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For PR1205: 

Make GetConstantFactor compute its result using an APInt.

llvm-svn: 34765
This commit is contained in:
Reid Spencer 2007-02-28 23:31:17 +00:00
parent 962fa8eb9a
commit b0170c4259
1 changed files with 20 additions and 16 deletions
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36
llvm/lib/Analysis/ScalarEvolution.cpp
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@ -1328,31 +1328,33 @@ SCEVHandle ScalarEvolutionsImpl::createNodeForPHI(PHINode *PN) {
/// GetConstantFactor - Determine the largest constant factor that S has. For
/// example, turn {4,+,8} -> 4. (S umod result) should always equal zero.
static uint64_t GetConstantFactor(SCEVHandle S) {
static APInt GetConstantFactor(SCEVHandle S) {
if (SCEVConstant *C = dyn_cast<SCEVConstant>(S)) {
if (uint64_t V = C->getValue()->getZExtValue())
APInt V = C->getValue()->getValue();
if (!V.isMinValue())
return V;
else // Zero is a multiple of everything.
return 1ULL << (S->getType()->getPrimitiveSizeInBits()-1);
return APInt(C->getBitWidth(), 1).shl(C->getBitWidth()-1);
}
if (SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(S))
return GetConstantFactor(T->getOperand()) &
cast<IntegerType>(T->getType())->getBitMask();
cast<IntegerType>(T->getType())->getMask();
if (SCEVZeroExtendExpr *E = dyn_cast<SCEVZeroExtendExpr>(S))
return GetConstantFactor(E->getOperand());
if (SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(S)) {
// The result is the min of all operands.
uint64_t Res = GetConstantFactor(A->getOperand(0));
for (unsigned i = 1, e = A->getNumOperands(); i != e && Res > 1; ++i)
Res = std::min(Res, GetConstantFactor(A->getOperand(i)));
APInt Res = GetConstantFactor(A->getOperand(0));
for (unsigned i = 1, e = A->getNumOperands();
i != e && Res.ugt(APInt(Res.getBitWidth(),1)); ++i)
Res = APIntOps::umin(Res, GetConstantFactor(A->getOperand(i)));
return Res;
}
if (SCEVMulExpr *M = dyn_cast<SCEVMulExpr>(S)) {
// The result is the product of all the operands.
uint64_t Res = GetConstantFactor(M->getOperand(0));
APInt Res = GetConstantFactor(M->getOperand(0));
for (unsigned i = 1, e = M->getNumOperands(); i != e; ++i)
Res *= GetConstantFactor(M->getOperand(i));
return Res;
@ -1362,15 +1364,16 @@ static uint64_t GetConstantFactor(SCEVHandle S) {
// For now, we just handle linear expressions.
if (A->getNumOperands() == 2) {
// We want the GCD between the start and the stride value.
uint64_t Start = GetConstantFactor(A->getOperand(0));
if (Start == 1) return 1;
uint64_t Stride = GetConstantFactor(A->getOperand(1));
return GreatestCommonDivisor64(Start, Stride);
APInt Start = GetConstantFactor(A->getOperand(0));
if (Start == 1)
return APInt(A->getBitWidth(),1);
APInt Stride = GetConstantFactor(A->getOperand(1));
return APIntOps::GreatestCommonDivisor(Start, Stride);
}
}
// SCEVSDivExpr, SCEVUnknown.
return 1;
return APInt(S->getBitWidth(), 1);
}
/// createSCEV - We know that there is no SCEV for the specified value.
@ -1399,9 +1402,10 @@ SCEVHandle ScalarEvolutionsImpl::createSCEV(Value *V) {
// optimizations will transparently handle this case.
if (ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1))) {
SCEVHandle LHS = getSCEV(I->getOperand(0));
uint64_t CommonFact = GetConstantFactor(LHS);
assert(CommonFact && "Common factor should at least be 1!");
if (CommonFact > CI->getZExtValue()) {
APInt CommonFact = GetConstantFactor(LHS);
assert(!CommonFact.isMinValue() &&
"Common factor should at least be 1!");
if (CommonFact.ugt(CI->getValue())) {
// If the LHS is a multiple that is larger than the RHS, use +.
return SCEVAddExpr::get(LHS,
getSCEV(I->getOperand(1)));