Index: lib/Transforms/IPO/PassManagerBuilder.cpp
===================================================================
--- lib/Transforms/IPO/PassManagerBuilder.cpp
+++ lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -502,6 +502,15 @@
   if (Inliner) {
     MPM.add(Inliner);
     Inliner = nullptr;
+
+    // The inliner performs some kind of dead code elimination as it goes,
+    // but there are cases that are not really caught by it. We might
+    // at some point consider teaching the inliner about them, but it
+    // is OK for now to run GlobalOpt + GlobalDCE in tandem as their
+    // benefits generally outweight the cost, making the whole pipeline
+    // faster. See PR34652.
+    PM.add(createGlobalOptimizerPass());
+    PM.add(createGlobalDCEPass());
   }
   if (!DisableUnitAtATime)
     MPM.add(createPostOrderFunctionAttrsLegacyPass());