[llvm-commits] [llvm] r127590 - in /llvm/trunk: include/llvm/Analysis/ScalarEvolution.h include/llvm/Analysis/ScalarEvolutionExpressions.h lib/Analysis/ScalarEvolution.cpp lib/Analysis/ScalarEvolutionExpander.cpp lib/Analysis/ScalarEvolutionNormalization.cpp lib/Transforms/Scalar/LoopIdiomRecognize.cpp lib/Transforms/Scalar/LoopStrengthReduce.cpp
Andrew Trick
atrick at apple.com
Mon Mar 14 09:50:06 PDT 2011
Author: atrick
Date: Mon Mar 14 11:50:06 2011
New Revision: 127590
URL: http://llvm.org/viewvc/llvm-project?rev=127590&view=rev
Log:
Added SCEV::NoWrapFlags to manage unsigned, signed, and self wrap
properties.
Added the self-wrap flag for SCEV::AddRecExpr.
A slew of temporary FIXMEs indicate the intention of the no-self-wrap flag
without changing behavior in this revision.
Modified:
llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpressions.h
llvm/trunk/lib/Analysis/ScalarEvolution.cpp
llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp
llvm/trunk/lib/Analysis/ScalarEvolutionNormalization.cpp
llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
Modified: llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ScalarEvolution.h?rev=127590&r1=127589&r2=127590&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/ScalarEvolution.h (original)
+++ llvm/trunk/include/llvm/Analysis/ScalarEvolution.h Mon Mar 14 11:50:06 2011
@@ -72,6 +72,29 @@
void operator=(const SCEV &); // DO NOT IMPLEMENT
public:
+ /// NoWrapFlags are bitfield indices into SubclassData.
+ ///
+ /// Add and Mul expressions may have no-unsigned-wrap <NUW> or
+ /// no-signed-wrap <NSW> properties, which are derived from the IR
+ /// operator. NSW is a misnomer that we use to mean no signed overflow or
+ /// underflow.
+ ///
+ /// AddRec expression may have a no-self-wraparound <NW> property if the
+ /// result can never reach the start value. This property is independent of
+ /// the actual start value and step direction. Self-wraparound is defined
+ /// purely in terms of the recurrence's loop, step size, and
+ /// bitwidth. Formally, a recurrence with no self-wraparound satisfies:
+ /// abs(step) * max-iteration(loop) <= unsigned-max(bitwidth).
+ ///
+ /// Note that NUW and NSW are also valid properties of a recurrence, and
+ /// either implies NW. For convenience, NW will be set for a recurrence
+ /// whenever either NUW or NSW are set.
+ enum NoWrapFlags { FlagAnyWrap = 0, // No guarantee.
+ FlagNW = (1 << 0), // No self-wrap.
+ FlagNUW = (1 << 1), // No unsigned wrap.
+ FlagNSW = (1 << 2), // No signed wrap.
+ NoWrapMask = (1 << 3) -1 };
+
explicit SCEV(const FoldingSetNodeIDRef ID, unsigned SCEVTy) :
FastID(ID), SCEVType(SCEVTy), SubclassData(0) {}
@@ -159,6 +182,20 @@
ProperlyDominatesBlock ///< The SCEV properly dominates the block.
};
+ /// Convenient NoWrapFlags manipulation that hides enum casts and is
+ /// visible in the ScalarEvolution name space.
+ static SCEV::NoWrapFlags maskFlags(SCEV::NoWrapFlags Flags, int Mask) {
+ return (SCEV::NoWrapFlags)(Flags & Mask);
+ }
+ static SCEV::NoWrapFlags setFlags(SCEV::NoWrapFlags Flags,
+ SCEV::NoWrapFlags OnFlags) {
+ return (SCEV::NoWrapFlags)(Flags | OnFlags);
+ }
+ static SCEV::NoWrapFlags clearFlags(SCEV::NoWrapFlags Flags,
+ SCEV::NoWrapFlags OffFlags) {
+ return (SCEV::NoWrapFlags)(Flags & ~OffFlags);
+ }
+
private:
/// SCEVCallbackVH - A CallbackVH to arrange for ScalarEvolution to be
/// notified whenever a Value is deleted.
@@ -465,44 +502,41 @@
const SCEV *getSignExtendExpr(const SCEV *Op, const Type *Ty);
const SCEV *getAnyExtendExpr(const SCEV *Op, const Type *Ty);
const SCEV *getAddExpr(SmallVectorImpl<const SCEV *> &Ops,
- bool HasNUW = false, bool HasNSW = false);
+ SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap);
const SCEV *getAddExpr(const SCEV *LHS, const SCEV *RHS,
- bool HasNUW = false, bool HasNSW = false) {
+ SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap) {
SmallVector<const SCEV *, 2> Ops;
Ops.push_back(LHS);
Ops.push_back(RHS);
- return getAddExpr(Ops, HasNUW, HasNSW);
+ return getAddExpr(Ops, Flags);
}
- const SCEV *getAddExpr(const SCEV *Op0, const SCEV *Op1,
- const SCEV *Op2,
- bool HasNUW = false, bool HasNSW = false) {
+ const SCEV *getAddExpr(const SCEV *Op0, const SCEV *Op1, const SCEV *Op2,
+ SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap) {
SmallVector<const SCEV *, 3> Ops;
Ops.push_back(Op0);
Ops.push_back(Op1);
Ops.push_back(Op2);
- return getAddExpr(Ops, HasNUW, HasNSW);
+ return getAddExpr(Ops, Flags);
}
const SCEV *getMulExpr(SmallVectorImpl<const SCEV *> &Ops,
- bool HasNUW = false, bool HasNSW = false);
+ SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap);
const SCEV *getMulExpr(const SCEV *LHS, const SCEV *RHS,
- bool HasNUW = false, bool HasNSW = false) {
+ SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap)
+ {
SmallVector<const SCEV *, 2> Ops;
Ops.push_back(LHS);
Ops.push_back(RHS);
- return getMulExpr(Ops, HasNUW, HasNSW);
+ return getMulExpr(Ops, Flags);
}
const SCEV *getUDivExpr(const SCEV *LHS, const SCEV *RHS);
const SCEV *getAddRecExpr(const SCEV *Start, const SCEV *Step,
- const Loop *L,
- bool HasNUW = false, bool HasNSW = false);
+ const Loop *L, SCEV::NoWrapFlags Flags);
const SCEV *getAddRecExpr(SmallVectorImpl<const SCEV *> &Operands,
- const Loop *L,
- bool HasNUW = false, bool HasNSW = false);
+ const Loop *L, SCEV::NoWrapFlags Flags);
const SCEV *getAddRecExpr(const SmallVectorImpl<const SCEV *> &Operands,
- const Loop *L,
- bool HasNUW = false, bool HasNSW = false) {
+ const Loop *L, SCEV::NoWrapFlags Flags) {
SmallVector<const SCEV *, 4> NewOp(Operands.begin(), Operands.end());
- return getAddRecExpr(NewOp, L, HasNUW, HasNSW);
+ return getAddRecExpr(NewOp, L, Flags);
}
const SCEV *getSMaxExpr(const SCEV *LHS, const SCEV *RHS);
const SCEV *getSMaxExpr(SmallVectorImpl<const SCEV *> &Operands);
@@ -537,11 +571,9 @@
///
const SCEV *getNotSCEV(const SCEV *V);
- /// getMinusSCEV - Return LHS-RHS. Minus is represented in SCEV as A+B*-1,
- /// and thus the HasNUW and HasNSW bits apply to the resultant add, not
- /// whether the sub would have overflowed.
