New testcase for bug found by Vikram

llvm-svn: 2426

test/Regression/Transforms/LevelRaise/2002-05-02-BadCastElimination.ll

@@ -0,0 +1,24 @@
+; This test contains two cast instructions that cannot be eliminated.  If the
+; input of the "test" function is negative, it should be correctly converted
+; to a 32 bit version of the number with all upper 16 bits clear (ushort->uint
+; involves no sign extension).  Optimizing this to a single cast is invalid!
+;
+; RUN: as < %s | opt -raise -q | lli -abort-on-exception
+;
+implementation
+
+uint "test"(short %argc)
+begin
+	%cast223 = cast short %argc to ushort		; <ushort> [#uses=1]
+	%cast114 = cast ushort %cast223 to uint		; <uint> [#uses=1]
+	ret uint %cast114
+end
+
+int "main"()
+begin
+	%Ret = call uint %test(short -1)
+	%test = cast uint %Ret to int
+	%Res = seteq int %test, -1        ; If it returns -1 as int, it's a failure
+	%Res = cast bool %Res to int
+	ret int %Res
+end