deadrun.diff

diff --git a/llvm/lib/Passes/StandardInstrumentations.cpp b/llvm/lib/Passes/StandardInstrumentations.cpp
index 6259f8f736c8..bd751b81d0b2 100644
--- a/llvm/lib/Passes/StandardInstrumentations.cpp
+++ b/llvm/lib/Passes/StandardInstrumentations.cpp
@@ -2699,6 +2699,31 @@ bool DroppedVariableStats::isInlinedAtChildOfOrEqualTo(
 
 void StandardInstrumentations::registerCallbacks(
     PassInstrumentationCallbacks &PIC, ModuleAnalysisManager *MAM) {
+  PIC.registerBeforeNonSkippedPassCallback(
+      [&](StringRef PassID, Any IR) {
+    auto *F = unwrapIR<Function>(IR);
+    if (F) {
+      F->removeDeadConstantUsers();
+      if (F->isDefTriviallyDead() && !F->hasComdat()) {
+        errs() << "Dead run " << F->getName() << "\n";
+      }
+    }
+  });
+  PIC.registerAfterPassCallback([&](StringRef PassID, Any IR,
+                                    const PreservedAnalyses &PA) {
+    auto *M = unwrapModule(IR, /*Force=*/true);
+    // errs() << "Handling " << PassID << '\n';
+
+    for (auto &F: *M) {
+      if (F.isDeclaration())
+        continue;
+      F.removeDeadConstantUsers();
+      if (F.isDefTriviallyDead() && !F.hasComdat()) {
+        errs() << "Dead func " << F.getName() << " " << PassID
+              << "\n";
+      }
+    }
+  });
   PrintIR.registerCallbacks(PIC);
   PrintPass.registerCallbacks(PIC);
   TimePasses.registerCallbacks(PIC);