+ /// getMinusSCEV - Return LHS-RHS. Minus is represented in SCEV as A+B*-1.
const SCEV *getMinusSCEV(const SCEV *LHS, const SCEV *RHS,
- bool HasNUW = false, bool HasNSW = false);
+ SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap);
/// getTruncateOrZeroExtend - Return a SCEV corresponding to a conversion
/// of the input value to the specified type. If the type must be
Modified: llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpressions.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpressions.h?rev=127590&r1=127589&r2=127590&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpressions.h (original)
+++ llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpressions.h Mon Mar 14 11:50:06 2011
@@ -160,13 +160,8 @@
const Type *getType() const { return getOperand(0)->getType(); }
- bool hasNoUnsignedWrap() const { return SubclassData & (1 << 0); }
- void setHasNoUnsignedWrap(bool B) {
- SubclassData = (SubclassData & ~(1 << 0)) | (B << 0);
- }
- bool hasNoSignedWrap() const { return SubclassData & (1 << 1); }
- void setHasNoSignedWrap(bool B) {
- SubclassData = (SubclassData & ~(1 << 1)) | (B << 1);
+ NoWrapFlags getNoWrapFlags(NoWrapFlags Mask = NoWrapMask) const {
+ return (NoWrapFlags)(SubclassData & Mask);
}
/// Methods for support type inquiry through isa, cast, and dyn_cast:
@@ -199,6 +194,11 @@
S->getSCEVType() == scSMaxExpr ||
S->getSCEVType() == scUMaxExpr;
}
+
+ /// Set flags for a non-recurrence without clearing previously set flags.
+ void setNoWrapFlags(NoWrapFlags Flags) {
+ SubclassData |= Flags;
+ }
};
@@ -305,11 +305,12 @@
/// getStepRecurrence - This method constructs and returns the recurrence
/// indicating how much this expression steps by. If this is a polynomial
/// of degree N, it returns a chrec of degree N-1.
+ /// We cannot determine whether the step recurrence has self-wraparound.
const SCEV *getStepRecurrence(ScalarEvolution &SE) const {
if (isAffine()) return getOperand(1);
return SE.getAddRecExpr(SmallVector<const SCEV *, 3>(op_begin()+1,
op_end()),
- getLoop());
+ getLoop(), FlagAnyWrap);
}
/// isAffine - Return true if this is an affine AddRec (i.e., it represents
@@ -327,6 +328,15 @@
return getNumOperands() == 3;
}
+ /// Set flags for a recurrence without clearing any previously set flags.
+ /// For AddRec, either NUW or NSW implies NW. Keep track of this fact here
+ /// to make it easier to propagate flags.
+ void setNoWrapFlags(NoWrapFlags Flags) {
+ if (Flags & (FlagNUW | FlagNSW))
+ Flags = ScalarEvolution::setFlags(Flags, FlagNW);
+ SubclassData |= Flags;
+ }
+
/// evaluateAtIteration - Return the value of this chain of recurrences at
/// the specified iteration number.
const SCEV *evaluateAtIteration(const SCEV *It, ScalarEvolution &SE) const;
@@ -364,8 +374,7 @@
const SCEV *const *O, size_t N)
: SCEVCommutativeExpr(ID, scSMaxExpr, O, N) {
// Max never overflows.
- setHasNoUnsignedWrap(true);
- setHasNoSignedWrap(true);
+ setNoWrapFlags((NoWrapFlags)(FlagNUW | FlagNSW));
}
public:
@@ -387,8 +396,7 @@
const SCEV *const *O, size_t N)
: SCEVCommutativeExpr(ID, scUMaxExpr, O, N) {
// Max never overflows.
- setHasNoUnsignedWrap(true);
- setHasNoSignedWrap(true);
+ setNoWrapFlags((NoWrapFlags)(FlagNUW | FlagNSW));
}
public:
Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=127590&r1=127589&r2=127590&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Mon Mar 14 11:50:06 2011
@@ -157,10 +157,13 @@
for (unsigned i = 1, e = AR->getNumOperands(); i != e; ++i)
OS << ",+," << *AR->getOperand(i);
OS << "}<";
- if (AR->hasNoUnsignedWrap())
+ if (AR->getNoWrapFlags(FlagNUW))
OS << "nuw><";
- if (AR->hasNoSignedWrap())
+ if (AR->getNoWrapFlags(FlagNSW))
OS << "nsw><";
+ if (AR->getNoWrapFlags(FlagNW) &&
+ !AR->getNoWrapFlags((NoWrapFlags)(FlagNUW | FlagNSW)))
+ OS << "nw><";
WriteAsOperand(OS, AR->getLoop()->getHeader(), /*PrintType=*/false);
OS << ">";
return;
@@ -830,7 +833,7 @@
Operands.push_back(S);
}
if (!hasTrunc)
- return getAddExpr(Operands, false, false);
+ return getAddExpr(Operands);
UniqueSCEVs.FindNodeOrInsertPos(ID, IP); // Mutates IP, returns NULL.
}
@@ -845,7 +848,7 @@
Operands.push_back(S);
}
if (!hasTrunc)
- return getMulExpr(Operands, false, false);
+ return getMulExpr(Operands);
UniqueSCEVs.FindNodeOrInsertPos(ID, IP); // Mutates IP, returns NULL.
}
@@ -854,7 +857,7 @@
SmallVector<const SCEV *, 4> Operands;
for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i)
Operands.push_back(getTruncateExpr(AddRec->getOperand(i), Ty));
- return getAddRecExpr(Operands, AddRec->getLoop());
+ return getAddRecExpr(Operands, AddRec->getLoop(), SCEV::FlagAnyWrap);
}
// As a special case, fold trunc(undef) to undef. We don't want to
@@ -926,10 +929,11 @@
// If we have special knowledge that this addrec won't overflow,
// we don't need to do any further analysis.
- if (AR->hasNoUnsignedWrap())
+ if (AR->getNoWrapFlags(SCEV::FlagNUW))
return getAddRecExpr(getZeroExtendExpr(Start, Ty),
getZeroExtendExpr(Step, Ty),
- L);
+ // FIXME: Can use SCEV::FlagNUW
+ L, SCEV::FlagAnyWrap);
// Check whether the backedge-taken count is SCEVCouldNotCompute.
// Note that this serves two purposes: It filters out loops that are
@@ -963,7 +967,8 @@
// Return the expression with the addrec on the outside.
return getAddRecExpr(getZeroExtendExpr(Start, Ty),
getZeroExtendExpr(Step, Ty),
- L);
+ // FIXME: can use FlagNUW
+ L, SCEV::FlagAnyWrap);
// Similar to above, only this time treat the step value as signed.
// This covers loops that count down.
@@ -977,7 +982,8 @@
// Return the expression with the addrec on the outside.
return getAddRecExpr(getZeroExtendExpr(Start, Ty),
getSignExtendExpr(Step, Ty),
- L);
+ // FIXME: can use FlagNW
+ L, SCEV::FlagAnyWrap);
}
// If the backedge is guarded by a comparison with the pre-inc value
@@ -994,7 +1000,8 @@
// Return the expression with the addrec on the outside.
return getAddRecExpr(getZeroExtendExpr(Start, Ty),
getZeroExtendExpr(Step, Ty),
- L);
+ // FIXME: can use FlagNUW
+ L, SCEV::FlagAnyWrap);
} else if (isKnownNegative(Step)) {
const SCEV *N = getConstant(APInt::getMaxValue(BitWidth) -
getSignedRange(Step).getSignedMin());
@@ -1002,10 +1009,12 @@
(isLoopEntryGuardedByCond(L, ICmpInst::ICMP_UGT, Start, N) &&
isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_UGT,
AR->getPostIncExpr(*this), N)))
- // Return the expression with the addrec on the outside.
