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Expand GEPs in ScalarEvolution expressions. SCEV expressions can now

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have pointer types, though in contrast to C pointer types, SCEV
addition is never implicitly scaled. This not only eliminates the
need for special code like IndVars' EliminatePointerRecurrence
and LSR's own GEP expansion code, it also does a better job because
it lets the normal optimizations handle pointer expressions just
like integer expressions.

Also, since LLVM IR GEPs can't directly index into multi-dimensional
VLAs, moving the GEP analysis out of client code and into the SCEV
framework makes it easier for clients to handle multi-dimensional
VLAs the same way as other arrays.

Some existing regression tests show improved optimization.
test/CodeGen/ARM/2007-03-13-InstrSched.ll in particular improved to
the point where if-conversion started kicking in; I turned it off
for this test to preserve the intent of the test.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69258 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2009-04-16 03:18:22 +00:00
parent 9efac568f0
commit 2d1be87ee4
10 changed files with 450 additions and 453 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
include/llvm/Analysis/ScalarEvolution.h
View File

@ -32,6 +32,7 @@ namespace llvm {
class Type;
class SCEVHandle;
class ScalarEvolution;
class TargetData;
/// SCEV - This class represent an analyzed expression in the program. These
/// are reference counted opaque objects that the client is not allowed to
@ -71,10 +72,6 @@ namespace llvm {
///
virtual const Type *getType() const = 0;
/// getBitWidth - Get the bit width of the type, if it has one, 0 otherwise.
///
uint32_t getBitWidth() const;
/// isZero - Return true if the expression is a constant zero.
///
bool isZero() const;
@ -199,6 +196,10 @@ namespace llvm {
static char ID; // Pass identification, replacement for typeid
ScalarEvolution() : FunctionPass(&ID), Impl(0) {}
// getTargetData - Return the TargetData object contained in this
// ScalarEvolution.
const TargetData &getTargetData() const;
/// getSCEV - Return a SCEV expression handle for the full generality of the
/// specified expression.
SCEVHandle getSCEV(Value *V) const;

10
include/llvm/Analysis/ScalarEvolutionExpander.h
View File

@ -20,6 +20,8 @@
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
namespace llvm {
class TargetData;
/// SCEVExpander - This class uses information about analyze scalars to
/// rewrite expressions in canonical form.
///
@ -29,6 +31,7 @@ namespace llvm {
struct SCEVExpander : public SCEVVisitor<SCEVExpander, Value*> {
ScalarEvolution &SE;
LoopInfo &LI;
const TargetData &TD;
std::map<SCEVHandle, Value*> InsertedExpressions;
std::set<Instruction*> InsertedInstructions;
@ -36,7 +39,8 @@ namespace llvm {
friend struct SCEVVisitor<SCEVExpander, Value*>;
public:
SCEVExpander(ScalarEvolution &se, LoopInfo &li) : SE(se), LI(li) {}
SCEVExpander(ScalarEvolution &se, LoopInfo &li, const TargetData &td)
: SE(se), LI(li), TD(td) {}
LoopInfo &getLoopInfo() const { return LI; }
@ -75,7 +79,7 @@ namespace llvm {
/// expandCodeFor - Insert code to directly compute the specified SCEV
/// expression into the program. The inserted code is inserted into the
/// specified block.
Value *expandCodeFor(SCEVHandle SH, Instruction *IP);
Value *expandCodeFor(SCEVHandle SH, const Type *Ty, Instruction *IP);
/// InsertCastOfTo - Insert a cast of V to the specified type, doing what
/// we can to share the casts.
@ -87,7 +91,7 @@ namespace llvm {
Value *RHS, Instruction *InsertPt);
protected:
Value *expand(SCEV *S);
Value *visitConstant(SCEVConstant *S) {
return S->getValue();
}

