diff --git a/clang/lib/Analysis/FlowSensitive/Arena.cpp b/clang/lib/Analysis/FlowSensitive/Arena.cpp
--- a/clang/lib/Analysis/FlowSensitive/Arena.cpp
+++ b/clang/lib/Analysis/FlowSensitive/Arena.cpp
@@ -10,6 +10,10 @@
 
 namespace clang::dataflow {
 
+// Compute a canonical key for an unordered pair of operands, so that we
+// can intern (A & B) and (B & A) to the same formula.
+// This does not affect the actual order used in the formula, which is always
+// that of the first call to makeAnd().
 static std::pair<BoolValue *, BoolValue *>
 makeCanonicalBoolValuePair(BoolValue &LHS, BoolValue &RHS) {
   auto Res = std::make_pair(&LHS, &RHS);
diff --git a/clang/unittests/Analysis/FlowSensitive/ArenaTest.cpp b/clang/unittests/Analysis/FlowSensitive/ArenaTest.cpp
--- a/clang/unittests/Analysis/FlowSensitive/ArenaTest.cpp
+++ b/clang/unittests/Analysis/FlowSensitive/ArenaTest.cpp
@@ -147,5 +147,28 @@
   EXPECT_EQ(&Formula1, &Formula2);
 }
 
+// Tests that the structure of the formula we end up with does not depend on
+// details like the pointer address of internal values.
+TEST_F(ArenaTest, Canonicalization) {
+  StringRef Expected = "((V0 | V1) = (V1 & V0))";
+
+  auto &AX = A.create<AtomicBoolValue>();
+  auto &AY = A.create<AtomicBoolValue>();
+  auto &AOr = A.makeOr(AX, AY);
+  auto &AAnd = A.makeAnd(AY, AX);
+  auto &AEqual = A.makeEquals(AOr, AAnd);
+  EXPECT_EQ(Expected, llvm::to_string(A.getFormula(AEqual)));
+
+  // Same, but create the & clause first.
+  // The relative order of (&AOr, &AAnd) and (&BOr, &BAnd) likely differs.
+  Arena B;
+  auto &BX = B.create<AtomicBoolValue>();
+  auto &BY = B.create<AtomicBoolValue>();
+  auto &BAnd = B.makeAnd(BX, BY);
+  auto &BOr = B.makeOr(BY, BX);
+  auto &BEqual = B.makeEquals(BOr, BAnd);
+  EXPECT_EQ(Expected, llvm::to_string(B.getFormula(BEqual)));
+}
+
 } // namespace
 } // namespace clang::dataflow