+ // Return the expression with the addrec on the outside. The
+ // negative step causes unsigned wrap, but it still can't self-wrap.
return getAddRecExpr(getZeroExtendExpr(Start, Ty),
getSignExtendExpr(Step, Ty),
- L);
+ // FIXME: can use FlagNW
+ L, SCEV::FlagAnyWrap);
}
}
}
@@ -1080,10 +1089,11 @@
// If we have special knowledge that this addrec won't overflow,
// we don't need to do any further analysis.
- if (AR->hasNoSignedWrap())
+ if (AR->getNoWrapFlags(SCEV::FlagNSW))
return getAddRecExpr(getSignExtendExpr(Start, Ty),
getSignExtendExpr(Step, Ty),
- L);
+ // FIXME: can use SCEV::FlagNSW
+ L, SCEV::FlagAnyWrap);
// Check whether the backedge-taken count is SCEVCouldNotCompute.
// Note that this serves two purposes: It filters out loops that are
@@ -1117,7 +1127,8 @@
// Return the expression with the addrec on the outside.
return getAddRecExpr(getSignExtendExpr(Start, Ty),
getSignExtendExpr(Step, Ty),
- L);
+ // FIXME: can use SCEV::FlagNSW
+ L, SCEV::FlagAnyWrap);
// Similar to above, only this time treat the step value as unsigned.
// This covers loops that count up with an unsigned step.
@@ -1131,7 +1142,8 @@
// Return the expression with the addrec on the outside.
return getAddRecExpr(getSignExtendExpr(Start, Ty),
getZeroExtendExpr(Step, Ty),
- L);
+ // FIXME: can use SCEV::FlagNSW
+ L, SCEV::FlagAnyWrap);
}
// If the backedge is guarded by a comparison with the pre-inc value
@@ -1148,7 +1160,8 @@
// Return the expression with the addrec on the outside.
return getAddRecExpr(getSignExtendExpr(Start, Ty),
getSignExtendExpr(Step, Ty),
- L);
+ // FIXME: can use SCEV::FlagNSW
+ L, SCEV::FlagAnyWrap);
} else if (isKnownNegative(Step)) {
const SCEV *N = getConstant(APInt::getSignedMaxValue(BitWidth) -
getSignedRange(Step).getSignedMin());
@@ -1159,7 +1172,8 @@
// Return the expression with the addrec on the outside.
return getAddRecExpr(getSignExtendExpr(Start, Ty),
getSignExtendExpr(Step, Ty),
- L);
+ // FIXME: can use SCEV::FlagNSW
+ L, SCEV::FlagAnyWrap);
}
}
}
@@ -1213,7 +1227,8 @@
for (SCEVAddRecExpr::op_iterator I = AR->op_begin(), E = AR->op_end();
I != E; ++I)
Ops.push_back(getAnyExtendExpr(*I, Ty));
- return getAddRecExpr(Ops, AR->getLoop());
+ // FIXME: can use AR->getNoWrapFlags(SCEV::FlagNW)
+ return getAddRecExpr(Ops, AR->getLoop(), SCEV::FlagAnyWrap);
}
// As a special case, fold anyext(undef) to undef. We don't want to
@@ -1334,7 +1349,9 @@
/// getAddExpr - Get a canonical add expression, or something simpler if
/// possible.
const SCEV *ScalarEvolution::getAddExpr(SmallVectorImpl<const SCEV *> &Ops,
- bool HasNUW, bool HasNSW) {
+ SCEV::NoWrapFlags Flags) {
+ assert(!(Flags & ~(SCEV::FlagNUW | SCEV::FlagNSW)) &&
+ "only nuw or nsw allowed");
assert(!Ops.empty() && "Cannot get empty add!");
if (Ops.size() == 1) return Ops[0];
#ifndef NDEBUG
@@ -1344,8 +1361,8 @@
"SCEVAddExpr operand types don't match!");
#endif
- // If HasNSW is true and all the operands are non-negative, infer HasNUW.
- if (!HasNUW && HasNSW) {
+ // If FlagNSW is true and all the operands are non-negative, infer FlagNUW.
+ if (!(Flags & SCEV::FlagNUW) && (Flags & SCEV::FlagNSW)) {
bool All = true;
for (SmallVectorImpl<const SCEV *>::const_iterator I = Ops.begin(),
E = Ops.end(); I != E; ++I)
@@ -1353,7 +1370,7 @@
All = false;
break;
}
- if (All) HasNUW = true;
+ if (All) Flags = setFlags(Flags, SCEV::FlagNUW);
}
// Sort by complexity, this groups all similar expression types together.
@@ -1404,7 +1421,7 @@
FoundMatch = true;
}
if (FoundMatch)
- return getAddExpr(Ops, HasNUW, HasNSW);
+ return getAddExpr(Ops, Flags);
// Check for truncates. If all the operands are truncated from the same
// type, see if factoring out the truncate would permit the result to be
@@ -1454,7 +1471,7 @@
}
if (Ok) {
// Evaluate the expression in the larger type.
- const SCEV *Fold = getAddExpr(LargeOps, HasNUW, HasNSW);
+ const SCEV *Fold = getAddExpr(LargeOps, Flags);
// If it folds to something simple, use it. Otherwise, don't.
if (isa<SCEVConstant>(Fold) || isa<SCEVUnknown>(Fold))
return getTruncateExpr(Fold, DstType);
@@ -1625,9 +1642,10 @@
// Build the new addrec. Propagate the NUW and NSW flags if both the
// outer add and the inner addrec are guaranteed to have no overflow.
- const SCEV *NewRec = getAddRecExpr(AddRecOps, AddRecLoop,
- HasNUW && AddRec->hasNoUnsignedWrap(),
- HasNSW && AddRec->hasNoSignedWrap());
+ // FIXME: Always propagate NW
+ // AddRec->getNoWrapFlags(setFlags(Flags, SCEV::FlagNW))
+ Flags = AddRec->getNoWrapFlags(Flags);
+ const SCEV *NewRec = getAddRecExpr(AddRecOps, AddRecLoop, Flags);
// If all of the other operands were loop invariant, we are done.
if (Ops.size() == 1) return NewRec;
@@ -1668,7 +1686,8 @@
}
Ops.erase(Ops.begin() + OtherIdx); --OtherIdx;
}
- Ops[Idx] = getAddRecExpr(AddRecOps, AddRecLoop);
+ // Step size has changed, so we cannot guarantee no self-wraparound.
+ Ops[Idx] = getAddRecExpr(AddRecOps, AddRecLoop, SCEV::FlagAnyWrap);
return getAddExpr(Ops);
}
@@ -1692,15 +1711,16 @@
O, Ops.size());
UniqueSCEVs.InsertNode(S, IP);
}
- if (HasNUW) S->setHasNoUnsignedWrap(true);
- if (HasNSW) S->setHasNoSignedWrap(true);
+ S->setNoWrapFlags(Flags);
return S;
}
/// getMulExpr - Get a canonical multiply expression, or something simpler if
/// possible.
const SCEV *ScalarEvolution::getMulExpr(SmallVectorImpl<const SCEV *> &Ops,
- bool HasNUW, bool HasNSW) {
+ SCEV::NoWrapFlags Flags) {
+ assert(Flags == maskFlags(Flags, SCEV::FlagNUW | SCEV::FlagNSW) &&
+ "only nuw or nsw allowed");
assert(!Ops.empty() && "Cannot get empty mul!");
if (Ops.size() == 1) return Ops[0];
#ifndef NDEBUG
@@ -1710,8 +1730,8 @@
"SCEVMulExpr operand types don't match!");
#endif
- // If HasNSW is true and all the operands are non-negative, infer HasNUW.