405
lib/Analysis/ScalarEvolution.cpp
View File

@ -69,16 +69,19 @@
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/ConstantRange.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "llvm/Support/InstIterator.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Streams.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/STLExtras.h"
#include <ostream>
#include <algorithm>
#include <cmath>
@ -116,12 +119,6 @@ void SCEV::dump() const {
cerr << '\n';
}
uint32_t SCEV::getBitWidth() const {
if (const IntegerType* ITy = dyn_cast<IntegerType>(getType()))
return ITy->getBitWidth();
return 0;
}
bool SCEV::isZero() const {
if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(this))
return SC->getValue()->isZero();
@ -196,10 +193,13 @@ static ManagedStatic<std::map<std::pair<SCEV*, const Type*>,
SCEVTruncateExpr::SCEVTruncateExpr(const SCEVHandle &op, const Type *ty)
: SCEV(scTruncate), Op(op), Ty(ty) {
assert(Op->getType()->isInteger() && Ty->isInteger() &&
assert((Op->getType()->isInteger() || isa<PointerType>(Op->getType())) &&
(Ty->isInteger() || isa<PointerType>(Ty)) &&
"Cannot truncate non-integer value!");
assert(Op->getType()->getPrimitiveSizeInBits() > Ty->getPrimitiveSizeInBits()
&& "This is not a truncating conversion!");
assert((!Op->getType()->isInteger() || !Ty->isInteger() ||
Op->getType()->getPrimitiveSizeInBits() >
Ty->getPrimitiveSizeInBits()) &&
"This is not a truncating conversion!");
}
SCEVTruncateExpr::~SCEVTruncateExpr() {
@ -222,7 +222,8 @@ static ManagedStatic<std::map<std::pair<SCEV*, const Type*>,
SCEVZeroExtendExpr::SCEVZeroExtendExpr(const SCEVHandle &op, const Type *ty)
: SCEV(scZeroExtend), Op(op), Ty(ty) {
assert(Op->getType()->isInteger() && Ty->isInteger() &&
assert((Op->getType()->isInteger() || isa<PointerType>(Op->getType())) &&
(Ty->isInteger() || isa<PointerType>(Ty)) &&
"Cannot zero extend non-integer value!");
assert(Op->getType()->getPrimitiveSizeInBits() < Ty->getPrimitiveSizeInBits()
&& "This is not an extending conversion!");
@ -248,7 +249,8 @@ static ManagedStatic<std::map<std::pair<SCEV*, const Type*>,
SCEVSignExtendExpr::SCEVSignExtendExpr(const SCEVHandle &op, const Type *ty)
: SCEV(scSignExtend), Op(op), Ty(ty) {
assert(Op->getType()->isInteger() && Ty->isInteger() &&
assert((Op->getType()->isInteger() || isa<PointerType>(Op->getType())) &&
(Ty->isInteger() || isa<PointerType>(Ty)) &&
"Cannot sign extend non-integer value!");
assert(Op->getType()->getPrimitiveSizeInBits() < Ty->getPrimitiveSizeInBits()
&& "This is not an extending conversion!");
@ -436,7 +438,11 @@ const Type *SCEVUnknown::getType() const {
}
void SCEVUnknown::print(std::ostream &OS) const {
if (isa<PointerType>(V->getType()))
OS << "(ptrtoint " << *V->getType() << " ";
WriteAsOperand(OS, V, false);
if (isa<PointerType>(V->getType()))
OS << " to iPTR)";
}
//===----------------------------------------------------------------------===//
@ -504,52 +510,11 @@ static void GroupByComplexity(std::vector<SCEVHandle> &Ops) {
// Simple SCEV method implementations
//===----------------------------------------------------------------------===//
/// getIntegerSCEV - Given an integer or FP type, create a constant for the
/// specified signed integer value and return a SCEV for the constant.
SCEVHandle ScalarEvolution::getIntegerSCEV(int Val, const Type *Ty) {
Constant *C;
if (Val == 0)
C = Constant::getNullValue(Ty);
else if (Ty->isFloatingPoint())
C = ConstantFP::get(APFloat(Ty==Type::FloatTy ? APFloat::IEEEsingle :
APFloat::IEEEdouble, Val));
else
C = ConstantInt::get(Ty, Val);
return getUnknown(C);
}
/// getNegativeSCEV - Return a SCEV corresponding to -V = -1*V
///
SCEVHandle ScalarEvolution::getNegativeSCEV(const SCEVHandle &V) {
if (SCEVConstant *VC = dyn_cast<SCEVConstant>(V))
return getUnknown(ConstantExpr::getNeg(VC->getValue()));
return getMulExpr(V, getConstant(ConstantInt::getAllOnesValue(V->getType())));
}
/// getNotSCEV - Return a SCEV corresponding to ~V = -1-V
SCEVHandle ScalarEvolution::getNotSCEV(const SCEVHandle &V) {
if (SCEVConstant *VC = dyn_cast<SCEVConstant>(V))
return getUnknown(ConstantExpr::getNot(VC->getValue()));
SCEVHandle AllOnes = getConstant(ConstantInt::getAllOnesValue(V->getType()));
return getMinusSCEV(AllOnes, V);
}
/// getMinusSCEV - Return a SCEV corresponding to LHS - RHS.
///
SCEVHandle ScalarEvolution::getMinusSCEV(const SCEVHandle &LHS,
const SCEVHandle &RHS) {
// X - Y --> X + -Y
return getAddExpr(LHS, getNegativeSCEV(RHS));
}
/// BinomialCoefficient - Compute BC(It, K). The result has width W.
// Assume, K > 0.
static SCEVHandle BinomialCoefficient(SCEVHandle It, unsigned K,
ScalarEvolution &SE,
const IntegerType* ResultTy) {
const Type* ResultTy) {
// Handle the simplest case efficiently.
if (K == 1)
return SE.getTruncateOrZeroExtend(It, ResultTy);
@ -608,7 +573,7 @@ static SCEVHandle BinomialCoefficient(SCEVHandle It, unsigned K,
if (K > 1000)
return new SCEVCouldNotCompute();
unsigned W = ResultTy->getBitWidth();
unsigned W = SE.getTargetData().getTypeSizeInBits(ResultTy);
// Calculate K! / 2^T and T; we divide out the factors of two before
// multiplying for calculating K! / 2^T to avoid overflow.
@ -672,8 +637,7 @@ SCEVHandle SCEVAddRecExpr::evaluateAtIteration(SCEVHandle It,
// The computation is correct in the face of overflow provided that the
// multiplication is performed _after_ the evaluation of the binomial
// coefficient.
SCEVHandle Coeff = BinomialCoefficient(It, i, SE,
cast<IntegerType>(getType()));
SCEVHandle Coeff = BinomialCoefficient(It, i, SE, getType());
if (isa<SCEVCouldNotCompute>(Coeff))
return Coeff;
@ -711,9 +675,13 @@ SCEVHandle ScalarEvolution::getTruncateExpr(const SCEVHandle &Op, const Type *Ty
}
SCEVHandle ScalarEvolution::getZeroExtendExpr(const SCEVHandle &Op, const Type *Ty) {
if (SCEVConstant *SC = dyn_cast<SCEVConstant>(Op))
return getUnknown(
ConstantExpr::getZExt(SC->getValue(), Ty));
if (SCEVConstant *SC = dyn_cast<SCEVConstant>(Op)) {
const Type *IntTy = Ty;
if (isa<PointerType>(IntTy)) IntTy = getTargetData().getIntPtrType();
Constant *C = ConstantExpr::getZExt(SC->getValue(), IntTy);
if (IntTy != Ty) C = ConstantExpr::getIntToPtr(C, Ty);
return getUnknown(C);
}
// FIXME: If the input value is a chrec scev, and we can prove that the value
// did not overflow the old, smaller, value, we can zero extend all of the
@ -726,9 +694,13 @@ SCEVHandle ScalarEvolution::getZeroExtendExpr(const SCEVHandle &Op, const Type *
}
SCEVHandle ScalarEvolution::getSignExtendExpr(const SCEVHandle &Op, const Type *Ty) {
if (SCEVConstant *SC = dyn_cast<SCEVConstant>(Op))
return getUnknown(
ConstantExpr::getSExt(SC->getValue(), Ty));
if (SCEVConstant *SC = dyn_cast<SCEVConstant>(Op)) {
const Type *IntTy = Ty;
if (isa<PointerType>(IntTy)) IntTy = getTargetData().getIntPtrType();
Constant *C = ConstantExpr::getSExt(SC->getValue(), IntTy);
if (IntTy != Ty) C = ConstantExpr::getIntToPtr(C, Ty);
return getUnknown(C);
}
// FIXME: If the input value is a chrec scev, and we can prove that the value
// did not overflow the old, smaller, value, we can sign extend all of the
@ -740,36 +712,6 @@ SCEVHandle ScalarEvolution::getSignExtendExpr(const SCEVHandle &Op, const Type *
return Result;
}
/// getTruncateOrZeroExtend - Return a SCEV corresponding to a conversion
/// of the input value to the specified type. If the type must be
/// extended, it is zero extended.
SCEVHandle ScalarEvolution::getTruncateOrZeroExtend(const SCEVHandle &V,
const Type *Ty) {
const Type *SrcTy = V->getType();
assert(SrcTy->isInteger() && Ty->isInteger() &&
"Cannot truncate or zero extend with non-integer arguments!");
if (SrcTy->getPrimitiveSizeInBits() == Ty->getPrimitiveSizeInBits())
return V; // No conversion
if (SrcTy->getPrimitiveSizeInBits() > Ty->getPrimitiveSizeInBits())
return getTruncateExpr(V, Ty);
return getZeroExtendExpr(V, Ty);
}
/// getTruncateOrSignExtend - Return a SCEV corresponding to a conversion
/// of the input value to the specified type. If the type must be
/// extended, it is sign extended.
SCEVHandle ScalarEvolution::getTruncateOrSignExtend(const SCEVHandle &V,
const Type *Ty) {
const Type *SrcTy = V->getType();
assert(SrcTy->isInteger() && Ty->isInteger() &&
"Cannot truncate or sign extend with non-integer arguments!");
if (SrcTy->getPrimitiveSizeInBits() == Ty->getPrimitiveSizeInBits())
return V; // No conversion
if (SrcTy->getPrimitiveSizeInBits() > Ty->getPrimitiveSizeInBits())
return getTruncateExpr(V, Ty);
return getSignExtendExpr(V, Ty);
}
// get - Get a canonical add expression, or something simpler if possible.
SCEVHandle ScalarEvolution::getAddExpr(std::vector<SCEVHandle> &Ops) {
assert(!Ops.empty() && "Cannot get empty add!");
@ -1385,6 +1327,8 @@ SCEVHandle ScalarEvolution::getUMaxExpr(std::vector<SCEVHandle> Ops) {
SCEVHandle ScalarEvolution::getUnknown(Value *V) {
if (ConstantInt *CI = dyn_cast<ConstantInt>(V))
return getConstant(CI);
if (isa<ConstantPointerNull>(V))
return getIntegerSCEV(0, V->getType());
SCEVUnknown *&Result = (*SCEVUnknowns)[V];
if (Result == 0) Result = new SCEVUnknown(V);
return Result;
@ -1411,6 +1355,10 @@ namespace {
///
LoopInfo &LI;
/// TD - The target data information for the target we are targetting.
///
TargetData &TD;
/// UnknownValue - This SCEV is used to represent unknown trip counts and
/// things.
SCEVHandle UnknownValue;
@ -1431,8 +1379,35 @@ namespace {
std::map<PHINode*, Constant*> ConstantEvolutionLoopExitValue;
public:
ScalarEvolutionsImpl(ScalarEvolution &se, Function &f, LoopInfo &li)
: SE(se), F(f), LI(li), UnknownValue(new SCEVCouldNotCompute()) {}
ScalarEvolutionsImpl(ScalarEvolution &se, Function &f, LoopInfo &li,
TargetData &td)
: SE(se), F(f), LI(li), TD(td), UnknownValue(new SCEVCouldNotCompute()) {}
/// getIntegerSCEV - Given an integer or FP type, create a constant for the
/// specified signed integer value and return a SCEV for the constant.
SCEVHandle getIntegerSCEV(int Val, const Type *Ty);
/// getNegativeSCEV - Return a SCEV corresponding to -V = -1*V
///
SCEVHandle getNegativeSCEV(const SCEVHandle &V);
/// getNotSCEV - Return a SCEV corresponding to ~V = -1-V
///
SCEVHandle getNotSCEV(const SCEVHandle &V);
/// getMinusSCEV - Return a SCEV corresponding to LHS - RHS.
///
SCEVHandle getMinusSCEV(const SCEVHandle &LHS, const SCEVHandle &RHS);
/// getTruncateOrZeroExtend - Return a SCEV corresponding to a conversion
/// of the input value to the specified type. If the type must be extended,
/// it is zero extended.
SCEVHandle getTruncateOrZeroExtend(const SCEVHandle &V, const Type *Ty);
/// getTruncateOrSignExtend - Return a SCEV corresponding to a conversion
/// of the input value to the specified type. If the type must be extended,
/// it is sign extended.
SCEVHandle getTruncateOrSignExtend(const SCEVHandle &V, const Type *Ty);
/// getSCEV - Return an existing SCEV if it exists, otherwise analyze the
/// expression and create a new one.
@ -1492,6 +1467,9 @@ namespace {
/// that no dangling references are left around.
void deleteValueFromRecords(Value *V);
/// getTargetData - Return the TargetData.
const TargetData &getTargetData() const;
private:
/// createSCEV - We know that there is no SCEV for the specified value.
/// Analyze the expression.
@ -1592,6 +1570,9 @@ void ScalarEvolutionsImpl::deleteValueFromRecords(Value *V) {
}
}
const TargetData &ScalarEvolutionsImpl::getTargetData() const {
return TD;
}
/// getSCEV - Return an existing SCEV if it exists, otherwise analyze the
/// expression and create a new one.
@ -1605,6 +1586,88 @@ SCEVHandle ScalarEvolutionsImpl::getSCEV(Value *V) {
return S;
}
/// getIntegerSCEV - Given an integer or FP type, create a constant for the
/// specified signed integer value and return a SCEV for the constant.
SCEVHandle ScalarEvolutionsImpl::getIntegerSCEV(int Val, const Type *Ty) {
if (isa<PointerType>(Ty))
Ty = TD.getIntPtrType();
Constant *C;
if (Val == 0)
C = Constant::getNullValue(Ty);
else if (Ty->isFloatingPoint())
C = ConstantFP::get(APFloat(Ty==Type::FloatTy ? APFloat::IEEEsingle :
APFloat::IEEEdouble, Val));
else
C = ConstantInt::get(Ty, Val);
return SE.getUnknown(C);
}
/// getNegativeSCEV - Return a SCEV corresponding to -V = -1*V
///
SCEVHandle ScalarEvolutionsImpl::getNegativeSCEV(const SCEVHandle &V) {
if (SCEVConstant *VC = dyn_cast<SCEVConstant>(V))
return SE.getUnknown(ConstantExpr::getNeg(VC->getValue()));
const Type *Ty = V->getType();
if (isa<PointerType>(Ty))
Ty = TD.getIntPtrType();
return SE.getMulExpr(V, SE.getConstant(ConstantInt::getAllOnesValue(Ty)));
}
/// getNotSCEV - Return a SCEV corresponding to ~V = -1-V
SCEVHandle ScalarEvolutionsImpl::getNotSCEV(const SCEVHandle &V) {
if (SCEVConstant *VC = dyn_cast<SCEVConstant>(V))
return SE.getUnknown(ConstantExpr::getNot(VC->getValue()));
const Type *Ty = V->getType();
if (isa<PointerType>(Ty))
Ty = TD.getIntPtrType();
SCEVHandle AllOnes = SE.getConstant(ConstantInt::getAllOnesValue(Ty));
return getMinusSCEV(AllOnes, V);
}
