diff --git a/lib/SIL/IR/SILModule.cpp b/lib/SIL/IR/SILModule.cpp
index 22bcbe9f1ac35..fbe26a3d4c7e5 100644
--- a/lib/SIL/IR/SILModule.cpp
+++ b/lib/SIL/IR/SILModule.cpp
@@ -167,6 +167,9 @@ void SILModule::checkForLeaks() const {
 }
 
 void SILModule::checkForLeaksAfterDestruction() {
+// Disabled in release (non-assert) builds because this check fails in rare
+// cases in lldb, causing crashes. rdar://70826934
+#ifndef NDEBUG
   int numAllocated = SILInstruction::getNumCreatedInstructions() -
                      SILInstruction::getNumDeletedInstructions();
 
@@ -174,6 +177,7 @@ void SILModule::checkForLeaksAfterDestruction() {
     llvm::errs() << "Leaking " << numAllocated << " instructions!\n";
     llvm_unreachable("leaking instructions");
   }
+#endif
 }
 
 std::unique_ptr<SILModule> SILModule::createEmptyModule(