+
+ // It may not be safe to reorder shuffles and things like div, urem, etc.
+ // because we may trap when executing those ops on unknown vector elements.
+ // See PR20059.
+ if (!isSafeToSpeculativelyExecute(&Inst, DL)) return nullptr;
+
+ unsigned VWidth = cast<VectorType>(Inst.getType())->getNumElements();
+ Value *LHS = Inst.getOperand(0), *RHS = Inst.getOperand(1);
+ assert(cast<VectorType>(LHS->getType())->getNumElements() == VWidth);
+ assert(cast<VectorType>(RHS->getType())->getNumElements() == VWidth);
+
+ // If both arguments of binary operation are shuffles, which use the same
+ // mask and shuffle within a single vector, it is worthwhile to move the
+ // shuffle after binary operation:
+ // Op(shuffle(v1, m), shuffle(v2, m)) -> shuffle(Op(v1, v2), m)
+ if (isa<ShuffleVectorInst>(LHS) && isa<ShuffleVectorInst>(RHS)) {
+ ShuffleVectorInst *LShuf = cast<ShuffleVectorInst>(LHS);
+ ShuffleVectorInst *RShuf = cast<ShuffleVectorInst>(RHS);
+ if (isa<UndefValue>(LShuf->getOperand(1)) &&
+ isa<UndefValue>(RShuf->getOperand(1)) &&
+ LShuf->getOperand(0)->getType() == RShuf->getOperand(0)->getType() &&
+ LShuf->getMask() == RShuf->getMask()) {
+ Value *NewBO = CreateBinOpAsGiven(Inst, LShuf->getOperand(0),
+ RShuf->getOperand(0), Builder);
+ Value *Res = Builder->CreateShuffleVector(NewBO,
+ UndefValue::get(NewBO->getType()), LShuf->getMask());
+ return Res;
+ }
+ }
+
+ // If one argument is a shuffle within one vector, the other is a constant,
+ // try moving the shuffle after the binary operation.
+ ShuffleVectorInst *Shuffle = nullptr;
+ Constant *C1 = nullptr;
+ if (isa<ShuffleVectorInst>(LHS)) Shuffle = cast<ShuffleVectorInst>(LHS);
+ if (isa<ShuffleVectorInst>(RHS)) Shuffle = cast<ShuffleVectorInst>(RHS);
+ if (isa<Constant>(LHS)) C1 = cast<Constant>(LHS);
+ if (isa<Constant>(RHS)) C1 = cast<Constant>(RHS);
+ if (Shuffle && C1 &&
+ (isa<ConstantVector>(C1) || isa<ConstantDataVector>(C1)) &&
+ isa<UndefValue>(Shuffle->getOperand(1)) &&
+ Shuffle->getType() == Shuffle->getOperand(0)->getType()) {
+ SmallVector<int, 16> ShMask = Shuffle->getShuffleMask();
+ // Find constant C2 that has property:
+ // shuffle(C2, ShMask) = C1
+ // If such constant does not exist (example: ShMask=<0,0> and C1=<1,2>)
+ // reorder is not possible.
+ SmallVector<Constant*, 16> C2M(VWidth,
+ UndefValue::get(C1->getType()->getScalarType()));
+ bool MayChange = true;
+ for (unsigned I = 0; I < VWidth; ++I) {
+ if (ShMask[I] >= 0) {
+ assert(ShMask[I] < (int)VWidth);
+ if (!isa<UndefValue>(C2M[ShMask[I]])) {
+ MayChange = false;
+ break;
+ }
+ C2M[ShMask[I]] = C1->getAggregateElement(I);
+ }
+ }
+ if (MayChange) {
+ Constant *C2 = ConstantVector::get(C2M);
+ Value *NewLHS, *NewRHS;
+ if (isa<Constant>(LHS)) {
+ NewLHS = C2;
+ NewRHS = Shuffle->getOperand(0);
+ } else {
+ NewLHS = Shuffle->getOperand(0);
+ NewRHS = C2;
+ }
+ Value *NewBO = CreateBinOpAsGiven(Inst, NewLHS, NewRHS, Builder);
+ Value *Res = Builder->CreateShuffleVector(NewBO,
+ UndefValue::get(Inst.getType()), Shuffle->getMask());
+ return Res;
+ }
+ }
+
+ return nullptr;
+}
+
Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
SmallVector<Value*, 8> Ops(GEP.op_begin(), GEP.op_end());
- if (Value *V = SimplifyGEPInst(Ops, TD))
+ if (Value *V = SimplifyGEPInst(Ops, DL, TLI, DT, AT))
return ReplaceInstUsesWith(GEP, V);
Value *PtrOp = GEP.getOperand(0);
// Eliminate unneeded casts for indices, and replace indices which displace
// by multiples of a zero size type with zero.
- if (TD) {
+ if (DL) {
bool MadeChange = false;
- Type *IntPtrTy = TD->getIntPtrType(GEP.getContext());
+ Type *IntPtrTy = DL->getIntPtrType(GEP.getPointerOperandType());
gep_type_iterator GTI = gep_type_begin(GEP);
for (User::op_iterator I = GEP.op_begin() + 1, E = GEP.op_end();
// If the element type has zero size then any index over it is equivalent
// to an index of zero, so replace it with zero if it is not zero already.
if (SeqTy->getElementType()->isSized() &&
- TD->getTypeAllocSize(SeqTy->getElementType()) == 0)
+ DL->getTypeAllocSize(SeqTy->getElementType()) == 0)
if (!isa<Constant>(*I) || !cast<Constant>(*I)->isNullValue()) {
*I = Constant::getNullValue(IntPtrTy);
MadeChange = true;
}
Type *IndexTy = (*I)->getType();
- if (IndexTy != IntPtrTy && !IndexTy->isVectorTy()) {
+ if (IndexTy != IntPtrTy) {
// If we are using a wider index than needed for this platform, shrink
// it to what we need. If narrower, sign-extend it to what we need.
// This explicit cast can make subsequent optimizations more obvious.
if (MadeChange) return &GEP;
}
+ // Check to see if the inputs to the PHI node are getelementptr instructions.
