//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "scalar-evolution"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/ConstantFolding.h"
-#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/IR/ConstantRange.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/GetElementPtrTypeIterator.h"
#include "llvm/IR/GlobalAlias.h"
#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/InstIterator.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Operator.h"
#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/ConstantRange.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/GetElementPtrTypeIterator.h"
-#include "llvm/Support/InstIterator.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetLibraryInfo.h"
#include <algorithm>
using namespace llvm;
+#define DEBUG_TYPE "scalar-evolution"
+
STATISTIC(NumArrayLenItCounts,
"Number of trip counts computed with array length");
STATISTIC(NumTripCountsComputed,
INITIALIZE_PASS_BEGIN(ScalarEvolution, "scalar-evolution",
"Scalar Evolution Analysis", false, true)
INITIALIZE_PASS_DEPENDENCY(LoopInfo)
-INITIALIZE_PASS_DEPENDENCY(DominatorTree)
+INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
INITIALIZE_PASS_END(ScalarEvolution, "scalar-evolution",
"Scalar Evolution Analysis", false, true)
#endif
void SCEV::print(raw_ostream &OS) const {
- switch (getSCEVType()) {
+ switch (static_cast<SCEVTypes>(getSCEVType())) {
case scConstant:
cast<SCEVConstant>(this)->getValue()->printAsOperand(OS, false);
return;
case scUMaxExpr:
case scSMaxExpr: {
const SCEVNAryExpr *NAry = cast<SCEVNAryExpr>(this);
- const char *OpStr = 0;
+ const char *OpStr = nullptr;
switch (NAry->getSCEVType()) {
case scAddExpr: OpStr = " + "; break;
case scMulExpr: OpStr = " * "; break;
for (SCEVNAryExpr::op_iterator I = NAry->op_begin(), E = NAry->op_end();
I != E; ++I) {
OS << **I;
- if (llvm::next(I) != E)
+ if (std::next(I) != E)
OS << OpStr;
}
OS << ")";
case scCouldNotCompute:
OS << "***COULDNOTCOMPUTE***";
return;
- default: break;
}
llvm_unreachable("Unknown SCEV kind!");
}
Type *SCEV::getType() const {
- switch (getSCEVType()) {
+ switch (static_cast<SCEVTypes>(getSCEVType())) {
case scConstant:
return cast<SCEVConstant>(this)->getType();
case scTruncate:
return cast<SCEVUnknown>(this)->getType();
case scCouldNotCompute:
llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
- default:
- llvm_unreachable("Unknown SCEV kind!");
}
+ llvm_unreachable("Unknown SCEV kind!");
}
bool SCEV::isZero() const {
FoldingSetNodeID ID;
ID.AddInteger(scConstant);
ID.AddPointer(V);
- void *IP = 0;
+ void *IP = nullptr;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
SCEV *S = new (SCEVAllocator) SCEVConstant(ID.Intern(SCEVAllocator), V);
UniqueSCEVs.InsertNode(S, IP);
return S;
}
-const SCEV *ScalarEvolution::getConstant(const APInt& Val) {
+const SCEV *ScalarEvolution::getConstant(const APInt &Val) {
return getConstant(ConstantInt::get(getContext(), Val));
}
SE->UniqueSCEVs.RemoveNode(this);
// Release the value.
- setValPtr(0);
+ setValPtr(nullptr);
}
void SCEVUnknown::allUsesReplacedWith(Value *New) {
// Aside from the getSCEVType() ordering, the particular ordering
// isn't very important except that it's beneficial to be consistent,
// so that (a + b) and (b + a) don't end up as different expressions.
- switch (LType) {
+ switch (static_cast<SCEVTypes>(LType)) {
case scUnknown: {
const SCEVUnknown *LU = cast<SCEVUnknown>(LHS);
const SCEVUnknown *RU = cast<SCEVUnknown>(RHS);
return compare(LC->getOperand(), RC->getOperand());
}
- default:
- llvm_unreachable("Unknown SCEV kind!");
+ case scCouldNotCompute:
+ llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
}
+ llvm_unreachable("Unknown SCEV kind!");
}
};
}
ID.AddInteger(scTruncate);
ID.AddPointer(Op);
ID.AddPointer(Ty);
- void *IP = 0;
+ void *IP = nullptr;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
// Fold if the operand is constant.
ID.AddInteger(scZeroExtend);
ID.AddPointer(Op);
ID.AddPointer(Ty);
- void *IP = 0;
+ void *IP = nullptr;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
// zext(trunc(x)) --> zext(x) or x or trunc(x)
return SE->getConstant(APInt::getSignedMaxValue(BitWidth) -
SE->getSignedRange(Step).getSignedMin());
}
- return 0;
+ return nullptr;
}
// The recurrence AR has been shown to have no signed wrap. Typically, if we can
// Check for a simple looking step prior to loop entry.
const SCEVAddExpr *SA = dyn_cast<SCEVAddExpr>(Start);
if (!SA)
- return 0;
+ return nullptr;
// Create an AddExpr for "PreStart" after subtracting Step. Full SCEV
// subtraction is expensive. For this purpose, perform a quick and dirty
DiffOps.push_back(*I);
}
if (DiffOps.size() == SA->getNumOperands())
- return 0;
+ return nullptr;
// This is a postinc AR. Check for overflow on the preinc recurrence using the
// same three conditions that getSignExtendedExpr checks.
SE->isLoopEntryGuardedByCond(L, Pred, PreStart, OverflowLimit)) {
return PreStart;
}
- return 0;
+ return nullptr;
}
// Get the normalized sign-extended expression for this AddRec's Start.
ID.AddInteger(scSignExtend);
ID.AddPointer(Op);
ID.AddPointer(Ty);
- void *IP = 0;
+ void *IP = nullptr;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
// If the input value is provably positive, build a zext instead.
/// what it does, given a sequence of operands that would form an add
/// expression like this:
///
-/// m + n + 13 + (A * (o + p + (B * q + m + 29))) + r + (-1 * r)
+/// m + n + 13 + (A * (o + p + (B * (q + m + 29)))) + r + (-1 * r)
///
/// where A and B are constants, update the map with these values:
///
ID.AddInteger(scAddExpr);
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
ID.AddPointer(Ops[i]);
- void *IP = 0;
+ void *IP = nullptr;
SCEVAddExpr *S =
static_cast<SCEVAddExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP));
if (!S) {
ID.AddInteger(scMulExpr);
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
ID.AddPointer(Ops[i]);
- void *IP = 0;
+ void *IP = nullptr;
SCEVMulExpr *S =
static_cast<SCEVMulExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP));
if (!S) {
ID.AddInteger(scUDivExpr);
ID.AddPointer(LHS);
ID.AddPointer(RHS);
- void *IP = 0;
+ void *IP = nullptr;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
SCEV *S = new (SCEVAllocator) SCEVUDivExpr(ID.Intern(SCEVAllocator),
LHS, RHS);
return S;
}
+static const APInt gcd(const SCEVConstant *C1, const SCEVConstant *C2) {
+ APInt A = C1->getValue()->getValue().abs();
+ APInt B = C2->getValue()->getValue().abs();
+ uint32_t ABW = A.getBitWidth();
+ uint32_t BBW = B.getBitWidth();
+
+ if (ABW > BBW)
+ B = B.zext(ABW);
+ else if (ABW < BBW)
+ A = A.zext(BBW);
+
+ return APIntOps::GreatestCommonDivisor(A, B);
+}
+
+/// getUDivExactExpr - Get a canonical unsigned division expression, or
+/// something simpler if possible. There is no representation for an exact udiv
+/// in SCEV IR, but we can attempt to remove factors from the LHS and RHS.
