Add a lint check for mismatched return types, inspired by PR6944.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108162 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Other/lint.ll b/test/Other/lint.ll
index 9a10abf..dee3d11 100644
--- a/test/Other/lint.ll
+++ b/test/Other/lint.ll
@@ -154,3 +154,12 @@
   %x = volatile load i32* %t3
   br label %exit
 }
+
+; CHECK: Call return type mismatches callee return type
+%struct = type { double, double }
+declare i32 @nonstruct_callee() nounwind
+define void @struct_caller() nounwind {
+entry:
+  call %struct bitcast (i32 ()* @foo to %struct ()*)()
+  ret void
+}