diff --git a/llvm/include/llvm/IR/GlobalIFunc.h b/llvm/include/llvm/IR/GlobalIFunc.h
--- a/llvm/include/llvm/IR/GlobalIFunc.h
+++ b/llvm/include/llvm/IR/GlobalIFunc.h
@@ -84,6 +84,11 @@
     return FunctionType::get(IFuncValTy->getPointerTo(), false);
   }
 
+  static bool isValidLinkage(LinkageTypes L) {
+    return isExternalLinkage(L) || isLocalLinkage(L) || isWeakLinkage(L) ||
+           isLinkOnceLinkage(L);
+  }
+
   // Methods for support type inquiry through isa, cast, and dyn_cast:
   static bool classof(const Value *V) {
     return V->getValueID() == Value::GlobalIFuncVal;
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -836,10 +836,15 @@
 }
 
 void Verifier::visitGlobalIFunc(const GlobalIFunc &GI) {
+  Assert(GlobalIFunc::isValidLinkage(GI.getLinkage()),
+         "IFunc should have private, internal, linkonce, weak, linkonce_odr, "
+         "weak_odr, or external linkage!", &GI);
   // Pierce through ConstantExprs and GlobalAliases and check that the resolver
-  // has a Function 
+  // is a Function definition
   const Function *Resolver = GI.getResolverFunction();
   Assert(Resolver, "IFunc must have a Function resolver", &GI);
+  Assert(!Resolver->isDeclarationForLinker(),
+         "IFunc resolver must be a definition", &GI);
 
   // Check that the immediate resolver operand (prior to any bitcasts) has the
   // correct type