Index: lib/Transforms/InstCombine/InstCombineCalls.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -4233,6 +4233,11 @@
       ValueHandleBase::ValueIsDeleted(Caller);
   }
 
+  // Drop references from bitcast constant expression to the callee.
+  if (auto *Op = dyn_cast<User>(Caller->getOperand(0)))
+    if (Op->hasOneUse())
+      Op->dropAllReferences();
+      
   eraseInstFromFunction(*Caller);
   return true;
 }
Index: test/Transforms/Inline/inline-constexpr-cast-call.ll
===================================================================
--- test/Transforms/Inline/inline-constexpr-cast-call.ll
+++ test/Transforms/Inline/inline-constexpr-cast-call.ll
@@ -0,0 +1,22 @@
+; RUN: opt < %s -instcombine -inline -inline-threshold=0
+
+; CHECK: define i32 @main() {
+; CHECK:   %1 = call i32 @rand()
+; CHECK:   %2 = call i32 @rand()
+; CHECK:   %3 = add nsw i32 %1, %2
+; CHECK:   ret i32 %3
+; CHECK: }
+
+define internal i32 @foo() #0 {
+  %1 = call i32 @rand() #2
+  %2 = call i32 @rand() #2
+  %3 = add nsw i32 %1, %2
+  ret i32 %3
+}
+
+declare i32 @rand() #1
+
+define i32 @main() #0 {
+  %1 = tail call i32 (...) bitcast (i32 ()* @foo to i32 (...)*)() #2
+  ret i32 %1
+}