no simple opt working

IC: Visiting:   br label %while.body
IC: Visiting:   %0 = phi i32 [ 0, %entry ], [ %inc.3, %while.body ]
IC: Visiting:   %shr = lshr i32 %0, 5
IC: Visiting:   %rem = and i32 %0, 28
IC: Visiting:   %shl = shl i32 1, %rem
IC: Visiting:   %arrayidx = getelementptr inbounds i32* %bitmap, i32 %shr
IC: Visiting:   %tmp6 = load i32* %arrayidx, align 4
IC: Visiting:   %xor = xor i32 %tmp6, %shl
IC: Visiting:   store i32 %xor, i32* %arrayidx, align 4
IC: Visiting:   %shr.1 = lshr i32 %0, 5
IC: Visiting:   %inc5 = and i32 %0, 28
IC: Visiting:   %rem.1 = or i32 %inc5, 1
IC: Visiting:   %shl.1 = shl i32 1, %rem.1