+/// We can't do this when it's not exact because the udiv may be clearing bits.
+const SCEV *ScalarEvolution::getUDivExactExpr(const SCEV *LHS,
+ const SCEV *RHS) {
+ // TODO: we could try to find factors in all sorts of things, but for now we
+ // just deal with u/exact (multiply, constant). See SCEVDivision towards the
+ // end of this file for inspiration.
+
+ const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(LHS);
+ if (!Mul)
+ return getUDivExpr(LHS, RHS);
+
+ if (const SCEVConstant *RHSCst = dyn_cast<SCEVConstant>(RHS)) {
+ // If the mulexpr multiplies by a constant, then that constant must be the
+ // first element of the mulexpr.
+ if (const SCEVConstant *LHSCst =
+ dyn_cast<SCEVConstant>(Mul->getOperand(0))) {
+ if (LHSCst == RHSCst) {
+ SmallVector<const SCEV *, 2> Operands;
+ Operands.append(Mul->op_begin() + 1, Mul->op_end());
+ return getMulExpr(Operands);
+ }
+
+ // We can't just assume that LHSCst divides RHSCst cleanly, it could be
+ // that there's a factor provided by one of the other terms. We need to
+ // check.
+ APInt Factor = gcd(LHSCst, RHSCst);
+ if (!Factor.isIntN(1)) {
+ LHSCst = cast<SCEVConstant>(
+ getConstant(LHSCst->getValue()->getValue().udiv(Factor)));
+ RHSCst = cast<SCEVConstant>(
+ getConstant(RHSCst->getValue()->getValue().udiv(Factor)));
+ SmallVector<const SCEV *, 2> Operands;
+ Operands.push_back(LHSCst);
+ Operands.append(Mul->op_begin() + 1, Mul->op_end());
+ LHS = getMulExpr(Operands);
+ RHS = RHSCst;
+ Mul = dyn_cast<SCEVMulExpr>(LHS);
+ if (!Mul)
+ return getUDivExactExpr(LHS, RHS);
+ }
+ }
+ }
+
+ for (int i = 0, e = Mul->getNumOperands(); i != e; ++i) {
+ if (Mul->getOperand(i) == RHS) {
+ SmallVector<const SCEV *, 2> Operands;
+ Operands.append(Mul->op_begin(), Mul->op_begin() + i);
+ Operands.append(Mul->op_begin() + i + 1, Mul->op_end());
+ return getMulExpr(Operands);
+ }
+ }
+
+ return getUDivExpr(LHS, RHS);
+}
/// getAddRecExpr - Get an add recurrence expression for the specified loop.
/// Simplify the expression as much as possible.
for (unsigned i = 0, e = Operands.size(); i != e; ++i)
ID.AddPointer(Operands[i]);
ID.AddPointer(L);
- void *IP = 0;
+ void *IP = nullptr;
SCEVAddRecExpr *S =
static_cast<SCEVAddRecExpr *>(UniqueSCEVs.FindNodeOrInsertPos(ID, IP));
if (!S) {
ID.AddInteger(scSMaxExpr);
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
ID.AddPointer(Ops[i]);
- void *IP = 0;
+ void *IP = nullptr;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size());
std::uninitialized_copy(Ops.begin(), Ops.end(), O);
ID.AddInteger(scUMaxExpr);
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
ID.AddPointer(Ops[i]);
- void *IP = 0;
+ void *IP = nullptr;
if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size());
std::uninitialized_copy(Ops.begin(), Ops.end(), O);
// If we have DataLayout, we can bypass creating a target-independent
// constant expression and then folding it back into a ConstantInt.
// This is just a compile-time optimization.
- if (TD)
- return getConstant(IntTy, TD->getTypeAllocSize(AllocTy));
+ if (DL)
+ return getConstant(IntTy, DL->getTypeAllocSize(AllocTy));
Constant *C = ConstantExpr::getSizeOf(AllocTy);
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
- if (Constant *Folded = ConstantFoldConstantExpression(CE, TD, TLI))
+ if (Constant *Folded = ConstantFoldConstantExpression(CE, DL, TLI))
C = Folded;
Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(AllocTy));
assert(Ty == IntTy && "Effective SCEV type doesn't match");
// If we have DataLayout, we can bypass creating a target-independent
// constant expression and then folding it back into a ConstantInt.
// This is just a compile-time optimization.
- if (TD) {
+ if (DL) {
return getConstant(IntTy,
- TD->getStructLayout(STy)->getElementOffset(FieldNo));
+ DL->getStructLayout(STy)->getElementOffset(FieldNo));
}
Constant *C = ConstantExpr::getOffsetOf(STy, FieldNo);
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
- if (Constant *Folded = ConstantFoldConstantExpression(CE, TD, TLI))
+ if (Constant *Folded = ConstantFoldConstantExpression(CE, DL, TLI))
C = Folded;
Type *Ty = getEffectiveSCEVType(PointerType::getUnqual(STy));
FoldingSetNodeID ID;
ID.AddInteger(scUnknown);
ID.AddPointer(V);
- void *IP = 0;
+ void *IP = nullptr;
if (SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) {
assert(cast<SCEVUnknown>(S)->getValue() == V &&
"Stale SCEVUnknown in uniquing map!");
assert(isSCEVable(Ty) && "Type is not SCEVable!");
// If we have a DataLayout, use it!
- if (TD)
- return TD->getTypeSizeInBits(Ty);
+ if (DL)
+ return DL->getTypeSizeInBits(Ty);
// Integer types have fixed sizes.
if (Ty->isIntegerTy())
// The only other support type is pointer.
assert(Ty->isPointerTy() && "Unexpected non-pointer non-integer type!");
- if (TD)
- return TD->getIntPtrType(Ty);
+ if (DL)
+ return DL->getIntPtrType(Ty);
// Without DataLayout, conservatively assume pointers are 64-bit.
return Type::getInt64Ty(getContext());
bool FindOne;
FindInvalidSCEVUnknown() { FindOne = false; }
bool follow(const SCEV *S) {
- switch (S->getSCEVType()) {
+ switch (static_cast<SCEVTypes>(S->getSCEVType())) {
case scConstant:
return false;
case scUnknown:
return getPointerBase(Cast->getOperand());
}
else if (const SCEVNAryExpr *NAry = dyn_cast<SCEVNAryExpr>(V)) {
- const SCEV *PtrOp = 0;
+ const SCEV *PtrOp = nullptr;
for (SCEVNAryExpr::op_iterator I = NAry->op_begin(), E = NAry->op_end();
I != E; ++I) {
if ((*I)->getType()->isPointerTy()) {
PushDefUseChildren(Instruction *I,
SmallVectorImpl<Instruction *> &Worklist) {
// Push the def-use children onto the Worklist stack.
