Add a test case for PR1271 (necessary, but not sufficient).
; PR1271
; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep and
define i1 @test(i32 %tmp13) {
entry:
	%tmp14 = shl i32 %tmp13, 12		; <i32> [#uses=1]
	%tmp15 = lshr i32 %tmp14, 12		; <i32> [#uses=1]
	%res = icmp ne i32 %tmp15, 0		; <i1>:3 [#uses=1]
        ret i1 %res
}