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Allow scalar evolution to compute iteration counts for loops with a

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pointer-based condition.  This fixes PR3171.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71354 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eli Friedman
2009-05-09 12:32:42 +00:00
parent cea03cdb69
commit 361e54d433
2 changed files with 34 additions and 18 deletions
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25
lib/Analysis/ScalarEvolution.cpp
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@ -2372,10 +2372,8 @@ ScalarEvolution::ComputeBackedgeTakenCount(const Loop *L) {
ICmpInst *ExitCond = dyn_cast<ICmpInst>(ExitBr->getCondition());
// If it's not an integer comparison then compute it the hard way.
// Note that ICmpInst deals with pointer comparisons too so we must check
// the type of the operand.
if (ExitCond == 0 || isa<PointerType>(ExitCond->getOperand(0)->getType()))
// If it's not an integer or pointer comparison then compute it the hard way.
if (ExitCond == 0)
return ComputeBackedgeTakenCountExhaustively(L, ExitBr->getCondition(),
ExitBr->getSuccessor(0) == ExitBlock);
@ -2416,21 +2414,12 @@ ScalarEvolution::ComputeBackedgeTakenCount(const Loop *L) {
if (const SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS))
if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(LHS))
if (AddRec->getLoop() == L) {
// Form the comparison range using the constant of the correct type so
// that the ConstantRange class knows to do a signed or unsigned
// comparison.
ConstantInt *CompVal = RHSC->getValue();
const Type *RealTy = ExitCond->getOperand(0)->getType();
CompVal = dyn_cast<ConstantInt>(
ConstantExpr::getBitCast(CompVal, RealTy));
if (CompVal) {
// Form the constant range.
ConstantRange CompRange(
ICmpInst::makeConstantRange(Cond, CompVal->getValue()));
// Form the constant range.
ConstantRange CompRange(
ICmpInst::makeConstantRange(Cond, RHSC->getValue()->getValue()));
SCEVHandle Ret = AddRec->getNumIterationsInRange(CompRange, *this);
if (!isa<SCEVCouldNotCompute>(Ret)) return Ret;
}
SCEVHandle Ret = AddRec->getNumIterationsInRange(CompRange, *this);
if (!isa<SCEVCouldNotCompute>(Ret)) return Ret;
}
switch (Cond) {