- for (Value::use_iterator UI = I->use_begin(), UE = I->use_end();
- UI != UE; ++UI)
- Worklist.push_back(cast<Instruction>(*UI));
+ for (User *U : I->users())
+ Worklist.push_back(cast<Instruction>(U));
}
/// ForgetSymbolicValue - This looks up computed SCEV values for all
// The loop may have multiple entrances or multiple exits; we can analyze
// this phi as an addrec if it has a unique entry value and a unique
// backedge value.
- Value *BEValueV = 0, *StartValueV = 0;
+ Value *BEValueV = nullptr, *StartValueV = nullptr;
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
Value *V = PN->getIncomingValue(i);
if (L->contains(PN->getIncomingBlock(i))) {
if (!BEValueV) {
BEValueV = V;
} else if (BEValueV != V) {
- BEValueV = 0;
+ BEValueV = nullptr;
break;
}
} else if (!StartValueV) {
StartValueV = V;
} else if (StartValueV != V) {
- StartValueV = 0;
+ StartValueV = nullptr;
break;
}
}
// PHI's incoming blocks are in a different loop, in which case doing so
// risks breaking LCSSA form. Instcombine would normally zap these, but
// it doesn't have DominatorTree information, so it may miss cases.
- if (Value *V = SimplifyInstruction(PN, TD, TLI, DT))
+ if (Value *V = SimplifyInstruction(PN, DL, TLI, DT))
if (LI->replacementPreservesLCSSAForm(PN, V))
return getSCEV(V);
const SCEV *TotalOffset = getConstant(IntPtrTy, 0);
gep_type_iterator GTI = gep_type_begin(GEP);
- for (GetElementPtrInst::op_iterator I = llvm::next(GEP->op_begin()),
+ for (GetElementPtrInst::op_iterator I = std::next(GEP->op_begin()),
E = GEP->op_end();
I != E; ++I) {
Value *Index = *I;
if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) {
// For a SCEVUnknown, ask ValueTracking.
APInt Zeros(BitWidth, 0), Ones(BitWidth, 0);
- ComputeMaskedBits(U->getValue(), Zeros, Ones, TD);
+ ComputeMaskedBits(U->getValue(), Zeros, Ones, DL);
if (Ones == ~Zeros + 1)
return setUnsignedRange(U, ConservativeResult);
return setUnsignedRange(U,
if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) {
// For a SCEVUnknown, ask ValueTracking.
- if (!U->getValue()->getType()->isIntegerTy() && !TD)
+ if (!U->getValue()->getType()->isIntegerTy() && !DL)
return setSignedRange(U, ConservativeResult);
- unsigned NS = ComputeNumSignBits(U->getValue(), TD);
+ unsigned NS = ComputeNumSignBits(U->getValue(), DL);
if (NS <= 1)
return setSignedRange(U, ConservativeResult);
return setSignedRange(U, ConservativeResult.intersectWith(
// Use ComputeMaskedBits to compute what ShrinkDemandedConstant
// knew about to reconstruct a low-bits mask value.
unsigned LZ = A.countLeadingZeros();
+ unsigned TZ = A.countTrailingZeros();
unsigned BitWidth = A.getBitWidth();
APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
- ComputeMaskedBits(U->getOperand(0), KnownZero, KnownOne, TD);
-
- APInt EffectiveMask = APInt::getLowBitsSet(BitWidth, BitWidth - LZ);
-
- if (LZ != 0 && !((~A & ~KnownZero) & EffectiveMask))
- return
- getZeroExtendExpr(getTruncateExpr(getSCEV(U->getOperand(0)),
- IntegerType::get(getContext(), BitWidth - LZ)),
- U->getType());
+ ComputeMaskedBits(U->getOperand(0), KnownZero, KnownOne, DL);
+
+ APInt EffectiveMask =
+ APInt::getLowBitsSet(BitWidth, BitWidth - LZ - TZ).shl(TZ);
+ if ((LZ != 0 || TZ != 0) && !((~A & ~KnownZero) & EffectiveMask)) {
+ const SCEV *MulCount = getConstant(
+ ConstantInt::get(getContext(), APInt::getOneBitSet(BitWidth, TZ)));
+ return getMulExpr(
+ getZeroExtendExpr(
+ getTruncateExpr(
+ getUDivExactExpr(getSCEV(U->getOperand(0)), MulCount),
+ IntegerType::get(getContext(), BitWidth - LZ - TZ)),
+ U->getType()),
+ MulCount);
+ }
}
break;
if (!ExitNotTaken.ExitingBlock) return SE->getCouldNotCompute();
assert(ExitNotTaken.ExactNotTaken && "uninitialized not-taken info");
- const SCEV *BECount = 0;
+ const SCEV *BECount = nullptr;
for (const ExitNotTakenInfo *ENT = &ExitNotTaken;
- ENT != 0; ENT = ENT->getNextExit()) {
+ ENT != nullptr; ENT = ENT->getNextExit()) {
assert(ENT->ExactNotTaken != SE->getCouldNotCompute() && "bad exit SCEV");
ScalarEvolution::BackedgeTakenInfo::getExact(BasicBlock *ExitingBlock,
ScalarEvolution *SE) const {
for (const ExitNotTakenInfo *ENT = &ExitNotTaken;
- ENT != 0; ENT = ENT->getNextExit()) {
+ ENT != nullptr; ENT = ENT->getNextExit()) {
if (ENT->ExitingBlock == ExitingBlock)
return ENT->ExactNotTaken;
return false;
for (const ExitNotTakenInfo *ENT = &ExitNotTaken;
- ENT != 0; ENT = ENT->getNextExit()) {
+ ENT != nullptr; ENT = ENT->getNextExit()) {
if (ENT->ExactNotTaken != SE->getCouldNotCompute()
&& SE->hasOperand(ENT->ExactNotTaken, S)) {
/// clear - Invalidate this result and free the ExitNotTakenInfo array.
void ScalarEvolution::BackedgeTakenInfo::clear() {
- ExitNotTaken.ExitingBlock = 0;
- ExitNotTaken.ExactNotTaken = 0;
+ ExitNotTaken.ExitingBlock = nullptr;
+ ExitNotTaken.ExactNotTaken = nullptr;
delete[] ExitNotTaken.getNextExit();
}
// Examine all exits and pick the most conservative values.
const SCEV *MaxBECount = getCouldNotCompute();
bool CouldComputeBECount = true;
+ BasicBlock *Latch = L->getLoopLatch(); // may be NULL.