/// getMinusSCEV - Return a SCEV corresponding to LHS - RHS.
///
SCEVHandle ScalarEvolutionsImpl::getMinusSCEV(const SCEVHandle &LHS,
const SCEVHandle &RHS) {
// X - Y --> X + -Y
return SE.getAddExpr(LHS, SE.getNegativeSCEV(RHS));
}
/// getTruncateOrZeroExtend - Return a SCEV corresponding to a conversion of the
/// input value to the specified type. If the type must be extended, it is zero
/// extended.
SCEVHandle
ScalarEvolutionsImpl::getTruncateOrZeroExtend(const SCEVHandle &V,
const Type *Ty) {
const Type *SrcTy = V->getType();
assert((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
(Ty->isInteger() || isa<PointerType>(Ty)) &&
"Cannot truncate or zero extend with non-integer arguments!");
if (TD.getTypeSizeInBits(SrcTy) == TD.getTypeSizeInBits(Ty))
return V; // No conversion
if (TD.getTypeSizeInBits(SrcTy) > TD.getTypeSizeInBits(Ty))
return SE.getTruncateExpr(V, Ty);
return SE.getZeroExtendExpr(V, Ty);
}
/// getTruncateOrSignExtend - Return a SCEV corresponding to a conversion of the
/// input value to the specified type. If the type must be extended, it is sign
/// extended.
SCEVHandle
ScalarEvolutionsImpl::getTruncateOrSignExtend(const SCEVHandle &V,
const Type *Ty) {
const Type *SrcTy = V->getType();
assert((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
(Ty->isInteger() || isa<PointerType>(Ty)) &&
"Cannot truncate or zero extend with non-integer arguments!");
if (TD.getTypeSizeInBits(SrcTy) == TD.getTypeSizeInBits(Ty))
return V; // No conversion
if (TD.getTypeSizeInBits(SrcTy) > TD.getTypeSizeInBits(Ty))
return SE.getTruncateExpr(V, Ty);
return SE.getSignExtendExpr(V, Ty);
}
/// ReplaceSymbolicValueWithConcrete - This looks up the computed SCEV value for
/// the specified instruction and replaces any references to the symbolic value
/// SymName with the specified value. This is used during PHI resolution.
@ -1728,63 +1791,66 @@ SCEVHandle ScalarEvolutionsImpl::createNodeForPHI(PHINode *PN) {
/// guaranteed to end in (at every loop iteration). It is, at the same time,
/// the minimum number of times S is divisible by 2. For example, given {4,+,8}
/// it returns 2. If S is guaranteed to be 0, it returns the bitwidth of S.
static uint32_t GetMinTrailingZeros(SCEVHandle S) {
static uint32_t GetMinTrailingZeros(SCEVHandle S, const TargetData &TD) {
if (SCEVConstant *C = dyn_cast<SCEVConstant>(S))
return C->getValue()->getValue().countTrailingZeros();
if (SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(S))
return std::min(GetMinTrailingZeros(T->getOperand()), T->getBitWidth());
return std::min(GetMinTrailingZeros(T->getOperand(), TD),
(uint32_t)TD.getTypeSizeInBits(T->getType()));
if (SCEVZeroExtendExpr *E = dyn_cast<SCEVZeroExtendExpr>(S)) {
uint32_t OpRes = GetMinTrailingZeros(E->getOperand());
return OpRes == E->getOperand()->getBitWidth() ? E->getBitWidth() : OpRes;
uint32_t OpRes = GetMinTrailingZeros(E->getOperand(), TD);
return OpRes == TD.getTypeSizeInBits(E->getOperand()->getType()) ?
TD.getTypeSizeInBits(E->getOperand()->getType()) : OpRes;
}
if (SCEVSignExtendExpr *E = dyn_cast<SCEVSignExtendExpr>(S)) {
uint32_t OpRes = GetMinTrailingZeros(E->getOperand());
return OpRes == E->getOperand()->getBitWidth() ? E->getBitWidth() : OpRes;
uint32_t OpRes = GetMinTrailingZeros(E->getOperand(), TD);
return OpRes == TD.getTypeSizeInBits(E->getOperand()->getType()) ?
TD.getTypeSizeInBits(E->getOperand()->getType()) : OpRes;
}
if (SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(S)) {
// The result is the min of all operands results.
uint32_t MinOpRes = GetMinTrailingZeros(A->getOperand(0));
uint32_t MinOpRes = GetMinTrailingZeros(A->getOperand(0), TD);
for (unsigned i = 1, e = A->getNumOperands(); MinOpRes && i != e; ++i)
MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(A->getOperand(i)));
MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(A->getOperand(i), TD));
return MinOpRes;
}
if (SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(S)) {
// The result is the sum of all operands results.
uint32_t SumOpRes = GetMinTrailingZeros(M->getOperand(0));
uint32_t BitWidth = M->getBitWidth();
uint32_t SumOpRes = GetMinTrailingZeros(M->getOperand(0), TD);
uint32_t BitWidth = TD.getTypeSizeInBits(M->getType());
for (unsigned i = 1, e = M->getNumOperands();
SumOpRes != BitWidth && i != e; ++i)
SumOpRes = std::min(SumOpRes + GetMinTrailingZeros(M->getOperand(i)),
SumOpRes = std::min(SumOpRes + GetMinTrailingZeros(M->getOperand(i), TD),
BitWidth);
return SumOpRes;
}
if (SCEVAddRecExpr *A = dyn_cast<SCEVAddRecExpr>(S)) {
// The result is the min of all operands results.
uint32_t MinOpRes = GetMinTrailingZeros(A->getOperand(0));
uint32_t MinOpRes = GetMinTrailingZeros(A->getOperand(0), TD);
for (unsigned i = 1, e = A->getNumOperands(); MinOpRes && i != e; ++i)
MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(A->getOperand(i)));
MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(A->getOperand(i), TD));
return MinOpRes;
}
if (SCEVSMaxExpr *M = dyn_cast<SCEVSMaxExpr>(S)) {
// The result is the min of all operands results.
uint32_t MinOpRes = GetMinTrailingZeros(M->getOperand(0));
uint32_t MinOpRes = GetMinTrailingZeros(M->getOperand(0), TD);
for (unsigned i = 1, e = M->getNumOperands(); MinOpRes && i != e; ++i)
MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(M->getOperand(i)));
MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(M->getOperand(i), TD));
return MinOpRes;
}
if (SCEVUMaxExpr *M = dyn_cast<SCEVUMaxExpr>(S)) {
// The result is the min of all operands results.
uint32_t MinOpRes = GetMinTrailingZeros(M->getOperand(0));
uint32_t MinOpRes = GetMinTrailingZeros(M->getOperand(0), TD);
for (unsigned i = 1, e = M->getNumOperands(); MinOpRes && i != e; ++i)
MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(M->getOperand(i)));
MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(M->getOperand(i), TD));
return MinOpRes;
}
@ -1796,9 +1862,10 @@ static uint32_t GetMinTrailingZeros(SCEVHandle S) {
/// Analyze the expression.
///
SCEVHandle ScalarEvolutionsImpl::createSCEV(Value *V) {
if (!isa<IntegerType>(V->getType()))
if (!isa<IntegerType>(V->getType()) &&
!isa<PointerType>(V->getType()))
return SE.getUnknown(V);
unsigned Opcode = Instruction::UserOp1;
if (Instruction *I = dyn_cast<Instruction>(V))
Opcode = I->getOpcode();
@ -1831,7 +1898,7 @@ SCEVHandle ScalarEvolutionsImpl::createSCEV(Value *V) {
if (ConstantInt *CI = dyn_cast<ConstantInt>(U->getOperand(1))) {
SCEVHandle LHS = getSCEV(U->getOperand(0));
const APInt &CIVal = CI->getValue();
if (GetMinTrailingZeros(LHS) >=
if (GetMinTrailingZeros(LHS, TD) >=
(CIVal.getBitWidth() - CIVal.countLeadingZeros()))
return SE.getAddExpr(LHS, getSCEV(U->getOperand(1)));
}
@ -1881,11 +1948,55 @@ SCEVHandle ScalarEvolutionsImpl::createSCEV(Value *V) {
case Instruction::BitCast:
// BitCasts are no-op casts so we just eliminate the cast.
if (U->getType()->isInteger() &&
U->getOperand(0)->getType()->isInteger())
if ((U->getType()->isInteger() ||
isa<PointerType>(U->getType())) &&
(U->getOperand(0)->getType()->isInteger() ||
isa<PointerType>(U->getOperand(0)->getType())))
return getSCEV(U->getOperand(0));
break;
case Instruction::IntToPtr:
return getTruncateOrZeroExtend(getSCEV(U->getOperand(0)),
TD.getIntPtrType());
case Instruction::PtrToInt:
return getTruncateOrZeroExtend(getSCEV(U->getOperand(0)),
U->getType());
case Instruction::GetElementPtr: {
const Type *IntPtrTy = TD.getIntPtrType();
Value *Base = U->getOperand(0);
SCEVHandle TotalOffset = SE.getIntegerSCEV(0, IntPtrTy);
gep_type_iterator GTI = gep_type_begin(U);
for (GetElementPtrInst::op_iterator I = next(U->op_begin()),
E = U->op_end();
I != E; ++I) {
Value *Index = *I;
// Compute the (potentially symbolic) offset in bytes for this index.
if (const StructType *STy = dyn_cast<StructType>(*GTI++)) {
// For a struct, add the member offset.
const StructLayout &SL = *TD.getStructLayout(STy);
unsigned FieldNo = cast<ConstantInt>(Index)->getZExtValue();
uint64_t Offset = SL.getElementOffset(FieldNo);
TotalOffset = SE.getAddExpr(TotalOffset,
SE.getIntegerSCEV(Offset, IntPtrTy));
} else {
// For an array, add the element offset, explicitly scaled.
SCEVHandle LocalOffset = getSCEV(Index);
if (!isa<PointerType>(LocalOffset->getType()))
// Getelementptr indicies are signed.
LocalOffset = getTruncateOrSignExtend(LocalOffset,
IntPtrTy);
LocalOffset =
SE.getMulExpr(LocalOffset,
SE.getIntegerSCEV(TD.getTypePaddedSize(*GTI),
IntPtrTy));
TotalOffset = SE.getAddExpr(TotalOffset, LocalOffset);
}
}
return SE.getAddExpr(getSCEV(Base), TotalOffset);
}
case Instruction::PHI:
return createNodeForPHI(cast<PHINode>(U));
@ -2324,6 +2435,7 @@ static PHINode *getConstantEvolvingPHI(Value *V, const Loop *L) {
static Constant *EvaluateExpression(Value *V, Constant *PHIVal) {
if (isa<PHINode>(V)) return PHIVal;
if (Constant *C = dyn_cast<Constant>(V)) return C;
if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) return GV;
Instruction *I = cast<Instruction>(V);
std::vector<Constant*> Operands;
@ -2490,10 +2602,12 @@ SCEVHandle ScalarEvolutionsImpl::getSCEVAtScope(SCEV *V, const Loop *L) {
Operands.push_back(C);
} else {
// If any of the operands is non-constant and if they are
// non-integer, don't even try to analyze them with scev techniques.
if (!isa<IntegerType>(Op->getType()))
// non-integer and non-pointer, don't even try to analyze them
// with scev techniques.
if (!isa<IntegerType>(Op->getType()) &&
!isa<PointerType>(Op->getType()))
return V;
SCEVHandle OpV = getSCEVAtScope(getSCEV(Op), L);
if (SCEVConstant *SC = dyn_cast<SCEVConstant>(OpV))
Operands.push_back(ConstantExpr::getIntegerCast(SC->getValue(),
@ -3003,7 +3117,8 @@ SCEVHandle SCEVAddRecExpr::getNumIterationsInRange(ConstantRange Range,
// First check to see if the range contains zero. If not, the first
// iteration exits.
if (!Range.contains(APInt(getBitWidth(),0)))
unsigned BitWidth = SE.getTargetData().getTypeSizeInBits(getType());
if (!Range.contains(APInt(BitWidth, 0)))
return SE.getConstant(ConstantInt::get(getType(),0));
if (isAffine()) {
@ -3014,7 +3129,7 @@ SCEVHandle SCEVAddRecExpr::getNumIterationsInRange(ConstantRange Range,
// the upper value of the range must be the first possible exit value.
// If A is negative then the lower of the range is the last possible loop
// value. Also note that we already checked for a full range.
APInt One(getBitWidth(),1);
APInt One(BitWidth,1);
APInt A = cast<SCEVConstant>(getOperand(1))->getValue()->getValue();
APInt End = A.sge(One) ? (Range.getUpper() - One) : Range.getLower();
@ -3094,7 +3209,9 @@ SCEVHandle SCEVAddRecExpr::getNumIterationsInRange(ConstantRange Range,
//===----------------------------------------------------------------------===//
bool ScalarEvolution::runOnFunction(Function &F) {
Impl = new ScalarEvolutionsImpl(*this, F, getAnalysis<LoopInfo>());
Impl = new ScalarEvolutionsImpl(*this, F,
getAnalysis<LoopInfo>(),
getAnalysis<TargetData>());
return false;
}
@ -3106,6 +3223,15 @@ void ScalarEvolution::releaseMemory() {
void ScalarEvolution::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequiredTransitive<LoopInfo>();
AU.addRequiredTransitive<TargetData>();
}
const TargetData &ScalarEvolution::getTargetData() const {
return ((ScalarEvolutionsImpl*)Impl)->getTargetData();
}
SCEVHandle ScalarEvolution::getIntegerSCEV(int Val, const Type *Ty) {
return ((ScalarEvolutionsImpl*)Impl)->getIntegerSCEV(Val, Ty);
}
SCEVHandle ScalarEvolution::getSCEV(Value *V) const {
@ -3125,6 +3251,41 @@ void ScalarEvolution::setSCEV(Value *V, const SCEVHandle &H) {
((ScalarEvolutionsImpl*)Impl)->setSCEV(V, H);
}
/// getNegativeSCEV - Return a SCEV corresponding to -V = -1*V
///
SCEVHandle ScalarEvolution::getNegativeSCEV(const SCEVHandle &V) {
return ((ScalarEvolutionsImpl*)Impl)->getNegativeSCEV(V);
}
/// getNotSCEV - Return a SCEV corresponding to ~V = -1-V
///
SCEVHandle ScalarEvolution::getNotSCEV(const SCEVHandle &V) {
return ((ScalarEvolutionsImpl*)Impl)->getNotSCEV(V);
}
/// getMinusSCEV - Return a SCEV corresponding to LHS - RHS.
///
SCEVHandle ScalarEvolution::getMinusSCEV(const SCEVHandle &LHS,
const SCEVHandle &RHS) {
return ((ScalarEvolutionsImpl*)Impl)->getMinusSCEV(LHS, RHS);
}
/// getTruncateOrZeroExtend - Return a SCEV corresponding to a conversion
/// of the input value to the specified type. If the type must be
/// extended, it is zero extended.
SCEVHandle ScalarEvolution::getTruncateOrZeroExtend(const SCEVHandle &V,
const Type *Ty) {
return ((ScalarEvolutionsImpl*)Impl)->getTruncateOrZeroExtend(V, Ty);
}
/// getTruncateOrSignExtend - Return a SCEV corresponding to a conversion
/// of the input value to the specified type. If the type must be
/// extended, it is sign extended.
SCEVHandle ScalarEvolution::getTruncateOrSignExtend(const SCEVHandle &V,
const Type *Ty) {
return ((ScalarEvolutionsImpl*)Impl)->getTruncateOrSignExtend(V, Ty);
}
bool ScalarEvolution::isLoopGuardedByCond(const Loop *L,
ICmpInst::Predicate Pred,

