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Recommit "[NFC] Move code between functions as a preparation step for further improvement"

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The bug should be fixed now.
This commit is contained in:
Max Kazantsev 2020-11-16 13:41:13 +07:00
parent 000e21d54d
commit 55b8c19420
1 changed files with 44 additions and 75 deletions
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119
lib/Transforms/Scalar/IndVarSimplify.cpp
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@ -1290,66 +1290,6 @@ bool IndVarSimplify::sinkUnusedInvariants(Loop *L) {
return MadeAnyChanges;
}
enum ExitCondAnalysisResult {
CanBeRemoved,
CanBeReplacedWithInvariant,
CannotOptimize
};
/// If the condition of BI is trivially true during at least first MaxIter
/// iterations, return CanBeRemoved.
/// If the condition is equivalent to loop-invariant condition expressed as
/// 'InvariantLHS `InvariantPred` InvariantRHS', fill them into respective
/// output parameters and return CanBeReplacedWithInvariant.
/// Otherwise, return CannotOptimize.
static ExitCondAnalysisResult
analyzeCond(const Loop *L, BranchInst *BI, ScalarEvolution *SE,
bool ProvingLoopExit, const SCEV *MaxIter,
ICmpInst::Predicate &InvariantPred, const SCEV *&InvariantLHS,
const SCEV *&InvariantRHS) {
ICmpInst::Predicate Pred;
Value *LHS, *RHS;
using namespace PatternMatch;
BasicBlock *TrueSucc, *FalseSucc;
if (!match(BI, m_Br(m_ICmp(Pred, m_Value(LHS), m_Value(RHS)),
m_BasicBlock(TrueSucc), m_BasicBlock(FalseSucc))))
return CannotOptimize;
assert((L->contains(TrueSucc) != L->contains(FalseSucc)) &&
"Not a loop exit!");
// 'LHS pred RHS' should now mean that we stay in loop.
if (L->contains(FalseSucc))
Pred = CmpInst::getInversePredicate(Pred);
// If we are proving loop exit, invert the predicate.
if (ProvingLoopExit)
Pred = CmpInst::getInversePredicate(Pred);
const SCEV *LHSS = SE->getSCEVAtScope(LHS, L);
const SCEV *RHSS = SE->getSCEVAtScope(RHS, L);
// Can we prove it to be trivially true?
if (SE->isKnownPredicateAt(Pred, LHSS, RHSS, BI))
return CanBeRemoved;
if (ProvingLoopExit)
return CannotOptimize;
// Check if there is a loop-invariant predicate equivalent to our check.
auto LIP = SE->getLoopInvariantExitCondDuringFirstIterations(Pred, LHSS, RHSS,
L, BI, MaxIter);
if (!LIP)
return CannotOptimize;
InvariantPred = LIP->Pred;
InvariantLHS = LIP->LHS;
InvariantRHS = LIP->RHS;
// Can we prove it to be trivially true?
if (SE->isKnownPredicateAt(InvariantPred, InvariantLHS, InvariantRHS, BI))
return CanBeRemoved;
return CanBeReplacedWithInvariant;
}
static void replaceExitCond(BranchInst *BI, Value *NewCond,
SmallVectorImpl<WeakTrackingVH> &DeadInsts) {
auto *OldCond = BI->getCondition();
@ -1390,26 +1330,55 @@ static bool optimizeLoopExitWithUnknownExitCount(
const SCEV *MaxIter, bool Inverted, bool SkipLastIter,
ScalarEvolution *SE, SCEVExpander &Rewriter,
SmallVectorImpl<WeakTrackingVH> &DeadInsts) {
ICmpInst::Predicate Pred;
Value *LHS, *RHS;
using namespace PatternMatch;
BasicBlock *TrueSucc, *FalseSucc;
if (!match(BI, m_Br(m_ICmp(Pred, m_Value(LHS), m_Value(RHS)),
m_BasicBlock(TrueSucc), m_BasicBlock(FalseSucc))))
return false;
assert((L->contains(TrueSucc) != L->contains(FalseSucc)) &&
"Not a loop exit!");
// 'LHS pred RHS' should now mean that we stay in loop.
if (L->contains(FalseSucc))
Pred = CmpInst::getInversePredicate(Pred);
// If we are proving loop exit, invert the predicate.
if (Inverted)
Pred = CmpInst::getInversePredicate(Pred);
const SCEV *LHSS = SE->getSCEVAtScope(LHS, L);
const SCEV *RHSS = SE->getSCEVAtScope(RHS, L);
// Can we prove it to be trivially true?
if (SE->isKnownPredicateAt(Pred, LHSS, RHSS, BI)) {
foldExit(L, ExitingBB, Inverted, DeadInsts);
return true;
}
// Further logic works for non-inverted condition only.
if (Inverted)
return false;
if (SkipLastIter) {
const SCEV *One = SE->getOne(MaxIter->getType());
MaxIter = SE->getMinusSCEV(MaxIter, One);
}
ICmpInst::Predicate InvariantPred;
const SCEV *InvariantLHS, *InvariantRHS;
switch (analyzeCond(L, BI, SE, Inverted, MaxIter, InvariantPred, InvariantLHS,
InvariantRHS)) {
case CanBeRemoved:
foldExit(L, ExitingBB, Inverted, DeadInsts);
return true;
case CanBeReplacedWithInvariant: {
replaceWithInvariantCond(L, ExitingBB, InvariantPred, InvariantLHS,
InvariantRHS, Rewriter, DeadInsts);
return true;
}
case CannotOptimize:
// Check if there is a loop-invariant predicate equivalent to our check.
auto LIP = SE->getLoopInvariantExitCondDuringFirstIterations(Pred, LHSS, RHSS,
L, BI, MaxIter);
if (!LIP)
return false;
}
llvm_unreachable("Unknown case!");
// Can we prove it to be trivially true?
if (SE->isKnownPredicateAt(LIP->Pred, LIP->LHS, LIP->RHS, BI))
foldExit(L, ExitingBB, Inverted, DeadInsts);
else
replaceWithInvariantCond(L, ExitingBB, LIP->Pred, LIP->LHS, LIP->RHS,
Rewriter, DeadInsts);
return true;
}
bool IndVarSimplify::optimizeLoopExits(Loop *L, SCEVExpander &Rewriter) {