diff --git a/llvm/lib/Analysis/CGSCCPassManager.cpp b/llvm/lib/Analysis/CGSCCPassManager.cpp
--- a/llvm/lib/Analysis/CGSCCPassManager.cpp
+++ b/llvm/lib/Analysis/CGSCCPassManager.cpp
@@ -981,8 +981,10 @@
     RefSCC &TargetRC = TargetC.getOuterRefSCC();
     (void)TargetRC;
     // TODO: This only allows trivial edges to be added for now.
+#ifdef EXPENSIVE_CHECKS
     assert((RC == &TargetRC ||
            RC->isAncestorOf(TargetRC)) && "New ref edge is not trivial!");
+#endif
     RC->insertTrivialRefEdge(N, *RefTarget);
   }
 
@@ -992,8 +994,10 @@
     RefSCC &TargetRC = TargetC.getOuterRefSCC();
     (void)TargetRC;
     // TODO: This only allows trivial edges to be added for now.
+#ifdef EXPENSIVE_CHECKS
     assert((RC == &TargetRC ||
            RC->isAncestorOf(TargetRC)) && "New call edge is not trivial!");
+#endif
     // Add a trivial ref edge to be promoted later on alongside
     // PromotedRefTargets.
     RC->insertTrivialRefEdge(N, *CallTarget);
@@ -1087,8 +1091,10 @@
     // The easy case is when the target RefSCC is not this RefSCC. This is
     // only supported when the target RefSCC is a child of this RefSCC.
     if (&TargetRC != RC) {
+#ifdef EXPENSIVE_CHECKS
       assert(RC->isAncestorOf(TargetRC) &&
              "Cannot potentially form RefSCC cycles here!");
+#endif
       RC->switchOutgoingEdgeToRef(N, *RefTarget);
       LLVM_DEBUG(dbgs() << "Switch outgoing call edge to a ref edge from '" << N
                         << "' to '" << *RefTarget << "'\n");
@@ -1121,8 +1127,10 @@
     // The easy case is when the target RefSCC is not this RefSCC. This is
     // only supported when the target RefSCC is a child of this RefSCC.
     if (&TargetRC != RC) {
+#ifdef EXPENSIVE_CHECKS
       assert(RC->isAncestorOf(TargetRC) &&
              "Cannot potentially form RefSCC cycles here!");
+#endif
       RC->switchOutgoingEdgeToCall(N, *CallTarget);
       LLVM_DEBUG(dbgs() << "Switch outgoing ref edge to a call edge from '" << N
                         << "' to '" << *CallTarget << "'\n");
diff --git a/llvm/lib/Analysis/LazyCallGraph.cpp b/llvm/lib/Analysis/LazyCallGraph.cpp
--- a/llvm/lib/Analysis/LazyCallGraph.cpp
+++ b/llvm/lib/Analysis/LazyCallGraph.cpp
@@ -588,9 +588,7 @@
   assert(!(*SourceN)[TargetN].isCall() && "Must start with a ref edge!");
   SmallVector<SCC *, 1> DeletedSCCs;
 
-#ifndef NDEBUG
-  // In a debug build, verify the RefSCC is valid to start with and when this
-  // routine finishes.
+#ifdef EXPENSIVE_CHECKS
   verify();
   auto VerifyOnExit = make_scope_exit([&]() { verify(); });
 #endif
@@ -620,7 +618,7 @@
 
   // Compute the SCCs which (transitively) reach the source.
   auto ComputeSourceConnectedSet = [&](SmallPtrSetImpl<SCC *> &ConnectedSet) {
-#ifndef NDEBUG
+#ifdef EXPENSIVE_CHECKS
     // Check that the RefSCC is still valid before computing this as the
     // results will be nonsensical of we've broken its invariants.
     verify();
@@ -646,7 +644,7 @@
   // but because this is forward connectivity we just "recurse" through the
   // edges.
   auto ComputeTargetConnectedSet = [&](SmallPtrSetImpl<SCC *> &ConnectedSet) {
-#ifndef NDEBUG
+#ifdef EXPENSIVE_CHECKS
     // Check that the RefSCC is still valid before computing this as the
     // results will be nonsensical of we've broken its invariants.
     verify();
@@ -694,7 +692,7 @@
     return false; // No new cycle.
   }
 