59
lib/Analysis/ScalarEvolutionExpander.cpp
View File

@ -15,12 +15,17 @@
#include "llvm/Analysis/ScalarEvolutionExpander.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Target/TargetData.h"
using namespace llvm;
/// InsertCastOfTo - Insert a cast of V to the specified type, doing what
/// we can to share the casts.
Value *SCEVExpander::InsertCastOfTo(Instruction::CastOps opcode, Value *V,
const Type *Ty) {
// Short-circuit unnecessary bitcasts.
if (opcode == Instruction::BitCast && V->getType() == Ty)
return V;
// FIXME: keep track of the cast instruction.
if (Constant *C = dyn_cast<Constant>(V))
return ConstantExpr::getCast(opcode, C, Ty);
@ -100,16 +105,23 @@ Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode, Value *LHS,
}
Value *SCEVExpander::visitAddExpr(SCEVAddExpr *S) {
const Type *Ty = S->getType();
if (isa<PointerType>(Ty)) Ty = TD.getIntPtrType();
Value *V = expand(S->getOperand(S->getNumOperands()-1));
V = InsertCastOfTo(CastInst::getCastOpcode(V, false, Ty, false), V, Ty);
// Emit a bunch of add instructions
for (int i = S->getNumOperands()-2; i >= 0; --i)
V = InsertBinop(Instruction::Add, V, expand(S->getOperand(i)),
InsertPt);
for (int i = S->getNumOperands()-2; i >= 0; --i) {
Value *W = expand(S->getOperand(i));
W = InsertCastOfTo(CastInst::getCastOpcode(W, false, Ty, false), W, Ty);
V = InsertBinop(Instruction::Add, V, W, InsertPt);
}
return V;
}
Value *SCEVExpander::visitMulExpr(SCEVMulExpr *S) {
const Type *Ty = S->getType();
if (isa<PointerType>(Ty)) Ty = TD.getIntPtrType();
int FirstOp = 0; // Set if we should emit a subtract.
if (SCEVConstant *SC = dyn_cast<SCEVConstant>(S->getOperand(0)))
if (SC->getValue()->isAllOnesValue())
@ -117,29 +129,37 @@ Value *SCEVExpander::visitMulExpr(SCEVMulExpr *S) {
int i = S->getNumOperands()-2;
Value *V = expand(S->getOperand(i+1));
V = InsertCastOfTo(CastInst::getCastOpcode(V, false, Ty, false), V, Ty);
// Emit a bunch of multiply instructions
for (; i >= FirstOp; --i)
V = InsertBinop(Instruction::Mul, V, expand(S->getOperand(i)),
InsertPt);
for (; i >= FirstOp; --i) {
Value *W = expand(S->getOperand(i));
W = InsertCastOfTo(CastInst::getCastOpcode(W, false, Ty, false), W, Ty);
V = InsertBinop(Instruction::Mul, V, W, InsertPt);
}
// -1 * ... ---> 0 - ...
if (FirstOp == 1)
V = InsertBinop(Instruction::Sub, Constant::getNullValue(V->getType()), V,
InsertPt);
V = InsertBinop(Instruction::Sub, Constant::getNullValue(Ty), V, InsertPt);
return V;
}
Value *SCEVExpander::visitUDivExpr(SCEVUDivExpr *S) {
const Type *Ty = S->getType();
if (isa<PointerType>(Ty)) Ty = TD.getIntPtrType();
Value *LHS = expand(S->getLHS());
LHS = InsertCastOfTo(CastInst::getCastOpcode(LHS, false, Ty, false), LHS, Ty);
if (SCEVConstant *SC = dyn_cast<SCEVConstant>(S->getRHS())) {
const APInt &RHS = SC->getValue()->getValue();
if (RHS.isPowerOf2())
return InsertBinop(Instruction::LShr, LHS,
ConstantInt::get(S->getType(), RHS.logBase2()),
ConstantInt::get(Ty, RHS.logBase2()),
InsertPt);
}
Value *RHS = expand(S->getRHS());
RHS = InsertCastOfTo(CastInst::getCastOpcode(RHS, false, Ty, false), RHS, Ty);
return InsertBinop(Instruction::UDiv, LHS, RHS, InsertPt);
}
@ -147,14 +167,19 @@ Value *SCEVExpander::visitAddRecExpr(SCEVAddRecExpr *S) {
const Type *Ty = S->getType();
const Loop *L = S->getLoop();
// We cannot yet do fp recurrences, e.g. the xform of {X,+,F} --> X+{0,+,F}
assert(Ty->isInteger() && "Cannot expand fp recurrences yet!");
assert((Ty->isInteger() || isa<PointerType>(Ty)) &&
"Cannot expand fp recurrences yet!");
// {X,+,F} --> X + {0,+,F}
if (!S->getStart()->isZero()) {
Value *Start = expand(S->getStart());
if (isa<PointerType>(Start->getType()))
Start = InsertCastOfTo(Instruction::PtrToInt, Start, TD.getIntPtrType());
std::vector<SCEVHandle> NewOps(S->op_begin(), S->op_end());
NewOps[0] = SE.getIntegerSCEV(0, Ty);
Value *Rest = expand(SE.getAddRecExpr(NewOps, L));
if (isa<PointerType>(Rest->getType()))
Rest = InsertCastOfTo(Instruction::PtrToInt, Rest, TD.getIntPtrType());
// FIXME: look for an existing add to use.
return InsertBinop(Instruction::Add, Rest, Start, InsertPt);
@ -242,16 +267,22 @@ Value *SCEVExpander::visitAddRecExpr(SCEVAddRecExpr *S) {
Value *SCEVExpander::visitTruncateExpr(SCEVTruncateExpr *S) {
Value *V = expand(S->getOperand());
if (isa<PointerType>(V->getType()))
V = InsertCastOfTo(Instruction::PtrToInt, V, TD.getIntPtrType());
return CastInst::CreateTruncOrBitCast(V, S->getType(), "tmp.", InsertPt);
}
Value *SCEVExpander::visitZeroExtendExpr(SCEVZeroExtendExpr *S) {
Value *V = expand(S->getOperand());
if (isa<PointerType>(V->getType()))
V = InsertCastOfTo(Instruction::PtrToInt, V, TD.getIntPtrType());
return CastInst::CreateZExtOrBitCast(V, S->getType(), "tmp.", InsertPt);
}
Value *SCEVExpander::visitSignExtendExpr(SCEVSignExtendExpr *S) {
Value *V = expand(S->getOperand());
if (isa<PointerType>(V->getType()))
V = InsertCastOfTo(Instruction::PtrToInt, V, TD.getIntPtrType());
return CastInst::CreateSExtOrBitCast(V, S->getType(), "tmp.", InsertPt);
}
@ -275,10 +306,14 @@ Value *SCEVExpander::visitUMaxExpr(SCEVUMaxExpr *S) {
return LHS;
}
Value *SCEVExpander::expandCodeFor(SCEVHandle SH, Instruction *IP) {
Value *SCEVExpander::expandCodeFor(SCEVHandle SH, const Type *Ty,
Instruction *IP) {
// Expand the code for this SCEV.
assert(TD.getTypeSizeInBits(Ty) == TD.getTypeSizeInBits(SH->getType()) &&
"non-trivial casts should be done with the SCEVs directly!");
this->InsertPt = IP;
return expand(SH);
Value *V = expand(SH);
return InsertCastOfTo(CastInst::getCastOpcode(V, false, Ty, false), V, Ty);
}
Value *SCEVExpander::expand(SCEV *S) {