+ if (PHINode *PN = dyn_cast<PHINode>(PtrOp)) {
+ GetElementPtrInst *Op1 = dyn_cast<GetElementPtrInst>(PN->getOperand(0));
+ if (!Op1)
+ return nullptr;
+
+ signed DI = -1;
+
+ for (auto I = PN->op_begin()+1, E = PN->op_end(); I !=E; ++I) {
+ GetElementPtrInst *Op2 = dyn_cast<GetElementPtrInst>(*I);
+ if (!Op2 || Op1->getNumOperands() != Op2->getNumOperands())
+ return nullptr;
+
+ // Keep track of the type as we walk the GEP.
+ Type *CurTy = Op1->getOperand(0)->getType()->getScalarType();
+
+ for (unsigned J = 0, F = Op1->getNumOperands(); J != F; ++J) {
+ if (Op1->getOperand(J)->getType() != Op2->getOperand(J)->getType())
+ return nullptr;
+
+ if (Op1->getOperand(J) != Op2->getOperand(J)) {
+ if (DI == -1) {
+ // We have not seen any differences yet in the GEPs feeding the
+ // PHI yet, so we record this one if it is allowed to be a
+ // variable.
+
+ // The first two arguments can vary for any GEP, the rest have to be
+ // static for struct slots
+ if (J > 1 && CurTy->isStructTy())
+ return nullptr;
+
+ DI = J;
+ } else {
+ // The GEP is different by more than one input. While this could be
+ // extended to support GEPs that vary by more than one variable it
+ // doesn't make sense since it greatly increases the complexity and
+ // would result in an R+R+R addressing mode which no backend
+ // directly supports and would need to be broken into several
+ // simpler instructions anyway.
+ return nullptr;
+ }
+ }
+
+ // Sink down a layer of the type for the next iteration.
+ if (J > 0) {
+ if (CompositeType *CT = dyn_cast<CompositeType>(CurTy)) {
+ CurTy = CT->getTypeAtIndex(Op1->getOperand(J));
+ } else {
+ CurTy = nullptr;
+ }
+ }
+ }
+ }
+
+ GetElementPtrInst *NewGEP = cast<GetElementPtrInst>(Op1->clone());
+
+ if (DI == -1) {
+ // All the GEPs feeding the PHI are identical. Clone one down into our
+ // BB so that it can be merged with the current GEP.
+ GEP.getParent()->getInstList().insert(GEP.getParent()->getFirstNonPHI(),
+ NewGEP);
+ } else {
+ // All the GEPs feeding the PHI differ at a single offset. Clone a GEP
+ // into the current block so it can be merged, and create a new PHI to
+ // set that index.
+ Instruction *InsertPt = Builder->GetInsertPoint();
+ Builder->SetInsertPoint(PN);
+ PHINode *NewPN = Builder->CreatePHI(Op1->getOperand(DI)->getType(),
+ PN->getNumOperands());
+ Builder->SetInsertPoint(InsertPt);
+
+ for (auto &I : PN->operands())
+ NewPN->addIncoming(cast<GEPOperator>(I)->getOperand(DI),
+ PN->getIncomingBlock(I));
+
+ NewGEP->setOperand(DI, NewPN);
+ GEP.getParent()->getInstList().insert(GEP.getParent()->getFirstNonPHI(),
+ NewGEP);
+ NewGEP->setOperand(DI, NewPN);
+ }
+
+ GEP.setOperand(0, NewGEP);
+ PtrOp = NewGEP;
+ }
+
// Combine Indices - If the source pointer to this getelementptr instruction
// is a getelementptr instruction, combine the indices of the two
// getelementptr instructions into a single instruction.
//
if (GEPOperator *Src = dyn_cast<GEPOperator>(PtrOp)) {
if (!shouldMergeGEPs(*cast<GEPOperator>(&GEP), *Src))
- return 0;
+ return nullptr;
- // Note that if our source is a gep chain itself that we wait for that
+ // Note that if our source is a gep chain itself then we wait for that
// chain to be resolved before we perform this transformation. This
// avoids us creating a TON of code in some cases.
if (GEPOperator *SrcGEP =
dyn_cast<GEPOperator>(Src->getOperand(0)))
if (SrcGEP->getNumOperands() == 2 && shouldMergeGEPs(*Src, *SrcGEP))
- return 0; // Wait until our source is folded to completion.
+ return nullptr; // Wait until our source is folded to completion.
SmallVector<Value*, 8> Indices;
// intptr_t). Just avoid transforming this until the input has been
// normalized.
if (SO1->getType() != GO1->getType())
- return 0;
+ return nullptr;
Sum = Builder->CreateAdd(SO1, GO1, PtrOp->getName()+".sum");
}
GetElementPtrInst::Create(Src->getOperand(0), Indices, GEP.getName());
}
+ if (DL && GEP.getNumIndices() == 1) {
+ unsigned AS = GEP.getPointerAddressSpace();
+ if (GEP.getOperand(1)->getType()->getScalarSizeInBits() ==
+ DL->getPointerSizeInBits(AS)) {
+ Type *PtrTy = GEP.getPointerOperandType();
+ Type *Ty = PtrTy->getPointerElementType();
+ uint64_t TyAllocSize = DL->getTypeAllocSize(Ty);
+
+ bool Matched = false;
+ uint64_t C;
+ Value *V = nullptr;
+ if (TyAllocSize == 1) {
+ V = GEP.getOperand(1);
+ Matched = true;
+ } else if (match(GEP.getOperand(1),
+ m_AShr(m_Value(V), m_ConstantInt(C)))) {
+ if (TyAllocSize == 1ULL << C)
+ Matched = true;
+ } else if (match(GEP.getOperand(1),
+ m_SDiv(m_Value(V), m_ConstantInt(C)))) {
+ if (TyAllocSize == C)
+ Matched = true;
+ }
+
+ if (Matched) {
+ // Canonicalize (gep i8* X, -(ptrtoint Y))
+ // to (inttoptr (sub (ptrtoint X), (ptrtoint Y)))
+ // The GEP pattern is emitted by the SCEV expander for certain kinds of
+ // pointer arithmetic.
