Index: lib/IR/LLVMContext.cpp
===================================================================
--- lib/IR/LLVMContext.cpp
+++ lib/IR/LLVMContext.cpp
@@ -160,7 +160,14 @@
                                          const Function &Fn,
                                          const DebugLoc &DLoc,
                                          const Twine &Msg) {
-  if (pImpl->optimizationRemarksEnabledFor(PassName))
+  // Optimization remark diagnostics can be enabled via -Rpass= from
+  // the front end or -pass-remarks= from opt. If there is a
+  // diagnostic handler installed, we defer to it to check whether a
+  // diagnostic should be generated for \p PassName. Otherwise, call
+  // LLVMContextImpl::optimizationRemarksEnabledFor to check the
+  // pattern passed in -pass-remarks.
+  if (pImpl->DiagnosticHandler ||
+      pImpl->optimizationRemarksEnabledFor(PassName))
     diagnose(DiagnosticInfoOptimizationRemark(PassName, Fn, DLoc, Msg));
 }