157
lib/Transforms/Scalar/IndVarSimplify.cpp
View File

@ -50,6 +50,7 @@
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/ADT/SmallVector.h"
@ -59,7 +60,6 @@
using namespace llvm;
STATISTIC(NumRemoved , "Number of aux indvars removed");
STATISTIC(NumPointer , "Number of pointer indvars promoted");
STATISTIC(NumInserted, "Number of canonical indvars added");
STATISTIC(NumReplaced, "Number of exit values replaced");
STATISTIC(NumLFTR , "Number of loop exit tests replaced");
@ -67,6 +67,7 @@ STATISTIC(NumLFTR , "Number of loop exit tests replaced");
namespace {
class VISIBILITY_HIDDEN IndVarSimplify : public LoopPass {
LoopInfo *LI;
TargetData *TD;
ScalarEvolution *SE;
bool Changed;
public:
@ -81,6 +82,7 @@ namespace {
AU.addRequiredID(LCSSAID);
AU.addRequiredID(LoopSimplifyID);
AU.addRequired<LoopInfo>();
AU.addRequired<TargetData>();
AU.addPreserved<ScalarEvolution>();
AU.addPreservedID(LoopSimplifyID);
AU.addPreservedID(LCSSAID);
@ -91,8 +93,6 @@ namespace {
void RewriteNonIntegerIVs(Loop *L);
void EliminatePointerRecurrence(PHINode *PN, BasicBlock *Preheader,
SmallPtrSet<Instruction*, 16> &DeadInsts);
void LinearFunctionTestReplace(Loop *L, SCEVHandle BackedgeTakenCount,
Value *IndVar,
BasicBlock *ExitingBlock,
@ -135,97 +135,6 @@ DeleteTriviallyDeadInstructions(SmallPtrSet<Instruction*, 16> &Insts) {
}
}
/// EliminatePointerRecurrence - Check to see if this is a trivial GEP pointer
/// recurrence. If so, change it into an integer recurrence, permitting
/// analysis by the SCEV routines.
void IndVarSimplify::EliminatePointerRecurrence(PHINode *PN,
BasicBlock *Preheader,
SmallPtrSet<Instruction*, 16> &DeadInsts) {
assert(PN->getNumIncomingValues() == 2 && "Noncanonicalized loop!");
unsigned PreheaderIdx = PN->getBasicBlockIndex(Preheader);
unsigned BackedgeIdx = PreheaderIdx^1;
if (GetElementPtrInst *GEPI =
dyn_cast<GetElementPtrInst>(PN->getIncomingValue(BackedgeIdx)))
if (GEPI->getOperand(0) == PN) {
assert(GEPI->getNumOperands() == 2 && "GEP types must match!");
DOUT << "INDVARS: Eliminating pointer recurrence: " << *GEPI;
// Okay, we found a pointer recurrence. Transform this pointer
// recurrence into an integer recurrence. Compute the value that gets
// added to the pointer at every iteration.
Value *AddedVal = GEPI->getOperand(1);
// Insert a new integer PHI node into the top of the block.
PHINode *NewPhi = PHINode::Create(AddedVal->getType(),
PN->getName()+".rec", PN);
NewPhi->addIncoming(Constant::getNullValue(NewPhi->getType()), Preheader);
// Create the new add instruction.
Value *NewAdd = BinaryOperator::CreateAdd(NewPhi, AddedVal,
GEPI->getName()+".rec", GEPI);
NewPhi->addIncoming(NewAdd, PN->getIncomingBlock(BackedgeIdx));
// Update the existing GEP to use the recurrence.
GEPI->setOperand(0, PN->getIncomingValue(PreheaderIdx));
// Update the GEP to use the new recurrence we just inserted.
GEPI->setOperand(1, NewAdd);
// If the incoming value is a constant expr GEP, try peeling out the array
// 0 index if possible to make things simpler.
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(GEPI->getOperand(0)))
if (CE->getOpcode() == Instruction::GetElementPtr) {
unsigned NumOps = CE->getNumOperands();
assert(NumOps > 1 && "CE folding didn't work!");
if (CE->getOperand(NumOps-1)->isNullValue()) {
// Check to make sure the last index really is an array index.
gep_type_iterator GTI = gep_type_begin(CE);
for (unsigned i = 1, e = CE->getNumOperands()-1;
i != e; ++i, ++GTI)
/*empty*/;
if (isa<SequentialType>(*GTI)) {
// Pull the last index out of the constant expr GEP.
SmallVector<Value*, 8> CEIdxs(CE->op_begin()+1, CE->op_end()-1);
Constant *NCE = ConstantExpr::getGetElementPtr(CE->getOperand(0),
&CEIdxs[0],
CEIdxs.size());
Value *Idx[2];
Idx[0] = Constant::getNullValue(Type::Int32Ty);
Idx[1] = NewAdd;
GetElementPtrInst *NGEPI = GetElementPtrInst::Create(
NCE, Idx, Idx + 2,
GEPI->getName(), GEPI);
SE->deleteValueFromRecords(GEPI);
GEPI->replaceAllUsesWith(NGEPI);
GEPI->eraseFromParent();
GEPI = NGEPI;
}
}
}
// Finally, if there are any other users of the PHI node, we must
// insert a new GEP instruction that uses the pre-incremented version
// of the induction amount.
if (!PN->use_empty()) {
BasicBlock::iterator InsertPos = PN; ++InsertPos;
while (isa<PHINode>(InsertPos)) ++InsertPos;
Value *PreInc =
GetElementPtrInst::Create(PN->getIncomingValue(PreheaderIdx),
NewPhi, "", InsertPos);
PreInc->takeName(PN);
PN->replaceAllUsesWith(PreInc);
}
// Delete the old PHI for sure, and the GEP if its otherwise unused.
DeadInsts.insert(PN);
++NumPointer;
Changed = true;
}
}
/// LinearFunctionTestReplace - This method rewrites the exit condition of the
/// loop to be a canonical != comparison against the incremented loop induction
/// variable. This pass is able to rewrite the exit tests of any loop where the
@ -275,7 +184,7 @@ void IndVarSimplify::LinearFunctionTestReplace(Loop *L,
// Expand the code for the iteration count into the preheader of the loop.
BasicBlock *Preheader = L->getLoopPreheader();
Value *ExitCnt = Rewriter.expandCodeFor(RHS,
Value *ExitCnt = Rewriter.expandCodeFor(RHS, IndVar->getType(),
Preheader->getTerminator());
// Insert a new icmp_ne or icmp_eq instruction before the branch.
@ -307,7 +216,7 @@ void IndVarSimplify::RewriteLoopExitValues(Loop *L, SCEV *BackedgeTakenCount) {
// Scan all of the instructions in the loop, looking at those that have
// extra-loop users and which are recurrences.
SCEVExpander Rewriter(*SE, *LI);
SCEVExpander Rewriter(*SE, *LI, *TD);
// We insert the code into the preheader of the loop if the loop contains
// multiple exit blocks, or in the exit block if there is exactly one.
@ -349,7 +258,8 @@ void IndVarSimplify::RewriteLoopExitValues(Loop *L, SCEV *BackedgeTakenCount) {
Value *InVal = PN->getIncomingValue(i);
if (!isa<Instruction>(InVal) ||
// SCEV only supports integer expressions for now.
!isa<IntegerType>(InVal->getType()))
(!isa<IntegerType>(InVal->getType()) &&
!isa<PointerType>(InVal->getType())))
continue;
// If this pred is for a subloop, not L itself, skip it.
@ -384,7 +294,7 @@ void IndVarSimplify::RewriteLoopExitValues(Loop *L, SCEV *BackedgeTakenCount) {
// just reuse it.
Value *&ExitVal = ExitValues[Inst];
if (!ExitVal)
ExitVal = Rewriter.expandCodeFor(ExitValue, InsertPt);
ExitVal = Rewriter.expandCodeFor(ExitValue, PN->getType(), InsertPt);
DOUT << "INDVARS: RLEV: AfterLoopVal = " << *ExitVal
<< " LoopVal = " << *Inst << "\n";
@ -413,23 +323,19 @@ void IndVarSimplify::RewriteLoopExitValues(Loop *L, SCEV *BackedgeTakenCount) {
}
void IndVarSimplify::RewriteNonIntegerIVs(Loop *L) {
// First step. Check to see if there are any trivial GEP pointer recurrences.
// First step. Check to see if there are any floating-point recurrences.
// If there are, change them into integer recurrences, permitting analysis by
// the SCEV routines.
//
BasicBlock *Header = L->getHeader();
BasicBlock *Preheader = L->getLoopPreheader();
SmallPtrSet<Instruction*, 16> DeadInsts;
for (BasicBlock::iterator I = Header->begin(); isa<PHINode>(I); ++I) {
PHINode *PN = cast<PHINode>(I);
if (isa<PointerType>(PN->getType()))
EliminatePointerRecurrence(PN, Preheader, DeadInsts);
else
HandleFloatingPointIV(L, PN, DeadInsts);
HandleFloatingPointIV(L, PN, DeadInsts);
}
// If the loop previously had a pointer or floating-point IV, ScalarEvolution
// If the loop previously had floating-point IV, ScalarEvolution
// may not have been able to compute a trip count. Now that we've done some
// re-writing, the trip count may be computable.
if (Changed)
@ -442,7 +348,8 @@ void IndVarSimplify::RewriteNonIntegerIVs(Loop *L) {
/// getEffectiveIndvarType - Determine the widest type that the
/// induction-variable PHINode Phi is cast to.
///
static const Type *getEffectiveIndvarType(const PHINode *Phi) {
static const Type *getEffectiveIndvarType(const PHINode *Phi,
const TargetData *TD) {
const Type *Ty = Phi->getType();
for (Value::use_const_iterator UI = Phi->use_begin(), UE = Phi->use_end();
@ -453,8 +360,7 @@ static const Type *getEffectiveIndvarType(const PHINode *Phi) {
else if (const SExtInst *SI = dyn_cast<SExtInst>(UI))
CandidateType = SI->getDestTy();
if (CandidateType &&
CandidateType->getPrimitiveSizeInBits() >
Ty->getPrimitiveSizeInBits())
TD->getTypeSizeInBits(CandidateType) > TD->getTypeSizeInBits(Ty))
Ty = CandidateType;
}
@ -482,6 +388,7 @@ static const Type *getEffectiveIndvarType(const PHINode *Phi) {
static const PHINode *TestOrigIVForWrap(const Loop *L,
const BranchInst *BI,
const Instruction *OrigCond,
const TargetData *TD,
bool &NoSignedWrap,
bool &NoUnsignedWrap,
const ConstantInt* &InitialVal,
@ -554,7 +461,7 @@ static const PHINode *TestOrigIVForWrap(const Loop *L,
if (const SExtInst *SI = dyn_cast<SExtInst>(CmpLHS)) {
if (!isa<ConstantInt>(CmpRHS) ||
!cast<ConstantInt>(CmpRHS)->getValue()
.isSignedIntN(IncrInst->getType()->getPrimitiveSizeInBits()))
.isSignedIntN(TD->getTypeSizeInBits(IncrInst->getType())))
return 0;
IncrInst = SI->getOperand(0);
}
@ -562,7 +469,7 @@ static const PHINode *TestOrigIVForWrap(const Loop *L,
if (const ZExtInst *ZI = dyn_cast<ZExtInst>(CmpLHS)) {
if (!isa<ConstantInt>(CmpRHS) ||
!cast<ConstantInt>(CmpRHS)->getValue()
.isIntN(IncrInst->getType()->getPrimitiveSizeInBits()))
.isIntN(TD->getTypeSizeInBits(IncrInst->getType())))
return 0;
IncrInst = ZI->getOperand(0);
}
@ -643,7 +550,7 @@ static Value *getSignExtendedTruncVar(const SCEVAddRecExpr *AR,
SE->getAddRecExpr(ExtendedStart, ExtendedStep, L);
if (LargestType != myType)
ExtendedAddRec = SE->getTruncateExpr(ExtendedAddRec, myType);
return Rewriter.expandCodeFor(ExtendedAddRec, InsertPt);
return Rewriter.expandCodeFor(ExtendedAddRec, myType, InsertPt);
}
static Value *getZeroExtendedTruncVar(const SCEVAddRecExpr *AR,
@ -660,7 +567,7 @@ static Value *getZeroExtendedTruncVar(const SCEVAddRecExpr *AR,
SE->getAddRecExpr(ExtendedStart, ExtendedStep, L);
if (LargestType != myType)
ExtendedAddRec = SE->getTruncateExpr(ExtendedAddRec, myType);
return Rewriter.expandCodeFor(ExtendedAddRec, InsertPt);
return Rewriter.expandCodeFor(ExtendedAddRec, myType, InsertPt);
}
/// allUsesAreSameTyped - See whether all Uses of I are instructions
@ -682,10 +589,11 @@ static bool allUsesAreSameTyped(unsigned int Opcode, Instruction *I) {
bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
LI = &getAnalysis<LoopInfo>();
TD = &getAnalysis<TargetData>();
SE = &getAnalysis<ScalarEvolution>();
Changed = false;
// If there are any floating-point or pointer recurrences, attempt to
// If there are any floating-point recurrences, attempt to
// transform them to use integer recurrences.
RewriteNonIntegerIVs(L);
@ -712,7 +620,7 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
for (BasicBlock::iterator I = Header->begin(); isa<PHINode>(I); ++I) {
PHINode *PN = cast<PHINode>(I);
if (PN->getType()->isInteger()) { // FIXME: when we have fast-math, enable!
if (PN->getType()->isInteger() || isa<PointerType>(PN->getType())) {
SCEVHandle SCEV = SE->getSCEV(PN);
// FIXME: It is an extremely bad idea to indvar substitute anything more
// complex than affine induction variables. Doing so will put expensive
@ -731,21 +639,26 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
SmallSetVector<const Type *, 4> SizesToInsert;
if (!isa<SCEVCouldNotCompute>(BackedgeTakenCount)) {
LargestType = BackedgeTakenCount->getType();
SizesToInsert.insert(BackedgeTakenCount->getType());
if (isa<PointerType>(LargestType))
LargestType = TD->getIntPtrType();
SizesToInsert.insert(LargestType);
}
for (unsigned i = 0, e = IndVars.size(); i != e; ++i) {
const PHINode *PN = IndVars[i].first;
SizesToInsert.insert(PN->getType());
const Type *EffTy = getEffectiveIndvarType(PN);
const Type *PNTy = PN->getType();
if (isa<PointerType>(PNTy)) PNTy = TD->getIntPtrType();
SizesToInsert.insert(PNTy);
const Type *EffTy = getEffectiveIndvarType(PN, TD);
if (isa<PointerType>(EffTy)) EffTy = TD->getIntPtrType();
SizesToInsert.insert(EffTy);
if (!LargestType ||
EffTy->getPrimitiveSizeInBits() >
LargestType->getPrimitiveSizeInBits())
TD->getTypeSizeInBits(EffTy) >
TD->getTypeSizeInBits(LargestType))
LargestType = EffTy;
}
// Create a rewriter object which we'll use to transform the code with.
SCEVExpander Rewriter(*SE, *LI);
SCEVExpander Rewriter(*SE, *LI, *TD);
// Now that we know the largest of of the induction variables in this loop,
// insert a canonical induction variable of the largest size.
@ -769,7 +682,7 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
if (Instruction *OrigCond = dyn_cast<Instruction>(BI->getCondition())) {
// Determine if the OrigIV will ever undergo overflow.
OrigControllingPHI =
TestOrigIVForWrap(L, BI, OrigCond,
TestOrigIVForWrap(L, BI, OrigCond, TD,
NoSignedWrap, NoUnsignedWrap,
InitialVal, IncrVal, LimitVal);
@ -804,7 +717,7 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
while (!IndVars.empty()) {
PHINode *PN = IndVars.back().first;
SCEVAddRecExpr *AR = cast<SCEVAddRecExpr>(IndVars.back().second);
Value *NewVal = Rewriter.expandCodeFor(AR, InsertPt);
Value *NewVal = Rewriter.expandCodeFor(AR, PN->getType(), InsertPt);
DOUT << "INDVARS: Rewrote IV '" << *AR << "' " << *PN
<< " into = " << *NewVal << "\n";
NewVal->takeName(PN);