+ if (match(V, m_Neg(m_PtrToInt(m_Value())))) {
+ Operator *Index = cast<Operator>(V);
+ Value *PtrToInt = Builder->CreatePtrToInt(PtrOp, Index->getType());
+ Value *NewSub = Builder->CreateSub(PtrToInt, Index->getOperand(1));
+ return CastInst::Create(Instruction::IntToPtr, NewSub, GEP.getType());
+ }
+ // Canonicalize (gep i8* X, (ptrtoint Y)-(ptrtoint X))
+ // to (bitcast Y)
+ Value *Y;
+ if (match(V, m_Sub(m_PtrToInt(m_Value(Y)),
+ m_PtrToInt(m_Specific(GEP.getOperand(0)))))) {
+ return CastInst::CreatePointerBitCastOrAddrSpaceCast(Y,
+ GEP.getType());
+ }
+ }
+ }
+ }
+
// Handle gep(bitcast x) and gep(gep x, 0, 0, 0).
Value *StrippedPtr = PtrOp->stripPointerCasts();
PointerType *StrippedPtrTy = dyn_cast<PointerType>(StrippedPtr->getType());
// We do not handle pointer-vector geps here.
if (!StrippedPtrTy)
- return 0;
-
- if (StrippedPtr != PtrOp &&
- StrippedPtrTy->getAddressSpace() == GEP.getPointerAddressSpace()) {
+ return nullptr;
+ if (StrippedPtr != PtrOp) {
bool HasZeroPointerIndex = false;
if (ConstantInt *C = dyn_cast<ConstantInt>(GEP.getOperand(1)))
HasZeroPointerIndex = C->isZero();
GetElementPtrInst *Res =
GetElementPtrInst::Create(StrippedPtr, Idx, GEP.getName());
Res->setIsInBounds(GEP.isInBounds());
- return Res;
+ if (StrippedPtrTy->getAddressSpace() == GEP.getAddressSpace())
+ return Res;
+ // Insert Res, and create an addrspacecast.
+ // e.g.,
+ // GEP (addrspacecast i8 addrspace(1)* X to [0 x i8]*), i32 0, ...
+ // ->
+ // %0 = GEP i8 addrspace(1)* X, ...
+ // addrspacecast i8 addrspace(1)* %0 to i8*
+ return new AddrSpaceCastInst(Builder->Insert(Res), GEP.getType());
}
if (ArrayType *XATy =
// to an array of the same type as the destination pointer
// array. Because the array type is never stepped over (there
// is a leading zero) we can fold the cast into this GEP.
- GEP.setOperand(0, StrippedPtr);
- return &GEP;
+ if (StrippedPtrTy->getAddressSpace() == GEP.getAddressSpace()) {
+ GEP.setOperand(0, StrippedPtr);
+ return &GEP;
+ }
+ // Cannot replace the base pointer directly because StrippedPtr's
+ // address space is different. Instead, create a new GEP followed by
+ // an addrspacecast.
+ // e.g.,
+ // GEP (addrspacecast [10 x i8] addrspace(1)* X to [0 x i8]*),
+ // i32 0, ...
+ // ->
+ // %0 = GEP [10 x i8] addrspace(1)* X, ...
+ // addrspacecast i8 addrspace(1)* %0 to i8*
+ SmallVector<Value*, 8> Idx(GEP.idx_begin(), GEP.idx_end());
+ Value *NewGEP = GEP.isInBounds() ?
+ Builder->CreateInBoundsGEP(StrippedPtr, Idx, GEP.getName()) :
+ Builder->CreateGEP(StrippedPtr, Idx, GEP.getName());
+ return new AddrSpaceCastInst(NewGEP, GEP.getType());
}
}
}
// %t = getelementptr i32* bitcast ([2 x i32]* %str to i32*), i32 %V
// into: %t1 = getelementptr [2 x i32]* %str, i32 0, i32 %V; bitcast
Type *SrcElTy = StrippedPtrTy->getElementType();
- Type *ResElTy=cast<PointerType>(PtrOp->getType())->getElementType();
- if (TD && SrcElTy->isArrayTy() &&
- TD->getTypeAllocSize(cast<ArrayType>(SrcElTy)->getElementType()) ==
- TD->getTypeAllocSize(ResElTy)) {
- Value *Idx[2];
- Idx[0] = Constant::getNullValue(Type::getInt32Ty(GEP.getContext()));
- Idx[1] = GEP.getOperand(1);
+ Type *ResElTy = PtrOp->getType()->getPointerElementType();
+ if (DL && SrcElTy->isArrayTy() &&
+ DL->getTypeAllocSize(SrcElTy->getArrayElementType()) ==
+ DL->getTypeAllocSize(ResElTy)) {
+ Type *IdxType = DL->getIntPtrType(GEP.getType());
+ Value *Idx[2] = { Constant::getNullValue(IdxType), GEP.getOperand(1) };
Value *NewGEP = GEP.isInBounds() ?
Builder->CreateInBoundsGEP(StrippedPtr, Idx, GEP.getName()) :
Builder->CreateGEP(StrippedPtr, Idx, GEP.getName());
+
// V and GEP are both pointer types --> BitCast
- return new BitCastInst(NewGEP, GEP.getType());
+ return CastInst::CreatePointerBitCastOrAddrSpaceCast(NewGEP,
+ GEP.getType());
}
// Transform things like:
- // getelementptr i8* bitcast ([100 x double]* X to i8*), i32 %tmp
- // (where tmp = 8*tmp2) into:
- // getelementptr [100 x double]* %arr, i32 0, i32 %tmp2; bitcast
-
- if (TD && SrcElTy->isArrayTy() && ResElTy->isIntegerTy(8)) {
- uint64_t ArrayEltSize =
- TD->getTypeAllocSize(cast<ArrayType>(SrcElTy)->getElementType());
-
- // Check to see if "tmp" is a scale by a multiple of ArrayEltSize. We
- // allow either a mul, shift, or constant here.
