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[ConstraintElim] Support arbitrary incoming values for inductions #68032

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Merged
fhahn merged 1 commit into from
Oct 3, 2023
Merged

[ConstraintElim] Support arbitrary incoming values for inductions #68032

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14 changes: 7 additions & 7 deletions llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -859,18 +859,18 @@ void State::addInfoForInductions(BasicBlock &BB) {
return;

auto *AR = dyn_cast_or_null<SCEVAddRecExpr>(SE.getSCEV(PN));
if (!AR)
BasicBlock *LoopPred = L->getLoopPredecessor();
if (!AR || !LoopPred)
return;

const SCEV *StartSCEV = AR->getStart();
Value *StartValue = nullptr;
if (auto *C = dyn_cast<SCEVConstant>(StartSCEV))
if (auto *C = dyn_cast<SCEVConstant>(StartSCEV)) {
StartValue = C->getValue();
else if (auto *U = dyn_cast<SCEVUnknown>(StartSCEV))
StartValue = U->getValue();

if (!StartValue)
return;
} else {
StartValue = PN->getIncomingValueForBlock(LoopPred);
assert(SE.getSCEV(StartValue) == StartSCEV && "inconsistent start value");
}

DomTreeNode *DTN = DT.getNode(InLoopSucc);
auto Inc = SE.getMonotonicPredicateType(AR, CmpInst::ICMP_UGT);
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3 changes: 1 addition & 2 deletions llvm/test/Transforms/ConstraintElimination/monotonic-int-phis-nested-loops.ll
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Expand Up @@ -17,8 +17,7 @@ define void @start_value_of_inner_add_rec_is_add_rec_condition_can_be_simplified
; CHECK-NEXT: [[CMP2_NOT:%.*]] = icmp eq i32 [[K_0]], [[LEN]]
; CHECK-NEXT: br i1 [[CMP2_NOT]], label [[OUTER_LATCH]], label [[INNER_LATCH]]
; CHECK: inner.latch:
; CHECK-NEXT: [[CMP_NOT_I:%.*]] = icmp ult i32 [[K_0]], [[LEN]]
; CHECK-NEXT: call void @use(i1 [[CMP_NOT_I]])
; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[K_INC]] = add i32 [[K_0]], 1
; CHECK-NEXT: br label [[INNER_HEADER]]
; CHECK: outer.latch:
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