New testacse for information exposed by the 'tail' call marker.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21795 91177308-0d34-0410-b5e6-96231b3b80d8

test/Analysis/BasicAA/tailcall-modref.ll

@@ -0,0 +1,16 @@
+; RUN: llvm-as < %s | opt -basicaa -load-vn -gcse -instcombine | llvm-dis | grep 'ret int 0'
+declare void %foo(int*)
+declare void %bar()
+
+int %test() {
+	%A = alloca int
+	call void %foo(int* %A)
+
+	%X = load int* %A
+	tail call void %bar()   ;; Cannot modify *%A because it's on the stack.
+	%Y = load int* %A
+	%Z = sub int %X, %Y
+	ret int %Z
+}
+
+