- if (!HasNUW && HasNSW) {
+ // If FlagNSW is true and all the operands are non-negative, infer FlagNUW.
+ if (!(Flags & SCEV::FlagNUW) && (Flags & SCEV::FlagNSW)) {
bool All = true;
for (SmallVectorImpl<const SCEV *>::const_iterator I = Ops.begin(),
E = Ops.end(); I != E; ++I)
@@ -1719,7 +1739,7 @@
All = false;
break;
}
- if (All) HasNUW = true;
+ if (All) Flags = setFlags(Flags, SCEV::FlagNUW);
}
// Sort by complexity, this groups all similar expression types together.
@@ -1759,12 +1779,12 @@
} else if (Ops[0]->isAllOnesValue()) {
// If we have a mul by -1 of an add, try distributing the -1 among the
// add operands.
- if (Ops.size() == 2)
+ if (Ops.size() == 2) {
if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Ops[1])) {
SmallVector<const SCEV *, 4> NewOps;
bool AnyFolded = false;
- for (SCEVAddRecExpr::op_iterator I = Add->op_begin(), E = Add->op_end();
- I != E; ++I) {
+ for (SCEVAddRecExpr::op_iterator I = Add->op_begin(),
+ E = Add->op_end(); I != E; ++I) {
const SCEV *Mul = getMulExpr(Ops[0], *I);
if (!isa<SCEVMulExpr>(Mul)) AnyFolded = true;
NewOps.push_back(Mul);
@@ -1772,6 +1792,7 @@
if (AnyFolded)
return getAddExpr(NewOps);
}
+ }
}
if (Ops.size() == 1)
@@ -1831,9 +1852,11 @@
// Build the new addrec. Propagate the NUW and NSW flags if both the
// outer mul and the inner addrec are guaranteed to have no overflow.
- const SCEV *NewRec = getAddRecExpr(NewOps, AddRecLoop,
- HasNUW && AddRec->hasNoUnsignedWrap(),
- HasNSW && AddRec->hasNoSignedWrap());
+ //
+ // No self-wrap cannot be guaranteed after changing the step size, but
+ // will be infered if either NUW or NSW is true.
+ Flags = AddRec->getNoWrapFlags(clearFlags(Flags, SCEV::FlagNW));
+ const SCEV *NewRec = getAddRecExpr(NewOps, AddRecLoop, Flags);
// If all of the other operands were loop invariant, we are done.
if (Ops.size() == 1) return NewRec;
@@ -1869,7 +1892,8 @@
getMulExpr(G, B),
getMulExpr(B, D));
const SCEV *NewAddRec = getAddRecExpr(NewStart, NewStep,
- F->getLoop());
+ F->getLoop(),
+ SCEV::FlagAnyWrap);
if (Ops.size() == 2) return NewAddRec;
Ops[Idx] = AddRec = cast<SCEVAddRecExpr>(NewAddRec);
Ops.erase(Ops.begin() + OtherIdx); --OtherIdx;
@@ -1897,8 +1921,7 @@
O, Ops.size());
UniqueSCEVs.InsertNode(S, IP);
}
- if (HasNUW) S->setHasNoUnsignedWrap(true);
- if (HasNSW) S->setHasNoSignedWrap(true);
+ S->setNoWrapFlags(Flags);
return S;
}
@@ -1938,11 +1961,13 @@
getZeroExtendExpr(AR, ExtTy) ==
getAddRecExpr(getZeroExtendExpr(AR->getStart(), ExtTy),
getZeroExtendExpr(Step, ExtTy),
- AR->getLoop())) {
+ AR->getLoop(), SCEV::FlagAnyWrap)) {
SmallVector<const SCEV *, 4> Operands;
for (unsigned i = 0, e = AR->getNumOperands(); i != e; ++i)
Operands.push_back(getUDivExpr(AR->getOperand(i), RHS));
- return getAddRecExpr(Operands, AR->getLoop());
+ return getAddRecExpr(Operands, AR->getLoop(),
+ // FIXME: AR->getNoWrapFlags(SCEV::FlagNW)
+ SCEV::FlagAnyWrap);
}
// (A*B)/C --> A*(B/C) if safe and B/C can be folded.
if (const SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(LHS)) {
@@ -2006,27 +2031,27 @@
/// getAddRecExpr - Get an add recurrence expression for the specified loop.
/// Simplify the expression as much as possible.
-const SCEV *ScalarEvolution::getAddRecExpr(const SCEV *Start,
- const SCEV *Step, const Loop *L,
- bool HasNUW, bool HasNSW) {
+const SCEV *ScalarEvolution::getAddRecExpr(const SCEV *Start, const SCEV *Step,
+ const Loop *L,
+ SCEV::NoWrapFlags Flags) {
SmallVector<const SCEV *, 4> Operands;
Operands.push_back(Start);
if (const SCEVAddRecExpr *StepChrec = dyn_cast<SCEVAddRecExpr>(Step))
if (StepChrec->getLoop() == L) {
Operands.append(StepChrec->op_begin(), StepChrec->op_end());
- return getAddRecExpr(Operands, L);
+ // FIXME: can use maskFlags(Flags, SCEV::FlagNW)
+ return getAddRecExpr(Operands, L, SCEV::FlagAnyWrap);
}
Operands.push_back(Step);
- return getAddRecExpr(Operands, L, HasNUW, HasNSW);
+ return getAddRecExpr(Operands, L, Flags);
}
/// getAddRecExpr - Get an add recurrence expression for the specified loop.
/// Simplify the expression as much as possible.
const SCEV *
ScalarEvolution::getAddRecExpr(SmallVectorImpl<const SCEV *> &Operands,
- const Loop *L,
- bool HasNUW, bool HasNSW) {
+ const Loop *L, SCEV::NoWrapFlags Flags) {
if (Operands.size() == 1) return Operands[0];
#ifndef NDEBUG
const Type *ETy = getEffectiveSCEVType(Operands[0]->getType());
@@ -2040,7 +2065,7 @@
if (Operands.back()->isZero()) {
Operands.pop_back();
- return getAddRecExpr(Operands, L, HasNUW, HasNSW); // {X,+,0} --> X
+ return getAddRecExpr(Operands, L, SCEV::FlagAnyWrap); // {X,+,0} --> X
}
// It's tempting to want to call getMaxBackedgeTakenCount count here and
@@ -2049,8 +2074,8 @@
// meaningful BE count at this point (and if we don't, we'd be stuck
// with a SCEVCouldNotCompute as the cached BE count).
- // If HasNSW is true and all the operands are non-negative, infer HasNUW.
- if (!HasNUW && HasNSW) {
+ // If FlagNSW is true and all the operands are non-negative, infer FlagNUW.
+ if (!(Flags & SCEV::FlagNUW) && (Flags & SCEV::FlagNSW)) {
bool All = true;
for (SmallVectorImpl<const SCEV *>::const_iterator I = Operands.begin(),
E = Operands.end(); I != E; ++I)
@@ -2058,7 +2083,7 @@
All = false;
break;
}
- if (All) HasNUW = true;
+ if (All) Flags = setFlags(Flags, SCEV::FlagNUW);
}
// Canonicalize nested AddRecs in by nesting them in order of loop depth.