+ const SCEV *LatchMaxCount = nullptr;
SmallVector<std::pair<BasicBlock *, const SCEV *>, 4> ExitCounts;
for (unsigned i = 0, e = ExitingBlocks.size(); i != e; ++i) {
ExitLimit EL = ComputeExitLimit(L, ExitingBlocks[i]);
// We cannot take the "min" MaxBECount, because non-unit stride loops may
// skip some loop tests. Taking the max over the exits is sufficiently
// conservative. TODO: We could do better taking into consideration
- // that (1) the loop has unit stride (2) the last loop test is
- // less-than/greater-than (3) any loop test is less-than/greater-than AND
- // falls-through some constant times less then the other tests.
- MaxBECount = getUMaxFromMismatchedTypes(MaxBECount, EL.Max);
+ // non-latch exits that dominate the latch.
+ if (EL.MustExit && ExitingBlocks[i] == Latch)
+ LatchMaxCount = EL.Max;
+ else
+ MaxBECount = getUMaxFromMismatchedTypes(MaxBECount, EL.Max);
}
}
-
+ // Be more precise in the easy case of a loop latch that must exit.
+ if (LatchMaxCount) {
+ MaxBECount = getUMinFromMismatchedTypes(MaxBECount, LatchMaxCount);
+ }
return BackedgeTakenInfo(ExitCounts, CouldComputeBECount, MaxBECount);
}
ScalarEvolution::ComputeExitLimit(const Loop *L, BasicBlock *ExitingBlock) {
// Okay, we've chosen an exiting block. See what condition causes us to
- // exit at this block.
- //
- // FIXME: we should be able to handle switch instructions (with a single exit)
- BranchInst *ExitBr = dyn_cast<BranchInst>(ExitingBlock->getTerminator());
- if (ExitBr == 0) return getCouldNotCompute();
- assert(ExitBr->isConditional() && "If unconditional, it can't be in loop!");
+ // exit at this block and remember the exit block and whether all other targets
+ // lead to the loop header.
+ bool MustExecuteLoopHeader = true;
+ BasicBlock *Exit = nullptr;
+ for (succ_iterator SI = succ_begin(ExitingBlock), SE = succ_end(ExitingBlock);
+ SI != SE; ++SI)
+ if (!L->contains(*SI)) {
+ if (Exit) // Multiple exit successors.
+ return getCouldNotCompute();
+ Exit = *SI;
+ } else if (*SI != L->getHeader()) {
+ MustExecuteLoopHeader = false;
+ }
// At this point, we know we have a conditional branch that determines whether
// the loop is exited. However, we don't know if the branch is executed each
//
// More extensive analysis could be done to handle more cases here.
//
- if (ExitBr->getSuccessor(0) != L->getHeader() &&
- ExitBr->getSuccessor(1) != L->getHeader() &&
- ExitBr->getParent() != L->getHeader()) {
+ if (!MustExecuteLoopHeader && ExitingBlock != L->getHeader()) {
// The simple checks failed, try climbing the unique predecessor chain
// up to the header.
bool Ok = false;
- for (BasicBlock *BB = ExitBr->getParent(); BB; ) {
+ for (BasicBlock *BB = ExitingBlock; BB; ) {
BasicBlock *Pred = BB->getUniquePredecessor();
if (!Pred)
return getCouldNotCompute();
return getCouldNotCompute();
}
- // Proceed to the next level to examine the exit condition expression.
- return ComputeExitLimitFromCond(L, ExitBr->getCondition(),
- ExitBr->getSuccessor(0),
- ExitBr->getSuccessor(1),
- /*IsSubExpr=*/false);
+ TerminatorInst *Term = ExitingBlock->getTerminator();
+ if (BranchInst *BI = dyn_cast<BranchInst>(Term)) {
+ assert(BI->isConditional() && "If unconditional, it can't be in loop!");
+ // Proceed to the next level to examine the exit condition expression.
+ return ComputeExitLimitFromCond(L, BI->getCondition(), BI->getSuccessor(0),
+ BI->getSuccessor(1),
+ /*IsSubExpr=*/false);
+ }
+
+ if (SwitchInst *SI = dyn_cast<SwitchInst>(Term))
+ return ComputeExitLimitFromSingleExitSwitch(L, SI, Exit,
+ /*IsSubExpr=*/false);
+
+ return getCouldNotCompute();
}
/// ComputeExitLimitFromCond - Compute the number of times the
IsSubExpr || EitherMayExit);
const SCEV *BECount = getCouldNotCompute();
const SCEV *MaxBECount = getCouldNotCompute();
+ bool MustExit = false;
if (EitherMayExit) {
// Both conditions must be true for the loop to continue executing.
// Choose the less conservative count.
MaxBECount = EL0.Max;
else
MaxBECount = getUMinFromMismatchedTypes(EL0.Max, EL1.Max);
+ MustExit = EL0.MustExit || EL1.MustExit;
} else {
// Both conditions must be true at the same time for the loop to exit.
// For now, be conservative.
MaxBECount = EL0.Max;
if (EL0.Exact == EL1.Exact)
BECount = EL0.Exact;
+ MustExit = EL0.MustExit && EL1.MustExit;
}
- return ExitLimit(BECount, MaxBECount);
+ return ExitLimit(BECount, MaxBECount, MustExit);
}
if (BO->getOpcode() == Instruction::Or) {
// Recurse on the operands of the or.
IsSubExpr || EitherMayExit);
const SCEV *BECount = getCouldNotCompute();
const SCEV *MaxBECount = getCouldNotCompute();
+ bool MustExit = false;
if (EitherMayExit) {
// Both conditions must be false for the loop to continue executing.
// Choose the less conservative count.
MaxBECount = EL0.Max;
else
MaxBECount = getUMinFromMismatchedTypes(EL0.Max, EL1.Max);
+ MustExit = EL0.MustExit || EL1.MustExit;
} else {
// Both conditions must be false at the same time for the loop to exit.
// For now, be conservative.
MaxBECount = EL0.Max;
if (EL0.Exact == EL1.Exact)
BECount = EL0.Exact;
+ MustExit = EL0.MustExit && EL1.MustExit;
}
- return ExitLimit(BECount, MaxBECount);
+ return ExitLimit(BECount, MaxBECount, MustExit);
}
}
return ComputeExitCountExhaustively(L, ExitCond, !L->contains(TBB));
}
+ScalarEvolution::ExitLimit
+ScalarEvolution::ComputeExitLimitFromSingleExitSwitch(const Loop *L,
+ SwitchInst *Switch,
+ BasicBlock *ExitingBlock,
+ bool IsSubExpr) {
+ assert(!L->contains(ExitingBlock) && "Not an exiting block!");
+
+ // Give up if the exit is the default dest of a switch.