- Value *NewIdx = 0;
- ConstantInt *Scale = 0;
- if (ArrayEltSize == 1) {
- NewIdx = GEP.getOperand(1);
- Scale = ConstantInt::get(cast<IntegerType>(NewIdx->getType()), 1);
- } else if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP.getOperand(1))) {
- NewIdx = ConstantInt::get(CI->getType(), 1);
- Scale = CI;
- } else if (Instruction *Inst =dyn_cast<Instruction>(GEP.getOperand(1))){
- if (Inst->getOpcode() == Instruction::Shl &&
- isa<ConstantInt>(Inst->getOperand(1))) {
- ConstantInt *ShAmt = cast<ConstantInt>(Inst->getOperand(1));
- uint32_t ShAmtVal = ShAmt->getLimitedValue(64);
- Scale = ConstantInt::get(cast<IntegerType>(Inst->getType()),
- 1ULL << ShAmtVal);
- NewIdx = Inst->getOperand(0);
- } else if (Inst->getOpcode() == Instruction::Mul &&
- isa<ConstantInt>(Inst->getOperand(1))) {
- Scale = cast<ConstantInt>(Inst->getOperand(1));
- NewIdx = Inst->getOperand(0);
+ // %V = mul i64 %N, 4
+ // %t = getelementptr i8* bitcast (i32* %arr to i8*), i32 %V
+ // into: %t1 = getelementptr i32* %arr, i32 %N; bitcast
+ if (DL && ResElTy->isSized() && SrcElTy->isSized()) {
+ // Check that changing the type amounts to dividing the index by a scale
+ // factor.
+ uint64_t ResSize = DL->getTypeAllocSize(ResElTy);
+ uint64_t SrcSize = DL->getTypeAllocSize(SrcElTy);
+ if (ResSize && SrcSize % ResSize == 0) {
+ Value *Idx = GEP.getOperand(1);
+ unsigned BitWidth = Idx->getType()->getPrimitiveSizeInBits();
+ uint64_t Scale = SrcSize / ResSize;
+
+ // Earlier transforms ensure that the index has type IntPtrType, which
+ // considerably simplifies the logic by eliminating implicit casts.
+ assert(Idx->getType() == DL->getIntPtrType(GEP.getType()) &&
+ "Index not cast to pointer width?");
+
+ bool NSW;
+ if (Value *NewIdx = Descale(Idx, APInt(BitWidth, Scale), NSW)) {
+ // Successfully decomposed Idx as NewIdx * Scale, form a new GEP.
+ // If the multiplication NewIdx * Scale may overflow then the new
+ // GEP may not be "inbounds".
+ Value *NewGEP = GEP.isInBounds() && NSW ?
+ Builder->CreateInBoundsGEP(StrippedPtr, NewIdx, GEP.getName()) :
+ Builder->CreateGEP(StrippedPtr, NewIdx, GEP.getName());
+
+ // The NewGEP must be pointer typed, so must the old one -> BitCast
+ return CastInst::CreatePointerBitCastOrAddrSpaceCast(NewGEP,
+ GEP.getType());
}
}
+ }
- // If the index will be to exactly the right offset with the scale taken
- // out, perform the transformation. Note, we don't know whether Scale is
- // signed or not. We'll use unsigned version of division/modulo
- // operation after making sure Scale doesn't have the sign bit set.
- if (ArrayEltSize && Scale && Scale->getSExtValue() >= 0LL &&
- Scale->getZExtValue() % ArrayEltSize == 0) {
- Scale = ConstantInt::get(Scale->getType(),
- Scale->getZExtValue() / ArrayEltSize);
- if (Scale->getZExtValue() != 1) {
- Constant *C = ConstantExpr::getIntegerCast(Scale, NewIdx->getType(),
- false /*ZExt*/);
- NewIdx = Builder->CreateMul(NewIdx, C, "idxscale");
+ // Similarly, transform things like:
+ // getelementptr i8* bitcast ([100 x double]* X to i8*), i32 %tmp
+ // (where tmp = 8*tmp2) into:
+ // getelementptr [100 x double]* %arr, i32 0, i32 %tmp2; bitcast
+ if (DL && ResElTy->isSized() && SrcElTy->isSized() &&
+ SrcElTy->isArrayTy()) {
+ // Check that changing to the array element type amounts to dividing the
+ // index by a scale factor.
+ uint64_t ResSize = DL->getTypeAllocSize(ResElTy);
+ uint64_t ArrayEltSize
+ = DL->getTypeAllocSize(SrcElTy->getArrayElementType());
+ if (ResSize && ArrayEltSize % ResSize == 0) {
+ Value *Idx = GEP.getOperand(1);
+ unsigned BitWidth = Idx->getType()->getPrimitiveSizeInBits();
+ uint64_t Scale = ArrayEltSize / ResSize;
+
+ // Earlier transforms ensure that the index has type IntPtrType, which
+ // considerably simplifies the logic by eliminating implicit casts.
+ assert(Idx->getType() == DL->getIntPtrType(GEP.getType()) &&
+ "Index not cast to pointer width?");
+
+ bool NSW;
+ if (Value *NewIdx = Descale(Idx, APInt(BitWidth, Scale), NSW)) {
+ // Successfully decomposed Idx as NewIdx * Scale, form a new GEP.
+ // If the multiplication NewIdx * Scale may overflow then the new
+ // GEP may not be "inbounds".
+ Value *Off[2] = {
+ Constant::getNullValue(DL->getIntPtrType(GEP.getType())),
+ NewIdx
+ };
+
+ Value *NewGEP = GEP.isInBounds() && NSW ?
+ Builder->CreateInBoundsGEP(StrippedPtr, Off, GEP.getName()) :
+ Builder->CreateGEP(StrippedPtr, Off, GEP.getName());
+ // The NewGEP must be pointer typed, so must the old one -> BitCast
+ return CastInst::CreatePointerBitCastOrAddrSpaceCast(NewGEP,
+ GEP.getType());
}
-
- // Insert the new GEP instruction.
- Value *Idx[2];
- Idx[0] = Constant::getNullValue(Type::getInt32Ty(GEP.getContext()));
- Idx[1] = NewIdx;
- Value *NewGEP = GEP.isInBounds() ?
- Builder->CreateInBoundsGEP(StrippedPtr, Idx, GEP.getName()):
- Builder->CreateGEP(StrippedPtr, Idx, GEP.getName());
- // The NewGEP must be pointer typed, so must the old one -> BitCast
- return new BitCastInst(NewGEP, GEP.getType());
}
}
}
}
+ if (!DL)
+ return nullptr;
+
+ // addrspacecast between types is canonicalized as a bitcast, then an
+ // addrspacecast. To take advantage of the below bitcast + struct GEP, look
+ // through the addrspacecast.
