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[LifetimeSafety] Handle pruned-edges (null blocks) in dataflow #150670

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Merged
merged 1 commit into from
Aug 3, 2025
Merged

[LifetimeSafety] Handle pruned-edges (null blocks) in dataflow #150670

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2 changes: 2 additions & 0 deletions clang/lib/Analysis/LifetimeSafety.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -603,6 +603,8 @@ class DataflowAnalysis {
OutStates[B] = StateOut;
Visited.set(B->getBlockID());
for (const CFGBlock *AdjacentB : isForward() ? B->succs() : B->preds()) {
if (!AdjacentB)
continue;
Lattice OldInState = getInState(AdjacentB);
Lattice NewInState = D.join(OldInState, StateOut);
// Enqueue the adjacent block if its in-state has changed or if we have
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19 changes: 19 additions & 0 deletions clang/unittests/Analysis/LifetimeSafetyTest.cpp
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Expand Up @@ -512,6 +512,25 @@ TEST_F(LifetimeAnalysisTest, PointersAndExpirationInACycle) {
EXPECT_THAT(LoansTo({"temp"}), AreExpiredAt("after_loop"));
}

TEST_F(LifetimeAnalysisTest, InfiniteLoopPrunesEdges) {
SetupTest(R"(
void target(MyObj out) {
MyObj *p = &out;
POINT(before_loop);

for (;;) {
POINT(begin);
MyObj in;
p = ∈
POINT(end);
}
}
)");
EXPECT_THAT(Origin("p"), HasLoansTo({"out"}, "before_loop"));
EXPECT_THAT(Origin("p"), HasLoansTo({"in", "out"}, "begin"));
EXPECT_THAT(Origin("p"), HasLoansTo({"in"}, "end"));
}

TEST_F(LifetimeAnalysisTest, NestedScopes) {
SetupTest(R"(
void target() {
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