+ if (Switch->getDefaultDest() == ExitingBlock)
+ return getCouldNotCompute();
+
+ assert(L->contains(Switch->getDefaultDest()) &&
+ "Default case must not exit the loop!");
+ const SCEV *LHS = getSCEVAtScope(Switch->getCondition(), L);
+ const SCEV *RHS = getConstant(Switch->findCaseDest(ExitingBlock));
+
+ // while (X != Y) --> while (X-Y != 0)
+ ExitLimit EL = HowFarToZero(getMinusSCEV(LHS, RHS), L, IsSubExpr);
+ if (EL.hasAnyInfo())
+ return EL;
+
+ return getCouldNotCompute();
+}
+
static ConstantInt *
EvaluateConstantChrecAtConstant(const SCEVAddRecExpr *AddRec, ConstantInt *C,
ScalarEvolution &SE) {
return getCouldNotCompute();
// Okay, we allow one non-constant index into the GEP instruction.
- Value *VarIdx = 0;
+ Value *VarIdx = nullptr;
std::vector<Constant*> Indexes;
unsigned VarIdxNum = 0;
for (unsigned i = 2, e = GEP->getNumOperands(); i != e; ++i)
if (VarIdx) return getCouldNotCompute(); // Multiple non-constant idx's.
VarIdx = GEP->getOperand(i);
VarIdxNum = i-2;
- Indexes.push_back(0);
+ Indexes.push_back(nullptr);
}
// Loop-invariant loads may be a byproduct of loop optimization. Skip them.
Constant *Result = ConstantFoldLoadThroughGEPIndices(GV->getInitializer(),
Indexes);
- if (Result == 0) break; // Cannot compute!
+ if (!Result) break; // Cannot compute!
// Evaluate the condition for this iteration.
Result = ConstantExpr::getICmp(predicate, Result, RHS);
// Otherwise, we can evaluate this instruction if all of its operands are
// constant or derived from a PHI node themselves.
- PHINode *PHI = 0;
+ PHINode *PHI = nullptr;
for (Instruction::op_iterator OpI = UseInst->op_begin(),
OpE = UseInst->op_end(); OpI != OpE; ++OpI) {
if (isa<Constant>(*OpI)) continue;
Instruction *OpInst = dyn_cast<Instruction>(*OpI);
- if (!OpInst || !canConstantEvolve(OpInst, L)) return 0;
+ if (!OpInst || !canConstantEvolve(OpInst, L)) return nullptr;
PHINode *P = dyn_cast<PHINode>(OpInst);
if (!P)
P = getConstantEvolvingPHIOperands(OpInst, L, PHIMap);
PHIMap[OpInst] = P;
}
- if (P == 0) return 0; // Not evolving from PHI
- if (PHI && PHI != P) return 0; // Evolving from multiple different PHIs.
+ if (!P)
+ return nullptr; // Not evolving from PHI
+ if (PHI && PHI != P)
+ return nullptr; // Evolving from multiple different PHIs.
PHI = P;
}
// This is a expression evolving from a constant PHI!
/// constraints, return null.
static PHINode *getConstantEvolvingPHI(Value *V, const Loop *L) {
Instruction *I = dyn_cast<Instruction>(V);
- if (I == 0 || !canConstantEvolve(I, L)) return 0;
+ if (!I || !canConstantEvolve(I, L)) return nullptr;
if (PHINode *PN = dyn_cast<PHINode>(I)) {
return PN;
/// reason, return null.
static Constant *EvaluateExpression(Value *V, const Loop *L,
DenseMap<Instruction *, Constant *> &Vals,
- const DataLayout *TD,
+ const DataLayout *DL,
const TargetLibraryInfo *TLI) {
// Convenient constant check, but redundant for recursive calls.
if (Constant *C = dyn_cast<Constant>(V)) return C;
Instruction *I = dyn_cast<Instruction>(V);
- if (!I) return 0;
+ if (!I) return nullptr;
if (Constant *C = Vals.lookup(I)) return C;
// An instruction inside the loop depends on a value outside the loop that we
// weren't given a mapping for, or a value such as a call inside the loop.
- if (!canConstantEvolve(I, L)) return 0;
+ if (!canConstantEvolve(I, L)) return nullptr;
// An unmapped PHI can be due to a branch or another loop inside this loop,
// or due to this not being the initial iteration through a loop where we
// couldn't compute the evolution of this particular PHI last time.
- if (isa<PHINode>(I)) return 0;
+ if (isa<PHINode>(I)) return nullptr;
std::vector<Constant*> Operands(I->getNumOperands());
Instruction *Operand = dyn_cast<Instruction>(I->getOperand(i));
if (!Operand) {
Operands[i] = dyn_cast<Constant>(I->getOperand(i));
- if (!Operands[i]) return 0;
+ if (!Operands[i]) return nullptr;
continue;
}
- Constant *C = EvaluateExpression(Operand, L, Vals, TD, TLI);
+ Constant *C = EvaluateExpression(Operand, L, Vals, DL, TLI);
Vals[Operand] = C;
- if (!C) return 0;
+ if (!C) return nullptr;
Operands[i] = C;
}
if (CmpInst *CI = dyn_cast<CmpInst>(I))
return ConstantFoldCompareInstOperands(CI->getPredicate(), Operands[0],
- Operands[1], TD, TLI);
+ Operands[1], DL, TLI);
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
if (!LI->isVolatile())
- return ConstantFoldLoadFromConstPtr(Operands[0], TD);
+ return ConstantFoldLoadFromConstPtr(Operands[0], DL);
}
- return ConstantFoldInstOperands(I->getOpcode(), I->getType(), Operands, TD,
+ return ConstantFoldInstOperands(I->getOpcode(), I->getType(), Operands, DL,
TLI);
}
return I->second;
if (BEs.ugt(MaxBruteForceIterations))
- return ConstantEvolutionLoopExitValue[PN] = 0; // Not going to evaluate it.
+ return ConstantEvolutionLoopExitValue[PN] = nullptr; // Not going to evaluate it.
Constant *&RetVal = ConstantEvolutionLoopExitValue[PN];
// entry must be a constant (coming in from outside of the loop), and the
// second must be derived from the same PHI.
bool SecondIsBackedge = L->contains(PN->getIncomingBlock(1));
- PHINode *PHI = 0;
+ PHINode *PHI = nullptr;
for (BasicBlock::iterator I = Header->begin();
(PHI = dyn_cast<PHINode>(I)); ++I) {
Constant *StartCST =
dyn_cast<Constant>(PHI->getIncomingValue(!SecondIsBackedge));
- if (StartCST == 0) continue;
+ if (!StartCST) continue;
CurrentIterVals[PHI] = StartCST;
}
if (!CurrentIterVals.count(PN))
- return RetVal = 0;
+ return RetVal = nullptr;
Value *BEValue = PN->getIncomingValue(SecondIsBackedge);
// Execute the loop symbolically to determine the exit value.
if (BEs.getActiveBits() >= 32)
- return RetVal = 0; // More than 2^32-1 iterations?? Not doing it!
+ return RetVal = nullptr; // More than 2^32-1 iterations?? Not doing it!
unsigned NumIterations = BEs.getZExtValue(); // must be in range
unsigned IterationNum = 0;
// Compute the value of the PHIs for the next iteration.
// EvaluateExpression adds non-phi values to the CurrentIterVals map.
