Testcase for Preheaders problem

llvm-svn: 5654

llvm/test/Regression/Transforms/LICM/2003-02-27-PreheaderProblem.ll

@@ -0,0 +1,28 @@
+; Here we have a case where there are two loops and LICM is hoisting an 
+; instruction from one loop into the other loop!  This is obviously bad and 
+; happens because preheader insertion doesn't insert a preheader for this
+; case... bad.
+
+; RUN: if as < %s | opt -licm -adce -simplifycfg | dis | grep 'br '
+; RUN: then exit 1
+; RUN: else exit 0
+; RUN: fi
+
+int %main(int %argc) {
+        br label %bb5
+
+bb5:            ; preds = %bb5, %0
+	%I = phi int [0, %0], [%I2, %bb5]
+	%I2 = add int %I, 1
+	%c = seteq int %I2, 10
+        br bool %c, label %bb5, label %bb8
+
+bb8:            ; preds = %bb8, %bb5
+        %cann-indvar = phi uint [ 0, %bb8 ], [ 0, %bb5 ]
+	%X = add int %argc, %argc  ; Loop invariant
+        br bool false, label %bb8, label %bb10
+
+bb10:           ; preds = %bb8
+        ret int %X
+}
+