+ if (AddrSpaceCastInst *ASC = dyn_cast<AddrSpaceCastInst>(PtrOp)) {
+ // X = bitcast A addrspace(1)* to B addrspace(1)*
+ // Y = addrspacecast A addrspace(1)* to B addrspace(2)*
+ // Z = gep Y, <...constant indices...>
+ // Into an addrspacecasted GEP of the struct.
+ if (BitCastInst *BC = dyn_cast<BitCastInst>(ASC->getOperand(0)))
+ PtrOp = BC;
+ }
+
/// See if we can simplify:
/// X = bitcast A* to B*
/// Y = gep X, <...constant indices...>
/// into a gep of the original struct. This is important for SROA and alias
/// analysis of unions. If "A" is also a bitcast, wait for A/X to be merged.
if (BitCastInst *BCI = dyn_cast<BitCastInst>(PtrOp)) {
- if (TD &&
- !isa<BitCastInst>(BCI->getOperand(0)) && GEP.hasAllConstantIndices() &&
- StrippedPtrTy->getAddressSpace() == GEP.getPointerAddressSpace()) {
-
- // Determine how much the GEP moves the pointer.
- SmallVector<Value*, 8> Ops(GEP.idx_begin(), GEP.idx_end());
- int64_t Offset = TD->getIndexedOffset(GEP.getPointerOperandType(), Ops);
+ Value *Operand = BCI->getOperand(0);
+ PointerType *OpType = cast<PointerType>(Operand->getType());
+ unsigned OffsetBits = DL->getPointerTypeSizeInBits(GEP.getType());
+ APInt Offset(OffsetBits, 0);
+ if (!isa<BitCastInst>(Operand) &&
+ GEP.accumulateConstantOffset(*DL, Offset)) {
// If this GEP instruction doesn't move the pointer, just replace the GEP
// with a bitcast of the real input to the dest type.
- if (Offset == 0) {
+ if (!Offset) {
// If the bitcast is of an allocation, and the allocation will be
// converted to match the type of the cast, don't touch this.
- if (isa<AllocaInst>(BCI->getOperand(0)) ||
- isAllocationFn(BCI->getOperand(0))) {
+ if (isa<AllocaInst>(Operand) || isAllocationFn(Operand, TLI)) {
// See if the bitcast simplifies, if so, don't nuke this GEP yet.
if (Instruction *I = visitBitCast(*BCI)) {
if (I != BCI) {
return &GEP;
}
}
- return new BitCastInst(BCI->getOperand(0), GEP.getType());
+
+ if (Operand->getType()->getPointerAddressSpace() != GEP.getAddressSpace())
+ return new AddrSpaceCastInst(Operand, GEP.getType());
+ return new BitCastInst(Operand, GEP.getType());
}
// Otherwise, if the offset is non-zero, we need to find out if there is a
// field at Offset in 'A's type. If so, we can pull the cast through the
// GEP.
SmallVector<Value*, 8> NewIndices;
- Type *InTy =
- cast<PointerType>(BCI->getOperand(0)->getType())->getElementType();
- if (FindElementAtOffset(InTy, Offset, NewIndices)) {
+ if (FindElementAtOffset(OpType, Offset.getSExtValue(), NewIndices)) {
Value *NGEP = GEP.isInBounds() ?
- Builder->CreateInBoundsGEP(BCI->getOperand(0), NewIndices) :
- Builder->CreateGEP(BCI->getOperand(0), NewIndices);
+ Builder->CreateInBoundsGEP(Operand, NewIndices) :
+ Builder->CreateGEP(Operand, NewIndices);
if (NGEP->getType() == GEP.getType())
return ReplaceInstUsesWith(GEP, NGEP);
NGEP->takeName(&GEP);
+
+ if (NGEP->getType()->getPointerAddressSpace() != GEP.getAddressSpace())
+ return new AddrSpaceCastInst(NGEP, GEP.getType());
return new BitCastInst(NGEP, GEP.getType());
}
}
}
- return 0;
+ return nullptr;
}
-
-
static bool
-isAllocSiteRemovable(Instruction *AI, SmallVectorImpl<WeakVH> &Users) {
+isAllocSiteRemovable(Instruction *AI, SmallVectorImpl<WeakVH> &Users,
+ const TargetLibraryInfo *TLI) {
SmallVector<Instruction*, 4> Worklist;
Worklist.push_back(AI);
do {
Instruction *PI = Worklist.pop_back_val();
- for (Value::use_iterator UI = PI->use_begin(), UE = PI->use_end(); UI != UE;
- ++UI) {
- Instruction *I = cast<Instruction>(*UI);
+ for (User *U : PI->users()) {
+ Instruction *I = cast<Instruction>(U);
switch (I->getOpcode()) {
default:
// Give up the moment we see something we can't handle.
}
}
- if (isFreeCall(I)) {
+ if (isFreeCall(I, TLI)) {
Users.push_back(I);
continue;
}
// to null and free calls, delete the calls and replace the comparisons with
// true or false as appropriate.
SmallVector<WeakVH, 64> Users;
- if (isAllocSiteRemovable(&MI, Users)) {
+ if (isAllocSiteRemovable(&MI, Users, TLI)) {
for (unsigned i = 0, e = Users.size(); i != e; ++i) {
Instruction *I = cast_or_null<Instruction>(&*Users[i]);
if (!I) continue;
Module *M = II->getParent()->getParent()->getParent();
Function *F = Intrinsic::getDeclaration(M, Intrinsic::donothing);
InvokeInst::Create(F, II->getNormalDest(), II->getUnwindDest(),
- ArrayRef<Value *>(), "", II->getParent());
+ None, "", II->getParent());
}
return EraseInstFromFunction(MI);
}
- return 0;
+ return nullptr;
}
+/// \brief Move the call to free before a NULL test.
+///
+/// Check if this free is accessed after its argument has been test
+/// against NULL (property 0).
+/// If yes, it is legal to move this call in its predecessor block.
+///
+/// The move is performed only if the block containing the call to free
+/// will be removed, i.e.:
+/// 1. it has only one predecessor P, and P has two successors
+/// 2. it contains the call and an unconditional branch
+/// 3. its successor is the same as its predecessor's successor
+///
+/// The profitability is out-of concern here and this function should
+/// be called only if the caller knows this transformation would be
+/// profitable (e.g., for code size).