251
lib/Transforms/Scalar/LoopStrengthReduce.cpp
View File

@ -1,4 +1,4 @@
//===- LoopStrengthReduce.cpp - Strength Reduce GEPs in Loops -------------===//
//===- LoopStrengthReduce.cpp - Strength Reduce IVs in Loops --------------===//
//
// The LLVM Compiler Infrastructure
//
@ -8,10 +8,7 @@
//===----------------------------------------------------------------------===//
//
// This pass performs a strength reduction on array references inside loops that
// have as one or more of their components the loop induction variable. This is
// accomplished by creating a new Value to hold the initial value of the array
// access for the first iteration, and then creating a new GEP instruction in
// the loop to increment the value by the appropriate amount.
// have as one or more of their components the loop induction variable.
//
//===----------------------------------------------------------------------===//
@ -133,17 +130,6 @@ namespace {
/// dependent on random ordering of pointers in the process.
SmallVector<SCEVHandle, 16> StrideOrder;
/// GEPlist - A list of the GEP's that have been remembered in the SCEV
/// data structures. SCEV does not know to update these when the operands
/// of the GEP are changed, which means we cannot leave them live across
/// loops.
SmallVector<GetElementPtrInst *, 16> GEPlist;
/// CastedValues - As we need to cast values to uintptr_t, this keeps track
/// of the casted version of each value. This is accessed by
/// getCastedVersionOf.
DenseMap<Value*, Value*> CastedPointers;
/// DeadInsts - Keep track of instructions we may have made dead, so that
/// we can remove them after we are done working.
SmallVector<Instruction*, 16> DeadInsts;
@ -175,14 +161,10 @@ namespace {
AU.addRequired<ScalarEvolution>();
AU.addPreserved<ScalarEvolution>();
}
/// getCastedVersionOf - Return the specified value casted to uintptr_t.
///
Value *getCastedVersionOf(Instruction::CastOps opcode, Value *V);
private:
bool AddUsersIfInteresting(Instruction *I, Loop *L,
SmallPtrSet<Instruction*,16> &Processed);
SCEVHandle GetExpressionSCEV(Instruction *E);
ICmpInst *ChangeCompareStride(Loop *L, ICmpInst *Cond,
IVStrideUse* &CondUse,
const SCEVHandle* &CondStride);
@ -249,24 +231,6 @@ Pass *llvm::createLoopStrengthReducePass(const TargetLowering *TLI) {
return new LoopStrengthReduce(TLI);
}
/// getCastedVersionOf - Return the specified value casted to uintptr_t. This
/// assumes that the Value* V is of integer or pointer type only.
///
Value *LoopStrengthReduce::getCastedVersionOf(Instruction::CastOps opcode,
Value *V) {
if (V->getType() == UIntPtrTy) return V;
if (Constant *CB = dyn_cast<Constant>(V))
return ConstantExpr::getCast(opcode, CB, UIntPtrTy);
Value *&New = CastedPointers[V];
if (New) return New;
New = SCEVExpander::InsertCastOfTo(opcode, V, UIntPtrTy);
DeadInsts.push_back(cast<Instruction>(New));
return New;
}
/// DeleteTriviallyDeadInstructions - If any of the instructions is the
/// specified set are trivially dead, delete them and see if this makes any of
/// their operands subsequently dead.
@ -308,74 +272,6 @@ void LoopStrengthReduce::DeleteTriviallyDeadInstructions() {
}
}
/// GetExpressionSCEV - Compute and return the SCEV for the specified
/// instruction.
SCEVHandle LoopStrengthReduce::GetExpressionSCEV(Instruction *Exp) {
// Pointer to pointer bitcast instructions return the same value as their
// operand.
if (BitCastInst *BCI = dyn_cast<BitCastInst>(Exp)) {
if (SE->hasSCEV(BCI) || !isa<Instruction>(BCI->getOperand(0)))
return SE->getSCEV(BCI);
SCEVHandle R = GetExpressionSCEV(cast<Instruction>(BCI->getOperand(0)));
SE->setSCEV(BCI, R);
return R;
}
// Scalar Evolutions doesn't know how to compute SCEV's for GEP instructions.
// If this is a GEP that SE doesn't know about, compute it now and insert it.
// If this is not a GEP, or if we have already done this computation, just let
// SE figure it out.
GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Exp);
if (!GEP || SE->hasSCEV(GEP))
return SE->getSCEV(Exp);
// Analyze all of the subscripts of this getelementptr instruction, looking
// for uses that are determined by the trip count of the loop. First, skip
// all operands the are not dependent on the IV.
// Build up the base expression. Insert an LLVM cast of the pointer to
// uintptr_t first.
SCEVHandle GEPVal = SE->getUnknown(
getCastedVersionOf(Instruction::PtrToInt, GEP->getOperand(0)));
gep_type_iterator GTI = gep_type_begin(GEP);
for (User::op_iterator i = GEP->op_begin() + 1, e = GEP->op_end();
i != e; ++i, ++GTI) {
// If this is a use of a recurrence that we can analyze, and it comes before
// Op does in the GEP operand list, we will handle this when we process this
// operand.
if (const StructType *STy = dyn_cast<StructType>(*GTI)) {
const StructLayout *SL = TD->getStructLayout(STy);
unsigned Idx = cast<ConstantInt>(*i)->getZExtValue();
uint64_t Offset = SL->getElementOffset(Idx);
GEPVal = SE->getAddExpr(GEPVal,
SE->getIntegerSCEV(Offset, UIntPtrTy));
} else {
unsigned GEPOpiBits =
(*i)->getType()->getPrimitiveSizeInBits();
unsigned IntPtrBits = UIntPtrTy->getPrimitiveSizeInBits();
Instruction::CastOps opcode = (GEPOpiBits < IntPtrBits ?
Instruction::SExt : (GEPOpiBits > IntPtrBits ? Instruction::Trunc :
Instruction::BitCast));
Value *OpVal = getCastedVersionOf(opcode, *i);
SCEVHandle Idx = SE->getSCEV(OpVal);
uint64_t TypeSize = TD->getTypePaddedSize(GTI.getIndexedType());
if (TypeSize != 1)
Idx = SE->getMulExpr(Idx,
SE->getConstant(ConstantInt::get(UIntPtrTy,
TypeSize)));
GEPVal = SE->getAddExpr(GEPVal, Idx);
}
}
SE->setSCEV(GEP, GEPVal);
GEPlist.push_back(GEP);
return GEPVal;
}
/// containsAddRecFromDifferentLoop - Determine whether expression S involves a
/// subexpression that is an AddRec from a loop other than L. An outer loop
/// of L is OK, but not an inner loop nor a disjoint loop.
@ -602,7 +498,7 @@ bool LoopStrengthReduce::AddUsersIfInteresting(Instruction *I, Loop *L,
return true; // Instruction already handled.
// Get the symbolic expression for this instruction.
SCEVHandle ISE = GetExpressionSCEV(I);
SCEVHandle ISE = SE->getSCEV(I);
if (isa<SCEVCouldNotCompute>(ISE)) return false;
// Get the start and stride for this expression.
@ -722,6 +618,7 @@ namespace {
SmallVectorImpl<Instruction*> &DeadInsts);
Value *InsertCodeForBaseAtPosition(const SCEVHandle &NewBase,
const Type *Ty,
SCEVExpander &Rewriter,
Instruction *IP, Loop *L);
void dump() const;
@ -735,6 +632,7 @@ void BasedUser::dump() const {
}
Value *BasedUser::InsertCodeForBaseAtPosition(const SCEVHandle &NewBase,
const Type *Ty,
SCEVExpander &Rewriter,
Instruction *IP, Loop *L) {
// Figure out where we *really* want to insert this code. In particular, if
@ -755,7 +653,7 @@ Value *BasedUser::InsertCodeForBaseAtPosition(const SCEVHandle &NewBase,
InsertLoop = InsertLoop->getParentLoop();
}
Value *Base = Rewriter.expandCodeFor(NewBase, BaseInsertPt);
Value *Base = Rewriter.expandCodeFor(NewBase, Ty, BaseInsertPt);
// If there is no immediate value, skip the next part.
if (Imm->isZero())
@ -768,8 +666,7 @@ Value *BasedUser::InsertCodeForBaseAtPosition(const SCEVHandle &NewBase,
// Always emit the immediate (if non-zero) into the same block as the user.
SCEVHandle NewValSCEV = SE->getAddExpr(SE->getUnknown(Base), Imm);
return Rewriter.expandCodeFor(NewValSCEV, IP);
return Rewriter.expandCodeFor(NewValSCEV, Ty, IP);
}
@ -809,15 +706,9 @@ void BasedUser::RewriteInstructionToUseNewBase(const SCEVHandle &NewBase,
while (isa<PHINode>(InsertPt)) ++InsertPt;
}
}
Value *NewVal = InsertCodeForBaseAtPosition(NewBase, Rewriter, InsertPt, L);
// Adjust the type back to match the Inst. Note that we can't use InsertPt
// here because the SCEVExpander may have inserted the instructions after
// that point, in its efforts to avoid inserting redundant expressions.
if (isa<PointerType>(OperandValToReplace->getType())) {
NewVal = SCEVExpander::InsertCastOfTo(Instruction::IntToPtr,
NewVal,
OperandValToReplace->getType());
}
Value *NewVal = InsertCodeForBaseAtPosition(NewBase,
OperandValToReplace->getType(),
Rewriter, InsertPt, L);
// Replace the use of the operand Value with the new Phi we just created.
Inst->replaceUsesOfWith(OperandValToReplace, NewVal);
@ -875,17 +766,8 @@ void BasedUser::RewriteInstructionToUseNewBase(const SCEVHandle &NewBase,
Instruction *InsertPt = (L->contains(OldLoc->getParent())) ?
PN->getIncomingBlock(i)->getTerminator() :
OldLoc->getParent()->getTerminator();
Code = InsertCodeForBaseAtPosition(NewBase, Rewriter, InsertPt, L);
// Adjust the type back to match the PHI. Note that we can't use
// InsertPt here because the SCEVExpander may have inserted its
// instructions after that point, in its efforts to avoid inserting
// redundant expressions.
if (isa<PointerType>(PN->getType())) {
Code = SCEVExpander::InsertCastOfTo(Instruction::IntToPtr,
Code,
PN->getType());
}
Code = InsertCodeForBaseAtPosition(NewBase, PN->getType(),
Rewriter, InsertPt, L);
DOUT << " Changing PHI use to ";
DEBUG(WriteAsOperand(*DOUT, Code, /*PrintType=*/false));
@ -921,16 +803,13 @@ static bool fitsInAddressMode(const SCEVHandle &V, const Type *UseTy,
}
if (SCEVUnknown *SU = dyn_cast<SCEVUnknown>(V))
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(SU->getValue()))
if (TLI && CE->getOpcode() == Instruction::PtrToInt) {
Constant *Op0 = CE->getOperand(0);
if (GlobalValue *GV = dyn_cast<GlobalValue>(Op0)) {
TargetLowering::AddrMode AM;
AM.BaseGV = GV;
AM.HasBaseReg = HasBaseReg;
return TLI->isLegalAddressingMode(AM, UseTy);
}
}
if (GlobalValue *GV = dyn_cast<GlobalValue>(SU->getValue())) {
TargetLowering::AddrMode AM;
AM.BaseGV = GV;
AM.HasBaseReg = HasBaseReg;
return TLI->isLegalAddressingMode(AM, UseTy);
}
return false;
}
@ -1591,6 +1470,7 @@ bool LoopStrengthReduce::ShouldUseFullStrengthReductionMode(
///
static PHINode *InsertAffinePhi(SCEVHandle Start, SCEVHandle Step,
const Loop *L,
const TargetData *TD,
SCEVExpander &Rewriter) {
assert(Start->isLoopInvariant(L) && "New PHI start is not loop invariant!");
assert(Step->isLoopInvariant(L) && "New PHI stride is not loop invariant!");