@@ -2081,16 +2106,31 @@
break;
}
if (AllInvariant) {
- NestedOperands[0] = getAddRecExpr(Operands, L);
+ // Create a recurrence for the outer loop with the same step size.
+ //
+ // FIXME:
+ // The outer recurrence keeps its NW flag but only keeps NUW/NSW if the
+ // inner recurrence has the same property.
+ // maskFlags(Flags, SCEV::FlagNW | NestedAR->getNoWrapFlags());
+ SCEV::NoWrapFlags OuterFlags = SCEV::FlagAnyWrap;
+
+ NestedOperands[0] = getAddRecExpr(Operands, L, OuterFlags);
AllInvariant = true;
for (unsigned i = 0, e = NestedOperands.size(); i != e; ++i)
if (!isLoopInvariant(NestedOperands[i], NestedLoop)) {
AllInvariant = false;
break;
}
- if (AllInvariant)
+ if (AllInvariant) {
// Ok, both add recurrences are valid after the transformation.
- return getAddRecExpr(NestedOperands, NestedLoop, HasNUW, HasNSW);
+ //
+ // FIXME:
+ // The inner recurrence keeps its NW flag but only keeps NUW/NSW if
+ // the outer recurrence has the same property.
+ // maskFlags(NestedAR->getNoWrapFlags(), SCEV::FlagNW | Flags);
+ SCEV::NoWrapFlags InnerFlags = SCEV::FlagAnyWrap;
+ return getAddRecExpr(NestedOperands, NestedLoop, InnerFlags);
+ }
}
// Reset Operands to its original state.
Operands[0] = NestedAR;
@@ -2114,8 +2154,7 @@
O, Operands.size(), L);
UniqueSCEVs.InsertNode(S, IP);
}
- if (HasNUW) S->setHasNoUnsignedWrap(true);
- if (HasNSW) S->setHasNoSignedWrap(true);
+ S->setNoWrapFlags(Flags);
return S;
}
@@ -2510,17 +2549,17 @@
return getMinusSCEV(AllOnes, V);
}
-/// getMinusSCEV - Return LHS-RHS. Minus is represented in SCEV as A+B*-1,
-/// and thus the HasNUW and HasNSW bits apply to the resultant add, not
-/// whether the sub would have overflowed.
+/// getMinusSCEV - Return LHS-RHS. Minus is represented in SCEV as A+B*-1.
+///
+/// FIXME: prohibit FlagNUW here, as soon as getMinusSCEVForExitTest goes.
const SCEV *ScalarEvolution::getMinusSCEV(const SCEV *LHS, const SCEV *RHS,
- bool HasNUW, bool HasNSW) {
+ SCEV::NoWrapFlags Flags) {
// Fast path: X - X --> 0.
if (LHS == RHS)
return getConstant(LHS->getType(), 0);
// X - Y --> X + -Y
- return getAddExpr(LHS, getNegativeSCEV(RHS), HasNUW, HasNSW);
+ return getAddExpr(LHS, getNegativeSCEV(RHS), Flags);
}
/// getTruncateOrZeroExtend - Return a SCEV corresponding to a conversion of the
@@ -2773,44 +2812,35 @@
if (isLoopInvariant(Accum, L) ||
(isa<SCEVAddRecExpr>(Accum) &&
cast<SCEVAddRecExpr>(Accum)->getLoop() == L)) {
- bool HasNUW = false;
- bool HasNSW = false;
+ SCEV::NoWrapFlags Flags = SCEV::FlagAnyWrap;
// If the increment doesn't overflow, then neither the addrec nor
// the post-increment will overflow.
if (const AddOperator *OBO = dyn_cast<AddOperator>(BEValueV)) {
if (OBO->hasNoUnsignedWrap())
- HasNUW = true;
+ Flags = setFlags(Flags, SCEV::FlagNUW);
if (OBO->hasNoSignedWrap())
- HasNSW = true;
+ Flags = setFlags(Flags, SCEV::FlagNSW);
} else if (const GEPOperator *GEP =
- dyn_cast<GEPOperator>(BEValueV)) {
- // If the increment is a GEP, then we know it won't perform a
- // signed overflow, because the address space cannot be
- // wrapped around.
- //
- // NOTE: This isn't strictly true, because you could have an
- // object straddling the 2G address boundary in a 32-bit address
- // space (for example). We really want to model this as a "has
- // no signed/unsigned wrap" where the base pointer is treated as
- // unsigned and the increment is known to not have signed
- // wrapping.
- //
- // This is a highly theoretical concern though, and this is good
- // enough for all cases we know of at this point. :)
- //
- HasNSW |= GEP->isInBounds();
+ dyn_cast<GEPOperator>(BEValueV)) {
+ // If the increment is an inbounds GEP, then we know the address
+ // space cannot be wrapped around. We cannot make any guarantee
+ // about signed or unsigned overflow because pointers are
+ // unsigned but we may have a negative index from the base
+ // pointer.
+ if (GEP->isInBounds())
+ // FIXME: should be SCEV::FlagNW
+ Flags = setFlags(Flags, SCEV::FlagNSW);
}
const SCEV *StartVal = getSCEV(StartValueV);
- const SCEV *PHISCEV =
- getAddRecExpr(StartVal, Accum, L, HasNUW, HasNSW);
+ const SCEV *PHISCEV = getAddRecExpr(StartVal, Accum, L, Flags);
// Since the no-wrap flags are on the increment, they apply to the
// post-incremented value as well.
if (isLoopInvariant(Accum, L))
(void)getAddRecExpr(getAddExpr(StartVal, Accum),
- Accum, L, HasNUW, HasNSW);
+ Accum, L, Flags);
// Okay, for the entire analysis of this edge we assumed the PHI
// to be symbolic. We now need to go back and purge all of the
@@ -2834,8 +2864,11 @@
// initial step of the addrec evolution.
if (StartVal == getMinusSCEV(AddRec->getOperand(0),
AddRec->getOperand(1))) {
+ // FIXME: For constant StartVal, we should be able to infer
+ // no-wrap flags.
const SCEV *PHISCEV =
- getAddRecExpr(StartVal, AddRec->getOperand(1), L);
+ getAddRecExpr(StartVal, AddRec->getOperand(1), L,
+ SCEV::FlagAnyWrap);
// Okay, for the entire analysis of this edge we assumed the PHI
// to be symbolic. We now need to go back and purge all of the
@@ -2899,8 +2932,9 @@
IndexS = getTruncateOrSignExtend(IndexS, IntPtrTy);
// Multiply the index by the element size to compute the element offset.
- const SCEV *LocalOffset = getMulExpr(IndexS, ElementSize, /*NUW*/ false,
- /*NSW*/ isInBounds);
+ const SCEV *LocalOffset = getMulExpr(IndexS, ElementSize,
+ isInBounds ? SCEV::FlagNSW :
+ SCEV::FlagAnyWrap);
// Add the element offset to the running total offset.
TotalOffset = getAddExpr(TotalOffset, LocalOffset);
@@ -2911,8 +2945,8 @@
const SCEV *BaseS = getSCEV(Base);
// Add the total offset from all the GEP indices to the base.