+static Instruction *
+tryToMoveFreeBeforeNullTest(CallInst &FI) {
+ Value *Op = FI.getArgOperand(0);
+ BasicBlock *FreeInstrBB = FI.getParent();
+ BasicBlock *PredBB = FreeInstrBB->getSinglePredecessor();
+
+ // Validate part of constraint #1: Only one predecessor
+ // FIXME: We can extend the number of predecessor, but in that case, we
+ // would duplicate the call to free in each predecessor and it may
+ // not be profitable even for code size.
+ if (!PredBB)
+ return nullptr;
+
+ // Validate constraint #2: Does this block contains only the call to
+ // free and an unconditional branch?
+ // FIXME: We could check if we can speculate everything in the
+ // predecessor block
+ if (FreeInstrBB->size() != 2)
+ return nullptr;
+ BasicBlock *SuccBB;
+ if (!match(FreeInstrBB->getTerminator(), m_UnconditionalBr(SuccBB)))
+ return nullptr;
+
+ // Validate the rest of constraint #1 by matching on the pred branch.
+ TerminatorInst *TI = PredBB->getTerminator();
+ BasicBlock *TrueBB, *FalseBB;
+ ICmpInst::Predicate Pred;
+ if (!match(TI, m_Br(m_ICmp(Pred, m_Specific(Op), m_Zero()), TrueBB, FalseBB)))
+ return nullptr;
+ if (Pred != ICmpInst::ICMP_EQ && Pred != ICmpInst::ICMP_NE)
+ return nullptr;
+
+ // Validate constraint #3: Ensure the null case just falls through.
+ if (SuccBB != (Pred == ICmpInst::ICMP_EQ ? TrueBB : FalseBB))
+ return nullptr;
+ assert(FreeInstrBB == (Pred == ICmpInst::ICMP_EQ ? FalseBB : TrueBB) &&
+ "Broken CFG: missing edge from predecessor to successor");
+
+ FI.moveBefore(TI);
+ return &FI;
+}
Instruction *InstCombiner::visitFree(CallInst &FI) {
if (isa<ConstantPointerNull>(Op))
return EraseInstFromFunction(FI);
- return 0;
+ // If we optimize for code size, try to move the call to free before the null
+ // test so that simplify cfg can remove the empty block and dead code
+ // elimination the branch. I.e., helps to turn something like:
+ // if (foo) free(foo);
+ // into
+ // free(foo);
+ if (MinimizeSize)
+ if (Instruction *I = tryToMoveFreeBeforeNullTest(FI))
+ return I;
+
+ return nullptr;
}
+Instruction *InstCombiner::visitReturnInst(ReturnInst &RI) {
+ if (RI.getNumOperands() == 0) // ret void
+ return nullptr;
+
+ Value *ResultOp = RI.getOperand(0);
+ Type *VTy = ResultOp->getType();
+ if (!VTy->isIntegerTy())
+ return nullptr;
+ // There might be assume intrinsics dominating this return that completely
+ // determine the value. If so, constant fold it.
+ unsigned BitWidth = VTy->getPrimitiveSizeInBits();
+ APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
+ computeKnownBits(ResultOp, KnownZero, KnownOne, 0, &RI);
+ if ((KnownZero|KnownOne).isAllOnesValue())
+ RI.setOperand(0, Constant::getIntegerValue(VTy, KnownOne));
+
+ return nullptr;
+}
Instruction *InstCombiner::visitBranchInst(BranchInst &BI) {
// Change br (not X), label True, label False to: br X, label False, True
- Value *X = 0;
+ Value *X = nullptr;
BasicBlock *TrueDest;
BasicBlock *FalseDest;
if (match(&BI, m_Br(m_Not(m_Value(X)), TrueDest, FalseDest)) &&
return &BI;
}
- // Cannonicalize fcmp_one -> fcmp_oeq
+ // Canonicalize fcmp_one -> fcmp_oeq
FCmpInst::Predicate FPred; Value *Y;
if (match(&BI, m_Br(m_FCmp(FPred, m_Value(X), m_Value(Y)),
TrueDest, FalseDest)) &&
return &BI;
}
- // Cannonicalize icmp_ne -> icmp_eq
+ // Canonicalize icmp_ne -> icmp_eq
ICmpInst::Predicate IPred;
if (match(&BI, m_Br(m_ICmp(IPred, m_Value(X), m_Value(Y)),
TrueDest, FalseDest)) &&
return &BI;
}
- return 0;
+ return nullptr;
}
Instruction *InstCombiner::visitSwitchInst(SwitchInst &SI) {
Value *Cond = SI.getCondition();
+ unsigned BitWidth = cast<IntegerType>(Cond->getType())->getBitWidth();
+ APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
+ computeKnownBits(Cond, KnownZero, KnownOne);
+ unsigned LeadingKnownZeros = KnownZero.countLeadingOnes();
+ unsigned LeadingKnownOnes = KnownOne.countLeadingOnes();
+
+ // Compute the number of leading bits we can ignore.
+ for (auto &C : SI.cases()) {
+ LeadingKnownZeros = std::min(
+ LeadingKnownZeros, C.getCaseValue()->getValue().countLeadingZeros());
+ LeadingKnownOnes = std::min(
+ LeadingKnownOnes, C.getCaseValue()->getValue().countLeadingOnes());
+ }
+
+ unsigned NewWidth = BitWidth - std::max(LeadingKnownZeros, LeadingKnownOnes);
+
+ // Truncate the condition operand if the new type is equal to or larger than
+ // the largest legal integer type. We need to be conservative here since
+ // x86 generates redundant zero-extenstion instructions if the operand is
+ // truncated to i8 or i16.