@ -1598,9 +1478,11 @@ static PHINode *InsertAffinePhi(SCEVHandle Start, SCEVHandle Step,
BasicBlock *Header = L->getHeader();
BasicBlock *Preheader = L->getLoopPreheader();
BasicBlock *LatchBlock = L->getLoopLatch();
const Type *Ty = Start->getType();
if (isa<PointerType>(Ty)) Ty = TD->getIntPtrType();
PHINode *PN = PHINode::Create(Start->getType(), "lsr.iv", Header->begin());
PN->addIncoming(Rewriter.expandCodeFor(Start, Preheader->getTerminator()),
PHINode *PN = PHINode::Create(Ty, "lsr.iv", Header->begin());
PN->addIncoming(Rewriter.expandCodeFor(Start, Ty, Preheader->getTerminator()),
Preheader);
// If the stride is negative, insert a sub instead of an add for the
@ -1612,7 +1494,8 @@ static PHINode *InsertAffinePhi(SCEVHandle Start, SCEVHandle Step,
// Insert an add instruction right before the terminator corresponding
// to the back-edge.
Value *StepV = Rewriter.expandCodeFor(IncAmount, Preheader->getTerminator());
Value *StepV = Rewriter.expandCodeFor(IncAmount, Ty,
Preheader->getTerminator());
Instruction *IncV;
if (isNegative) {
IncV = BinaryOperator::CreateSub(PN, StepV, "lsr.iv.next",
@ -1683,7 +1566,7 @@ LoopStrengthReduce::PrepareToStrengthReduceFully(
SCEVHandle Imm = UsersToProcess[i].Imm;
SCEVHandle Base = UsersToProcess[i].Base;
SCEVHandle Start = SE->getAddExpr(CommonExprs, Base, Imm);
PHINode *Phi = InsertAffinePhi(Start, Stride, L,
PHINode *Phi = InsertAffinePhi(Start, Stride, L, TD,
PreheaderRewriter);
// Loop over all the users with the same base.
do {
@ -1710,7 +1593,7 @@ LoopStrengthReduce::PrepareToStrengthReduceWithNewPhi(
DOUT << " Inserting new PHI:\n";
PHINode *Phi = InsertAffinePhi(SE->getUnknown(CommonBaseV),
Stride, L,
Stride, L, TD,
PreheaderRewriter);
// Remember this in case a later stride is multiple of this.
@ -1816,6 +1699,7 @@ void LoopStrengthReduce::StrengthReduceStridedIVUsers(const SCEVHandle &Stride,
bool HaveCommonExprs = !CommonExprs->isZero();
const Type *ReplacedTy = CommonExprs->getType();
if (isa<PointerType>(ReplacedTy)) ReplacedTy = TD->getIntPtrType();
// If all uses are addresses, consider sinking the immediate part of the
// common expression back into uses if they can fit in the immediate fields.
@ -1829,11 +1713,8 @@ void LoopStrengthReduce::StrengthReduceStridedIVUsers(const SCEVHandle &Stride,
// If the immediate part of the common expression is a GV, check if it's
// possible to fold it into the target addressing mode.
GlobalValue *GV = 0;
if (SCEVUnknown *SU = dyn_cast<SCEVUnknown>(Imm)) {
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(SU->getValue()))
if (CE->getOpcode() == Instruction::PtrToInt)
GV = dyn_cast<GlobalValue>(CE->getOperand(0));
}
if (SCEVUnknown *SU = dyn_cast<SCEVUnknown>(Imm))
GV = dyn_cast<GlobalValue>(SU->getValue());
int64_t Offset = 0;
if (SCEVConstant *SC = dyn_cast<SCEVConstant>(Imm))
Offset = SC->getValue()->getSExtValue();
@ -1860,8 +1741,8 @@ void LoopStrengthReduce::StrengthReduceStridedIVUsers(const SCEVHandle &Stride,
<< *Stride << ":\n"
<< " Common base: " << *CommonExprs << "\n";
SCEVExpander Rewriter(*SE, *LI);
SCEVExpander PreheaderRewriter(*SE, *LI);
SCEVExpander Rewriter(*SE, *LI, *TD);
SCEVExpander PreheaderRewriter(*SE, *LI, *TD);
BasicBlock *Preheader = L->getLoopPreheader();
Instruction *PreInsertPt = Preheader->getTerminator();
@ -1882,7 +1763,8 @@ void LoopStrengthReduce::StrengthReduceStridedIVUsers(const SCEVHandle &Stride,
PreheaderRewriter);
} else {
// Emit the initial base value into the loop preheader.
CommonBaseV = PreheaderRewriter.expandCodeFor(CommonExprs, PreInsertPt);
CommonBaseV = PreheaderRewriter.expandCodeFor(CommonExprs, ReplacedTy,
PreInsertPt);
// If all uses are addresses, check if it is possible to reuse an IV with a
// stride that is a factor of this stride. And that the multiple is a number
@ -1910,19 +1792,21 @@ void LoopStrengthReduce::StrengthReduceStridedIVUsers(const SCEVHandle &Stride,
Instruction *Inst = UsersToProcess.back().Inst;
// Emit the code for Base into the preheader.
Value *BaseV = PreheaderRewriter.expandCodeFor(Base, PreInsertPt);
Value *BaseV = 0;
if (!Base->isZero()) {
BaseV = PreheaderRewriter.expandCodeFor(Base, Base->getType(),
PreInsertPt);
DOUT << " Examining uses with BASE ";
DEBUG(WriteAsOperand(*DOUT, BaseV, /*PrintType=*/false));
DOUT << ":\n";
DOUT << " INSERTING code for BASE = " << *Base << ":";
if (BaseV->hasName())
DOUT << " Result value name = %" << BaseV->getNameStr();
DOUT << "\n";
// If BaseV is a constant other than 0, make sure that it gets inserted into
// the preheader, instead of being forward substituted into the uses. We do
// this by forcing a BitCast (noop cast) to be inserted into the preheader
// in this case.
if (Constant *C = dyn_cast<Constant>(BaseV)) {
if (!C->isNullValue() && !fitsInAddressMode(Base, getAccessType(Inst),
TLI, false)) {
// If BaseV is a non-zero constant, make sure that it gets inserted into
// the preheader, instead of being forward substituted into the uses. We
// do this by forcing a BitCast (noop cast) to be inserted into the
// preheader in this case.
if (!fitsInAddressMode(Base, getAccessType(Inst), TLI, false)) {
// We want this constant emitted into the preheader! This is just
// using cast as a copy so BitCast (no-op cast) is appropriate
BaseV = new BitCastInst(BaseV, BaseV->getType(), "preheaderinsert",
@ -1953,10 +1837,11 @@ void LoopStrengthReduce::StrengthReduceStridedIVUsers(const SCEVHandle &Stride,
User.Inst->moveBefore(LatchBlock->getTerminator());
}
if (RewriteOp->getType() != ReplacedTy) {
Instruction::CastOps opcode = Instruction::Trunc;
if (ReplacedTy->getPrimitiveSizeInBits() ==
RewriteOp->getType()->getPrimitiveSizeInBits())
opcode = Instruction::BitCast;
Instruction::CastOps opcode =
CastInst::getCastOpcode(RewriteOp, false, ReplacedTy, false);
assert(opcode != Instruction::SExt &&
opcode != Instruction::ZExt &&
"Unexpected widening cast!");
RewriteOp = SCEVExpander::InsertCastOfTo(opcode, RewriteOp, ReplacedTy);
}
@ -1978,8 +1863,7 @@ void LoopStrengthReduce::StrengthReduceStridedIVUsers(const SCEVHandle &Stride,
// If we are reusing the iv, then it must be multiplied by a constant
// factor to take advantage of the addressing mode scale component.
if (!isa<SCEVConstant>(RewriteFactor) ||
!cast<SCEVConstant>(RewriteFactor)->isZero()) {
if (!RewriteFactor->isZero()) {
// If we're reusing an IV with a nonzero base (currently this happens
// only when all reuses are outside the loop) subtract that base here.
// The base has been used to initialize the PHI node but we don't want
@ -2010,8 +1894,7 @@ void LoopStrengthReduce::StrengthReduceStridedIVUsers(const SCEVHandle &Stride,
// When this use is outside the loop, we earlier subtracted the
// common base, and are adding it back here. Use the same expression
// as before, rather than CommonBaseV, so DAGCombiner will zap it.
if (!isa<ConstantInt>(CommonBaseV) ||
!cast<ConstantInt>(CommonBaseV)->isZero()) {
if (!CommonExprs->isZero()) {
if (L->contains(User.Inst->getParent()))
RewriteExpr = SE->getAddExpr(RewriteExpr,
SE->getUnknown(CommonBaseV));
@ -2022,7 +1905,7 @@ void LoopStrengthReduce::StrengthReduceStridedIVUsers(const SCEVHandle &Stride,
// Now that we know what we need to do, insert code before User for the
// immediate and any loop-variant expressions.
if (!isa<ConstantInt>(BaseV) || !cast<ConstantInt>(BaseV)->isZero())
if (BaseV)
// Add BaseV to the PHI value if needed.
RewriteExpr = SE->getAddExpr(RewriteExpr, SE->getUnknown(BaseV));
@ -2078,6 +1961,9 @@ namespace {
// e.g.
// 4, -1, X, 1, 2 ==> 1, -1, 2, 4, X
struct StrideCompare {
const TargetData *TD;
explicit StrideCompare(const TargetData *td) : TD(td) {}
bool operator()(const SCEVHandle &LHS, const SCEVHandle &RHS) {
SCEVConstant *LHSC = dyn_cast<SCEVConstant>(LHS);
SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS);
@ -2096,7 +1982,8 @@ namespace {
// If it's the same value but different type, sort by bit width so
// that we emit larger induction variables before smaller
// ones, letting the smaller be re-written in terms of larger ones.
return RHS->getBitWidth() < LHS->getBitWidth();
return TD->getTypeSizeInBits(RHS->getType()) <
TD->getTypeSizeInBits(LHS->getType());
}
return LHSC && !RHSC;
}
@ -2129,11 +2016,11 @@ ICmpInst *LoopStrengthReduce::ChangeCompareStride(Loop *L, ICmpInst *Cond,
ICmpInst::Predicate Predicate = Cond->getPredicate();
int64_t CmpSSInt = SC->getValue()->getSExtValue();
unsigned BitWidth = (*CondStride)->getBitWidth();
unsigned BitWidth = TD->getTypeSizeInBits((*CondStride)->getType());
uint64_t SignBit = 1ULL << (BitWidth-1);
const Type *CmpTy = Cond->getOperand(0)->getType();
const Type *NewCmpTy = NULL;
unsigned TyBits = CmpTy->getPrimitiveSizeInBits();
unsigned TyBits = TD->getTypeSizeInBits(CmpTy);
unsigned NewTyBits = 0;
SCEVHandle *NewStride = NULL;
Value *NewCmpLHS = NULL;
@ -2185,9 +2072,7 @@ ICmpInst *LoopStrengthReduce::ChangeCompareStride(Loop *L, ICmpInst *Cond,
continue;
NewCmpTy = NewCmpLHS->getType();
NewTyBits = isa<PointerType>(NewCmpTy)
? UIntPtrTy->getPrimitiveSizeInBits()
: NewCmpTy->getPrimitiveSizeInBits();
NewTyBits = TD->getTypeSizeInBits(NewCmpTy);
if (RequiresTypeConversion(NewCmpTy, CmpTy)) {
// Check if it is possible to rewrite it using
// an iv / stride of a smaller integer type.
@ -2604,7 +2489,7 @@ bool LoopStrengthReduce::runOnLoop(Loop *L, LPPassManager &LPM) {
#endif
// Sort the StrideOrder so we process larger strides first.
std::stable_sort(StrideOrder.begin(), StrideOrder.end(), StrideCompare());
std::stable_sort(StrideOrder.begin(), StrideOrder.end(), StrideCompare(TD));
// Optimize induction variables. Some indvar uses can be transformed to use
// strides that will be needed for other purposes. A common example of this
@ -2638,13 +2523,9 @@ bool LoopStrengthReduce::runOnLoop(Loop *L, LPPassManager &LPM) {
}
// We're done analyzing this loop; release all the state we built up for it.
CastedPointers.clear();
IVUsesByStride.clear();
IVsByStride.clear();
StrideOrder.clear();
for (unsigned i=0; i<GEPlist.size(); i++)
SE->deleteValueFromRecords(GEPlist[i]);
GEPlist.clear();
// Clean up after ourselves
if (!DeadInsts.empty()) {