- return getAddExpr(BaseS, TotalOffset, /*NUW*/ false,
- /*NSW*/ isInBounds);
+ return getAddExpr(BaseS, TotalOffset,
+ isInBounds ? SCEV::FlagNSW : SCEV::FlagAnyWrap);
}
/// GetMinTrailingZeros - Determine the minimum number of zero bits that S is
@@ -3074,7 +3108,8 @@
if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(S)) {
// If there's no unsigned wrap, the value will never be less than its
// initial value.
- if (AddRec->hasNoUnsignedWrap())
+ // FIXME: can broaden to FlagNW?
+ if (AddRec->getNoWrapFlags(SCEV::FlagNUW))
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(AddRec->getStart()))
if (!C->getValue()->isZero())
ConservativeResult =
@@ -3216,7 +3251,7 @@
if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(S)) {
// If there's no signed wrap, and all the operands have the same sign or
// zero, the value won't ever change sign.
- if (AddRec->hasNoSignedWrap()) {
+ if (AddRec->getNoWrapFlags(SCEV::FlagNSW)) {
bool AllNonNeg = true;
bool AllNonPos = true;
for (unsigned i = 0, e = AddRec->getNumOperands(); i != e; ++i) {
@@ -3411,10 +3446,8 @@
// transfer the no-wrap flags, since an or won't introduce a wrap.
if (const SCEVAddRecExpr *NewAR = dyn_cast<SCEVAddRecExpr>(S)) {
const SCEVAddRecExpr *OldAR = cast<SCEVAddRecExpr>(LHS);
- if (OldAR->hasNoUnsignedWrap())
- const_cast<SCEVAddRecExpr *>(NewAR)->setHasNoUnsignedWrap(true);
- if (OldAR->hasNoSignedWrap())
- const_cast<SCEVAddRecExpr *>(NewAR)->setHasNoSignedWrap(true);
+ const_cast<SCEVAddRecExpr *>(NewAR)->setNoWrapFlags(
+ OldAR->getNoWrapFlags());
}
return S;
}
@@ -4031,7 +4064,7 @@
return 0;
// The SCEV must be known to not wrap in some way to be interesting.
- if (!SA->hasNoUnsignedWrap() && !SA->hasNoSignedWrap())
+ if (!SA->getNoWrapFlags(SCEV::FlagNW))
return 0;
// The stride must be a constant so that we know if it is striding up or down.
@@ -4046,14 +4079,15 @@
/// advantage of the fact that this subtraction is only being used in a
/// comparison by zero context.
///
+/// FIXME: this can be completely removed once AddRec FlagNWs are propagated.
static const SCEV *getMinusSCEVForExitTest(const SCEV *LHS, const SCEV *RHS,
const Loop *L, ScalarEvolution &SE) {
// If either LHS or RHS is an AddRec SCEV (of this loop) that is known to not
- // wrap (either NSW or NUW), then we know that the value will either become
- // the other one (and thus the loop terminates), that the loop will terminate
- // through some other exit condition first, or that the loop has undefined
- // behavior. This information is useful when the addrec has a stride that is
- // != 1 or -1, because it means we can't "miss" the exit value.
+ // self-wrap, then we know that the value will either become the other one
+ // (and thus the loop terminates), that the loop will terminate through some
+ // other exit condition first, or that the loop has undefined behavior. This
+ // information is useful when the addrec has a stride that is != 1 or -1,
+ // because it means we can't "miss" the exit value.
//
// In any of these three cases, it is safe to turn the exit condition into a
// "counting down" AddRec (to zero) by subtracting the two inputs as normal,
@@ -4090,7 +4124,7 @@
if (Stride->getValue().isNegative())
std::swap(LHS, RHS);
- return SE.getMinusSCEV(RHS, LHS, true /*HasNUW*/);
+ return SE.getMinusSCEV(RHS, LHS, SCEV::FlagNUW);
}
// If both LHS and RHS are interesting, we have something like:
@@ -4118,7 +4152,7 @@
std::swap(LHS, RHS);
}
- return SE.getMinusSCEV(LHS, RHS, true /*HasNUW*/);
+ return SE.getMinusSCEV(LHS, RHS, SCEV::FlagNUW);
}
/// ComputeBackedgeTakenCountFromExitCondICmp - Compute the number of times the
@@ -4180,6 +4214,8 @@
switch (Cond) {
case ICmpInst::ICMP_NE: { // while (X != Y)
// Convert to: while (X-Y != 0)
+ // FIXME: Once AddRec FlagNW are propagated, should be:
+ // BackedgeTakenInfo BTI = HowFarToZero(getMinusSCEV(LHS, RHS), L);
BackedgeTakenInfo BTI = HowFarToZero(getMinusSCEVForExitTest(LHS, RHS, L,
*this), L);
if (BTI.hasAnyInfo()) return BTI;
@@ -4706,7 +4742,10 @@
for (++i; i != e; ++i)
NewOps.push_back(getSCEVAtScope(AddRec->getOperand(i), L));
- AddRec = cast<SCEVAddRecExpr>(getAddRecExpr(NewOps, AddRec->getLoop()));
+ AddRec = cast<SCEVAddRecExpr>(
+ getAddRecExpr(NewOps, AddRec->getLoop(),
+ // FIXME: AddRec->getNoWrapFlags(SCEV::FlagNW)
+ SCEV::FlagAnyWrap));
break;
}
@@ -4871,6 +4910,11 @@
/// HowFarToZero - Return the number of times a backedge comparing the specified
/// value to zero will execute. If not computable, return CouldNotCompute.
+///
+/// This is only used for loops with a "x != y" exit test. The exit condition is
+/// now expressed as a single expression, V = x-y. So the exit test is
+/// effectively V != 0. We know and take advantage of the fact that this
+/// expression only being used in a comparison by zero context.
ScalarEvolution::BackedgeTakenInfo
ScalarEvolution::HowFarToZero(const SCEV *V, const Loop *L) {
// If the value is a constant
@@ -4939,21 +4983,34 @@
// down, it cannot "miss" 0 (which would cause it to wrap), regardless of what
// the stride is. As such, NUW addrec's will always become zero in
// "start / -stride" steps, and we know that the division is exact.
- if (AddRec->hasNoUnsignedWrap())
+ if (AddRec->getNoWrapFlags(SCEV::FlagNUW))
// FIXME: We really want an "isexact" bit for udiv.
return getUDivExpr(Start, getNegativeSCEV(Step));
// For now we handle only constant steps.
+ //
+ // TODO: Handle a nonconstant Step given AddRec<NUW>. If the
+ // AddRec is NUW, then (in an unsigned sense) it cannot be counting up to wrap
+ // 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)
return getCouldNotCompute();
- // First, handle unitary steps.
+ // For positive steps (counting up until unsigned overflow):
+ // N = -Start/Step (as unsigned)
+ // For negative steps (counting down to zero):
+ // N = Start/-Step
+ // First compute the unsigned distance from zero in the direction of Step.
+ const SCEV *Distance = StepC->getValue()->getValue().isNonNegative() ?