+ if (BitWidth > NewWidth && NewWidth >= DL->getLargestLegalIntTypeSize()) {
+ IntegerType *Ty = IntegerType::get(SI.getContext(), NewWidth);
+ Builder->SetInsertPoint(&SI);
+ Value *NewCond = Builder->CreateTrunc(SI.getCondition(), Ty, "trunc");
+ SI.setCondition(NewCond);
+
+ for (auto &C : SI.cases())
+ static_cast<SwitchInst::CaseIt *>(&C)->setValue(ConstantInt::get(
+ SI.getContext(), C.getCaseValue()->getValue().trunc(NewWidth)));
+ }
+
if (Instruction *I = dyn_cast<Instruction>(Cond)) {
if (I->getOpcode() == Instruction::Add)
if (ConstantInt *AddRHS = dyn_cast<ConstantInt>(I->getOperand(1))) {
return &SI;
}
}
- return 0;
+ return nullptr;
}
Instruction *InstCombiner::visitExtractValueInst(ExtractValueInst &EV) {
// first index
return ExtractValueInst::Create(C2, EV.getIndices().slice(1));
}
- return 0; // Can't handle other constants
+ return nullptr; // Can't handle other constants
}
if (InsertValueInst *IV = dyn_cast<InsertValueInst>(Agg)) {
// and if again single-use then via load (gep (gep)) to load (gep).
// However, double extracts from e.g. function arguments or return values
// aren't handled yet.
- return 0;
+ return nullptr;
}
enum Personality_Type {
// Simplify the list of clauses, eg by removing repeated catch clauses
// (these are often created by inlining).
bool MakeNewInstruction = false; // If true, recreate using the following:
- SmallVector<Value *, 16> NewClauses; // - Clauses for the new instruction;
+ SmallVector<Constant *, 16> NewClauses; // - Clauses for the new instruction;
bool CleanupFlag = LI.isCleanup(); // - The new instruction is a cleanup.
SmallPtrSet<Value *, 16> AlreadyCaught; // Typeinfos known caught already.
bool isLastClause = i + 1 == e;
if (LI.isCatch(i)) {
// A catch clause.
- Value *CatchClause = LI.getClause(i);
- Constant *TypeInfo = cast<Constant>(CatchClause->stripPointerCasts());
+ Constant *CatchClause = LI.getClause(i);
+ Constant *TypeInfo = CatchClause->stripPointerCasts();
// If we already saw this clause, there is no point in having a second
// copy of it.
// equal (for example if one represents a C++ class, and the other some
// class derived from it).
assert(LI.isFilter(i) && "Unsupported landingpad clause!");
- Value *FilterClause = LI.getClause(i);
+ Constant *FilterClause = LI.getClause(i);
ArrayType *FilterType = cast<ArrayType>(FilterClause->getType());
unsigned NumTypeInfos = FilterType->getNumElements();
// catch-alls. If so, the filter can be discarded.
bool SawCatchAll = false;
for (unsigned j = 0; j != NumTypeInfos; ++j) {
- Value *Elt = Filter->getOperand(j);
- Constant *TypeInfo = cast<Constant>(Elt->stripPointerCasts());
+ Constant *Elt = Filter->getOperand(j);
+ Constant *TypeInfo = Elt->stripPointerCasts();
if (isCatchAll(Personality, TypeInfo)) {
// This element is a catch-all. Bail out, noting this fact.
SawCatchAll = true;
continue;
// If Filter is a subset of LFilter, i.e. every element of Filter is also
// an element of LFilter, then discard LFilter.
- SmallVector<Value *, 16>::iterator J = NewClauses.begin() + j;
+ SmallVectorImpl<Constant *>::iterator J = NewClauses.begin() + j;
// If Filter is empty then it is a subset of LFilter.
if (!FElts) {
// Discard LFilter.
return &LI;
}
- return 0;
+ return nullptr;
}
/// whose condition is a known constant, we only visit the reachable successors.
///
static bool AddReachableCodeToWorklist(BasicBlock *BB,
- SmallPtrSet<BasicBlock*, 64> &Visited,
+ SmallPtrSetImpl<BasicBlock*> &Visited,
InstCombiner &IC,
- const TargetData *TD,
+ const DataLayout *DL,
const TargetLibraryInfo *TLI) {
bool MadeIRChange = false;
SmallVector<BasicBlock*, 256> Worklist;
Instruction *Inst = BBI++;
// DCE instruction if trivially dead.
- if (isInstructionTriviallyDead(Inst)) {
+ if (isInstructionTriviallyDead(Inst, TLI)) {
++NumDeadInst;
- DEBUG(errs() << "IC: DCE: " << *Inst << '\n');
+ DEBUG(dbgs() << "IC: DCE: " << *Inst << '\n');
Inst->eraseFromParent();
continue;
}
// ConstantProp instruction if trivially constant.
if (!Inst->use_empty() && isa<Constant>(Inst->getOperand(0)))
- if (Constant *C = ConstantFoldInstruction(Inst, TD, TLI)) {
- DEBUG(errs() << "IC: ConstFold to: " << *C << " from: "
+ if (Constant *C = ConstantFoldInstruction(Inst, DL, TLI)) {
+ DEBUG(dbgs() << "IC: ConstFold to: " << *C << " from: "
<< *Inst << '\n');
Inst->replaceAllUsesWith(C);
++NumConstProp;
continue;
}
- if (TD) {
+ if (DL) {
// See if we can constant fold its operands.
for (User::op_iterator i = Inst->op_begin(), e = Inst->op_end();
i != e; ++i) {
ConstantExpr *CE = dyn_cast<ConstantExpr>(i);
- if (CE == 0) continue;
+ if (CE == nullptr) continue;
Constant*& FoldRes = FoldedConstants[CE];
if (!FoldRes)
- FoldRes = ConstantFoldConstantExpression(CE, TD, TLI);
+ FoldRes = ConstantFoldConstantExpression(CE, DL, TLI);
if (!FoldRes)
FoldRes = CE;
bool InstCombiner::DoOneIteration(Function &F, unsigned Iteration) {
MadeIRChange = false;
- DEBUG(errs() << "\n\nINSTCOMBINE ITERATION #" << Iteration << " on "
+ DEBUG(dbgs() << "\n\nINSTCOMBINE ITERATION #" << Iteration << " on "
<< F.getName() << "\n");
{
// the reachable instructions. Ignore blocks that are not reachable. Keep
// track of which blocks we visit.
SmallPtrSet<BasicBlock*, 64> Visited;
- MadeIRChange |= AddReachableCodeToWorklist(F.begin(), Visited, *this, TD,
+ MadeIRChange |= AddReachableCodeToWorklist(F.begin(), Visited, *this, DL,
TLI);
// Do a quick scan over the function. If we find any blocks that are
while (!Worklist.isEmpty()) {
Instruction *I = Worklist.RemoveOne();
- if (I == 0) continue; // skip null values.