-#ifndef NDEBUG
+#ifdef EXPENSIVE_CHECKS
   // Before merging, check that the RefSCC remains valid after all the
   // postorder updates.
   verify();
@@ -735,9 +733,7 @@
                                                            Node &TargetN) {
   assert((*SourceN)[TargetN].isCall() && "Must start with a call edge!");
 
-#ifndef NDEBUG
-  // In a debug build, verify the RefSCC is valid to start with and when this
-  // routine finishes.
+#ifdef EXPENSIVE_CHECKS
   verify();
   auto VerifyOnExit = make_scope_exit([&]() { verify(); });
 #endif
@@ -757,9 +753,7 @@
 LazyCallGraph::RefSCC::switchInternalEdgeToRef(Node &SourceN, Node &TargetN) {
   assert((*SourceN)[TargetN].isCall() && "Must start with a call edge!");
 
-#ifndef NDEBUG
-  // In a debug build, verify the RefSCC is valid to start with and when this
-  // routine finishes.
+#ifdef EXPENSIVE_CHECKS
   verify();
   auto VerifyOnExit = make_scope_exit([&]() { verify(); });
 #endif
@@ -956,8 +950,7 @@
   // just flip the edge here.
   SourceN->setEdgeKind(TargetN, Edge::Call);
 
-#ifndef NDEBUG
-  // Check that the RefSCC is still valid.
+#ifdef EXPENSIVE_CHECKS
   verify();
 #endif
 }
@@ -978,8 +971,7 @@
   // just flip the edge here.
   SourceN->setEdgeKind(TargetN, Edge::Ref);
 
-#ifndef NDEBUG
-  // Check that the RefSCC is still valid.
+#ifdef EXPENSIVE_CHECKS
   verify();
 #endif
 }
@@ -991,8 +983,7 @@
 
   SourceN->insertEdgeInternal(TargetN, Edge::Ref);
 
-#ifndef NDEBUG
-  // Check that the RefSCC is still valid.
+#ifdef EXPENSIVE_CHECKS
   verify();
 #endif
 }
@@ -1011,8 +1002,7 @@
          "Target must be a descendant of the Source.");
 #endif
 
-#ifndef NDEBUG
-  // Check that the RefSCC is still valid.
+#ifdef EXPENSIVE_CHECKS
   verify();
 #endif
 }
@@ -1029,9 +1019,7 @@
 
   SmallVector<RefSCC *, 1> DeletedRefSCCs;
 
-#ifndef NDEBUG
-  // In a debug build, verify the RefSCC is valid to start with and when this
-  // routine finishes.
+#ifdef EXPENSIVE_CHECKS
   verify();
   auto VerifyOnExit = make_scope_exit([&]() { verify(); });
 #endif
@@ -1167,9 +1155,7 @@
   assert(G->lookupRefSCC(TargetN) != this &&
          "The target must not be a member of this RefSCC");
 
-#ifndef NDEBUG
-  // In a debug build, verify the RefSCC is valid to start with and when this
-  // routine finishes.
+#ifdef EXPENSIVE_CHECKS
   verify();
   auto VerifyOnExit = make_scope_exit([&]() { verify(); });
 #endif
@@ -1186,10 +1172,10 @@
   // We return a list of the resulting *new* RefSCCs in post-order.
   SmallVector<RefSCC *, 1> Result;
 
-#ifndef NDEBUG
-  // In a debug build, verify the RefSCC is valid to start with and that either
-  // we return an empty list of result RefSCCs and this RefSCC remains valid,
-  // or we return new RefSCCs and this RefSCC is dead.
+#ifdef EXPENSIVE_CHECKS
+  // Verify the RefSCC is valid to start with and that either we return an empty
+  // list of result RefSCCs and this RefSCC remains valid, or we return new
+  // RefSCCs and this RefSCC is dead.
   verify();
   auto VerifyOnExit = make_scope_exit([&]() {
     // If we didn't replace our RefSCC with new ones, check that this one
@@ -1407,7 +1393,7 @@
   SCCs.clear();
   SCCIndices.clear();
 
