Index: lib/IR/Verifier.cpp
===================================================================
--- lib/IR/Verifier.cpp
+++ lib/IR/Verifier.cpp
@@ -314,17 +314,10 @@
     Context = &M.getContext();
     Broken = false;
 
-    // Scan through, checking all of the external function's linkage now...
-    for (const Function &F : M) {
-      visitGlobalValue(F);
-
-      // Check to make sure function prototypes are okay.
-      if (F.isDeclaration()) {
-        visitFunction(F);
-        if (F.getIntrinsicID() == Intrinsic::experimental_deoptimize)
-          DeoptimizeDeclarations.push_back(&F);
-      }
-    }
+    // Collect all declarations of the llvm.experimental.deoptimize intrinsic.
+    for (const Function &F : M)
+      if (F.getIntrinsicID() == Intrinsic::experimental_deoptimize)
+        DeoptimizeDeclarations.push_back(&F);
 
     // Now that we've visited every function, verify that we never asked to
     // recover a frame index that wasn't escaped.
@@ -1866,6 +1859,8 @@
 // visitFunction - Verify that a function is ok.
 //
 void Verifier::visitFunction(const Function &F) {
+  visitGlobalValue(F);
+
   // Check function arguments.
   FunctionType *FT = F.getFunctionType();
   unsigned NumArgs = F.arg_size();
@@ -4427,7 +4422,6 @@
 
 bool llvm::verifyFunction(const Function &f, raw_ostream *OS) {
   Function &F = const_cast<Function &>(f);
-  assert(!F.isDeclaration() && "Cannot verify external functions");
 
   // Don't use a raw_null_ostream.  Printing IR is expensive.
   Verifier V(OS, /*ShouldTreatBrokenDebugInfoAsError=*/true);
@@ -4444,8 +4438,7 @@
 
   bool Broken = false;
   for (const Function &F : M)
-    if (!F.isDeclaration() && !F.isMaterializable())
-      Broken |= !V.verify(F);
+    Broken |= !V.verify(F);
 
   Broken |= !V.verify(M);
   if (BrokenDebugInfo)
@@ -4482,7 +4475,12 @@
   }
 
   bool doFinalization(Module &M) override {
-    bool HasErrors = !V.verify(M);
+    bool HasErrors = false;
+    for (Function &F : M)
+      if (F.isDeclaration())
+        HasErrors |= !V.verify(F);
+
+    HasErrors |= !V.verify(M);
     if (FatalErrors) {
       if (HasErrors)
         report_fatal_error("Broken module found, compilation aborted!");
Index: unittests/IR/MetadataTest.cpp
===================================================================
--- unittests/IR/MetadataTest.cpp
+++ unittests/IR/MetadataTest.cpp
@@ -2253,7 +2253,12 @@
   // be verified directly, so check that the module fails to verify).
   EXPECT_TRUE(verifyModule(*F->getParent()));
 
+  // Nor can materializable functions.
+  F->setIsMaterializable(true);
+  EXPECT_TRUE(verifyModule(*F->getParent()));
+
   // Functions with a body can.
+  F->setIsMaterializable(false);
   (void)new UnreachableInst(Context, BasicBlock::Create(Context, "bb", F));
   EXPECT_FALSE(verifyModule(*F->getParent()));
   EXPECT_FALSE(verifyFunction(*F));