1 files changed, 7 insertions, 3 deletions
diff --git a/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
index beb3785eda3..0fd966457ec 100644
--- a/llvm/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
@@ -2298,10 +2298,14 @@ OptimizeFunctions(Module &M,
     // So, remove unreachable blocks from the function, because a) there's
     // no point in analyzing them and b) GlobalOpt should otherwise grow
     // some more complicated logic to break these cycles.
+    // Removing unreachable blocks might invalidate the dominator so we
+    // recalculate it.
     if (!F->isDeclaration()) {
-      auto &DT = LookupDomTree(*F);
-      DomTreeUpdater DTU(DT, DomTreeUpdater::UpdateStrategy::Lazy);
-      Changed |= removeUnreachableBlocks(*F, &DTU);
+      if (removeUnreachableBlocks(*F)) {
+        auto &DT = LookupDomTree(*F);
+        DT.recalculate(*F);
+        Changed = true;
+      }
     }
 
     Changed |= processGlobal(*F, GetTLI, LookupDomTree);