+ if (I == nullptr) continue; // skip null values.
// Check to see if we can DCE the instruction.
- if (isInstructionTriviallyDead(I)) {
- DEBUG(errs() << "IC: DCE: " << *I << '\n');
+ if (isInstructionTriviallyDead(I, TLI)) {
+ DEBUG(dbgs() << "IC: DCE: " << *I << '\n');
EraseInstFromFunction(*I);
++NumDeadInst;
MadeIRChange = true;
// Instruction isn't dead, see if we can constant propagate it.
if (!I->use_empty() && isa<Constant>(I->getOperand(0)))
- if (Constant *C = ConstantFoldInstruction(I, TD, TLI)) {
- DEBUG(errs() << "IC: ConstFold to: " << *C << " from: " << *I << '\n');
+ if (Constant *C = ConstantFoldInstruction(I, DL, TLI)) {
+ DEBUG(dbgs() << "IC: ConstFold to: " << *C << " from: " << *I << '\n');
// Add operands to the worklist.
ReplaceInstUsesWith(*I, C);
// See if we can trivially sink this instruction to a successor basic block.
if (I->hasOneUse()) {
BasicBlock *BB = I->getParent();
- Instruction *UserInst = cast<Instruction>(I->use_back());
+ Instruction *UserInst = cast<Instruction>(*I->user_begin());
BasicBlock *UserParent;
// Get the block the use occurs in.
if (PHINode *PN = dyn_cast<PHINode>(UserInst))
- UserParent = PN->getIncomingBlock(I->use_begin().getUse());
+ UserParent = PN->getIncomingBlock(*I->use_begin());
else
UserParent = UserInst->getParent();
// If the user is one of our immediate successors, and if that successor
// only has us as a predecessors (we'd have to split the critical edge
// otherwise), we can keep going.
- if (UserIsSuccessor && UserParent->getSinglePredecessor())
+ if (UserIsSuccessor && UserParent->getSinglePredecessor()) {
// Okay, the CFG is simple enough, try to sink this instruction.
- MadeIRChange |= TryToSinkInstruction(I, UserParent);
+ if (TryToSinkInstruction(I, UserParent)) {
+ MadeIRChange = true;
+ // We'll add uses of the sunk instruction below, but since sinking
+ // can expose opportunities for it's *operands* add them to the
+ // worklist
+ for (Use &U : I->operands())
+ if (Instruction *OpI = dyn_cast<Instruction>(U.get()))
+ Worklist.Add(OpI);
+ }
+ }
}
}
std::string OrigI;
#endif
DEBUG(raw_string_ostream SS(OrigI); I->print(SS); OrigI = SS.str(););
- DEBUG(errs() << "IC: Visiting: " << OrigI << '\n');
+ DEBUG(dbgs() << "IC: Visiting: " << OrigI << '\n');
if (Instruction *Result = visit(*I)) {
++NumCombined;
// Should we replace the old instruction with a new one?
if (Result != I) {
- DEBUG(errs() << "IC: Old = " << *I << '\n'
+ DEBUG(dbgs() << "IC: Old = " << *I << '\n'
<< " New = " << *Result << '\n');
if (!I->getDebugLoc().isUnknown())
EraseInstFromFunction(*I);
} else {
#ifndef NDEBUG
- DEBUG(errs() << "IC: Mod = " << OrigI << '\n'
+ DEBUG(dbgs() << "IC: Mod = " << OrigI << '\n'
<< " New = " << *I << '\n');
#endif
// If the instruction was modified, it's possible that it is now dead.
// if so, remove it.
- if (isInstructionTriviallyDead(I)) {
+ if (isInstructionTriviallyDead(I, TLI)) {
EraseInstFromFunction(*I);
} else {
Worklist.Add(I);
return MadeIRChange;
}
+namespace {
+class InstCombinerLibCallSimplifier final : public LibCallSimplifier {
+ InstCombiner *IC;
+public:
+ InstCombinerLibCallSimplifier(const DataLayout *DL,
+ const TargetLibraryInfo *TLI,
+ InstCombiner *IC)
+ : LibCallSimplifier(DL, TLI, EnableUnsafeFPShrink) {
+ this->IC = IC;
+ }
+
+ /// replaceAllUsesWith - override so that instruction replacement
+ /// can be defined in terms of the instruction combiner framework.
+ void replaceAllUsesWith(Instruction *I, Value *With) const override {
+ IC->ReplaceInstUsesWith(*I, With);
+ }
+};
+}
bool InstCombiner::runOnFunction(Function &F) {
- TD = getAnalysisIfAvailable<TargetData>();
+ if (skipOptnoneFunction(F))
+ return false;
+
+ AT = &getAnalysis<AssumptionTracker>();
+ DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
+ DL = DLP ? &DLP->getDataLayout() : nullptr;
TLI = &getAnalysis<TargetLibraryInfo>();
+ DominatorTreeWrapperPass *DTWP =
+ getAnalysisIfAvailable<DominatorTreeWrapperPass>();
+ DT = DTWP ? &DTWP->getDomTree() : nullptr;
+
+ // Minimizing size?
+ MinimizeSize = F.getAttributes().hasAttribute(AttributeSet::FunctionIndex,
+ Attribute::MinSize);
+
/// Builder - This is an IRBuilder that automatically inserts new
/// instructions into the worklist when they are created.
IRBuilder<true, TargetFolder, InstCombineIRInserter>
- TheBuilder(F.getContext(), TargetFolder(TD),
- InstCombineIRInserter(Worklist));
+ TheBuilder(F.getContext(), TargetFolder(DL),
+ InstCombineIRInserter(Worklist, AT));
Builder = &TheBuilder;
+ InstCombinerLibCallSimplifier TheSimplifier(DL, TLI, this);
+ Simplifier = &TheSimplifier;
+
bool EverMadeChange = false;
// Lower dbg.declare intrinsics otherwise their value may be clobbered
while (DoOneIteration(F, Iteration++))
EverMadeChange = true;
- Builder = 0;
+ Builder = nullptr;
return EverMadeChange;
}
projects / oota-llvm.git / blobdiff