-#ifndef NDEBUG
+#ifdef EXPENSIVE_CHECKS
   // Verify the new RefSCCs we've built.
   for (RefSCC *RC : Result)
     RC->verify();
@@ -1419,11 +1405,9 @@
 
 void LazyCallGraph::RefSCC::insertTrivialCallEdge(Node &SourceN,
                                                   Node &TargetN) {
-#ifndef NDEBUG
-  // Check that the RefSCC is still valid when we finish.
+#ifdef EXPENSIVE_CHECKS
   auto ExitVerifier = make_scope_exit([this] { verify(); });
 
-#ifdef EXPENSIVE_CHECKS
   // Check that we aren't breaking some invariants of the SCC graph. Note that
   // this is quadratic in the number of edges in the call graph!
   SCC &SourceC = *G->lookupSCC(SourceN);
@@ -1431,8 +1415,7 @@
   if (&SourceC != &TargetC)
     assert(SourceC.isAncestorOf(TargetC) &&
            "Call edge is not trivial in the SCC graph!");
-#endif // EXPENSIVE_CHECKS
-#endif // NDEBUG
+#endif
 
   // First insert it into the source or find the existing edge.
   auto InsertResult =
@@ -1450,19 +1433,16 @@
 }
 
 void LazyCallGraph::RefSCC::insertTrivialRefEdge(Node &SourceN, Node &TargetN) {
-#ifndef NDEBUG
-  // Check that the RefSCC is still valid when we finish.
+#ifdef EXPENSIVE_CHECKS
   auto ExitVerifier = make_scope_exit([this] { verify(); });
 
-#ifdef EXPENSIVE_CHECKS
   // Check that we aren't breaking some invariants of the RefSCC graph.
   RefSCC &SourceRC = *G->lookupRefSCC(SourceN);
   RefSCC &TargetRC = *G->lookupRefSCC(TargetN);
   if (&SourceRC != &TargetRC)
     assert(SourceRC.isAncestorOf(TargetRC) &&
            "Ref edge is not trivial in the RefSCC graph!");
-#endif // EXPENSIVE_CHECKS
-#endif // NDEBUG
+#endif
 
   // First insert it into the source or find the existing edge.
   auto InsertResult =
@@ -1478,8 +1458,7 @@
 void LazyCallGraph::RefSCC::replaceNodeFunction(Node &N, Function &NewF) {
   Function &OldF = N.getFunction();
 
-#ifndef NDEBUG
-  // Check that the RefSCC is still valid when we finish.
+#ifdef EXPENSIVE_CHECKS
   auto ExitVerifier = make_scope_exit([this] { verify(); });
 
   assert(G->lookupRefSCC(N) == this &&
@@ -1638,7 +1617,7 @@
   SCC *OriginalC = lookupSCC(OriginalN);
   RefSCC *OriginalRC = lookupRefSCC(OriginalN);
 
-#ifndef NDEBUG
+#ifdef EXPENSIVE_CHECKS
   OriginalRC->verify();
   auto VerifyOnExit = make_scope_exit([&]() { OriginalRC->verify(); });
 #endif
@@ -1717,14 +1696,12 @@
   Node &OriginalN = get(OriginalFunction);
   RefSCC *OriginalRC = lookupRefSCC(OriginalN);
 
-#ifndef NDEBUG
+#ifdef EXPENSIVE_CHECKS
   OriginalRC->verify();
   auto VerifyOnExit = make_scope_exit([&]() {
     OriginalRC->verify();
-#ifdef EXPENSIVE_CHECKS
     for (Function *NewFunction : NewFunctions)
       lookupRefSCC(get(*NewFunction))->verify();
-#endif
   });
 #endif
 
@@ -1979,7 +1956,7 @@
         (void)Inserted;
         assert(Inserted && "Cannot already have this RefSCC in the index map!");
         PostOrderRefSCCs.push_back(NewRC);
-#ifndef NDEBUG
+#ifdef EXPENSIVE_CHECKS
         NewRC->verify();
 #endif
       });