+ getNegativeSCEV(Start) : Start;
+
+ // Handle unitary steps, which cannot wraparound.
if (StepC->getValue()->equalsInt(1)) // 1*N = -Start (mod 2^BW), so:
- return getNegativeSCEV(Start); // N = -Start (as unsigned)
+ return Distance; // N = -Start (as unsigned)
if (StepC->getValue()->isAllOnesValue()) // -1*N = -Start (mod 2^BW), so:
- return Start; // N = Start (as unsigned)
+ return Distance; // N = Start (as unsigned)
// Then, try to solve the above equation provided that Start is constant.
if (const SCEVConstant *StartC = dyn_cast<SCEVConstant>(Start))
@@ -5220,12 +5277,12 @@
case ICmpInst::ICMP_SLE:
if (!getSignedRange(RHS).getSignedMax().isMaxSignedValue()) {
RHS = getAddExpr(getConstant(RHS->getType(), 1, true), RHS,
- /*HasNUW=*/false, /*HasNSW=*/true);
+ SCEV::FlagNSW);
Pred = ICmpInst::ICMP_SLT;
Changed = true;
} else if (!getSignedRange(LHS).getSignedMin().isMinSignedValue()) {
LHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), LHS,
- /*HasNUW=*/false, /*HasNSW=*/true);
+ SCEV::FlagNSW);
Pred = ICmpInst::ICMP_SLT;
Changed = true;
}
@@ -5233,12 +5290,12 @@
case ICmpInst::ICMP_SGE:
if (!getSignedRange(RHS).getSignedMin().isMinSignedValue()) {
RHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), RHS,
- /*HasNUW=*/false, /*HasNSW=*/true);
+ SCEV::FlagNSW);
Pred = ICmpInst::ICMP_SGT;
Changed = true;
} else if (!getSignedRange(LHS).getSignedMax().isMaxSignedValue()) {
LHS = getAddExpr(getConstant(RHS->getType(), 1, true), LHS,
- /*HasNUW=*/false, /*HasNSW=*/true);
+ SCEV::FlagNSW);
Pred = ICmpInst::ICMP_SGT;
Changed = true;
}
@@ -5246,12 +5303,12 @@
case ICmpInst::ICMP_ULE:
if (!getUnsignedRange(RHS).getUnsignedMax().isMaxValue()) {
RHS = getAddExpr(getConstant(RHS->getType(), 1, true), RHS,
- /*HasNUW=*/true, /*HasNSW=*/false);
+ SCEV::FlagNUW);
Pred = ICmpInst::ICMP_ULT;
Changed = true;
} else if (!getUnsignedRange(LHS).getUnsignedMin().isMinValue()) {
LHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), LHS,
- /*HasNUW=*/true, /*HasNSW=*/false);
+ SCEV::FlagNUW);
Pred = ICmpInst::ICMP_ULT;
Changed = true;
}
@@ -5259,12 +5316,12 @@
case ICmpInst::ICMP_UGE:
if (!getUnsignedRange(RHS).getUnsignedMin().isMinValue()) {
RHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), RHS,
- /*HasNUW=*/true, /*HasNSW=*/false);
+ SCEV::FlagNUW);
Pred = ICmpInst::ICMP_UGT;
Changed = true;
} else if (!getUnsignedRange(LHS).getUnsignedMax().isMaxValue()) {
LHS = getAddExpr(getConstant(RHS->getType(), 1, true), LHS,
- /*HasNUW=*/true, /*HasNSW=*/false);
+ SCEV::FlagNUW);
Pred = ICmpInst::ICMP_UGT;
Changed = true;
}
@@ -5690,8 +5747,8 @@
return getCouldNotCompute();
// Check to see if we have a flag which makes analysis easy.
- bool NoWrap = isSigned ? AddRec->hasNoSignedWrap() :
- AddRec->hasNoUnsignedWrap();
+ bool NoWrap = isSigned ? AddRec->getNoWrapFlags(SCEV::FlagNSW) :
+ AddRec->getNoWrapFlags(SCEV::FlagNUW);
if (AddRec->isAffine()) {
unsigned BitWidth = getTypeSizeInBits(AddRec->getType());
@@ -5807,7 +5864,9 @@
if (!SC->getValue()->isZero()) {
SmallVector<const SCEV *, 4> Operands(op_begin(), op_end());
Operands[0] = SE.getConstant(SC->getType(), 0);
- const SCEV *Shifted = SE.getAddRecExpr(Operands, getLoop());
+ const SCEV *Shifted = SE.getAddRecExpr(Operands, getLoop(),
+ // FIXME: getNoWrapFlags(FlagNW)
+ FlagAnyWrap);
if (const SCEVAddRecExpr *ShiftedAddRec =
dyn_cast<SCEVAddRecExpr>(Shifted))
return ShiftedAddRec->getNumIterationsInRange(
@@ -5868,7 +5927,9 @@
// Range.getUpper() is crossed.
SmallVector<const SCEV *, 4> NewOps(op_begin(), op_end());
NewOps[0] = SE.getNegativeSCEV(SE.getConstant(Range.getUpper()));
- const SCEV *NewAddRec = SE.getAddRecExpr(NewOps, getLoop());
+ const SCEV *NewAddRec = SE.getAddRecExpr(NewOps, getLoop(),
+ // getNoWrapFlags(FlagNW)
+ FlagAnyWrap);
// Next, solve the constructed addrec
std::pair<const SCEV *,const SCEV *> Roots =
Modified: llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp?rev=127590&r1=127589&r2=127590&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp Mon Mar 14 11:50:06 2011
@@ -262,7 +262,8 @@
const SCEV *Start = A->getStart();
if (!FactorOutConstant(Start, Remainder, Factor, SE, TD))
return false;
- S = SE.getAddRecExpr(Start, Step, A->getLoop());
+ // FIXME: can use A->getNoWrapFlags(FlagNW)
+ S = SE.getAddRecExpr(Start, Step, A->getLoop(), SCEV::FlagAnyWrap);
return true;
}
@@ -314,7 +315,9 @@
const SCEV *Zero = SE.getConstant(Ty, 0);
AddRecs.push_back(SE.getAddRecExpr(Zero,
A->getStepRecurrence(SE),
- A->getLoop()));
+ A->getLoop(),
+ // FIXME: A->getNoWrapFlags(FlagNW)
+ SCEV::FlagAnyWrap));
if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Start)) {
Ops[i] = Zero;
Ops.append(Add->op_begin(), Add->op_end());
@@ -823,7 +826,9 @@
Rest = SE.getAddExpr(Rest,
SE.getAddRecExpr(SE.getConstant(A->getType(), 0),
A->getStepRecurrence(SE),
- A->getLoop()));
+ A->getLoop(),
+ // FIXME: A->getNoWrapFlags(FlagNW)
+ SCEV::FlagAnyWrap));
}
if (const SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(Base)) {
Base = A->getOperand(A->getNumOperands()-1);
@@ -1005,10 +1010,11 @@
if (!SE.properlyDominates(Start, L->getHeader())) {
PostLoopOffset = Start;
Start = SE.getConstant(Normalized->getType(), 0);
- Normalized =
- cast<SCEVAddRecExpr>(SE.getAddRecExpr(Start,
- Normalized->getStepRecurrence(SE),
- Normalized->getLoop()));
+ Normalized = cast<SCEVAddRecExpr>(
+ SE.getAddRecExpr(Start, Normalized->getStepRecurrence(SE),
+ Normalized->getLoop(),
+ // FIXME: Normalized->getNoWrapFlags(FlagNW)
+ SCEV::FlagAnyWrap));
}
// Strip off any non-loop-dominating component from the addrec step.