2
test/CodeGen/ARM/2007-03-13-InstrSched.ll
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@ -1,5 +1,5 @@
; RUN: llvm-as < %s | llc -mtriple=arm-apple-darwin -relocation-model=pic \
; RUN: -mattr=+v6 -stats |& grep asm-printer | grep 41
; RUN: -mattr=+v6 -ifcvt-limit=0 -stats |& grep asm-printer | grep 35
define void @test(i32 %tmp56222, i32 %tmp36224, i32 %tmp46223, i32 %i.0196.0.ph, i32 %tmp8, i32* %tmp1011, i32** %tmp1, i32* %d2.1.out, i32* %d3.1.out, i32* %d0.1.out, i32* %d1.1.out) {
newFuncRoot:

3
test/CodeGen/X86/iv-users-in-other-loops.ll
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@ -1,7 +1,8 @@
; RUN: llvm-as < %s | llc -march=x86-64 -f -o %t
; RUN: grep inc %t | count 2
; RUN: grep addq %t | count 13
; RUN: grep leaq %t | count 9
; RUN: grep leaq %t | count 8
; RUN: grep leal %t | count 4
; RUN: grep movq %t | count 5
; IV users in each of the loops from other loops shouldn't cause LSR

5
test/CodeGen/X86/pr3495.ll
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@ -1,5 +1,6 @@
; RUN: llvm-as < %s | llc -march=x86 -stats |& grep {Number of reloads omited}
; RUN: llvm-as < %s | llc -march=x86 -stats |& grep {Number of available reloads turned into copies}
; RUN: llvm-as < %s | llc -march=x86 -stats |& grep {Number of reloads omited} | grep 2
; RUN: llvm-as < %s | llc -march=x86 -stats |& not grep {Number of available reloads turned into copies}
; RUN: llvm-as < %s | llc -march=x86 -stats |& grep {Number of machine instrs printed} | grep 39
; PR3495
target triple = "i386-pc-linux-gnu"

2
test/CodeGen/X86/stride-nine-with-base-reg.ll
View File

@ -1,7 +1,7 @@
; RUN: llvm-as < %s | llc -march=x86 -relocation-model=static | not grep lea
; RUN: llvm-as < %s | llc -march=x86-64 | not grep lea
; _P should be sunk into the loop and folded into the address mode. There
; P should be sunk into the loop and folded into the address mode. There
; shouldn't be any lea instructions inside the loop.
@B = external global [1000 x i8], align 32