Add a testcase that checks to make sure LICM uses basicaa correctly.

Add another gcse testcase.

llvm-svn: 3471

llvm/test/Regression/Transforms/BasicAA/gcsetest.ll

@@ -21,3 +21,19 @@ int %test() {
 	ret int %X
 }
 
+int %test2() {
+        %A1 = load int* %A
+        br label %Loop
+Loop:
+        %AP = phi int [0, %0], [%X, %Loop]
+        store int %AP, int* %B  ; Store cannot alias %A
+
+        %A2 = load int* %A
+        %X = sub int %A1, %A2
+        %c = seteq int %X, 0
+        br bool %c, label %out, label %Loop
+
+out:
+        ret int %X
+}
+

llvm/test/Regression/Transforms/BasicAA/licmtest.ll

@@ -0,0 +1,31 @@
+; Test that LICM uses basicaa to do alias analysis, which is capable of 
+; disambiguating some obvious cases.  The ToRemove load should be eliminated
+; in this testcase.  This testcase was carefully contrived so that GCSE would
+; not be able to eliminate the load itself, without licm's help.  This is 
+; because, for GCSE, the load is killed by the dummy basic block.
+
+; RUN: if as < %s | opt -basicaa -licm -gcse -simplifycfg -instcombine | dis | grep ToRemove
+; RUN: then exit 1
+; RUN: else exit 0
+; RUN: fi
+
+%A = global int 7
+%B = global int 8
+implementation
+
+int %test(bool %c) {
+	%Atmp = load int* %A
+	br label %Loop
+Loop:
+	%ToRemove = load int* %A
+	store int %ToRemove, int* %B  ; Store cannot alias %A
+
+	br bool %c, label %Out, label %Loop
+Out:
+	ret int 7
+
+Dummy:
+	store int 7, int* %A
+	br label %Loop
+}
+