Index: llvm/trunk/lib/Transforms/IPO/PartialInlining.cpp
===================================================================
--- llvm/trunk/lib/Transforms/IPO/PartialInlining.cpp
+++ llvm/trunk/lib/Transforms/IPO/PartialInlining.cpp
@@ -85,6 +85,25 @@
   if (ReturnCount != 1)
     return nullptr;
 
+  auto canAllUsesBeReplaced = [](Function *F) {
+    std::vector<User *> Users(F->user_begin(), F->user_end());
+    for (User *User : Users) {
+      Function *Callee = nullptr;
+      if (CallInst *CI = dyn_cast<CallInst>(User))
+        Callee = CallSite(CI).getCalledFunction();
+      else if (InvokeInst *II = dyn_cast<InvokeInst>(User))
+        Callee = CallSite(II).getCalledFunction();
+
+      if (Callee != F)
+        return false;
+    }
+
+    return true;
+  };
+
+  if (!canAllUsesBeReplaced(F))
+    return nullptr;
+
   // Clone the function, so that we can hack away on it.
   ValueToValueMapTy VMap;
   Function *DuplicateFunction = CloneFunction(F, VMap);
Index: llvm/trunk/test/Transforms/CodeExtractor/PartialInlineCallRef.ll
===================================================================
--- llvm/trunk/test/Transforms/CodeExtractor/PartialInlineCallRef.ll
+++ llvm/trunk/test/Transforms/CodeExtractor/PartialInlineCallRef.ll
@@ -0,0 +1,56 @@
+; RUN: opt < %s -partial-inliner -S  | FileCheck %s
+; RUN: opt < %s -passes=partial-inliner -S  | FileCheck %s
+
+
+; Function Attrs: nounwind
+declare void @foo(...) local_unnamed_addr #0
+
+; Function Attrs: noinline
+define i32 @caller(i32 (i32)* nocapture %arg, i32 (i32)* nocapture %arg1, i32 %arg2) local_unnamed_addr #1 {
+bb:
+  %tmp = tail call i32 %arg(i32 %arg2) #0
+  %tmp3 = tail call i32 %arg1(i32 %arg2) #0
+  %tmp4 = add nsw i32 %tmp3, %tmp
+  ret i32 %tmp4
+}
+
+; Function Attrs: nounwind
+define i32 @bar(i32 %arg) #0 {
+bb:
+  %tmp = icmp slt i32 %arg, 0
+  br i1 %tmp, label %bb1, label %bb2
+
+bb1:                                              ; preds = %bb
+  tail call void (...) @foo() #0
+  tail call void (...) @foo() #0
+  tail call void (...) @foo() #0
+  tail call void (...) @foo() #0
+  tail call void (...) @foo() #0
+  tail call void (...) @foo() #0
+  tail call void (...) @foo() #0
+  tail call void (...) @foo() #0
+  tail call void (...) @foo() #0
+  br label %bb2
+
+bb2:                                              ; preds = %bb1, %bb
+  %tmp3 = phi i32 [ 0, %bb1 ], [ 1, %bb ]
+  ret i32 %tmp3
+}
+
+; Function Attrs: nounwind
+define i32 @dummy_caller(i32 %arg) local_unnamed_addr #0 {
+bb:
+; CHECK-LABEL: @dummy_caller
+; check that caller is not wrongly inlined by partial inliner
+; CHECK: call i32 @caller
+; CHECK-NOT: call .* @bar
+  %tmp = tail call i32 @caller(i32 (i32)* nonnull @bar, i32 (i32)* nonnull @bar, i32 %arg)
+  ret i32 %tmp
+}
+
+attributes #0 = { nounwind }
+attributes #1 = { noinline }
+
+!llvm.ident = !{!0}
+
+!0 = !{!"clang version 5.0.0 (trunk 300897) (llvm/trunk 300947)"}