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[LoopDeletion] Move ICmpInst handling to getValueOnFirstIteration() 

As noticed in https://reviews.llvm.org/D105688, it would be great to move
handling of ICmpInst which was in canProveExitOnFirstIteration() to
getValueOnFirstIteration().

Patch by Dmitry Makogon!

Differential Revision: https://reviews.llvm.org/D108978
Reviewed By: reames
This commit is contained in:
Max Kazantsev 2021-09-03 16:32:47 +07:00
parent 90d5298759
commit 718157283c
1 changed files with 12 additions and 8 deletions
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20
llvm/lib/Transforms/Scalar/LoopDeletion.cpp
View File

@ -191,6 +191,12 @@ getValueOnFirstIteration(Value *V, DenseMap<Value *, Value *> &FirstIterValue,
Value *RHS =
getValueOnFirstIteration(BO->getOperand(1), FirstIterValue, SQ);
FirstIterV = SimplifyBinOp(BO->getOpcode(), LHS, RHS, SQ);
} else if (auto *Cmp = dyn_cast<ICmpInst>(V)) {
Value *LHS =
getValueOnFirstIteration(Cmp->getOperand(0), FirstIterValue, SQ);
Value *RHS =
getValueOnFirstIteration(Cmp->getOperand(1), FirstIterValue, SQ);
FirstIterV = SimplifyICmpInst(Cmp->getPredicate(), LHS, RHS, SQ);
}
if (!FirstIterV)
FirstIterV = V;
@ -314,22 +320,20 @@ static bool canProveExitOnFirstIteration(Loop *L, DominatorTree &DT,
}
using namespace PatternMatch;
ICmpInst::Predicate Pred;
Value *LHS, *RHS;
Value *Cond;
BasicBlock *IfTrue, *IfFalse;
auto *Term = BB->getTerminator();
if (match(Term, m_Br(m_ICmp(Pred, m_Value(LHS), m_Value(RHS)),
if (match(Term, m_Br(m_Value(Cond),
m_BasicBlock(IfTrue), m_BasicBlock(IfFalse)))) {
if (!LHS->getType()->isIntegerTy()) {
auto *ICmp = dyn_cast<ICmpInst>(Cond);
if (!ICmp || !ICmp->getType()->isIntegerTy()) {
MarkAllSuccessorsLive(BB);
continue;
}
// Can we prove constant true or false for this condition?
LHS = getValueOnFirstIteration(LHS, FirstIterValue, SQ);
RHS = getValueOnFirstIteration(RHS, FirstIterValue, SQ);
auto *KnownCondition = SimplifyICmpInst(Pred, LHS, RHS, SQ);
if (!KnownCondition) {
auto *KnownCondition = getValueOnFirstIteration(ICmp, FirstIterValue, SQ);
if (KnownCondition == ICmp) {
// Failed to simplify.
MarkAllSuccessorsLive(BB);
continue;