DenseMap<Instruction *, Constant *> NextIterVals;
- Constant *NextPHI = EvaluateExpression(BEValue, L, CurrentIterVals, TD,
+ Constant *NextPHI = EvaluateExpression(BEValue, L, CurrentIterVals, DL,
TLI);
- if (NextPHI == 0)
- return 0; // Couldn't evaluate!
+ if (!NextPHI)
+ return nullptr; // Couldn't evaluate!
NextIterVals[PN] = NextPHI;
bool StoppedEvolving = NextPHI == CurrentIterVals[PN];
Constant *&NextPHI = NextIterVals[PHI];
if (!NextPHI) { // Not already computed.
Value *BEValue = PHI->getIncomingValue(SecondIsBackedge);
- NextPHI = EvaluateExpression(BEValue, L, CurrentIterVals, TD, TLI);
+ NextPHI = EvaluateExpression(BEValue, L, CurrentIterVals, DL, TLI);
}
if (NextPHI != I->second)
StoppedEvolving = false;
Value *Cond,
bool ExitWhen) {
PHINode *PN = getConstantEvolvingPHI(Cond, L);
- if (PN == 0) return getCouldNotCompute();
+ if (!PN) return getCouldNotCompute();
// If the loop is canonicalized, the PHI will have exactly two entries.
// That's the only form we support here.
// One entry must be a constant (coming in from outside of the loop), and the
// second must be derived from the same PHI.
bool SecondIsBackedge = L->contains(PN->getIncomingBlock(1));
- PHINode *PHI = 0;
+ PHINode *PHI = nullptr;
for (BasicBlock::iterator I = Header->begin();
(PHI = dyn_cast<PHINode>(I)); ++I) {
Constant *StartCST =
dyn_cast<Constant>(PHI->getIncomingValue(!SecondIsBackedge));
- if (StartCST == 0) continue;
+ if (!StartCST) continue;
CurrentIterVals[PHI] = StartCST;
}
if (!CurrentIterVals.count(PN))
for (unsigned IterationNum = 0; IterationNum != MaxIterations;++IterationNum){
ConstantInt *CondVal =
dyn_cast_or_null<ConstantInt>(EvaluateExpression(Cond, L, CurrentIterVals,
- TD, TLI));
+ DL, TLI));
// Couldn't symbolically evaluate.
if (!CondVal) return getCouldNotCompute();
if (NextPHI) continue; // Already computed!
Value *BEValue = PHI->getIncomingValue(SecondIsBackedge);
- NextPHI = EvaluateExpression(BEValue, L, CurrentIterVals, TD, TLI);
+ NextPHI = EvaluateExpression(BEValue, L, CurrentIterVals, DL, TLI);
}
CurrentIterVals.swap(NextIterVals);
}
if (Values[u].first == L)
return Values[u].second ? Values[u].second : V;
}
- Values.push_back(std::make_pair(L, static_cast<const SCEV *>(0)));
+ Values.push_back(std::make_pair(L, static_cast<const SCEV *>(nullptr)));
// Otherwise compute it.
const SCEV *C = computeSCEVAtScope(V, L);
SmallVector<std::pair<const Loop *, const SCEV *>, 2> &Values2 = ValuesAtScopes[V];
/// SCEVConstant, because SCEVConstant is restricted to ConstantInt.
/// Returns NULL if the SCEV isn't representable as a Constant.
static Constant *BuildConstantFromSCEV(const SCEV *V) {
- switch (V->getSCEVType()) {
- default: // TODO: smax, umax.
+ switch (static_cast<SCEVTypes>(V->getSCEVType())) {
case scCouldNotCompute:
case scAddRecExpr:
break;
}
for (unsigned i = 1, e = SA->getNumOperands(); i != e; ++i) {
Constant *C2 = BuildConstantFromSCEV(SA->getOperand(i));
- if (!C2) return 0;
+ if (!C2) return nullptr;
// First pointer!
if (!C->getType()->isPointerTy() && C2->getType()->isPointerTy()) {
// Don't bother trying to sum two pointers. We probably can't
// statically compute a load that results from it anyway.
if (C2->getType()->isPointerTy())
- return 0;
+ return nullptr;
if (PointerType *PTy = dyn_cast<PointerType>(C->getType())) {
if (PTy->getElementType()->isStructTy())
const SCEVMulExpr *SM = cast<SCEVMulExpr>(V);
if (Constant *C = BuildConstantFromSCEV(SM->getOperand(0))) {
// Don't bother with pointers at all.
- if (C->getType()->isPointerTy()) return 0;
+ if (C->getType()->isPointerTy()) return nullptr;
for (unsigned i = 1, e = SM->getNumOperands(); i != e; ++i) {
Constant *C2 = BuildConstantFromSCEV(SM->getOperand(i));
- if (!C2 || C2->getType()->isPointerTy()) return 0;
+ if (!C2 || C2->getType()->isPointerTy()) return nullptr;
C = ConstantExpr::getMul(C, C2);
}
return C;
return ConstantExpr::getUDiv(LHS, RHS);
break;
}
+ case scSMaxExpr:
+ case scUMaxExpr:
+ break; // TODO: smax, umax.
}
- return 0;
+ return nullptr;
}
const SCEV *ScalarEvolution::computeSCEVAtScope(const SCEV *V, const Loop *L) {
// Check to see if getSCEVAtScope actually made an improvement.
if (MadeImprovement) {
- Constant *C = 0;
+ Constant *C = nullptr;
if (const CmpInst *CI = dyn_cast<CmpInst>(I))
C = ConstantFoldCompareInstOperands(CI->getPredicate(),
- Operands[0], Operands[1], TD,
+ Operands[0], Operands[1], DL,
TLI);
else if (const LoadInst *LI = dyn_cast<LoadInst>(I)) {
if (!LI->isVolatile())
- C = ConstantFoldLoadFromConstPtr(Operands[0], TD);
+ C = ConstantFoldLoadFromConstPtr(Operands[0], DL);
} else
C = ConstantFoldInstOperands(I->getOpcode(), I->getType(),
- Operands, TD, TLI);
+ Operands, DL, TLI);
if (!C) return V;
return getSCEV(C);
}
// to 0, it must be counting down to equal 0. Consequently, N = Start / -Step.
// We have not yet seen any such cases.
const SCEVConstant *StepC = dyn_cast<SCEVConstant>(Step);
- if (StepC == 0 || StepC->getValue()->equalsInt(0))
+ if (!StepC || StepC->getValue()->equalsInt(0))
return getCouldNotCompute();
// For positive steps (counting up until unsigned overflow):
else
MaxBECount = getConstant(CountDown ? CR.getUnsignedMax()
: -CR.getUnsignedMin());
- return ExitLimit(Distance, MaxBECount);
+ return ExitLimit(Distance, MaxBECount, /*MustExit=*/true);
}
// If the recurrence is known not to wraparound, unsigned divide computes the
// that the value will either become zero (and thus the loop terminates), that
// the loop will terminate through some other exit condition first, or that
// the loop has undefined behavior. This means we can't "miss" the exit
- // value, even with nonunit stride.