@@ -1019,7 +1025,10 @@
Step = SE.getConstant(Normalized->getType(), 1);
Normalized =
cast<SCEVAddRecExpr>(SE.getAddRecExpr(Start, Step,
- Normalized->getLoop()));
+ Normalized->getLoop(),
+ // FIXME: Normalized
+ // ->getNoWrapFlags(FlagNW)
+ SCEV::FlagAnyWrap));
}
// Expand the core addrec. If we need post-loop scaling, force it to
@@ -1082,7 +1091,9 @@
SmallVector<const SCEV *, 4> NewOps(S->getNumOperands());
for (unsigned i = 0, e = S->getNumOperands(); i != e; ++i)
NewOps[i] = SE.getAnyExtendExpr(S->op_begin()[i], CanonicalIV->getType());
- Value *V = expand(SE.getAddRecExpr(NewOps, S->getLoop()));
+ Value *V = expand(SE.getAddRecExpr(NewOps, S->getLoop(),
+ // FIXME: S->getNoWrapFlags(FlagNW)
+ SCEV::FlagAnyWrap));
BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
BasicBlock::iterator NewInsertPt =
@@ -1099,7 +1110,8 @@
if (!S->getStart()->isZero()) {
SmallVector<const SCEV *, 4> NewOps(S->op_begin(), S->op_end());
NewOps[0] = SE.getConstant(Ty, 0);
- const SCEV *Rest = SE.getAddRecExpr(NewOps, L);
+ // FIXME: can use S->getNoWrapFlags()
+ const SCEV *Rest = SE.getAddRecExpr(NewOps, L, SCEV::FlagAnyWrap);
// Turn things like ptrtoint+arithmetic+inttoptr into GEP. See the
// comments on expandAddToGEP for details.
@@ -1334,7 +1346,7 @@
InsertedValues.insert(I);
// If we just claimed an existing instruction and that instruction had
- // been the insert point, adjust the insert point forward so that
+ // been the insert point, adjust the insert point forward so that
// subsequently inserted code will be dominated.
if (Builder.GetInsertPoint() == I) {
BasicBlock::iterator It = cast<Instruction>(I);
@@ -1362,8 +1374,9 @@
assert(Ty->isIntegerTy() && "Can only insert integer induction variables!");
// Build a SCEV for {0,+,1}<L>.
+ // Conservatively use FlagAnyWrap for now.
const SCEV *H = SE.getAddRecExpr(SE.getConstant(Ty, 0),
- SE.getConstant(Ty, 1), L);
+ SE.getConstant(Ty, 1), L, SCEV::FlagAnyWrap);
// Emit code for it.
BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
Modified: llvm/trunk/lib/Analysis/ScalarEvolutionNormalization.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolutionNormalization.cpp?rev=127590&r1=127589&r2=127590&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolutionNormalization.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolutionNormalization.cpp Mon Mar 14 11:50:06 2011
@@ -97,7 +97,8 @@
const SCEV *N = TransformForPostIncUse(Kind, O, LUser, 0, Loops, SE, DT);
Operands.push_back(N);
}
- const SCEV *Result = SE.getAddRecExpr(Operands, L);
+ // Conservatively use AnyWrap until/unless we need FlagNW.
+ const SCEV *Result = SE.getAddRecExpr(Operands, L, SCEV::FlagAnyWrap);
switch (Kind) {
default: llvm_unreachable("Unexpected transform name!");
case NormalizeAutodetect:
Modified: llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp?rev=127590&r1=127589&r2=127590&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp Mon Mar 14 11:50:06 2011
@@ -485,10 +485,10 @@
BECount = SE->getTruncateOrZeroExtend(BECount, IntPtr);
const SCEV *NumBytesS = SE->getAddExpr(BECount, SE->getConstant(IntPtr, 1),
- true /*no unsigned overflow*/);
+ SCEV::FlagNUW);
if (StoreSize != 1)
NumBytesS = SE->getMulExpr(NumBytesS, SE->getConstant(IntPtr, StoreSize),
- true /*no unsigned overflow*/);
+ SCEV::FlagNUW);
Value *NumBytes =
Expander.expandCodeFor(NumBytesS, IntPtr, Preheader->getTerminator());
@@ -581,10 +581,10 @@
BECount = SE->getTruncateOrZeroExtend(BECount, IntPtr);
const SCEV *NumBytesS = SE->getAddExpr(BECount, SE->getConstant(IntPtr, 1),
- true /*no unsigned overflow*/);
+ SCEV::FlagNUW);
if (StoreSize != 1)
NumBytesS = SE->getMulExpr(NumBytesS, SE->getConstant(IntPtr, StoreSize),
- true /*no unsigned overflow*/);
+ SCEV::FlagNUW);
Value *NumBytes =
Expander.expandCodeFor(NumBytesS, IntPtr, Preheader->getTerminator());
Modified: llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp?rev=127590&r1=127589&r2=127590&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp Mon Mar 14 11:50:06 2011
@@ -253,7 +253,8 @@
DoInitialMatch(AR->getStart(), L, Good, Bad, SE);
DoInitialMatch(SE.getAddRecExpr(SE.getConstant(AR->getType(), 0),
AR->getStepRecurrence(SE),
- AR->getLoop()),
+ // FIXME: AR->getNoWrapFlags()
+ AR->getLoop(), SCEV::FlagAnyWrap),
L, Good, Bad, SE);
return;
}
@@ -455,7 +456,10 @@
const SCEV *Start = getExactSDiv(AR->getStart(), RHS, SE,
IgnoreSignificantBits);
if (!Start) return 0;
- return SE.getAddRecExpr(Start, Step, AR->getLoop());
+ // FlagNW is independent of the start value, step direction, and is
+ // preserved with smaller magnitude steps.
+ // FIXME: AR->getNoWrapFlags(SCEV::FlagNW)
+ return SE.getAddRecExpr(Start, Step, AR->getLoop(), SCEV::FlagAnyWrap);
}
return 0;
}
@@ -520,7 +524,9 @@
SmallVector<const SCEV *, 8> NewOps(AR->op_begin(), AR->op_end());
int64_t Result = ExtractImmediate(NewOps.front(), SE);
if (Result != 0)
- S = SE.getAddRecExpr(NewOps, AR->getLoop());
+ S = SE.getAddRecExpr(NewOps, AR->getLoop(),
+ // FIXME: AR->getNoWrapFlags(SCEV::FlagNW)
+ SCEV::FlagAnyWrap);
return Result;
}
return 0;
@@ -545,7 +551,9 @@
SmallVector<const SCEV *, 8> NewOps(AR->op_begin(), AR->op_end());
GlobalValue *Result = ExtractSymbol(NewOps.front(), SE);
if (Result)
- S = SE.getAddRecExpr(NewOps, AR->getLoop());
+ S = SE.getAddRecExpr(NewOps, AR->getLoop(),
+ // FIXME: AR->getNoWrapFlags(SCEV::FlagNW)
+ SCEV::FlagAnyWrap);
return Result;
}
return 0;
@@ -2236,7 +2244,9 @@
if (!AR->getStart()->isZero()) {
CollectSubexprs(SE.getAddRecExpr(SE.getConstant(AR->getType(), 0),
AR->getStepRecurrence(SE),
- AR->getLoop()),
+ AR->getLoop(),
+ //FIXME: AR->getNoWrapFlags(SCEV::FlagNW)
+ SCEV::FlagAnyWrap),
C, Ops, L, SE);
CollectSubexprs(AR->getStart(), C, Ops, L, SE);
return;
@@ -3047,7 +3057,7 @@
}
}
-/// NarrowSearchSpaceByRefilteringUndesirableDedicatedRegisters - Call
+/// NarrowSearchSpaceByRefilteringUndesirableDedicatedRegisters - Call
/// FilterOutUndesirableDedicatedRegisters again, if necessary, now that
/// we've done more filtering, as it may be able to find more formulae to
/// eliminate.
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