Testcases for andersen's alias analysis.

I think this is all of the stuff I had pending in my tree..


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13703 91177308-0d34-0410-b5e6-96231b3b80d8

test/Analysis/Andersens/arg-must-alias.ll

@@ -0,0 +1,17 @@
+; RUN: llvm-as < %s | opt -anders-aa -load-vn -gcse -deadargelim | llvm-dis | not grep ARG
+
+%G = internal constant int* null
+
+implementation
+
+internal int %internal(int* %ARG) {
+	;; The 'Arg' argument must-aliases the null pointer, so it can be subsituted
+	;; directly here, making it dead.
+	store int* %ARG, int** %G
+	ret int 0
+}
+
+int %foo() {
+	%V = call int %internal(int* null)
+	ret int %V
+}

test/Analysis/Andersens/basictest.ll

@@ -0,0 +1,29 @@
+
+implementation
+
+void %test1() {
+	%X = malloc int*
+	%Y = malloc int
+	%Z = cast int* %Y to int
+	%W = cast int %Z to int*
+	store int* %W, int** %X
+	ret void
+}
+
+void %test2(int* %P) {
+	%X = malloc int*
+	%Y = malloc int
+	store int* %P, int** %X
+	ret void
+}
+
+internal int *%test3(int* %P) {
+	ret int* %P
+}
+
+void %test4() {
+	%X = malloc int
+	%Y = call int* %test3(int* %X)
+	%ZZ = getelementptr int* null, int 17
+	ret void
+}

test/Analysis/Andersens/external.ll

@@ -0,0 +1,22 @@
+; RUN: llvm-as < %s | opt -anders-aa -load-vn -gcse -deadargelim | llvm-dis | grep store | not grep null
+
+; Because the 'internal' function is passed to an external function, we don't
+; know what the incoming values will alias.  As such, we cannot do the 
+; optimization checked by the 'arg-must-alias.llx' test.
+
+declare void %external(int(int*)*)
+%G = internal constant int* null
+
+implementation
+
+internal int %internal(int* %ARG) {
+	;;; We *DON'T* know that ARG always points to null!
+	store int* %ARG, int** %G
+	ret int 0
+}
+
+int %foo() {
+	call void %external(int(int*)* %internal)
+	%V = call int %internal(int* null)
+	ret int %V
+}