+ // value, even with nonunit stride, and exit later via the same branch. Note
+ // that we can skip this exit if loop later exits via a different
+ // branch. Hence MustExit=false.
//
// This is only valid for expressions that directly compute the loop exit. It
// is invalid for subexpressions in which the loop may exit through this
// branch even if this subexpression is false. In that case, the trip count
// computed by this udiv could be smaller than the number of well-defined
// iterations.
- if (!IsSubExpr && AddRec->getNoWrapFlags(SCEV::FlagNW))
- return getUDivExpr(Distance, CountDown ? getNegativeSCEV(Step) : Step);
+ if (!IsSubExpr && AddRec->getNoWrapFlags(SCEV::FlagNW)) {
+ const SCEV *Exact =
+ getUDivExpr(Distance, CountDown ? getNegativeSCEV(Step) : Step);
+ return ExitLimit(Exact, Exact, /*MustExit=*/false);
+ }
+
+ // If Step is a power of two that evenly divides Start we know that the loop
+ // will always terminate. Start may not be a constant so we just have the
+ // number of trailing zeros available. This is safe even in presence of
+ // overflow as the recurrence will overflow to exactly 0.
+ const APInt &StepV = StepC->getValue()->getValue();
+ if (StepV.isPowerOf2() &&
+ GetMinTrailingZeros(getNegativeSCEV(Start)) >= StepV.countTrailingZeros())
+ return getUDivExactExpr(Distance, CountDown ? getNegativeSCEV(Step) : Step);
// Then, try to solve the above equation provided that Start is constant.
if (const SCEVConstant *StartC = dyn_cast<SCEVConstant>(Start))
default:
llvm_unreachable("Unexpected ICmpInst::Predicate value!");
case ICmpInst::ICMP_SGT:
- Pred = ICmpInst::ICMP_SLT;
std::swap(LHS, RHS);
case ICmpInst::ICMP_SLT: {
ConstantRange LHSRange = getSignedRange(LHS);
break;
}
case ICmpInst::ICMP_SGE:
- Pred = ICmpInst::ICMP_SLE;
std::swap(LHS, RHS);
case ICmpInst::ICMP_SLE: {
ConstantRange LHSRange = getSignedRange(LHS);
break;
}
case ICmpInst::ICMP_UGT:
- Pred = ICmpInst::ICMP_ULT;
std::swap(LHS, RHS);
case ICmpInst::ICMP_ULT: {
ConstantRange LHSRange = getUnsignedRange(LHS);
break;
}
case ICmpInst::ICMP_UGE:
- Pred = ICmpInst::ICMP_ULE;
std::swap(LHS, RHS);
case ICmpInst::ICMP_ULE: {
ConstantRange LHSRange = getUnsignedRange(LHS);
IsSigned ? APIntOps::smin(getSignedRange(RHS).getSignedMax(), Limit)
: APIntOps::umin(getUnsignedRange(RHS).getUnsignedMax(), Limit);
- const SCEV *MaxBECount = getCouldNotCompute();
+ const SCEV *MaxBECount;
if (isa<SCEVConstant>(BECount))
MaxBECount = BECount;
else
if (isa<SCEVCouldNotCompute>(MaxBECount))
MaxBECount = BECount;
- return ExitLimit(BECount, MaxBECount);
+ return ExitLimit(BECount, MaxBECount, /*MustExit=*/true);
}
ScalarEvolution::ExitLimit
if (isa<SCEVCouldNotCompute>(MaxBECount))
MaxBECount = BECount;
- return ExitLimit(BECount, MaxBECount);
+ return ExitLimit(BECount, MaxBECount, /*MustExit=*/true);
}
/// getNumIterationsInRange - Return the number of iterations of this loop that
return SE.getCouldNotCompute();
}
-static const APInt gcd(const SCEVConstant *C1, const SCEVConstant *C2) {
- APInt A = C1->getValue()->getValue().abs();
- APInt B = C2->getValue()->getValue().abs();
- uint32_t ABW = A.getBitWidth();
- uint32_t BBW = B.getBitWidth();
-
- if (ABW > BBW)
- B = B.zext(ABW);
- else if (ABW < BBW)
- A = A.zext(BBW);
-
- return APIntOps::GreatestCommonDivisor(A, B);
-}
-
static const APInt srem(const SCEVConstant *C1, const SCEVConstant *C2) {
APInt A = C1->getValue()->getValue();
APInt B = C2->getValue()->getValue();
if (PartialGCD != One)
return PartialGCD;
+ // Failed to find a PartialGCD: set the Remainder to the full expression,
+ // and return the GCD.
Remainder = Expr;
const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(GCD);
if (!Mul)
- return PartialGCD;
+ return GCD;
// When the GCD is a multiply expression, try to decompose it:
// this occurs when Step does not divide the Start expression
}
}
- return PartialGCD;
+ return GCD;
}
const SCEV *visitUDivExpr(const SCEVUDivExpr *Expr) {
const SCEV *Rem = Zero;
const SCEV *Res = findGCD(SE, Expr->getOperand(0), GCD, &Rem);
+ if (Res == One || Res->isAllOnesValue()) {
+ Remainder = Expr;
+ return GCD;
+ }
+
if (Rem != Zero)
Remainder = SE.getAddExpr(Remainder, Rem);
Rem = Zero;
Res = findGCD(SE, Expr->getOperand(1), Res, &Rem);
- if (Rem != Zero) {
+ if (Rem != Zero || Res == One || Res->isAllOnesValue()) {
Remainder = Expr;
return GCD;
}
Operands.push_back(Expr->getOperand(i));
}
} else {
- FoundGCDTerm = false;
const SCEV *PartialGCD = One;
for (int i = 0, e = Expr->getNumOperands(); i < e; ++i) {
if (PartialGCD == GCD) {
const SCEV *Res = SCEVGCD::findGCD(SE, Expr->getOperand(i), GCD, &Rem);
if (Rem == Zero) {
PartialGCD = SE.getMulExpr(PartialGCD, Res);
- Operands.push_back(divide(SE, Expr->getOperand(i), GCD));
+ Operands.push_back(divide(SE, Expr->getOperand(i), Res));
} else {
Operands.push_back(Expr->getOperand(i));
}
const SCEV *Start = this->getStart();
const SCEV *Step = this->getStepRecurrence(SE);
- // Build the SCEV representation of the cannonical induction variable in the
+ // Build the SCEV representation of the canonical induction variable in the
// loop of this SCEV.
const SCEV *Zero = SE.getConstant(this->getType(), 0);
const SCEV *One = SE.getConstant(this->getType(), 1);
DEBUG(dbgs() << "(delinearize: " << *this << "\n");
- // Currently we fail to delinearize when the stride of this SCEV is 1. We
- // could decide to not fail in this case: we could just return 1 for the size
- // of the subscript, and this same SCEV for the access function.
- if (Step == One) {
- DEBUG(dbgs() << "failed to delinearize " << *this << "\n)\n");
- return this;
- }
+ // When the stride of this SCEV is 1, do not compute the GCD: the size of this
+ // subscript is 1, and this same SCEV for the access function.
+ const SCEV *Remainder = Zero;
+ const SCEV *GCD = One;
// Find the GCD and Remainder of the Start and Step coefficients of this SCEV.
- const SCEV *Remainder = NULL;
- const SCEV *GCD = SCEVGCD::findGCD(SE, Start, Step, &Remainder);
+ if (Step != One && !Step->isAllOnesValue())
+ GCD = SCEVGCD::findGCD(SE, Start, Step, &Remainder);
DEBUG(dbgs() << "GCD: " << *GCD << "\n");
DEBUG(dbgs() << "Remainder: " << *Remainder << "\n");
- // Same remark as above: we currently fail the delinearization, although we
- // can very well handle this special case.
- if (GCD == One) {
- DEBUG(dbgs() << "failed to delinearize " << *this << "\n)\n");
- return this;
- }
+ const SCEV *Quotient = Start;
+ if (GCD != One && !GCD->isAllOnesValue())
+ // As findGCD computed Remainder, GCD divides "Start - Remainder." The
+ // Quotient is then this SCEV without Remainder, scaled down by the GCD. The
+ // Quotient is what will be used in the next subscript delinearization.
+ Quotient = SCEVDivision::divide(SE, SE.getMinusSCEV(Start, Remainder), GCD);
- // As findGCD computed Remainder, GCD divides "Start - Remainder." The
- // Quotient is then this SCEV without Remainder, scaled down by the GCD. The
- // Quotient is what will be used in the next subscript delinearization.
- const SCEV *Quotient =
- SCEVDivision::divide(SE, SE.getMinusSCEV(Start, Remainder), GCD);
DEBUG(dbgs() << "Quotient: " << *Quotient << "\n");
- const SCEV *Rem;
+ const SCEV *Rem = Quotient;
if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Quotient))
// Recursively call delinearize on the Quotient until there are no more
// multiples that can be recognized.
Rem = AR->delinearize(SE, Subscripts, Sizes);
- else
- Rem = Quotient;
- // Scale up the cannonical induction variable IV by whatever remains from the
+ // Scale up the canonical induction variable IV by whatever remains from the
// Step after division by the GCD: the GCD is the size of all the sub-array.
- if (Step != GCD) {
+ if (Step != One && !Step->isAllOnesValue() && GCD != One &&
+ !GCD->isAllOnesValue() && Step != GCD) {
Step = SCEVDivision::divide(SE, Step, GCD);
IV = SE.getMulExpr(IV, Step);
}
- // The access function in the current subscript is computed as the cannonical
+ // The access function in the current subscript is computed as the canonical
// induction variable IV (potentially scaled up by the step) and offset by
// Rem, the offset of delinearization in the sub-array.
const SCEV *Index = SE.getAddExpr(IV, Rem);
// so that future queries will recompute the expressions using the new
// value.
Value *Old = getValPtr();
- SmallVector<User *, 16> Worklist;
+ SmallVector<User *, 16> Worklist(Old->user_begin(), Old->user_end());
SmallPtrSet<User *, 8> Visited;
- for (Value::use_iterator UI = Old->use_begin(), UE = Old->use_end();
- UI != UE; ++UI)
- Worklist.push_back(*UI);
while (!Worklist.empty()) {
User *U = Worklist.pop_back_val();
// Deleting the Old value will cause this to dangle. Postpone
if (PHINode *PN = dyn_cast<PHINode>(U))
SE->ConstantEvolutionLoopExitValue.erase(PN);
SE->ValueExprMap.erase(U);
- for (Value::use_iterator UI = U->use_begin(), UE = U->use_end();
- UI != UE; ++UI)
- Worklist.push_back(*UI);
+ Worklist.insert(Worklist.end(), U->user_begin(), U->user_end());
}
// Delete the Old value.
if (PHINode *PN = dyn_cast<PHINode>(Old))
//===----------------------------------------------------------------------===//
ScalarEvolution::ScalarEvolution()
- : FunctionPass(ID), ValuesAtScopes(64), LoopDispositions(64), BlockDispositions(64), FirstUnknown(0) {
+ : FunctionPass(ID), ValuesAtScopes(64), LoopDispositions(64),
+ BlockDispositions(64), FirstUnknown(nullptr) {
initializeScalarEvolutionPass(*PassRegistry::getPassRegistry());
}
bool ScalarEvolution::runOnFunction(Function &F) {
this->F = &F;
LI = &getAnalysis<LoopInfo>();
- TD = getAnalysisIfAvailable<DataLayout>();
+ DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
+ DL = DLP ? &DLP->getDataLayout() : nullptr;
TLI = &getAnalysis<TargetLibraryInfo>();
- DT = &getAnalysis<DominatorTree>();
+ DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
return false;
}
// destructors, so that they release their references to their values.
for (SCEVUnknown *U = FirstUnknown; U; U = U->Next)
U->~SCEVUnknown();
- FirstUnknown = 0;
+ FirstUnknown = nullptr;
ValueExprMap.clear();
void ScalarEvolution::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequiredTransitive<LoopInfo>();
- AU.addRequiredTransitive<DominatorTree>();
+ AU.addRequiredTransitive<DominatorTreeWrapperPass>();
AU.addRequired<TargetLibraryInfo>();
}
ScalarEvolution::LoopDisposition
ScalarEvolution::computeLoopDisposition(const SCEV *S, const Loop *L) {
- switch (S->getSCEVType()) {
+ switch (static_cast<SCEVTypes>(S->getSCEVType())) {
case scConstant:
return LoopInvariant;
case scTruncate:
return LoopInvariant;
case scCouldNotCompute:
llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
- default: llvm_unreachable("Unknown SCEV kind!");
}
+ llvm_unreachable("Unknown SCEV kind!");
}
bool ScalarEvolution::isLoopInvariant(const SCEV *S, const Loop *L) {
ScalarEvolution::BlockDisposition
ScalarEvolution::computeBlockDisposition(const SCEV *S, const BasicBlock *BB) {
- switch (S->getSCEVType()) {
+ switch (static_cast<SCEVTypes>(S->getSCEVType())) {
case scConstant:
return ProperlyDominatesBlock;
case scTruncate:
return ProperlyDominatesBlock;
case scCouldNotCompute:
llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
- default:
- llvm_unreachable("Unknown SCEV kind!");
}
+ llvm_unreachable("Unknown SCEV kind!");
}
bool ScalarEvolution::dominates(const SCEV *S, const BasicBlock *BB) {
typedef DenseMap<const Loop *, std::string> VerifyMap;
-/// replaceSubString - Replaces all occurences of From in Str with To.
+/// replaceSubString - Replaces all occurrences of From in Str with To.
static void replaceSubString(std::string &Str, StringRef From, StringRef To) {
size_t Pos = 0;
while ((Pos = Str.find(From, Pos)) != std::string::npos) {
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